Adding upstream version 115.8.0esr.upstream/115.8.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

134 files changed, 30266 insertions, 0 deletions

diff --git a/third_party/libwebrtc/call/BUILD.gn b/third_party/libwebrtc/call/BUILD.gn
new file mode 100644
index 0000000000..2bc7aaec92
--- /dev/null
+++ b/third_party/libwebrtc/call/BUILD.gn
@@ -0,0 +1,696 @@
+# Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
+#
+# Use of this source code is governed by a BSD-style license
+# that can be found in the LICENSE file in the root of the source
+# tree. An additional intellectual property rights grant can be found
+# in the file PATENTS.  All contributing project authors may
+# be found in the AUTHORS file in the root of the source tree.
+
+import("../webrtc.gni")
+
+rtc_library("version") {
+  sources = [
+    "version.cc",
+    "version.h",
+  ]
+  visibility = [ ":*" ]
+}
+
+rtc_library("call_interfaces") {
+  sources = [
+    "audio_receive_stream.cc",
+    "audio_receive_stream.h",
+    "audio_send_stream.cc",
+    "audio_send_stream.h",
+    "audio_state.cc",
+    "audio_state.h",
+    "call.h",
+    "call_config.cc",
+    "call_config.h",
+    "flexfec_receive_stream.cc",
+    "flexfec_receive_stream.h",
+    "packet_receiver.h",
+    "syncable.cc",
+    "syncable.h",
+  ]
+  if (build_with_mozilla) {
+    sources += [
+      "call_basic_stats.cc",
+      "call_basic_stats.h",
+    ]
+  }
+
+  deps = [
+    ":audio_sender_interface",
+    ":receive_stream_interface",
+    ":rtp_interfaces",
+    ":video_stream_api",
+    "../api:fec_controller_api",
+    "../api:field_trials_view",
+    "../api:frame_transformer_interface",
+    "../api:network_state_predictor_api",
+    "../api:rtc_error",
+    "../api:rtp_headers",
+    "../api:rtp_parameters",
+    "../api:rtp_sender_setparameters_callback",
+    "../api:scoped_refptr",
+    "../api:transport_api",
+    "../api/adaptation:resource_adaptation_api",
+    "../api/audio:audio_frame_processor",
+    "../api/audio:audio_mixer_api",
+    "../api/audio_codecs:audio_codecs_api",
+    "../api/crypto:frame_encryptor_interface",
+    "../api/crypto:options",
+    "../api/metronome",
+    "../api/neteq:neteq_api",
+    "../api/task_queue",
+    "../api/transport:bitrate_settings",
+    "../api/transport:network_control",
+    "../modules/async_audio_processing",
+    "../modules/audio_device",
+    "../modules/audio_processing",
+    "../modules/audio_processing:api",
+    "../modules/audio_processing:audio_processing_statistics",
+    "../modules/rtp_rtcp:rtp_rtcp_format",
+    "../rtc_base:audio_format_to_string",
+    "../rtc_base:checks",
+    "../rtc_base:copy_on_write_buffer",
+    "../rtc_base:network_route",
+    "../rtc_base:refcount",
+    "../rtc_base:stringutils",
+    "../rtc_base/network:sent_packet",
+  ]
+  absl_deps = [
+    "//third_party/abseil-cpp/absl/functional:any_invocable",
+    "//third_party/abseil-cpp/absl/functional:bind_front",
+    "//third_party/abseil-cpp/absl/strings",
+    "//third_party/abseil-cpp/absl/types:optional",
+  ]
+}
+
+rtc_source_set("audio_sender_interface") {
+  visibility = [ "*" ]
+  sources = [ "audio_sender.h" ]
+  deps = [ "../api/audio:audio_frame_api" ]
+}
+
+# TODO(nisse): These RTP targets should be moved elsewhere
+# when interfaces have stabilized. See also TODO for `mock_rtp_interfaces`.
+rtc_library("rtp_interfaces") {
+  # Client code SHOULD NOT USE THIS TARGET, but for now it needs to be public
+  # because there exists client code that uses it.
+  # TODO(bugs.webrtc.org/9808): Move to private visibility as soon as that
+  # client code gets updated.
+  visibility = [ "*" ]
+  sources = [
+    "rtp_config.cc",
+    "rtp_config.h",
+    "rtp_packet_sink_interface.h",
+    "rtp_stream_receiver_controller_interface.h",
+    "rtp_transport_config.h",
+    "rtp_transport_controller_send_factory_interface.h",
+    "rtp_transport_controller_send_interface.h",
+  ]
+  deps = [
+    "../api:array_view",
+    "../api:fec_controller_api",
+    "../api:field_trials_view",
+    "../api:frame_transformer_interface",
+    "../api:network_state_predictor_api",
+    "../api:rtp_headers",
+    "../api:rtp_parameters",
+    "../api/crypto:options",
+    "../api/rtc_event_log",
+    "../api/transport:bitrate_settings",
+    "../api/transport:network_control",
+    "../api/units:timestamp",
+    "../common_video:frame_counts",
+    "../modules/rtp_rtcp:rtp_rtcp_format",
+    "../rtc_base:checks",
+    "../rtc_base:rtc_task_queue",
+    "../rtc_base:stringutils",
+  ]
+  absl_deps = [
+    "//third_party/abseil-cpp/absl/algorithm:container",
+    "//third_party/abseil-cpp/absl/strings",
+    "//third_party/abseil-cpp/absl/types:optional",
+  ]
+}
+
+rtc_library("rtp_receiver") {
+  visibility = [ "*" ]
+  sources = [
+    "rtp_demuxer.cc",
+    "rtp_demuxer.h",
+    "rtp_stream_receiver_controller.cc",
+    "rtp_stream_receiver_controller.h",
+    "rtx_receive_stream.cc",
+    "rtx_receive_stream.h",
+  ]
+  deps = [
+    ":rtp_interfaces",
+    "../api:array_view",
+    "../api:rtp_headers",
+    "../api:sequence_checker",
+    "../modules/rtp_rtcp",
+    "../modules/rtp_rtcp:rtp_rtcp_format",
+    "../rtc_base:checks",
+    "../rtc_base:logging",
+    "../rtc_base:stringutils",
+    "../rtc_base/containers:flat_map",
+    "../rtc_base/containers:flat_set",
+    "../rtc_base/system:no_unique_address",
+  ]
+  absl_deps = [
+    "//third_party/abseil-cpp/absl/strings:strings",
+    "//third_party/abseil-cpp/absl/types:optional",
+  ]
+}
+
+rtc_library("rtp_sender") {
+  sources = [
+    "rtp_payload_params.cc",
+    "rtp_payload_params.h",
+    "rtp_transport_controller_send.cc",
+    "rtp_transport_controller_send.h",
+    "rtp_transport_controller_send_factory.h",
+    "rtp_video_sender.cc",
+    "rtp_video_sender.h",
+    "rtp_video_sender_interface.h",
+  ]
+  deps = [
+    ":bitrate_configurator",
+    ":rtp_interfaces",
+    "../api:array_view",
+    "../api:bitrate_allocation",
+    "../api:fec_controller_api",
+    "../api:field_trials_view",
+    "../api:network_state_predictor_api",
+    "../api:rtp_parameters",
+    "../api:sequence_checker",
+    "../api:transport_api",
+    "../api/rtc_event_log",
+    "../api/task_queue:pending_task_safety_flag",
+    "../api/task_queue:task_queue",
+    "../api/transport:field_trial_based_config",
+    "../api/transport:goog_cc",
+    "../api/transport:network_control",
+    "../api/units:data_rate",
+    "../api/units:time_delta",
+    "../api/units:timestamp",
+    "../api/video:video_frame",
+    "../api/video:video_layers_allocation",
+    "../api/video:video_rtp_headers",
+    "../api/video_codecs:video_codecs_api",
+    "../logging:rtc_event_bwe",
+    "../modules/congestion_controller",
+    "../modules/congestion_controller/rtp:control_handler",
+    "../modules/congestion_controller/rtp:transport_feedback",
+    "../modules/pacing",
+    "../modules/rtp_rtcp",
+    "../modules/rtp_rtcp:rtp_rtcp_format",
+    "../modules/rtp_rtcp:rtp_video_header",
+    "../modules/utility:utility",
+    "../modules/video_coding:chain_diff_calculator",
+    "../modules/video_coding:codec_globals_headers",
+    "../modules/video_coding:frame_dependencies_calculator",
+    "../modules/video_coding:video_codec_interface",
+    "../rtc_base:checks",
+    "../rtc_base:event_tracer",
+    "../rtc_base:logging",
+    "../rtc_base:macromagic",
+    "../rtc_base:network_route",
+    "../rtc_base:race_checker",
+    "../rtc_base:random",
+    "../rtc_base:rate_limiter",
+    "../rtc_base:rtc_task_queue",
+    "../rtc_base:timeutils",
+    "../rtc_base/synchronization:mutex",
+    "../rtc_base/task_utils:repeating_task",
+  ]
+  absl_deps = [
+    "//third_party/abseil-cpp/absl/algorithm:container",
+    "//third_party/abseil-cpp/absl/container:inlined_vector",
+    "//third_party/abseil-cpp/absl/strings:strings",
+    "//third_party/abseil-cpp/absl/types:optional",
+    "//third_party/abseil-cpp/absl/types:variant",
+  ]
+}
+
+rtc_library("bitrate_configurator") {
+  sources = [
+    "rtp_bitrate_configurator.cc",
+    "rtp_bitrate_configurator.h",
+  ]
+  deps = [
+    ":rtp_interfaces",
+
+    # For api/bitrate_constraints.h
+    "../api:libjingle_peerconnection_api",
+    "../api/transport:bitrate_settings",
+    "../api/units:data_rate",
+    "../rtc_base:checks",
+  ]
+  absl_deps = [ "//third_party/abseil-cpp/absl/types:optional" ]
+}
+
+rtc_library("bitrate_allocator") {
+  sources = [
+    "bitrate_allocator.cc",
+    "bitrate_allocator.h",
+  ]
+  deps = [
+    "../api:bitrate_allocation",
+    "../api:sequence_checker",
+    "../api/transport:network_control",
+    "../api/units:data_rate",
+    "../api/units:time_delta",
+    "../rtc_base:checks",
+    "../rtc_base:logging",
+    "../rtc_base:safe_minmax",
+    "../rtc_base/system:no_unique_address",
+    "../system_wrappers",
+    "../system_wrappers:field_trial",
+    "../system_wrappers:metrics",
+  ]
+  absl_deps = [ "//third_party/abseil-cpp/absl/algorithm:container" ]
+}
+
+rtc_library("call") {
+  sources = [
+    "call.cc",
+    "call_factory.cc",
+    "call_factory.h",
+    "degraded_call.cc",
+    "degraded_call.h",
+    "flexfec_receive_stream_impl.cc",
+    "flexfec_receive_stream_impl.h",
+    "receive_time_calculator.cc",
+    "receive_time_calculator.h",
+  ]
+
+  deps = [
+    ":bitrate_allocator",
+    ":call_interfaces",
+    ":fake_network",
+    ":rtp_interfaces",
+    ":rtp_receiver",
+    ":rtp_sender",
+    ":simulated_network",
+    ":version",
+    ":video_stream_api",
+    "../api:array_view",
+    "../api:callfactory_api",
+    "../api:fec_controller_api",
+    "../api:field_trials_view",
+    "../api:rtp_headers",
+    "../api:rtp_parameters",
+    "../api:sequence_checker",
+    "../api:simulated_network_api",
+    "../api:transport_api",
+    "../api/rtc_event_log",
+    "../api/task_queue:pending_task_safety_flag",
+    "../api/transport:network_control",
+    "../api/units:time_delta",
+    "../api/video_codecs:video_codecs_api",
+    "../audio",
+    "../logging:rtc_event_audio",
+    "../logging:rtc_event_rtp_rtcp",
+    "../logging:rtc_event_video",
+    "../logging:rtc_stream_config",
+    "../modules/congestion_controller",
+    "../modules/pacing",
+    "../modules/rtp_rtcp",
+    "../modules/rtp_rtcp:rtp_rtcp_format",
+    "../modules/video_coding",
+    "../rtc_base:checks",
+    "../rtc_base:copy_on_write_buffer",
+    "../rtc_base:event_tracer",
+    "../rtc_base:logging",
+    "../rtc_base:macromagic",
+    "../rtc_base:rate_limiter",
+    "../rtc_base:rtc_event",
+    "../rtc_base:rtc_task_queue",
+    "../rtc_base:safe_minmax",
+    "../rtc_base:stringutils",
+    "../rtc_base:timeutils",
+    "../rtc_base/experiments:field_trial_parser",
+    "../rtc_base/network:sent_packet",
+    "../rtc_base/system:no_unique_address",
+    "../rtc_base/task_utils:repeating_task",
+    "../system_wrappers",
+    "../system_wrappers:field_trial",
+    "../system_wrappers:metrics",
+    "../video",
+    "../video:decode_synchronizer",
+    "../video/config:encoder_config",
+    "adaptation:resource_adaptation",
+  ]
+  absl_deps = [
+    "//third_party/abseil-cpp/absl/functional:bind_front",
+    "//third_party/abseil-cpp/absl/memory",
+    "//third_party/abseil-cpp/absl/strings",
+    "//third_party/abseil-cpp/absl/types:optional",
+  ]
+  if (build_with_mozilla) { # See Bug 1820869.
+    sources -= [
+      "call_factory.cc",
+      "degraded_call.cc",
+    ]
+    deps -= [
+      ":fake_network",
+      ":simulated_network",
+    ]
+  }
+}
+
+rtc_source_set("receive_stream_interface") {
+  sources = [ "receive_stream.h" ]
+  deps = [
+    "../api:frame_transformer_interface",
+    "../api:rtp_parameters",
+    "../api:scoped_refptr",
+    "../api/crypto:frame_decryptor_interface",
+    "../api/transport/rtp:rtp_source",
+    "../modules/rtp_rtcp:rtp_rtcp_format",
+  ]
+}
+
+rtc_library("video_stream_api") {
+  sources = [
+    "video_receive_stream.cc",
+    "video_receive_stream.h",
+    "video_send_stream.cc",
+    "video_send_stream.h",
+  ]
+  deps = [
+    ":receive_stream_interface",
+    ":rtp_interfaces",
+    "../api:frame_transformer_interface",
+    "../api:rtp_headers",
+    "../api:rtp_parameters",
+    "../api:rtp_sender_setparameters_callback",
+    "../api:scoped_refptr",
+    "../api:transport_api",
+    "../api/adaptation:resource_adaptation_api",
+    "../api/crypto:frame_encryptor_interface",
+    "../api/crypto:options",
+    "../api/video:recordable_encoded_frame",
+    "../api/video:video_frame",
+    "../api/video:video_rtp_headers",
+    "../api/video:video_stream_encoder",
+    "../api/video_codecs:scalability_mode",
+    "../api/video_codecs:video_codecs_api",
+    "../common_video",
+    "../common_video:frame_counts",
+    "../modules/rtp_rtcp:rtp_rtcp_format",
+    "../rtc_base:checks",
+    "../rtc_base:stringutils",
+    "../video/config:encoder_config",
+  ]
+  absl_deps = [
+    "//third_party/abseil-cpp/absl/functional:any_invocable",
+    "//third_party/abseil-cpp/absl/types:optional",
+  ]
+}
+
+rtc_library("simulated_network") {
+  sources = [
+    "simulated_network.cc",
+    "simulated_network.h",
+  ]
+  deps = [
+    "../api:sequence_checker",
+    "../api:simulated_network_api",
+    "../api/units:data_rate",
+    "../api/units:data_size",
+    "../api/units:time_delta",
+    "../api/units:timestamp",
+    "../rtc_base:checks",
+    "../rtc_base:macromagic",
+    "../rtc_base:race_checker",
+    "../rtc_base:random",
+    "../rtc_base/synchronization:mutex",
+  ]
+  absl_deps = [ "//third_party/abseil-cpp/absl/types:optional" ]
+}
+
+rtc_source_set("simulated_packet_receiver") {
+  sources = [ "simulated_packet_receiver.h" ]
+  deps = [
+    ":call_interfaces",
+    "../api:simulated_network_api",
+  ]
+}
+
+rtc_library("fake_network") {
+  sources = [
+    "fake_network_pipe.cc",
+    "fake_network_pipe.h",
+  ]
+  deps = [
+    ":call_interfaces",
+    ":simulated_network",
+    ":simulated_packet_receiver",
+    "../api:rtp_parameters",
+    "../api:sequence_checker",
+    "../api:simulated_network_api",
+    "../api:transport_api",
+    "../api/units:timestamp",
+    "../modules/rtp_rtcp:rtp_rtcp_format",
+    "../rtc_base:checks",
+    "../rtc_base:logging",
+    "../rtc_base:macromagic",
+    "../rtc_base/synchronization:mutex",
+    "../system_wrappers",
+  ]
+}
+
+if (rtc_include_tests) {
+  if (!build_with_chromium) {
+    rtc_library("call_tests") {
+      testonly = true
+
+      sources = [
+        "bitrate_allocator_unittest.cc",
+        "bitrate_estimator_tests.cc",
+        "call_unittest.cc",
+        "flexfec_receive_stream_unittest.cc",
+        "receive_time_calculator_unittest.cc",
+        "rtp_bitrate_configurator_unittest.cc",
+        "rtp_demuxer_unittest.cc",
+        "rtp_payload_params_unittest.cc",
+        "rtp_video_sender_unittest.cc",
+        "rtx_receive_stream_unittest.cc",
+      ]
+      deps = [
+        ":bitrate_allocator",
+        ":bitrate_configurator",
+        ":call",
+        ":call_interfaces",
+        ":mock_rtp_interfaces",
+        ":rtp_interfaces",
+        ":rtp_receiver",
+        ":rtp_sender",
+        ":simulated_network",
+        "../api:array_view",
+        "../api:create_frame_generator",
+        "../api:mock_audio_mixer",
+        "../api:rtp_headers",
+        "../api:rtp_parameters",
+        "../api:transport_api",
+        "../api/audio_codecs:builtin_audio_decoder_factory",
+        "../api/rtc_event_log",
+        "../api/task_queue:default_task_queue_factory",
+        "../api/test/video:function_video_factory",
+        "../api/transport:field_trial_based_config",
+        "../api/video:builtin_video_bitrate_allocator_factory",
+        "../api/video:video_frame",
+        "../api/video:video_rtp_headers",
+        "../audio",
+        "../modules/audio_device:mock_audio_device",
+        "../modules/audio_mixer",
+        "../modules/audio_mixer:audio_mixer_impl",
+        "../modules/audio_processing:mocks",
+        "../modules/congestion_controller",
+        "../modules/pacing",
+        "../modules/rtp_rtcp",
+        "../modules/rtp_rtcp:mock_rtp_rtcp",
+        "../modules/rtp_rtcp:rtp_rtcp_format",
+        "../modules/video_coding",
+        "../modules/video_coding:codec_globals_headers",
+        "../modules/video_coding:video_codec_interface",
+        "../rtc_base:checks",
+        "../rtc_base:logging",
+        "../rtc_base:macromagic",
+        "../rtc_base:random",
+        "../rtc_base:rate_limiter",
+        "../rtc_base:rtc_event",
+        "../rtc_base:safe_conversions",
+        "../rtc_base:task_queue_for_test",
+        "../rtc_base:threading",
+        "../rtc_base:timeutils",
+        "../rtc_base/synchronization:mutex",
+        "../system_wrappers",
+        "../test:audio_codec_mocks",
+        "../test:direct_transport",
+        "../test:encoder_settings",
+        "../test:explicit_key_value_config",
+        "../test:fake_video_codecs",
+        "../test:field_trial",
+        "../test:mock_frame_transformer",
+        "../test:mock_transport",
+        "../test:run_loop",
+        "../test:scoped_key_value_config",
+        "../test:test_common",
+        "../test:test_support",
+        "../test:video_test_common",
+        "../test/scenario",
+        "../test/time_controller:time_controller",
+        "../video",
+        "adaptation:resource_adaptation_test_utilities",
+        "//testing/gmock",
+        "//testing/gtest",
+      ]
+      absl_deps = [
+        "//third_party/abseil-cpp/absl/container:inlined_vector",
+        "//third_party/abseil-cpp/absl/functional:any_invocable",
+        "//third_party/abseil-cpp/absl/memory",
+        "//third_party/abseil-cpp/absl/strings",
+        "//third_party/abseil-cpp/absl/types:optional",
+        "//third_party/abseil-cpp/absl/types:variant",
+      ]
+    }
+
+    rtc_library("call_perf_tests") {
+      testonly = true
+
+      sources = [
+        "call_perf_tests.cc",
+        "rampup_tests.cc",
+        "rampup_tests.h",
+      ]
+      deps = [
+        ":call_interfaces",
+        ":simulated_network",
+        ":video_stream_api",
+        "../api:rtc_event_log_output_file",
+        "../api:simulated_network_api",
+        "../api/audio_codecs:builtin_audio_encoder_factory",
+        "../api/numerics",
+        "../api/rtc_event_log",
+        "../api/rtc_event_log:rtc_event_log_factory",
+        "../api/task_queue",
+        "../api/task_queue:default_task_queue_factory",
+        "../api/task_queue:pending_task_safety_flag",
+        "../api/test/metrics:global_metrics_logger_and_exporter",
+        "../api/test/metrics:metric",
+        "../api/video:builtin_video_bitrate_allocator_factory",
+        "../api/video:video_bitrate_allocation",
+        "../api/video_codecs:video_codecs_api",
+        "../media:rtc_internal_video_codecs",
+        "../media:rtc_simulcast_encoder_adapter",
+        "../modules/audio_coding",
+        "../modules/audio_device",
+        "../modules/audio_device:audio_device_impl",
+        "../modules/audio_mixer:audio_mixer_impl",
+        "../modules/rtp_rtcp",
+        "../modules/rtp_rtcp:rtp_rtcp_format",
+        "../rtc_base:checks",
+        "../rtc_base:logging",
+        "../rtc_base:macromagic",
+        "../rtc_base:platform_thread",
+        "../rtc_base:rtc_event",
+        "../rtc_base:stringutils",
+        "../rtc_base:task_queue_for_test",
+        "../rtc_base:threading",
+        "../rtc_base:timeutils",
+        "../rtc_base/synchronization:mutex",
+        "../rtc_base/task_utils:repeating_task",
+        "../system_wrappers",
+        "../system_wrappers:metrics",
+        "../test:direct_transport",
+        "../test:encoder_settings",
+        "../test:fake_video_codecs",
+        "../test:field_trial",
+        "../test:fileutils",
+        "../test:null_transport",
+        "../test:test_common",
+        "../test:test_support",
+        "../test:video_test_common",
+        "../video",
+        "../video/config:encoder_config",
+        "//testing/gtest",
+      ]
+      absl_deps = [
+        "//third_party/abseil-cpp/absl/flags:flag",
+        "//third_party/abseil-cpp/absl/strings",
+      ]
+    }
+  }
+
+  # TODO(eladalon): This should be moved, as with the TODO for `rtp_interfaces`.
+  rtc_source_set("mock_rtp_interfaces") {
+    testonly = true
+
+    sources = [
+      "test/mock_rtp_packet_sink_interface.h",
+      "test/mock_rtp_transport_controller_send.h",
+    ]
+    deps = [
+      ":rtp_interfaces",
+      "../api:frame_transformer_interface",
+      "../api:libjingle_peerconnection_api",
+      "../api/crypto:frame_encryptor_interface",
+      "../api/crypto:options",
+      "../api/transport:bitrate_settings",
+      "../modules/pacing",
+      "../rtc_base:network_route",
+      "../rtc_base:rate_limiter",
+      "../rtc_base/network:sent_packet",
+      "../test:test_support",
+    ]
+    absl_deps = [ "//third_party/abseil-cpp/absl/strings" ]
+  }
+  rtc_source_set("mock_bitrate_allocator") {
+    testonly = true
+
+    sources = [ "test/mock_bitrate_allocator.h" ]
+    deps = [
+      ":bitrate_allocator",
+      "../test:test_support",
+    ]
+  }
+  rtc_source_set("mock_call_interfaces") {
+    testonly = true
+
+    sources = [ "test/mock_audio_send_stream.h" ]
+    deps = [
+      ":call_interfaces",
+      "../test:test_support",
+    ]
+  }
+
+  rtc_library("fake_network_pipe_unittests") {
+    testonly = true
+
+    sources = [
+      "fake_network_pipe_unittest.cc",
+      "simulated_network_unittest.cc",
+    ]
+    deps = [
+      ":fake_network",
+      ":simulated_network",
+      "../api:simulated_network_api",
+      "../api/units:data_rate",
+      "../api/units:time_delta",
+      "../api/units:timestamp",
+      "../modules/rtp_rtcp:rtp_rtcp_format",
+      "../rtc_base:checks",
+      "../system_wrappers",
+      "../test:test_support",
+      "//testing/gtest",
+    ]
+    absl_deps = [ "//third_party/abseil-cpp/absl/algorithm:container" ]
+  }
+}
diff --git a/third_party/libwebrtc/call/DEPS b/third_party/libwebrtc/call/DEPS
new file mode 100644
index 0000000000..b1b66ac3ce
--- /dev/null
+++ b/third_party/libwebrtc/call/DEPS
@@ -0,0 +1,32 @@
+include_rules = [
+  "+audio",
+  "+logging/rtc_event_log",
+  "+modules/async_audio_processing",
+  "+modules/audio_coding",
+  "+modules/audio_device",
+  "+modules/audio_mixer",
+  "+modules/audio_processing",
+  "+modules/bitrate_controller",
+  "+modules/congestion_controller",
+  "+modules/video_coding",
+  "+modules/pacing",
+  "+modules/rtp_rtcp",
+  "+modules/utility",
+  "+system_wrappers",
+  "+video",
+]
+
+specific_include_rules = {
+  "video_receive_stream\.h": [
+    "+common_video/frame_counts.h",
+  ],
+  "video_send_stream\.h": [
+    "+common_video",
+  ],
+  "rtp_transport_controller_send_interface\.h": [
+    "+common_video/frame_counts.h",
+  ],
+  "call_perf_tests\.cc": [
+    "+media/engine",
+  ]
+}
diff --git a/third_party/libwebrtc/call/OWNERS b/third_party/libwebrtc/call/OWNERS
new file mode 100644
index 0000000000..e275834bb4
--- /dev/null
+++ b/third_party/libwebrtc/call/OWNERS
@@ -0,0 +1,8 @@
+sprang@webrtc.org
+danilchap@webrtc.org
+brandtr@webrtc.org
+tommi@webrtc.org
+mflodman@webrtc.org
+stefan@webrtc.org
+
+per-file version.cc=webrtc-version-updater@webrtc-ci.iam.gserviceaccount.com
diff --git a/third_party/libwebrtc/call/adaptation/BUILD.gn b/third_party/libwebrtc/call/adaptation/BUILD.gn
new file mode 100644
index 0000000000..58fadc421d
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/BUILD.gn
@@ -0,0 +1,136 @@
+# Copyright (c) 2019 The WebRTC project authors. All Rights Reserved.
+#
+# Use of this source code is governed by a BSD-style license
+# that can be found in the LICENSE file in the root of the source
+# tree. An additional intellectual property rights grant can be found
+# in the file PATENTS.  All contributing project authors may
+# be found in the AUTHORS file in the root of the source tree.
+
+import("../../webrtc.gni")
+
+rtc_library("resource_adaptation") {
+  sources = [
+    "adaptation_constraint.cc",
+    "adaptation_constraint.h",
+    "broadcast_resource_listener.cc",
+    "broadcast_resource_listener.h",
+    "degradation_preference_provider.cc",
+    "degradation_preference_provider.h",
+    "encoder_settings.cc",
+    "encoder_settings.h",
+    "resource_adaptation_processor.cc",
+    "resource_adaptation_processor.h",
+    "resource_adaptation_processor_interface.cc",
+    "resource_adaptation_processor_interface.h",
+    "video_source_restrictions.cc",
+    "video_source_restrictions.h",
+    "video_stream_adapter.cc",
+    "video_stream_adapter.h",
+    "video_stream_input_state.cc",
+    "video_stream_input_state.h",
+    "video_stream_input_state_provider.cc",
+    "video_stream_input_state_provider.h",
+  ]
+  deps = [
+    "../../api:field_trials_view",
+    "../../api:make_ref_counted",
+    "../../api:rtp_parameters",
+    "../../api:scoped_refptr",
+    "../../api:sequence_checker",
+    "../../api/adaptation:resource_adaptation_api",
+    "../../api/task_queue:task_queue",
+    "../../api/video:video_adaptation",
+    "../../api/video:video_frame",
+    "../../api/video:video_stream_encoder",
+    "../../api/video_codecs:video_codecs_api",
+    "../../modules/video_coding:video_coding_utility",
+    "../../rtc_base:checks",
+    "../../rtc_base:logging",
+    "../../rtc_base:macromagic",
+    "../../rtc_base:refcount",
+    "../../rtc_base:rtc_task_queue",
+    "../../rtc_base:safe_conversions",
+    "../../rtc_base:stringutils",
+    "../../rtc_base/experiments:balanced_degradation_settings",
+    "../../rtc_base/synchronization:mutex",
+    "../../rtc_base/system:no_unique_address",
+    "../../video:video_stream_encoder_interface",
+    "../../video/config:encoder_config",
+  ]
+  absl_deps = [
+    "//third_party/abseil-cpp/absl/algorithm:container",
+    "//third_party/abseil-cpp/absl/strings",
+    "//third_party/abseil-cpp/absl/types:optional",
+    "//third_party/abseil-cpp/absl/types:variant",
+  ]
+}
+
+if (rtc_include_tests) {
+  rtc_library("resource_adaptation_tests") {
+    testonly = true
+
+    sources = [
+      "broadcast_resource_listener_unittest.cc",
+      "resource_adaptation_processor_unittest.cc",
+      "resource_unittest.cc",
+      "video_source_restrictions_unittest.cc",
+      "video_stream_adapter_unittest.cc",
+      "video_stream_input_state_provider_unittest.cc",
+    ]
+    deps = [
+      ":resource_adaptation",
+      ":resource_adaptation_test_utilities",
+      "../../api:scoped_refptr",
+      "../../api/adaptation:resource_adaptation_api",
+      "../../api/task_queue:default_task_queue_factory",
+      "../../api/task_queue:task_queue",
+      "../../api/video:video_adaptation",
+      "../../api/video_codecs:video_codecs_api",
+      "../../rtc_base:checks",
+      "../../rtc_base:gunit_helpers",
+      "../../rtc_base:rtc_event",
+      "../../rtc_base:rtc_task_queue",
+      "../../rtc_base:stringutils",
+      "../../rtc_base:task_queue_for_test",
+      "../../rtc_base/synchronization:mutex",
+      "../../test:field_trial",
+      "../../test:rtc_expect_death",
+      "../../test:scoped_key_value_config",
+      "../../test:test_support",
+      "../../video/config:encoder_config",
+    ]
+    absl_deps = [ "//third_party/abseil-cpp/absl/types:optional" ]
+  }
+
+  rtc_source_set("resource_adaptation_test_utilities") {
+    testonly = true
+
+    sources = [
+      "test/fake_adaptation_constraint.cc",
+      "test/fake_adaptation_constraint.h",
+      "test/fake_frame_rate_provider.cc",
+      "test/fake_frame_rate_provider.h",
+      "test/fake_resource.cc",
+      "test/fake_resource.h",
+      "test/fake_video_stream_input_state_provider.cc",
+      "test/fake_video_stream_input_state_provider.h",
+      "test/mock_resource_listener.h",
+    ]
+    deps = [
+      ":resource_adaptation",
+      "../../api:make_ref_counted",
+      "../../api:scoped_refptr",
+      "../../api:sequence_checker",
+      "../../api/adaptation:resource_adaptation_api",
+      "../../api/task_queue:task_queue",
+      "../../api/video:video_stream_encoder",
+      "../../test:test_support",
+      "../../video:video_stream_encoder_interface",
+      "../../video/config:encoder_config",
+    ]
+    absl_deps = [
+      "//third_party/abseil-cpp/absl/strings",
+      "//third_party/abseil-cpp/absl/types:optional",
+    ]
+  }
+}
diff --git a/third_party/libwebrtc/call/adaptation/OWNERS b/third_party/libwebrtc/call/adaptation/OWNERS
new file mode 100644
index 0000000000..bd56595d2e
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/OWNERS
@@ -0,0 +1,3 @@
+eshr@webrtc.org
+hbos@webrtc.org
+ilnik@webrtc.org
diff --git a/third_party/libwebrtc/call/adaptation/adaptation_constraint.cc b/third_party/libwebrtc/call/adaptation/adaptation_constraint.cc
new file mode 100644
index 0000000000..d62bb74f87
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/adaptation_constraint.cc
@@ -0,0 +1,17 @@
+/*
+ *  Copyright 2020 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/adaptation/adaptation_constraint.h"
+
+namespace webrtc {
+
+AdaptationConstraint::~AdaptationConstraint() {}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/adaptation/adaptation_constraint.h b/third_party/libwebrtc/call/adaptation/adaptation_constraint.h
new file mode 100644
index 0000000000..9ad6414cd1
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/adaptation_constraint.h
@@ -0,0 +1,41 @@
+/*
+ *  Copyright 2020 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_ADAPTATION_ADAPTATION_CONSTRAINT_H_
+#define CALL_ADAPTATION_ADAPTATION_CONSTRAINT_H_
+
+#include <string>
+
+#include "api/adaptation/resource.h"
+#include "call/adaptation/video_source_restrictions.h"
+#include "call/adaptation/video_stream_input_state.h"
+
+namespace webrtc {
+
+// Adaptation constraints have the ability to prevent applying a proposed
+// adaptation (expressed as restrictions before/after adaptation).
+class AdaptationConstraint {
+ public:
+  virtual ~AdaptationConstraint();
+
+  virtual std::string Name() const = 0;
+
+  // TODO(https://crbug.com/webrtc/11172): When we have multi-stream adaptation
+  // support, this interface needs to indicate which stream the adaptation
+  // applies to.
+  virtual bool IsAdaptationUpAllowed(
+      const VideoStreamInputState& input_state,
+      const VideoSourceRestrictions& restrictions_before,
+      const VideoSourceRestrictions& restrictions_after) const = 0;
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_ADAPTATION_ADAPTATION_CONSTRAINT_H_
diff --git a/third_party/libwebrtc/call/adaptation/broadcast_resource_listener.cc b/third_party/libwebrtc/call/adaptation/broadcast_resource_listener.cc
new file mode 100644
index 0000000000..505036db3d
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/broadcast_resource_listener.cc
@@ -0,0 +1,122 @@
+/*
+ *  Copyright 2020 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/adaptation/broadcast_resource_listener.h"
+
+#include <algorithm>
+#include <string>
+#include <utility>
+
+#include "absl/strings/string_view.h"
+#include "api/make_ref_counted.h"
+#include "rtc_base/checks.h"
+#include "rtc_base/synchronization/mutex.h"
+
+namespace webrtc {
+
+// The AdapterResource redirects resource usage measurements from its parent to
+// a single ResourceListener.
+class BroadcastResourceListener::AdapterResource : public Resource {
+ public:
+  explicit AdapterResource(absl::string_view name) : name_(std::move(name)) {}
+  ~AdapterResource() override { RTC_DCHECK(!listener_); }
+
+  // The parent is letting us know we have a usage neasurement.
+  void OnResourceUsageStateMeasured(ResourceUsageState usage_state) {
+    MutexLock lock(&lock_);
+    if (!listener_)
+      return;
+    listener_->OnResourceUsageStateMeasured(rtc::scoped_refptr<Resource>(this),
+                                            usage_state);
+  }
+
+  // Resource implementation.
+  std::string Name() const override { return name_; }
+  void SetResourceListener(ResourceListener* listener) override {
+    MutexLock lock(&lock_);
+    RTC_DCHECK(!listener_ || !listener);
+    listener_ = listener;
+  }
+
+ private:
+  const std::string name_;
+  Mutex lock_;
+  ResourceListener* listener_ RTC_GUARDED_BY(lock_) = nullptr;
+};
+
+BroadcastResourceListener::BroadcastResourceListener(
+    rtc::scoped_refptr<Resource> source_resource)
+    : source_resource_(source_resource), is_listening_(false) {
+  RTC_DCHECK(source_resource_);
+}
+
+BroadcastResourceListener::~BroadcastResourceListener() {
+  RTC_DCHECK(!is_listening_);
+}
+
+rtc::scoped_refptr<Resource> BroadcastResourceListener::SourceResource() const {
+  return source_resource_;
+}
+
+void BroadcastResourceListener::StartListening() {
+  MutexLock lock(&lock_);
+  RTC_DCHECK(!is_listening_);
+  source_resource_->SetResourceListener(this);
+  is_listening_ = true;
+}
+
+void BroadcastResourceListener::StopListening() {
+  MutexLock lock(&lock_);
+  RTC_DCHECK(is_listening_);
+  RTC_DCHECK(adapters_.empty());
+  source_resource_->SetResourceListener(nullptr);
+  is_listening_ = false;
+}
+
+rtc::scoped_refptr<Resource>
+BroadcastResourceListener::CreateAdapterResource() {
+  MutexLock lock(&lock_);
+  RTC_DCHECK(is_listening_);
+  rtc::scoped_refptr<AdapterResource> adapter =
+      rtc::make_ref_counted<AdapterResource>(source_resource_->Name() +
+                                             "Adapter");
+  adapters_.push_back(adapter);
+  return adapter;
+}
+
+void BroadcastResourceListener::RemoveAdapterResource(
+    rtc::scoped_refptr<Resource> resource) {
+  MutexLock lock(&lock_);
+  auto it = std::find(adapters_.begin(), adapters_.end(), resource);
+  RTC_DCHECK(it != adapters_.end());
+  adapters_.erase(it);
+}
+
+std::vector<rtc::scoped_refptr<Resource>>
+BroadcastResourceListener::GetAdapterResources() {
+  std::vector<rtc::scoped_refptr<Resource>> resources;
+  MutexLock lock(&lock_);
+  for (const auto& adapter : adapters_) {
+    resources.push_back(adapter);
+  }
+  return resources;
+}
+
+void BroadcastResourceListener::OnResourceUsageStateMeasured(
+    rtc::scoped_refptr<Resource> resource,
+    ResourceUsageState usage_state) {
+  RTC_DCHECK_EQ(resource, source_resource_);
+  MutexLock lock(&lock_);
+  for (const auto& adapter : adapters_) {
+    adapter->OnResourceUsageStateMeasured(usage_state);
+  }
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/adaptation/broadcast_resource_listener.h b/third_party/libwebrtc/call/adaptation/broadcast_resource_listener.h
new file mode 100644
index 0000000000..2c5a5c703b
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/broadcast_resource_listener.h
@@ -0,0 +1,75 @@
+/*
+ *  Copyright 2020 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_ADAPTATION_BROADCAST_RESOURCE_LISTENER_H_
+#define CALL_ADAPTATION_BROADCAST_RESOURCE_LISTENER_H_
+
+#include <vector>
+
+#include "api/adaptation/resource.h"
+#include "api/scoped_refptr.h"
+#include "rtc_base/synchronization/mutex.h"
+
+namespace webrtc {
+
+// Responsible for forwarding 1 resource usage measurement to N listeners by
+// creating N "adapter" resources.
+//
+// Example:
+// If we have ResourceA, ResourceListenerX and ResourceListenerY we can create a
+// BroadcastResourceListener that listens to ResourceA, use CreateAdapter() to
+// spawn adapter resources ResourceX and ResourceY and let ResourceListenerX
+// listen to ResourceX and ResourceListenerY listen to ResourceY. When ResourceA
+// makes a measurement it will be echoed by both ResourceX and ResourceY.
+//
+// TODO(https://crbug.com/webrtc/11565): When the ResourceAdaptationProcessor is
+// moved to call there will only be one ResourceAdaptationProcessor that needs
+// to listen to the injected resources. When this is the case, delete this class
+// and DCHECK that a Resource's listener is never overwritten.
+class BroadcastResourceListener : public ResourceListener {
+ public:
+  explicit BroadcastResourceListener(
+      rtc::scoped_refptr<Resource> source_resource);
+  ~BroadcastResourceListener() override;
+
+  rtc::scoped_refptr<Resource> SourceResource() const;
+  void StartListening();
+  void StopListening();
+
+  // Creates a Resource that redirects any resource usage measurements that
+  // BroadcastResourceListener receives to its listener.
+  rtc::scoped_refptr<Resource> CreateAdapterResource();
+
+  // Unregister the adapter from the BroadcastResourceListener; it will no
+  // longer receive resource usage measurement and will no longer be referenced.
+  // Use this to prevent memory leaks of old adapters.
+  void RemoveAdapterResource(rtc::scoped_refptr<Resource> resource);
+  std::vector<rtc::scoped_refptr<Resource>> GetAdapterResources();
+
+  // ResourceListener implementation.
+  void OnResourceUsageStateMeasured(rtc::scoped_refptr<Resource> resource,
+                                    ResourceUsageState usage_state) override;
+
+ private:
+  class AdapterResource;
+  friend class AdapterResource;
+
+  const rtc::scoped_refptr<Resource> source_resource_;
+  Mutex lock_;
+  bool is_listening_ RTC_GUARDED_BY(lock_);
+  // The AdapterResource unregisters itself prior to destruction, guaranteeing
+  // that these pointers are safe to use.
+  std::vector<rtc::scoped_refptr<AdapterResource>> adapters_
+      RTC_GUARDED_BY(lock_);
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_ADAPTATION_BROADCAST_RESOURCE_LISTENER_H_
diff --git a/third_party/libwebrtc/call/adaptation/broadcast_resource_listener_unittest.cc b/third_party/libwebrtc/call/adaptation/broadcast_resource_listener_unittest.cc
new file mode 100644
index 0000000000..9cd80500c2
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/broadcast_resource_listener_unittest.cc
@@ -0,0 +1,121 @@
+/*
+ *  Copyright 2020 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/adaptation/broadcast_resource_listener.h"
+
+#include "call/adaptation/test/fake_resource.h"
+#include "call/adaptation/test/mock_resource_listener.h"
+#include "test/gmock.h"
+#include "test/gtest.h"
+
+namespace webrtc {
+
+using ::testing::_;
+using ::testing::StrictMock;
+
+TEST(BroadcastResourceListenerTest, CreateAndRemoveAdapterResource) {
+  rtc::scoped_refptr<FakeResource> source_resource =
+      FakeResource::Create("SourceResource");
+  BroadcastResourceListener broadcast_resource_listener(source_resource);
+  broadcast_resource_listener.StartListening();
+
+  EXPECT_TRUE(broadcast_resource_listener.GetAdapterResources().empty());
+  rtc::scoped_refptr<Resource> adapter =
+      broadcast_resource_listener.CreateAdapterResource();
+  StrictMock<MockResourceListener> listener;
+  adapter->SetResourceListener(&listener);
+  EXPECT_EQ(std::vector<rtc::scoped_refptr<Resource>>{adapter},
+            broadcast_resource_listener.GetAdapterResources());
+
+  // The removed adapter is not referenced by the broadcaster.
+  broadcast_resource_listener.RemoveAdapterResource(adapter);
+  EXPECT_TRUE(broadcast_resource_listener.GetAdapterResources().empty());
+  // The removed adapter is not forwarding measurements.
+  EXPECT_CALL(listener, OnResourceUsageStateMeasured(_, _)).Times(0);
+  source_resource->SetUsageState(ResourceUsageState::kOveruse);
+  // Cleanup.
+  adapter->SetResourceListener(nullptr);
+  broadcast_resource_listener.StopListening();
+}
+
+TEST(BroadcastResourceListenerTest, AdapterNameIsBasedOnSourceResourceName) {
+  rtc::scoped_refptr<FakeResource> source_resource =
+      FakeResource::Create("FooBarResource");
+  BroadcastResourceListener broadcast_resource_listener(source_resource);
+  broadcast_resource_listener.StartListening();
+
+  rtc::scoped_refptr<Resource> adapter =
+      broadcast_resource_listener.CreateAdapterResource();
+  EXPECT_EQ("FooBarResourceAdapter", adapter->Name());
+
+  broadcast_resource_listener.RemoveAdapterResource(adapter);
+  broadcast_resource_listener.StopListening();
+}
+
+TEST(BroadcastResourceListenerTest, AdaptersForwardsUsageMeasurements) {
+  rtc::scoped_refptr<FakeResource> source_resource =
+      FakeResource::Create("SourceResource");
+  BroadcastResourceListener broadcast_resource_listener(source_resource);
+  broadcast_resource_listener.StartListening();
+
+  StrictMock<MockResourceListener> destination_listener1;
+  StrictMock<MockResourceListener> destination_listener2;
+  rtc::scoped_refptr<Resource> adapter1 =
+      broadcast_resource_listener.CreateAdapterResource();
+  adapter1->SetResourceListener(&destination_listener1);
+  rtc::scoped_refptr<Resource> adapter2 =
+      broadcast_resource_listener.CreateAdapterResource();
+  adapter2->SetResourceListener(&destination_listener2);
+
+  // Expect kOveruse to be echoed.
+  EXPECT_CALL(destination_listener1, OnResourceUsageStateMeasured(_, _))
+      .Times(1)
+      .WillOnce([adapter1](rtc::scoped_refptr<Resource> resource,
+                           ResourceUsageState usage_state) {
+        EXPECT_EQ(adapter1, resource);
+        EXPECT_EQ(ResourceUsageState::kOveruse, usage_state);
+      });
+  EXPECT_CALL(destination_listener2, OnResourceUsageStateMeasured(_, _))
+      .Times(1)
+      .WillOnce([adapter2](rtc::scoped_refptr<Resource> resource,
+                           ResourceUsageState usage_state) {
+        EXPECT_EQ(adapter2, resource);
+        EXPECT_EQ(ResourceUsageState::kOveruse, usage_state);
+      });
+  source_resource->SetUsageState(ResourceUsageState::kOveruse);
+
+  // Expect kUnderuse to be echoed.
+  EXPECT_CALL(destination_listener1, OnResourceUsageStateMeasured(_, _))
+      .Times(1)
+      .WillOnce([adapter1](rtc::scoped_refptr<Resource> resource,
+                           ResourceUsageState usage_state) {
+        EXPECT_EQ(adapter1, resource);
+        EXPECT_EQ(ResourceUsageState::kUnderuse, usage_state);
+      });
+  EXPECT_CALL(destination_listener2, OnResourceUsageStateMeasured(_, _))
+      .Times(1)
+      .WillOnce([adapter2](rtc::scoped_refptr<Resource> resource,
+                           ResourceUsageState usage_state) {
+        EXPECT_EQ(adapter2, resource);
+        EXPECT_EQ(ResourceUsageState::kUnderuse, usage_state);
+      });
+  source_resource->SetUsageState(ResourceUsageState::kUnderuse);
+
+  // Adapters have to be unregistered before they or the broadcaster is
+  // destroyed, ensuring safe use of raw pointers.
+  adapter1->SetResourceListener(nullptr);
+  adapter2->SetResourceListener(nullptr);
+
+  broadcast_resource_listener.RemoveAdapterResource(adapter1);
+  broadcast_resource_listener.RemoveAdapterResource(adapter2);
+  broadcast_resource_listener.StopListening();
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/adaptation/degradation_preference_provider.cc b/third_party/libwebrtc/call/adaptation/degradation_preference_provider.cc
new file mode 100644
index 0000000000..c87e49f366
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/degradation_preference_provider.cc
@@ -0,0 +1,14 @@
+/*
+ *  Copyright 2020 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/adaptation/degradation_preference_provider.h"
+
+webrtc::DegradationPreferenceProvider::~DegradationPreferenceProvider() =
+    default;
diff --git a/third_party/libwebrtc/call/adaptation/degradation_preference_provider.h b/third_party/libwebrtc/call/adaptation/degradation_preference_provider.h
new file mode 100644
index 0000000000..1f75901cc5
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/degradation_preference_provider.h
@@ -0,0 +1,27 @@
+/*
+ *  Copyright 2020 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_ADAPTATION_DEGRADATION_PREFERENCE_PROVIDER_H_
+#define CALL_ADAPTATION_DEGRADATION_PREFERENCE_PROVIDER_H_
+
+#include "api/rtp_parameters.h"
+
+namespace webrtc {
+
+class DegradationPreferenceProvider {
+ public:
+  virtual ~DegradationPreferenceProvider();
+
+  virtual DegradationPreference degradation_preference() const = 0;
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_ADAPTATION_DEGRADATION_PREFERENCE_PROVIDER_H_
diff --git a/third_party/libwebrtc/call/adaptation/encoder_settings.cc b/third_party/libwebrtc/call/adaptation/encoder_settings.cc
new file mode 100644
index 0000000000..c894e833ed
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/encoder_settings.cc
@@ -0,0 +1,54 @@
+/*
+ *  Copyright 2020 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/adaptation/encoder_settings.h"
+
+#include <utility>
+
+namespace webrtc {
+
+EncoderSettings::EncoderSettings(VideoEncoder::EncoderInfo encoder_info,
+                                 VideoEncoderConfig encoder_config,
+                                 VideoCodec video_codec)
+    : encoder_info_(std::move(encoder_info)),
+      encoder_config_(std::move(encoder_config)),
+      video_codec_(std::move(video_codec)) {}
+
+EncoderSettings::EncoderSettings(const EncoderSettings& other)
+    : encoder_info_(other.encoder_info_),
+      encoder_config_(other.encoder_config_.Copy()),
+      video_codec_(other.video_codec_) {}
+
+EncoderSettings& EncoderSettings::operator=(const EncoderSettings& other) {
+  encoder_info_ = other.encoder_info_;
+  encoder_config_ = other.encoder_config_.Copy();
+  video_codec_ = other.video_codec_;
+  return *this;
+}
+
+const VideoEncoder::EncoderInfo& EncoderSettings::encoder_info() const {
+  return encoder_info_;
+}
+
+const VideoEncoderConfig& EncoderSettings::encoder_config() const {
+  return encoder_config_;
+}
+
+const VideoCodec& EncoderSettings::video_codec() const {
+  return video_codec_;
+}
+
+VideoCodecType GetVideoCodecTypeOrGeneric(
+    const absl::optional<EncoderSettings>& settings) {
+  return settings.has_value() ? settings->encoder_config().codec_type
+                              : kVideoCodecGeneric;
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/adaptation/encoder_settings.h b/third_party/libwebrtc/call/adaptation/encoder_settings.h
new file mode 100644
index 0000000000..30ce0a05bc
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/encoder_settings.h
@@ -0,0 +1,48 @@
+/*
+ *  Copyright 2020 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_ADAPTATION_ENCODER_SETTINGS_H_
+#define CALL_ADAPTATION_ENCODER_SETTINGS_H_
+
+#include "absl/types/optional.h"
+#include "api/video_codecs/video_codec.h"
+#include "api/video_codecs/video_encoder.h"
+#include "video/config/video_encoder_config.h"
+
+namespace webrtc {
+
+// Information about an encoder available when reconfiguring the encoder.
+class EncoderSettings {
+ public:
+  EncoderSettings(VideoEncoder::EncoderInfo encoder_info,
+                  VideoEncoderConfig encoder_config,
+                  VideoCodec video_codec);
+  EncoderSettings(const EncoderSettings& other);
+  EncoderSettings& operator=(const EncoderSettings& other);
+
+  // Encoder capabilities, implementation info, etc.
+  const VideoEncoder::EncoderInfo& encoder_info() const;
+  // Configuration parameters, ultimately coming from the API and negotiation.
+  const VideoEncoderConfig& encoder_config() const;
+  // Lower level config, heavily based on the VideoEncoderConfig.
+  const VideoCodec& video_codec() const;
+
+ private:
+  VideoEncoder::EncoderInfo encoder_info_;
+  VideoEncoderConfig encoder_config_;
+  VideoCodec video_codec_;
+};
+
+VideoCodecType GetVideoCodecTypeOrGeneric(
+    const absl::optional<EncoderSettings>& settings);
+
+}  // namespace webrtc
+
+#endif  // CALL_ADAPTATION_ENCODER_SETTINGS_H_
diff --git a/third_party/libwebrtc/call/adaptation/resource_adaptation_gn/moz.build b/third_party/libwebrtc/call/adaptation/resource_adaptation_gn/moz.build
new file mode 100644
index 0000000000..2e88747157
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/resource_adaptation_gn/moz.build
@@ -0,0 +1,241 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+  ### This moz.build was AUTOMATICALLY GENERATED from a GN config,  ###
+  ### DO NOT edit it by hand.                                       ###
+
+COMPILE_FLAGS["OS_INCLUDES"] = []
+AllowCompilerWarnings()
+
+DEFINES["ABSL_ALLOCATOR_NOTHROW"] = "1"
+DEFINES["RTC_DAV1D_IN_INTERNAL_DECODER_FACTORY"] = True
+DEFINES["RTC_ENABLE_VP9"] = True
+DEFINES["WEBRTC_ENABLE_PROTOBUF"] = "0"
+DEFINES["WEBRTC_LIBRARY_IMPL"] = True
+DEFINES["WEBRTC_MOZILLA_BUILD"] = True
+DEFINES["WEBRTC_NON_STATIC_TRACE_EVENT_HANDLERS"] = "0"
+DEFINES["WEBRTC_STRICT_FIELD_TRIALS"] = "0"
+
+FINAL_LIBRARY = "webrtc"
+
+
+LOCAL_INCLUDES += [
+    "!/ipc/ipdl/_ipdlheaders",
+    "!/third_party/libwebrtc/gen",
+    "/ipc/chromium/src",
+    "/third_party/libwebrtc/",
+    "/third_party/libwebrtc/third_party/abseil-cpp/",
+    "/tools/profiler/public"
+]
+
+UNIFIED_SOURCES += [
+    "/third_party/libwebrtc/call/adaptation/adaptation_constraint.cc",
+    "/third_party/libwebrtc/call/adaptation/broadcast_resource_listener.cc",
+    "/third_party/libwebrtc/call/adaptation/degradation_preference_provider.cc",
+    "/third_party/libwebrtc/call/adaptation/encoder_settings.cc",
+    "/third_party/libwebrtc/call/adaptation/resource_adaptation_processor.cc",
+    "/third_party/libwebrtc/call/adaptation/resource_adaptation_processor_interface.cc",
+    "/third_party/libwebrtc/call/adaptation/video_source_restrictions.cc",
+    "/third_party/libwebrtc/call/adaptation/video_stream_adapter.cc",
+    "/third_party/libwebrtc/call/adaptation/video_stream_input_state.cc",
+    "/third_party/libwebrtc/call/adaptation/video_stream_input_state_provider.cc"
+]
+
+if not CONFIG["MOZ_DEBUG"]:
+
+    DEFINES["DYNAMIC_ANNOTATIONS_ENABLED"] = "0"
+    DEFINES["NDEBUG"] = True
+    DEFINES["NVALGRIND"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1":
+
+    DEFINES["DYNAMIC_ANNOTATIONS_ENABLED"] = "1"
+
+if CONFIG["OS_TARGET"] == "Android":
+
+    DEFINES["ANDROID"] = True
+    DEFINES["ANDROID_NDK_VERSION_ROLL"] = "r22_1"
+    DEFINES["HAVE_SYS_UIO_H"] = True
+    DEFINES["WEBRTC_ANDROID"] = True
+    DEFINES["WEBRTC_ANDROID_OPENSLES"] = True
+    DEFINES["WEBRTC_LINUX"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_GNU_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+    OS_LIBS += [
+        "log"
+    ]
+
+if CONFIG["OS_TARGET"] == "Darwin":
+
+    DEFINES["WEBRTC_MAC"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_LIBCPP_HAS_NO_ALIGNED_ALLOCATION"] = True
+    DEFINES["__ASSERT_MACROS_DEFINE_VERSIONS_WITHOUT_UNDERSCORES"] = "0"
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+if CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["USE_AURA"] = "1"
+    DEFINES["USE_GLIB"] = "1"
+    DEFINES["USE_NSS_CERTS"] = "1"
+    DEFINES["USE_OZONE"] = "1"
+    DEFINES["USE_UDEV"] = True
+    DEFINES["WEBRTC_LINUX"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_FILE_OFFSET_BITS"] = "64"
+    DEFINES["_LARGEFILE64_SOURCE"] = True
+    DEFINES["_LARGEFILE_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+    OS_LIBS += [
+        "rt"
+    ]
+
+if CONFIG["OS_TARGET"] == "OpenBSD":
+
+    DEFINES["USE_GLIB"] = "1"
+    DEFINES["USE_OZONE"] = "1"
+    DEFINES["USE_X11"] = "1"
+    DEFINES["WEBRTC_BSD"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_FILE_OFFSET_BITS"] = "64"
+    DEFINES["_LARGEFILE64_SOURCE"] = True
+    DEFINES["_LARGEFILE_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+if CONFIG["OS_TARGET"] == "WINNT":
+
+    DEFINES["CERT_CHAIN_PARA_HAS_EXTRA_FIELDS"] = True
+    DEFINES["NOMINMAX"] = True
+    DEFINES["NTDDI_VERSION"] = "0x0A000000"
+    DEFINES["PSAPI_VERSION"] = "2"
+    DEFINES["UNICODE"] = True
+    DEFINES["USE_AURA"] = "1"
+    DEFINES["WEBRTC_WIN"] = True
+    DEFINES["WIN32"] = True
+    DEFINES["WIN32_LEAN_AND_MEAN"] = True
+    DEFINES["WINAPI_FAMILY"] = "WINAPI_FAMILY_DESKTOP_APP"
+    DEFINES["WINVER"] = "0x0A00"
+    DEFINES["_ATL_NO_OPENGL"] = True
+    DEFINES["_CRT_RAND_S"] = True
+    DEFINES["_CRT_SECURE_NO_DEPRECATE"] = True
+    DEFINES["_ENABLE_EXTENDED_ALIGNED_STORAGE"] = True
+    DEFINES["_HAS_EXCEPTIONS"] = "0"
+    DEFINES["_HAS_NODISCARD"] = True
+    DEFINES["_SCL_SECURE_NO_DEPRECATE"] = True
+    DEFINES["_SECURE_ATL"] = True
+    DEFINES["_UNICODE"] = True
+    DEFINES["_WIN32_WINNT"] = "0x0A00"
+    DEFINES["_WINDOWS"] = True
+    DEFINES["__STD_C"] = True
+
+    OS_LIBS += [
+        "crypt32",
+        "iphlpapi",
+        "secur32",
+        "winmm"
+    ]
+
+if CONFIG["CPU_ARCH"] == "aarch64":
+
+    DEFINES["WEBRTC_ARCH_ARM64"] = True
+    DEFINES["WEBRTC_HAS_NEON"] = True
+
+if CONFIG["CPU_ARCH"] == "arm":
+
+    CXXFLAGS += [
+        "-mfpu=neon"
+    ]
+
+    DEFINES["WEBRTC_ARCH_ARM"] = True
+    DEFINES["WEBRTC_ARCH_ARM_V7"] = True
+    DEFINES["WEBRTC_HAS_NEON"] = True
+
+if CONFIG["CPU_ARCH"] == "mips32":
+
+    DEFINES["MIPS32_LE"] = True
+    DEFINES["MIPS_FPU_LE"] = True
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "mips64":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86":
+
+    DEFINES["WEBRTC_ENABLE_AVX2"] = True
+
+if CONFIG["CPU_ARCH"] == "x86_64":
+
+    DEFINES["WEBRTC_ENABLE_AVX2"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Android":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Darwin":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "OpenBSD":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "WINNT":
+
+    DEFINES["_HAS_ITERATOR_DEBUGGING"] = "0"
+
+if CONFIG["MOZ_X11"] == "1" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["USE_X11"] = "1"
+
+if CONFIG["CPU_ARCH"] == "arm" and CONFIG["OS_TARGET"] == "Android":
+
+    OS_LIBS += [
+        "android_support",
+        "unwind"
+    ]
+
+if CONFIG["CPU_ARCH"] == "x86" and CONFIG["OS_TARGET"] == "Android":
+
+    CXXFLAGS += [
+        "-msse2"
+    ]
+
+    OS_LIBS += [
+        "android_support"
+    ]
+
+if CONFIG["CPU_ARCH"] == "aarch64" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "arm" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86" and CONFIG["OS_TARGET"] == "Linux":
+
+    CXXFLAGS += [
+        "-msse2"
+    ]
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86_64" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+Library("resource_adaptation_gn")
diff --git a/third_party/libwebrtc/call/adaptation/resource_adaptation_processor.cc b/third_party/libwebrtc/call/adaptation/resource_adaptation_processor.cc
new file mode 100644
index 0000000000..f4d1bf3538
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/resource_adaptation_processor.cc
@@ -0,0 +1,378 @@
+/*
+ *  Copyright 2020 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/adaptation/resource_adaptation_processor.h"
+
+#include <algorithm>
+#include <string>
+#include <utility>
+
+#include "absl/algorithm/container.h"
+#include "absl/strings/string_view.h"
+#include "api/sequence_checker.h"
+#include "api/video/video_adaptation_counters.h"
+#include "call/adaptation/video_stream_adapter.h"
+#include "rtc_base/logging.h"
+#include "rtc_base/strings/string_builder.h"
+
+namespace webrtc {
+
+ResourceAdaptationProcessor::ResourceListenerDelegate::ResourceListenerDelegate(
+    ResourceAdaptationProcessor* processor)
+    : task_queue_(TaskQueueBase::Current()), processor_(processor) {
+  RTC_DCHECK(task_queue_);
+}
+
+void ResourceAdaptationProcessor::ResourceListenerDelegate::
+    OnProcessorDestroyed() {
+  RTC_DCHECK_RUN_ON(task_queue_);
+  processor_ = nullptr;
+}
+
+void ResourceAdaptationProcessor::ResourceListenerDelegate::
+    OnResourceUsageStateMeasured(rtc::scoped_refptr<Resource> resource,
+                                 ResourceUsageState usage_state) {
+  if (!task_queue_->IsCurrent()) {
+    task_queue_->PostTask(
+        [this_ref = rtc::scoped_refptr<ResourceListenerDelegate>(this),
+         resource, usage_state] {
+          this_ref->OnResourceUsageStateMeasured(resource, usage_state);
+        });
+    return;
+  }
+  RTC_DCHECK_RUN_ON(task_queue_);
+  if (processor_) {
+    processor_->OnResourceUsageStateMeasured(resource, usage_state);
+  }
+}
+
+ResourceAdaptationProcessor::MitigationResultAndLogMessage::
+    MitigationResultAndLogMessage()
+    : result(MitigationResult::kAdaptationApplied), message() {}
+
+ResourceAdaptationProcessor::MitigationResultAndLogMessage::
+    MitigationResultAndLogMessage(MitigationResult result,
+                                  absl::string_view message)
+    : result(result), message(message) {}
+
+ResourceAdaptationProcessor::ResourceAdaptationProcessor(
+    VideoStreamAdapter* stream_adapter)
+    : task_queue_(TaskQueueBase::Current()),
+      resource_listener_delegate_(
+          rtc::make_ref_counted<ResourceListenerDelegate>(this)),
+      resources_(),
+      stream_adapter_(stream_adapter),
+      last_reported_source_restrictions_(),
+      previous_mitigation_results_() {
+  RTC_DCHECK(task_queue_);
+  stream_adapter_->AddRestrictionsListener(this);
+}
+
+ResourceAdaptationProcessor::~ResourceAdaptationProcessor() {
+  RTC_DCHECK_RUN_ON(task_queue_);
+  RTC_DCHECK(resources_.empty())
+      << "There are resource(s) attached to a ResourceAdaptationProcessor "
+      << "being destroyed.";
+  stream_adapter_->RemoveRestrictionsListener(this);
+  resource_listener_delegate_->OnProcessorDestroyed();
+}
+
+void ResourceAdaptationProcessor::AddResourceLimitationsListener(
+    ResourceLimitationsListener* limitations_listener) {
+  RTC_DCHECK_RUN_ON(task_queue_);
+  RTC_DCHECK(std::find(resource_limitations_listeners_.begin(),
+                       resource_limitations_listeners_.end(),
+                       limitations_listener) ==
+             resource_limitations_listeners_.end());
+  resource_limitations_listeners_.push_back(limitations_listener);
+}
+
+void ResourceAdaptationProcessor::RemoveResourceLimitationsListener(
+    ResourceLimitationsListener* limitations_listener) {
+  RTC_DCHECK_RUN_ON(task_queue_);
+  auto it =
+      std::find(resource_limitations_listeners_.begin(),
+                resource_limitations_listeners_.end(), limitations_listener);
+  RTC_DCHECK(it != resource_limitations_listeners_.end());
+  resource_limitations_listeners_.erase(it);
+}
+
+void ResourceAdaptationProcessor::AddResource(
+    rtc::scoped_refptr<Resource> resource) {
+  RTC_DCHECK(resource);
+  {
+    MutexLock crit(&resources_lock_);
+    RTC_DCHECK(absl::c_find(resources_, resource) == resources_.end())
+        << "Resource \"" << resource->Name() << "\" was already registered.";
+    resources_.push_back(resource);
+  }
+  resource->SetResourceListener(resource_listener_delegate_.get());
+  RTC_LOG(LS_INFO) << "Registered resource \"" << resource->Name() << "\".";
+}
+
+std::vector<rtc::scoped_refptr<Resource>>
+ResourceAdaptationProcessor::GetResources() const {
+  MutexLock crit(&resources_lock_);
+  return resources_;
+}
+
+void ResourceAdaptationProcessor::RemoveResource(
+    rtc::scoped_refptr<Resource> resource) {
+  RTC_DCHECK(resource);
+  RTC_LOG(LS_INFO) << "Removing resource \"" << resource->Name() << "\".";
+  resource->SetResourceListener(nullptr);
+  {
+    MutexLock crit(&resources_lock_);
+    auto it = absl::c_find(resources_, resource);
+    RTC_DCHECK(it != resources_.end()) << "Resource \"" << resource->Name()
+                                       << "\" was not a registered resource.";
+    resources_.erase(it);
+  }
+  RemoveLimitationsImposedByResource(std::move(resource));
+}
+
+void ResourceAdaptationProcessor::RemoveLimitationsImposedByResource(
+    rtc::scoped_refptr<Resource> resource) {
+  if (!task_queue_->IsCurrent()) {
+    task_queue_->PostTask(
+        [this, resource]() { RemoveLimitationsImposedByResource(resource); });
+    return;
+  }
+  RTC_DCHECK_RUN_ON(task_queue_);
+  auto resource_adaptation_limits =
+      adaptation_limits_by_resources_.find(resource);
+  if (resource_adaptation_limits != adaptation_limits_by_resources_.end()) {
+    VideoStreamAdapter::RestrictionsWithCounters adaptation_limits =
+        resource_adaptation_limits->second;
+    adaptation_limits_by_resources_.erase(resource_adaptation_limits);
+    if (adaptation_limits_by_resources_.empty()) {
+      // Only the resource being removed was adapted so clear restrictions.
+      stream_adapter_->ClearRestrictions();
+      return;
+    }
+
+    VideoStreamAdapter::RestrictionsWithCounters most_limited =
+        FindMostLimitedResources().second;
+
+    if (adaptation_limits.counters.Total() <= most_limited.counters.Total()) {
+      // The removed limitations were less limited than the most limited
+      // resource. Don't change the current restrictions.
+      return;
+    }
+
+    // Apply the new most limited resource as the next restrictions.
+    Adaptation adapt_to = stream_adapter_->GetAdaptationTo(
+        most_limited.counters, most_limited.restrictions);
+    RTC_DCHECK_EQ(adapt_to.status(), Adaptation::Status::kValid);
+    stream_adapter_->ApplyAdaptation(adapt_to, nullptr);
+
+    RTC_LOG(LS_INFO)
+        << "Most limited resource removed. Restoring restrictions to "
+           "next most limited restrictions: "
+        << most_limited.restrictions.ToString() << " with counters "
+        << most_limited.counters.ToString();
+  }
+}
+
+void ResourceAdaptationProcessor::OnResourceUsageStateMeasured(
+    rtc::scoped_refptr<Resource> resource,
+    ResourceUsageState usage_state) {
+  RTC_DCHECK_RUN_ON(task_queue_);
+  RTC_DCHECK(resource);
+  // `resource` could have been removed after signalling.
+  {
+    MutexLock crit(&resources_lock_);
+    if (absl::c_find(resources_, resource) == resources_.end()) {
+      RTC_LOG(LS_INFO) << "Ignoring signal from removed resource \""
+                       << resource->Name() << "\".";
+      return;
+    }
+  }
+  MitigationResultAndLogMessage result_and_message;
+  switch (usage_state) {
+    case ResourceUsageState::kOveruse:
+      result_and_message = OnResourceOveruse(resource);
+      break;
+    case ResourceUsageState::kUnderuse:
+      result_and_message = OnResourceUnderuse(resource);
+      break;
+  }
+  // Maybe log the result of the operation.
+  auto it = previous_mitigation_results_.find(resource.get());
+  if (it != previous_mitigation_results_.end() &&
+      it->second == result_and_message.result) {
+    // This resource has previously reported the same result and we haven't
+    // successfully adapted since - don't log to avoid spam.
+    return;
+  }
+  RTC_LOG(LS_INFO) << "Resource \"" << resource->Name() << "\" signalled "
+                   << ResourceUsageStateToString(usage_state) << ". "
+                   << result_and_message.message;
+  if (result_and_message.result == MitigationResult::kAdaptationApplied) {
+    previous_mitigation_results_.clear();
+  } else {
+    previous_mitigation_results_.insert(
+        std::make_pair(resource.get(), result_and_message.result));
+  }
+}
+
+ResourceAdaptationProcessor::MitigationResultAndLogMessage
+ResourceAdaptationProcessor::OnResourceUnderuse(
+    rtc::scoped_refptr<Resource> reason_resource) {
+  RTC_DCHECK_RUN_ON(task_queue_);
+  // How can this stream be adapted up?
+  Adaptation adaptation = stream_adapter_->GetAdaptationUp();
+  if (adaptation.status() != Adaptation::Status::kValid) {
+    rtc::StringBuilder message;
+    message << "Not adapting up because VideoStreamAdapter returned "
+            << Adaptation::StatusToString(adaptation.status());
+    return MitigationResultAndLogMessage(MitigationResult::kRejectedByAdapter,
+                                         message.Release());
+  }
+  // Check that resource is most limited.
+  std::vector<rtc::scoped_refptr<Resource>> most_limited_resources;
+  VideoStreamAdapter::RestrictionsWithCounters most_limited_restrictions;
+  std::tie(most_limited_resources, most_limited_restrictions) =
+      FindMostLimitedResources();
+
+  // If the most restricted resource is less limited than current restrictions
+  // then proceed with adapting up.
+  if (!most_limited_resources.empty() &&
+      most_limited_restrictions.counters.Total() >=
+          stream_adapter_->adaptation_counters().Total()) {
+    // If `reason_resource` is not one of the most limiting resources then abort
+    // adaptation.
+    if (absl::c_find(most_limited_resources, reason_resource) ==
+        most_limited_resources.end()) {
+      rtc::StringBuilder message;
+      message << "Resource \"" << reason_resource->Name()
+              << "\" was not the most limited resource.";
+      return MitigationResultAndLogMessage(
+          MitigationResult::kNotMostLimitedResource, message.Release());
+    }
+
+    if (most_limited_resources.size() > 1) {
+      // If there are multiple most limited resources, all must signal underuse
+      // before the adaptation is applied.
+      UpdateResourceLimitations(reason_resource, adaptation.restrictions(),
+                                adaptation.counters());
+      rtc::StringBuilder message;
+      message << "Resource \"" << reason_resource->Name()
+              << "\" was not the only most limited resource.";
+      return MitigationResultAndLogMessage(
+          MitigationResult::kSharedMostLimitedResource, message.Release());
+    }
+  }
+  // Apply adaptation.
+  stream_adapter_->ApplyAdaptation(adaptation, reason_resource);
+  rtc::StringBuilder message;
+  message << "Adapted up successfully. Unfiltered adaptations: "
+          << stream_adapter_->adaptation_counters().ToString();
+  return MitigationResultAndLogMessage(MitigationResult::kAdaptationApplied,
+                                       message.Release());
+}
+
+ResourceAdaptationProcessor::MitigationResultAndLogMessage
+ResourceAdaptationProcessor::OnResourceOveruse(
+    rtc::scoped_refptr<Resource> reason_resource) {
+  RTC_DCHECK_RUN_ON(task_queue_);
+  // How can this stream be adapted up?
+  Adaptation adaptation = stream_adapter_->GetAdaptationDown();
+  if (adaptation.status() == Adaptation::Status::kLimitReached) {
+    // Add resource as most limited.
+    VideoStreamAdapter::RestrictionsWithCounters restrictions;
+    std::tie(std::ignore, restrictions) = FindMostLimitedResources();
+    UpdateResourceLimitations(reason_resource, restrictions.restrictions,
+                              restrictions.counters);
+  }
+  if (adaptation.status() != Adaptation::Status::kValid) {
+    rtc::StringBuilder message;
+    message << "Not adapting down because VideoStreamAdapter returned "
+            << Adaptation::StatusToString(adaptation.status());
+    return MitigationResultAndLogMessage(MitigationResult::kRejectedByAdapter,
+                                         message.Release());
+  }
+  // Apply adaptation.
+  UpdateResourceLimitations(reason_resource, adaptation.restrictions(),
+                            adaptation.counters());
+  stream_adapter_->ApplyAdaptation(adaptation, reason_resource);
+  rtc::StringBuilder message;
+  message << "Adapted down successfully. Unfiltered adaptations: "
+          << stream_adapter_->adaptation_counters().ToString();
+  return MitigationResultAndLogMessage(MitigationResult::kAdaptationApplied,
+                                       message.Release());
+}
+
+std::pair<std::vector<rtc::scoped_refptr<Resource>>,
+          VideoStreamAdapter::RestrictionsWithCounters>
+ResourceAdaptationProcessor::FindMostLimitedResources() const {
+  std::vector<rtc::scoped_refptr<Resource>> most_limited_resources;
+  VideoStreamAdapter::RestrictionsWithCounters most_limited_restrictions{
+      VideoSourceRestrictions(), VideoAdaptationCounters()};
+
+  for (const auto& resource_and_adaptation_limit_ :
+       adaptation_limits_by_resources_) {
+    const auto& restrictions_with_counters =
+        resource_and_adaptation_limit_.second;
+    if (restrictions_with_counters.counters.Total() >
+        most_limited_restrictions.counters.Total()) {
+      most_limited_restrictions = restrictions_with_counters;
+      most_limited_resources.clear();
+      most_limited_resources.push_back(resource_and_adaptation_limit_.first);
+    } else if (most_limited_restrictions.counters ==
+               restrictions_with_counters.counters) {
+      most_limited_resources.push_back(resource_and_adaptation_limit_.first);
+    }
+  }
+  return std::make_pair(std::move(most_limited_resources),
+                        most_limited_restrictions);
+}
+
+void ResourceAdaptationProcessor::UpdateResourceLimitations(
+    rtc::scoped_refptr<Resource> reason_resource,
+    const VideoSourceRestrictions& restrictions,
+    const VideoAdaptationCounters& counters) {
+  auto& adaptation_limits = adaptation_limits_by_resources_[reason_resource];
+  if (adaptation_limits.restrictions == restrictions &&
+      adaptation_limits.counters == counters) {
+    return;
+  }
+  adaptation_limits = {restrictions, counters};
+
+  std::map<rtc::scoped_refptr<Resource>, VideoAdaptationCounters> limitations;
+  for (const auto& p : adaptation_limits_by_resources_) {
+    limitations.insert(std::make_pair(p.first, p.second.counters));
+  }
+  for (auto limitations_listener : resource_limitations_listeners_) {
+    limitations_listener->OnResourceLimitationChanged(reason_resource,
+                                                      limitations);
+  }
+}
+
+void ResourceAdaptationProcessor::OnVideoSourceRestrictionsUpdated(
+    VideoSourceRestrictions restrictions,
+    const VideoAdaptationCounters& adaptation_counters,
+    rtc::scoped_refptr<Resource> reason,
+    const VideoSourceRestrictions& unfiltered_restrictions) {
+  RTC_DCHECK_RUN_ON(task_queue_);
+  if (reason) {
+    UpdateResourceLimitations(reason, unfiltered_restrictions,
+                              adaptation_counters);
+  } else if (adaptation_counters.Total() == 0) {
+    // Adaptations are cleared.
+    adaptation_limits_by_resources_.clear();
+    previous_mitigation_results_.clear();
+    for (auto limitations_listener : resource_limitations_listeners_) {
+      limitations_listener->OnResourceLimitationChanged(nullptr, {});
+    }
+  }
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/adaptation/resource_adaptation_processor.h b/third_party/libwebrtc/call/adaptation/resource_adaptation_processor.h
new file mode 100644
index 0000000000..db3b4c2506
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/resource_adaptation_processor.h
@@ -0,0 +1,167 @@
+/*
+ *  Copyright 2020 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_ADAPTATION_RESOURCE_ADAPTATION_PROCESSOR_H_
+#define CALL_ADAPTATION_RESOURCE_ADAPTATION_PROCESSOR_H_
+
+#include <map>
+#include <memory>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "absl/strings/string_view.h"
+#include "absl/types/optional.h"
+#include "api/adaptation/resource.h"
+#include "api/rtp_parameters.h"
+#include "api/scoped_refptr.h"
+#include "api/task_queue/task_queue_base.h"
+#include "api/video/video_adaptation_counters.h"
+#include "api/video/video_frame.h"
+#include "call/adaptation/resource_adaptation_processor_interface.h"
+#include "call/adaptation/video_source_restrictions.h"
+#include "call/adaptation/video_stream_adapter.h"
+#include "call/adaptation/video_stream_input_state.h"
+#include "call/adaptation/video_stream_input_state_provider.h"
+#include "video/video_stream_encoder_observer.h"
+
+namespace webrtc {
+
+// The Resource Adaptation Processor is responsible for reacting to resource
+// usage measurements (e.g. overusing or underusing CPU). When a resource is
+// overused the Processor is responsible for performing mitigations in order to
+// consume less resources.
+//
+// Today we have one Processor per VideoStreamEncoder and the Processor is only
+// capable of restricting resolution or frame rate of the encoded stream. In the
+// future we should have a single Processor responsible for all encoded streams,
+// and it should be capable of reconfiguring other things than just
+// VideoSourceRestrictions (e.g. reduce render frame rate).
+// See Resource-Adaptation hotlist:
+// https://bugs.chromium.org/u/590058293/hotlists/Resource-Adaptation
+//
+// The ResourceAdaptationProcessor is single-threaded. It may be constructed on
+// any thread but MUST subsequently be used and destroyed on a single sequence,
+// i.e. the "resource adaptation task queue". Resources can be added and removed
+// from any thread.
+class ResourceAdaptationProcessor : public ResourceAdaptationProcessorInterface,
+                                    public VideoSourceRestrictionsListener,
+                                    public ResourceListener {
+ public:
+  explicit ResourceAdaptationProcessor(
+      VideoStreamAdapter* video_stream_adapter);
+  ~ResourceAdaptationProcessor() override;
+
+  // ResourceAdaptationProcessorInterface implementation.
+  void AddResourceLimitationsListener(
+      ResourceLimitationsListener* limitations_listener) override;
+  void RemoveResourceLimitationsListener(
+      ResourceLimitationsListener* limitations_listener) override;
+  void AddResource(rtc::scoped_refptr<Resource> resource) override;
+  std::vector<rtc::scoped_refptr<Resource>> GetResources() const override;
+  void RemoveResource(rtc::scoped_refptr<Resource> resource) override;
+
+  // ResourceListener implementation.
+  // Triggers OnResourceUnderuse() or OnResourceOveruse().
+  void OnResourceUsageStateMeasured(rtc::scoped_refptr<Resource> resource,
+                                    ResourceUsageState usage_state) override;
+
+  // VideoSourceRestrictionsListener implementation.
+  void OnVideoSourceRestrictionsUpdated(
+      VideoSourceRestrictions restrictions,
+      const VideoAdaptationCounters& adaptation_counters,
+      rtc::scoped_refptr<Resource> reason,
+      const VideoSourceRestrictions& unfiltered_restrictions) override;
+
+ private:
+  // If resource usage measurements happens off the adaptation task queue, this
+  // class takes care of posting the measurement for the processor to handle it
+  // on the adaptation task queue.
+  class ResourceListenerDelegate : public rtc::RefCountInterface,
+                                   public ResourceListener {
+   public:
+    explicit ResourceListenerDelegate(ResourceAdaptationProcessor* processor);
+
+    void OnProcessorDestroyed();
+
+    // ResourceListener implementation.
+    void OnResourceUsageStateMeasured(rtc::scoped_refptr<Resource> resource,
+                                      ResourceUsageState usage_state) override;
+
+   private:
+    TaskQueueBase* task_queue_;
+    ResourceAdaptationProcessor* processor_ RTC_GUARDED_BY(task_queue_);
+  };
+
+  enum class MitigationResult {
+    kNotMostLimitedResource,
+    kSharedMostLimitedResource,
+    kRejectedByAdapter,
+    kAdaptationApplied,
+  };
+
+  struct MitigationResultAndLogMessage {
+    MitigationResultAndLogMessage();
+    MitigationResultAndLogMessage(MitigationResult result,
+                                  absl::string_view message);
+    MitigationResult result;
+    std::string message;
+  };
+
+  // Performs the adaptation by getting the next target, applying it and
+  // informing listeners of the new VideoSourceRestriction and adaptation
+  // counters.
+  MitigationResultAndLogMessage OnResourceUnderuse(
+      rtc::scoped_refptr<Resource> reason_resource);
+  MitigationResultAndLogMessage OnResourceOveruse(
+      rtc::scoped_refptr<Resource> reason_resource);
+
+  void UpdateResourceLimitations(rtc::scoped_refptr<Resource> reason_resource,
+                                 const VideoSourceRestrictions& restrictions,
+                                 const VideoAdaptationCounters& counters)
+      RTC_RUN_ON(task_queue_);
+
+  // Searches `adaptation_limits_by_resources_` for each resource with the
+  // highest total adaptation counts. Adaptation up may only occur if the
+  // resource performing the adaptation is the only most limited resource. This
+  // function returns the list of all most limited resources as well as the
+  // corresponding adaptation of that resource.
+  std::pair<std::vector<rtc::scoped_refptr<Resource>>,
+            VideoStreamAdapter::RestrictionsWithCounters>
+  FindMostLimitedResources() const RTC_RUN_ON(task_queue_);
+
+  void RemoveLimitationsImposedByResource(
+      rtc::scoped_refptr<Resource> resource);
+
+  TaskQueueBase* task_queue_;
+  rtc::scoped_refptr<ResourceListenerDelegate> resource_listener_delegate_;
+  // Input and output.
+  mutable Mutex resources_lock_;
+  std::vector<rtc::scoped_refptr<Resource>> resources_
+      RTC_GUARDED_BY(resources_lock_);
+  std::vector<ResourceLimitationsListener*> resource_limitations_listeners_
+      RTC_GUARDED_BY(task_queue_);
+  // Purely used for statistics, does not ensure mapped resources stay alive.
+  std::map<rtc::scoped_refptr<Resource>,
+           VideoStreamAdapter::RestrictionsWithCounters>
+      adaptation_limits_by_resources_ RTC_GUARDED_BY(task_queue_);
+  // Responsible for generating and applying possible adaptations.
+  VideoStreamAdapter* const stream_adapter_ RTC_GUARDED_BY(task_queue_);
+  VideoSourceRestrictions last_reported_source_restrictions_
+      RTC_GUARDED_BY(task_queue_);
+  // Keeps track of previous mitigation results per resource since the last
+  // successful adaptation. Used to avoid RTC_LOG spam.
+  std::map<Resource*, MitigationResult> previous_mitigation_results_
+      RTC_GUARDED_BY(task_queue_);
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_ADAPTATION_RESOURCE_ADAPTATION_PROCESSOR_H_
diff --git a/third_party/libwebrtc/call/adaptation/resource_adaptation_processor_interface.cc b/third_party/libwebrtc/call/adaptation/resource_adaptation_processor_interface.cc
new file mode 100644
index 0000000000..79f099b267
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/resource_adaptation_processor_interface.cc
@@ -0,0 +1,20 @@
+/*
+ *  Copyright 2020 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/adaptation/resource_adaptation_processor_interface.h"
+
+namespace webrtc {
+
+ResourceAdaptationProcessorInterface::~ResourceAdaptationProcessorInterface() =
+    default;
+
+ResourceLimitationsListener::~ResourceLimitationsListener() = default;
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/adaptation/resource_adaptation_processor_interface.h b/third_party/libwebrtc/call/adaptation/resource_adaptation_processor_interface.h
new file mode 100644
index 0000000000..4729488150
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/resource_adaptation_processor_interface.h
@@ -0,0 +1,67 @@
+/*
+ *  Copyright 2020 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_ADAPTATION_RESOURCE_ADAPTATION_PROCESSOR_INTERFACE_H_
+#define CALL_ADAPTATION_RESOURCE_ADAPTATION_PROCESSOR_INTERFACE_H_
+
+#include <map>
+#include <vector>
+
+#include "absl/types/optional.h"
+#include "api/adaptation/resource.h"
+#include "api/rtp_parameters.h"
+#include "api/scoped_refptr.h"
+#include "api/task_queue/task_queue_base.h"
+#include "api/video/video_adaptation_counters.h"
+#include "api/video/video_frame.h"
+#include "call/adaptation/adaptation_constraint.h"
+#include "call/adaptation/encoder_settings.h"
+#include "call/adaptation/video_source_restrictions.h"
+
+namespace webrtc {
+
+class ResourceLimitationsListener {
+ public:
+  virtual ~ResourceLimitationsListener();
+
+  // The limitations on a resource were changed. This does not mean the current
+  // video restrictions have changed.
+  virtual void OnResourceLimitationChanged(
+      rtc::scoped_refptr<Resource> resource,
+      const std::map<rtc::scoped_refptr<Resource>, VideoAdaptationCounters>&
+          resource_limitations) = 0;
+};
+
+// The Resource Adaptation Processor is responsible for reacting to resource
+// usage measurements (e.g. overusing or underusing CPU). When a resource is
+// overused the Processor is responsible for performing mitigations in order to
+// consume less resources.
+class ResourceAdaptationProcessorInterface {
+ public:
+  virtual ~ResourceAdaptationProcessorInterface();
+
+  virtual void AddResourceLimitationsListener(
+      ResourceLimitationsListener* limitations_listener) = 0;
+  virtual void RemoveResourceLimitationsListener(
+      ResourceLimitationsListener* limitations_listener) = 0;
+  // Starts or stops listening to resources, effectively enabling or disabling
+  // processing. May be called from anywhere.
+  // TODO(https://crbug.com/webrtc/11172): Automatically register and unregister
+  // with AddResource() and RemoveResource() instead. When the processor is
+  // multi-stream aware, stream-specific resouces will get added and removed
+  // over time.
+  virtual void AddResource(rtc::scoped_refptr<Resource> resource) = 0;
+  virtual std::vector<rtc::scoped_refptr<Resource>> GetResources() const = 0;
+  virtual void RemoveResource(rtc::scoped_refptr<Resource> resource) = 0;
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_ADAPTATION_RESOURCE_ADAPTATION_PROCESSOR_INTERFACE_H_
diff --git a/third_party/libwebrtc/call/adaptation/resource_adaptation_processor_unittest.cc b/third_party/libwebrtc/call/adaptation/resource_adaptation_processor_unittest.cc
new file mode 100644
index 0000000000..ccccd3fe04
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/resource_adaptation_processor_unittest.cc
@@ -0,0 +1,740 @@
+/*
+ *  Copyright (c) 2020 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/adaptation/resource_adaptation_processor.h"
+
+#include "api/adaptation/resource.h"
+#include "api/scoped_refptr.h"
+#include "api/video/video_adaptation_counters.h"
+#include "call/adaptation/resource_adaptation_processor_interface.h"
+#include "call/adaptation/test/fake_frame_rate_provider.h"
+#include "call/adaptation/test/fake_resource.h"
+#include "call/adaptation/video_source_restrictions.h"
+#include "call/adaptation/video_stream_input_state_provider.h"
+#include "rtc_base/event.h"
+#include "rtc_base/gunit.h"
+#include "rtc_base/synchronization/mutex.h"
+#include "rtc_base/task_queue_for_test.h"
+#include "test/gtest.h"
+#include "test/scoped_key_value_config.h"
+
+namespace webrtc {
+
+namespace {
+
+const int kDefaultFrameRate = 30;
+const int kDefaultFrameSize = 1280 * 720;
+constexpr TimeDelta kDefaultTimeout = TimeDelta::Seconds(5);
+
+class VideoSourceRestrictionsListenerForTesting
+    : public VideoSourceRestrictionsListener {
+ public:
+  VideoSourceRestrictionsListenerForTesting()
+      : restrictions_updated_count_(0),
+        restrictions_(),
+        adaptation_counters_(),
+        reason_(nullptr) {}
+  ~VideoSourceRestrictionsListenerForTesting() override {}
+
+  size_t restrictions_updated_count() const {
+    RTC_DCHECK_RUN_ON(&sequence_checker_);
+    return restrictions_updated_count_;
+  }
+  VideoSourceRestrictions restrictions() const {
+    RTC_DCHECK_RUN_ON(&sequence_checker_);
+    return restrictions_;
+  }
+  VideoAdaptationCounters adaptation_counters() const {
+    RTC_DCHECK_RUN_ON(&sequence_checker_);
+    return adaptation_counters_;
+  }
+  rtc::scoped_refptr<Resource> reason() const {
+    RTC_DCHECK_RUN_ON(&sequence_checker_);
+    return reason_;
+  }
+
+  // VideoSourceRestrictionsListener implementation.
+  void OnVideoSourceRestrictionsUpdated(
+      VideoSourceRestrictions restrictions,
+      const VideoAdaptationCounters& adaptation_counters,
+      rtc::scoped_refptr<Resource> reason,
+      const VideoSourceRestrictions& unfiltered_restrictions) override {
+    RTC_DCHECK_RUN_ON(&sequence_checker_);
+    ++restrictions_updated_count_;
+    restrictions_ = restrictions;
+    adaptation_counters_ = adaptation_counters;
+    reason_ = reason;
+  }
+
+ private:
+  SequenceChecker sequence_checker_;
+  size_t restrictions_updated_count_ RTC_GUARDED_BY(&sequence_checker_);
+  VideoSourceRestrictions restrictions_ RTC_GUARDED_BY(&sequence_checker_);
+  VideoAdaptationCounters adaptation_counters_
+      RTC_GUARDED_BY(&sequence_checker_);
+  rtc::scoped_refptr<Resource> reason_ RTC_GUARDED_BY(&sequence_checker_);
+};
+
+class ResourceAdaptationProcessorTest : public ::testing::Test {
+ public:
+  ResourceAdaptationProcessorTest()
+      : frame_rate_provider_(),
+        input_state_provider_(&frame_rate_provider_),
+        resource_(FakeResource::Create("FakeResource")),
+        other_resource_(FakeResource::Create("OtherFakeResource")),
+        video_stream_adapter_(
+            std::make_unique<VideoStreamAdapter>(&input_state_provider_,
+                                                 &frame_rate_provider_,
+                                                 field_trials_)),
+        processor_(std::make_unique<ResourceAdaptationProcessor>(
+            video_stream_adapter_.get())) {
+    video_stream_adapter_->AddRestrictionsListener(&restrictions_listener_);
+    processor_->AddResource(resource_);
+    processor_->AddResource(other_resource_);
+  }
+  ~ResourceAdaptationProcessorTest() override {
+    if (processor_) {
+      DestroyProcessor();
+    }
+  }
+
+  void SetInputStates(bool has_input, int fps, int frame_size) {
+    input_state_provider_.OnHasInputChanged(has_input);
+    frame_rate_provider_.set_fps(fps);
+    input_state_provider_.OnFrameSizeObserved(frame_size);
+  }
+
+  void RestrictSource(VideoSourceRestrictions restrictions) {
+    SetInputStates(
+        true, restrictions.max_frame_rate().value_or(kDefaultFrameRate),
+        restrictions.target_pixels_per_frame().has_value()
+            ? restrictions.target_pixels_per_frame().value()
+            : restrictions.max_pixels_per_frame().value_or(kDefaultFrameSize));
+  }
+
+  void DestroyProcessor() {
+    if (resource_) {
+      processor_->RemoveResource(resource_);
+    }
+    if (other_resource_) {
+      processor_->RemoveResource(other_resource_);
+    }
+    video_stream_adapter_->RemoveRestrictionsListener(&restrictions_listener_);
+    processor_.reset();
+  }
+
+  static void WaitUntilTaskQueueIdle() {
+    ASSERT_TRUE(rtc::Thread::Current()->ProcessMessages(0));
+  }
+
+ protected:
+  rtc::AutoThread main_thread_;
+  webrtc::test::ScopedKeyValueConfig field_trials_;
+  FakeFrameRateProvider frame_rate_provider_;
+  VideoStreamInputStateProvider input_state_provider_;
+  rtc::scoped_refptr<FakeResource> resource_;
+  rtc::scoped_refptr<FakeResource> other_resource_;
+  std::unique_ptr<VideoStreamAdapter> video_stream_adapter_;
+  std::unique_ptr<ResourceAdaptationProcessor> processor_;
+  VideoSourceRestrictionsListenerForTesting restrictions_listener_;
+};
+
+}  // namespace
+
+TEST_F(ResourceAdaptationProcessorTest, DisabledByDefault) {
+  SetInputStates(true, kDefaultFrameRate, kDefaultFrameSize);
+  // Adaptation does not happen when disabled.
+  resource_->SetUsageState(ResourceUsageState::kOveruse);
+  EXPECT_EQ(0u, restrictions_listener_.restrictions_updated_count());
+}
+
+TEST_F(ResourceAdaptationProcessorTest, InsufficientInput) {
+  video_stream_adapter_->SetDegradationPreference(
+      DegradationPreference::MAINTAIN_FRAMERATE);
+  // Adaptation does not happen if input is insufficient.
+  // When frame size is missing (OnFrameSizeObserved not called yet).
+  input_state_provider_.OnHasInputChanged(true);
+  resource_->SetUsageState(ResourceUsageState::kOveruse);
+  EXPECT_EQ(0u, restrictions_listener_.restrictions_updated_count());
+  // When "has input" is missing.
+  SetInputStates(false, kDefaultFrameRate, kDefaultFrameSize);
+  resource_->SetUsageState(ResourceUsageState::kOveruse);
+  EXPECT_EQ(0u, restrictions_listener_.restrictions_updated_count());
+  // Note: frame rate cannot be missing, if unset it is 0.
+}
+
+// These tests verify that restrictions are applied, but not exactly how much
+// the source is restricted. This ensures that the VideoStreamAdapter is wired
+// up correctly but not exactly how the VideoStreamAdapter generates
+// restrictions. For that, see video_stream_adapter_unittest.cc.
+TEST_F(ResourceAdaptationProcessorTest,
+       OveruseTriggersRestrictingResolutionInMaintainFrameRate) {
+  video_stream_adapter_->SetDegradationPreference(
+      DegradationPreference::MAINTAIN_FRAMERATE);
+  SetInputStates(true, kDefaultFrameRate, kDefaultFrameSize);
+  resource_->SetUsageState(ResourceUsageState::kOveruse);
+  EXPECT_EQ(1u, restrictions_listener_.restrictions_updated_count());
+  EXPECT_TRUE(
+      restrictions_listener_.restrictions().max_pixels_per_frame().has_value());
+}
+
+TEST_F(ResourceAdaptationProcessorTest,
+       OveruseTriggersRestrictingFrameRateInMaintainResolution) {
+  video_stream_adapter_->SetDegradationPreference(
+      DegradationPreference::MAINTAIN_RESOLUTION);
+  SetInputStates(true, kDefaultFrameRate, kDefaultFrameSize);
+  resource_->SetUsageState(ResourceUsageState::kOveruse);
+  EXPECT_EQ(1u, restrictions_listener_.restrictions_updated_count());
+  EXPECT_TRUE(
+      restrictions_listener_.restrictions().max_frame_rate().has_value());
+}
+
+TEST_F(ResourceAdaptationProcessorTest,
+       OveruseTriggersRestrictingFrameRateAndResolutionInBalanced) {
+  video_stream_adapter_->SetDegradationPreference(
+      DegradationPreference::BALANCED);
+  SetInputStates(true, kDefaultFrameRate, kDefaultFrameSize);
+  // Adapting multiple times eventually resticts both frame rate and
+  // resolution. Exactly many times we need to adapt depends on
+  // BalancedDegradationSettings, VideoStreamAdapter and default input
+  // states. This test requires it to be achieved within 4 adaptations.
+  for (size_t i = 0; i < 4; ++i) {
+    resource_->SetUsageState(ResourceUsageState::kOveruse);
+    EXPECT_EQ(i + 1, restrictions_listener_.restrictions_updated_count());
+    RestrictSource(restrictions_listener_.restrictions());
+  }
+  EXPECT_TRUE(
+      restrictions_listener_.restrictions().max_pixels_per_frame().has_value());
+  EXPECT_TRUE(
+      restrictions_listener_.restrictions().max_frame_rate().has_value());
+}
+
+TEST_F(ResourceAdaptationProcessorTest, AwaitingPreviousAdaptation) {
+  video_stream_adapter_->SetDegradationPreference(
+      DegradationPreference::MAINTAIN_FRAMERATE);
+  SetInputStates(true, kDefaultFrameRate, kDefaultFrameSize);
+  resource_->SetUsageState(ResourceUsageState::kOveruse);
+  EXPECT_EQ(1u, restrictions_listener_.restrictions_updated_count());
+  // If we don't restrict the source then adaptation will not happen again
+  // due to "awaiting previous adaptation". This prevents "double-adapt".
+  resource_->SetUsageState(ResourceUsageState::kOveruse);
+  EXPECT_EQ(1u, restrictions_listener_.restrictions_updated_count());
+}
+
+TEST_F(ResourceAdaptationProcessorTest, CannotAdaptUpWhenUnrestricted) {
+  video_stream_adapter_->SetDegradationPreference(
+      DegradationPreference::MAINTAIN_FRAMERATE);
+  SetInputStates(true, kDefaultFrameRate, kDefaultFrameSize);
+  resource_->SetUsageState(ResourceUsageState::kUnderuse);
+  EXPECT_EQ(0u, restrictions_listener_.restrictions_updated_count());
+}
+
+TEST_F(ResourceAdaptationProcessorTest, UnderuseTakesUsBackToUnrestricted) {
+  video_stream_adapter_->SetDegradationPreference(
+      DegradationPreference::MAINTAIN_FRAMERATE);
+  SetInputStates(true, kDefaultFrameRate, kDefaultFrameSize);
+  resource_->SetUsageState(ResourceUsageState::kOveruse);
+  EXPECT_EQ(1u, restrictions_listener_.restrictions_updated_count());
+  RestrictSource(restrictions_listener_.restrictions());
+  resource_->SetUsageState(ResourceUsageState::kUnderuse);
+  EXPECT_EQ(2u, restrictions_listener_.restrictions_updated_count());
+  EXPECT_EQ(VideoSourceRestrictions(), restrictions_listener_.restrictions());
+}
+
+TEST_F(ResourceAdaptationProcessorTest,
+       ResourcesCanNotAdaptUpIfNeverAdaptedDown) {
+  video_stream_adapter_->SetDegradationPreference(
+      DegradationPreference::MAINTAIN_FRAMERATE);
+  SetInputStates(true, kDefaultFrameRate, kDefaultFrameSize);
+  resource_->SetUsageState(ResourceUsageState::kOveruse);
+  EXPECT_EQ(1u, restrictions_listener_.restrictions_updated_count());
+  RestrictSource(restrictions_listener_.restrictions());
+
+  // Other resource signals under-use
+  other_resource_->SetUsageState(ResourceUsageState::kUnderuse);
+  EXPECT_EQ(1u, restrictions_listener_.restrictions_updated_count());
+}
+
+TEST_F(ResourceAdaptationProcessorTest,
+       ResourcesCanNotAdaptUpIfNotAdaptedDownAfterReset) {
+  video_stream_adapter_->SetDegradationPreference(
+      DegradationPreference::MAINTAIN_FRAMERATE);
+  SetInputStates(true, kDefaultFrameRate, kDefaultFrameSize);
+  resource_->SetUsageState(ResourceUsageState::kOveruse);
+  EXPECT_EQ(1u, restrictions_listener_.restrictions_updated_count());
+
+  video_stream_adapter_->ClearRestrictions();
+  EXPECT_EQ(0, restrictions_listener_.adaptation_counters().Total());
+  other_resource_->SetUsageState(ResourceUsageState::kOveruse);
+  EXPECT_EQ(1, restrictions_listener_.adaptation_counters().Total());
+  RestrictSource(restrictions_listener_.restrictions());
+
+  // resource_ did not overuse after we reset the restrictions, so adapt
+  // up should be disallowed.
+  resource_->SetUsageState(ResourceUsageState::kUnderuse);
+  EXPECT_EQ(1, restrictions_listener_.adaptation_counters().Total());
+}
+
+TEST_F(ResourceAdaptationProcessorTest, OnlyMostLimitedResourceMayAdaptUp) {
+  video_stream_adapter_->SetDegradationPreference(
+      DegradationPreference::MAINTAIN_FRAMERATE);
+  SetInputStates(true, kDefaultFrameRate, kDefaultFrameSize);
+  resource_->SetUsageState(ResourceUsageState::kOveruse);
+  EXPECT_EQ(1, restrictions_listener_.adaptation_counters().Total());
+  RestrictSource(restrictions_listener_.restrictions());
+  other_resource_->SetUsageState(ResourceUsageState::kOveruse);
+  EXPECT_EQ(2, restrictions_listener_.adaptation_counters().Total());
+  RestrictSource(restrictions_listener_.restrictions());
+
+  // `other_resource_` is most limited, resource_ can't adapt up.
+  resource_->SetUsageState(ResourceUsageState::kUnderuse);
+  EXPECT_EQ(2, restrictions_listener_.adaptation_counters().Total());
+  RestrictSource(restrictions_listener_.restrictions());
+  other_resource_->SetUsageState(ResourceUsageState::kUnderuse);
+  EXPECT_EQ(1, restrictions_listener_.adaptation_counters().Total());
+  RestrictSource(restrictions_listener_.restrictions());
+
+  // `resource_` and `other_resource_` are now most limited, so both must
+  // signal underuse to adapt up.
+  other_resource_->SetUsageState(ResourceUsageState::kUnderuse);
+  EXPECT_EQ(1, restrictions_listener_.adaptation_counters().Total());
+  RestrictSource(restrictions_listener_.restrictions());
+  resource_->SetUsageState(ResourceUsageState::kUnderuse);
+  EXPECT_EQ(0, restrictions_listener_.adaptation_counters().Total());
+  RestrictSource(restrictions_listener_.restrictions());
+}
+
+TEST_F(ResourceAdaptationProcessorTest,
+       MultipleResourcesCanTriggerMultipleAdaptations) {
+  video_stream_adapter_->SetDegradationPreference(
+      DegradationPreference::MAINTAIN_FRAMERATE);
+  SetInputStates(true, kDefaultFrameRate, kDefaultFrameSize);
+  resource_->SetUsageState(ResourceUsageState::kOveruse);
+  EXPECT_EQ(1, restrictions_listener_.adaptation_counters().Total());
+  RestrictSource(restrictions_listener_.restrictions());
+  other_resource_->SetUsageState(ResourceUsageState::kOveruse);
+  EXPECT_EQ(2, restrictions_listener_.adaptation_counters().Total());
+  RestrictSource(restrictions_listener_.restrictions());
+  other_resource_->SetUsageState(ResourceUsageState::kOveruse);
+  EXPECT_EQ(3, restrictions_listener_.adaptation_counters().Total());
+  RestrictSource(restrictions_listener_.restrictions());
+
+  // resource_ is not most limited so can't adapt from underuse.
+  resource_->SetUsageState(ResourceUsageState::kUnderuse);
+  EXPECT_EQ(3, restrictions_listener_.adaptation_counters().Total());
+  RestrictSource(restrictions_listener_.restrictions());
+  other_resource_->SetUsageState(ResourceUsageState::kUnderuse);
+  EXPECT_EQ(2, restrictions_listener_.adaptation_counters().Total());
+  RestrictSource(restrictions_listener_.restrictions());
+  // resource_ is still not most limited so can't adapt from underuse.
+  resource_->SetUsageState(ResourceUsageState::kUnderuse);
+  EXPECT_EQ(2, restrictions_listener_.adaptation_counters().Total());
+  RestrictSource(restrictions_listener_.restrictions());
+
+  // However it will be after overuse
+  resource_->SetUsageState(ResourceUsageState::kOveruse);
+  EXPECT_EQ(3, restrictions_listener_.adaptation_counters().Total());
+  RestrictSource(restrictions_listener_.restrictions());
+
+  // Now other_resource_ can't adapt up as it is not most restricted.
+  other_resource_->SetUsageState(ResourceUsageState::kUnderuse);
+  EXPECT_EQ(3, restrictions_listener_.adaptation_counters().Total());
+  RestrictSource(restrictions_listener_.restrictions());
+
+  // resource_ is limited at 3 adaptations and other_resource_ 2.
+  // With the most limited resource signalling underuse in the following
+  // order we get back to unrestricted video.
+  resource_->SetUsageState(ResourceUsageState::kUnderuse);
+  EXPECT_EQ(2, restrictions_listener_.adaptation_counters().Total());
+  RestrictSource(restrictions_listener_.restrictions());
+  // Both resource_ and other_resource_ are most limited.
+  other_resource_->SetUsageState(ResourceUsageState::kUnderuse);
+  EXPECT_EQ(2, restrictions_listener_.adaptation_counters().Total());
+  RestrictSource(restrictions_listener_.restrictions());
+  resource_->SetUsageState(ResourceUsageState::kUnderuse);
+  EXPECT_EQ(1, restrictions_listener_.adaptation_counters().Total());
+  RestrictSource(restrictions_listener_.restrictions());
+  // Again both are most limited.
+  resource_->SetUsageState(ResourceUsageState::kUnderuse);
+  EXPECT_EQ(1, restrictions_listener_.adaptation_counters().Total());
+  RestrictSource(restrictions_listener_.restrictions());
+  other_resource_->SetUsageState(ResourceUsageState::kUnderuse);
+  EXPECT_EQ(0, restrictions_listener_.adaptation_counters().Total());
+}
+
+TEST_F(ResourceAdaptationProcessorTest,
+       MostLimitedResourceAdaptationWorksAfterChangingDegradataionPreference) {
+  video_stream_adapter_->SetDegradationPreference(
+      DegradationPreference::MAINTAIN_FRAMERATE);
+  SetInputStates(true, kDefaultFrameRate, kDefaultFrameSize);
+  // Adapt down until we can't anymore.
+  resource_->SetUsageState(ResourceUsageState::kOveruse);
+  RestrictSource(restrictions_listener_.restrictions());
+  resource_->SetUsageState(ResourceUsageState::kOveruse);
+  RestrictSource(restrictions_listener_.restrictions());
+  resource_->SetUsageState(ResourceUsageState::kOveruse);
+  RestrictSource(restrictions_listener_.restrictions());
+  resource_->SetUsageState(ResourceUsageState::kOveruse);
+  RestrictSource(restrictions_listener_.restrictions());
+  resource_->SetUsageState(ResourceUsageState::kOveruse);
+  RestrictSource(restrictions_listener_.restrictions());
+  int last_total = restrictions_listener_.adaptation_counters().Total();
+
+  video_stream_adapter_->SetDegradationPreference(
+      DegradationPreference::MAINTAIN_RESOLUTION);
+  // resource_ can not adapt up since we have never reduced FPS.
+  resource_->SetUsageState(ResourceUsageState::kUnderuse);
+  EXPECT_EQ(last_total, restrictions_listener_.adaptation_counters().Total());
+
+  other_resource_->SetUsageState(ResourceUsageState::kOveruse);
+  EXPECT_EQ(last_total + 1,
+            restrictions_listener_.adaptation_counters().Total());
+  RestrictSource(restrictions_listener_.restrictions());
+  // other_resource_ is most limited so should be able to adapt up.
+  other_resource_->SetUsageState(ResourceUsageState::kUnderuse);
+  EXPECT_EQ(last_total, restrictions_listener_.adaptation_counters().Total());
+}
+
+TEST_F(ResourceAdaptationProcessorTest,
+       AdaptsDownWhenOtherResourceIsAlwaysUnderused) {
+  video_stream_adapter_->SetDegradationPreference(
+      DegradationPreference::MAINTAIN_FRAMERATE);
+  SetInputStates(true, kDefaultFrameRate, kDefaultFrameSize);
+  other_resource_->SetUsageState(ResourceUsageState::kUnderuse);
+  // Does not trigger adapataion because there's no restriction.
+  EXPECT_EQ(0, restrictions_listener_.adaptation_counters().Total());
+
+  RestrictSource(restrictions_listener_.restrictions());
+  resource_->SetUsageState(ResourceUsageState::kOveruse);
+  // Adapts down even if other resource asked for adapting up.
+  EXPECT_EQ(1, restrictions_listener_.adaptation_counters().Total());
+
+  RestrictSource(restrictions_listener_.restrictions());
+  other_resource_->SetUsageState(ResourceUsageState::kUnderuse);
+  // Doesn't adapt up because adaptation is due to another resource.
+  EXPECT_EQ(1, restrictions_listener_.adaptation_counters().Total());
+  RestrictSource(restrictions_listener_.restrictions());
+}
+
+TEST_F(ResourceAdaptationProcessorTest,
+       TriggerOveruseNotOnAdaptationTaskQueue) {
+  video_stream_adapter_->SetDegradationPreference(
+      DegradationPreference::MAINTAIN_FRAMERATE);
+  SetInputStates(true, kDefaultFrameRate, kDefaultFrameSize);
+
+  TaskQueueForTest resource_task_queue("ResourceTaskQueue");
+  resource_task_queue.PostTask(
+      [&]() { resource_->SetUsageState(ResourceUsageState::kOveruse); });
+
+  EXPECT_EQ_WAIT(1u, restrictions_listener_.restrictions_updated_count(),
+                 kDefaultTimeout.ms());
+}
+
+TEST_F(ResourceAdaptationProcessorTest,
+       DestroyProcessorWhileResourceListenerDelegateHasTaskInFlight) {
+  video_stream_adapter_->SetDegradationPreference(
+      DegradationPreference::MAINTAIN_FRAMERATE);
+  SetInputStates(true, kDefaultFrameRate, kDefaultFrameSize);
+
+  // Wait for `resource_` to signal oversue first so we know that the delegate
+  // has passed it on to the processor's task queue.
+  rtc::Event resource_event;
+  TaskQueueForTest resource_task_queue("ResourceTaskQueue");
+  resource_task_queue.PostTask([&]() {
+    resource_->SetUsageState(ResourceUsageState::kOveruse);
+    resource_event.Set();
+  });
+
+  EXPECT_TRUE(resource_event.Wait(kDefaultTimeout));
+  // Now destroy the processor while handling the overuse is in flight.
+  DestroyProcessor();
+
+  // Because the processor was destroyed by the time the delegate's task ran,
+  // the overuse signal must not have been handled.
+  EXPECT_EQ(0u, restrictions_listener_.restrictions_updated_count());
+}
+
+TEST_F(ResourceAdaptationProcessorTest,
+       ResourceOveruseIgnoredWhenSignalledDuringRemoval) {
+  video_stream_adapter_->SetDegradationPreference(
+      DegradationPreference::MAINTAIN_FRAMERATE);
+  SetInputStates(true, kDefaultFrameRate, kDefaultFrameSize);
+
+  rtc::Event overuse_event;
+  TaskQueueForTest resource_task_queue("ResourceTaskQueue");
+  // Queues task for `resource_` overuse while `processor_` is still listening.
+  resource_task_queue.PostTask([&]() {
+    resource_->SetUsageState(ResourceUsageState::kOveruse);
+    overuse_event.Set();
+  });
+  EXPECT_TRUE(overuse_event.Wait(kDefaultTimeout));
+  // Once we know the overuse task is queued, remove `resource_` so that
+  // `processor_` is not listening to it.
+  processor_->RemoveResource(resource_);
+
+  // Runs the queued task so `processor_` gets signalled kOveruse from
+  // `resource_` even though `processor_` was not listening.
+  WaitUntilTaskQueueIdle();
+
+  // No restrictions should change even though `resource_` signaled `kOveruse`.
+  EXPECT_EQ(0u, restrictions_listener_.restrictions_updated_count());
+
+  // Delete `resource_` for cleanup.
+  resource_ = nullptr;
+}
+
+TEST_F(ResourceAdaptationProcessorTest,
+       RemovingOnlyAdaptedResourceResetsAdaptation) {
+  video_stream_adapter_->SetDegradationPreference(
+      DegradationPreference::MAINTAIN_FRAMERATE);
+  SetInputStates(true, kDefaultFrameRate, kDefaultFrameSize);
+
+  resource_->SetUsageState(ResourceUsageState::kOveruse);
+  EXPECT_EQ(1, restrictions_listener_.adaptation_counters().Total());
+  RestrictSource(restrictions_listener_.restrictions());
+
+  processor_->RemoveResource(resource_);
+  EXPECT_EQ(0, restrictions_listener_.adaptation_counters().Total());
+
+  // Delete `resource_` for cleanup.
+  resource_ = nullptr;
+}
+
+TEST_F(ResourceAdaptationProcessorTest,
+       RemovingMostLimitedResourceSetsAdaptationToNextLimitedLevel) {
+  video_stream_adapter_->SetDegradationPreference(
+      DegradationPreference::BALANCED);
+  SetInputStates(true, kDefaultFrameRate, kDefaultFrameSize);
+
+  other_resource_->SetUsageState(ResourceUsageState::kOveruse);
+  RestrictSource(restrictions_listener_.restrictions());
+  EXPECT_EQ(1, restrictions_listener_.adaptation_counters().Total());
+  VideoSourceRestrictions next_limited_restrictions =
+      restrictions_listener_.restrictions();
+  VideoAdaptationCounters next_limited_counters =
+      restrictions_listener_.adaptation_counters();
+
+  resource_->SetUsageState(ResourceUsageState::kOveruse);
+  RestrictSource(restrictions_listener_.restrictions());
+  EXPECT_EQ(2, restrictions_listener_.adaptation_counters().Total());
+
+  // Removing most limited `resource_` should revert us back to
+  processor_->RemoveResource(resource_);
+  EXPECT_EQ(1, restrictions_listener_.adaptation_counters().Total());
+  EXPECT_EQ(next_limited_restrictions, restrictions_listener_.restrictions());
+  EXPECT_EQ(next_limited_counters,
+            restrictions_listener_.adaptation_counters());
+
+  // Delete `resource_` for cleanup.
+  resource_ = nullptr;
+}
+
+TEST_F(ResourceAdaptationProcessorTest,
+       RemovingMostLimitedResourceSetsAdaptationIfInputStateUnchanged) {
+  video_stream_adapter_->SetDegradationPreference(
+      DegradationPreference::MAINTAIN_FRAMERATE);
+  SetInputStates(true, kDefaultFrameRate, kDefaultFrameSize);
+
+  other_resource_->SetUsageState(ResourceUsageState::kOveruse);
+  RestrictSource(restrictions_listener_.restrictions());
+  EXPECT_EQ(1, restrictions_listener_.adaptation_counters().Total());
+  VideoSourceRestrictions next_limited_restrictions =
+      restrictions_listener_.restrictions();
+  VideoAdaptationCounters next_limited_counters =
+      restrictions_listener_.adaptation_counters();
+
+  // Overuse twice and underuse once. After the underuse we don't restrict the
+  // source. Normally this would block future underuses.
+  resource_->SetUsageState(ResourceUsageState::kOveruse);
+  RestrictSource(restrictions_listener_.restrictions());
+  resource_->SetUsageState(ResourceUsageState::kOveruse);
+  RestrictSource(restrictions_listener_.restrictions());
+  resource_->SetUsageState(ResourceUsageState::kUnderuse);
+  EXPECT_EQ(2, restrictions_listener_.adaptation_counters().Total());
+
+  // Removing most limited `resource_` should revert us back to, even though we
+  // did not call RestrictSource() after `resource_` was overused. Normally
+  // adaptation for MAINTAIN_FRAMERATE would be blocked here but for removal we
+  // allow this anyways.
+  processor_->RemoveResource(resource_);
+  EXPECT_EQ(1, restrictions_listener_.adaptation_counters().Total());
+  EXPECT_EQ(next_limited_restrictions, restrictions_listener_.restrictions());
+  EXPECT_EQ(next_limited_counters,
+            restrictions_listener_.adaptation_counters());
+
+  // Delete `resource_` for cleanup.
+  resource_ = nullptr;
+}
+
+TEST_F(ResourceAdaptationProcessorTest,
+       RemovingResourceNotMostLimitedHasNoEffectOnLimitations) {
+  video_stream_adapter_->SetDegradationPreference(
+      DegradationPreference::BALANCED);
+  SetInputStates(true, kDefaultFrameRate, kDefaultFrameSize);
+
+  other_resource_->SetUsageState(ResourceUsageState::kOveruse);
+  RestrictSource(restrictions_listener_.restrictions());
+  EXPECT_EQ(1, restrictions_listener_.adaptation_counters().Total());
+
+  resource_->SetUsageState(ResourceUsageState::kOveruse);
+  RestrictSource(restrictions_listener_.restrictions());
+  VideoSourceRestrictions current_restrictions =
+      restrictions_listener_.restrictions();
+  VideoAdaptationCounters current_counters =
+      restrictions_listener_.adaptation_counters();
+  EXPECT_EQ(2, restrictions_listener_.adaptation_counters().Total());
+
+  // Removing most limited `resource_` should revert us back to
+  processor_->RemoveResource(other_resource_);
+  EXPECT_EQ(current_restrictions, restrictions_listener_.restrictions());
+  EXPECT_EQ(current_counters, restrictions_listener_.adaptation_counters());
+
+  // Delete `other_resource_` for cleanup.
+  other_resource_ = nullptr;
+}
+
+TEST_F(ResourceAdaptationProcessorTest,
+       RemovingMostLimitedResourceAfterSwitchingDegradationPreferences) {
+  video_stream_adapter_->SetDegradationPreference(
+      DegradationPreference::MAINTAIN_FRAMERATE);
+  SetInputStates(true, kDefaultFrameRate, kDefaultFrameSize);
+
+  other_resource_->SetUsageState(ResourceUsageState::kOveruse);
+  RestrictSource(restrictions_listener_.restrictions());
+  EXPECT_EQ(1, restrictions_listener_.adaptation_counters().Total());
+  VideoSourceRestrictions next_limited_restrictions =
+      restrictions_listener_.restrictions();
+  VideoAdaptationCounters next_limited_counters =
+      restrictions_listener_.adaptation_counters();
+
+  video_stream_adapter_->SetDegradationPreference(
+      DegradationPreference::MAINTAIN_RESOLUTION);
+  resource_->SetUsageState(ResourceUsageState::kOveruse);
+  RestrictSource(restrictions_listener_.restrictions());
+  EXPECT_EQ(2, restrictions_listener_.adaptation_counters().Total());
+
+  // Revert to `other_resource_` when removing `resource_` even though the
+  // degradation preference was different when it was overused.
+  processor_->RemoveResource(resource_);
+  EXPECT_EQ(next_limited_counters,
+            restrictions_listener_.adaptation_counters());
+
+  // After switching back to MAINTAIN_FRAMERATE, the next most limited settings
+  // are restored.
+  video_stream_adapter_->SetDegradationPreference(
+      DegradationPreference::MAINTAIN_FRAMERATE);
+  EXPECT_EQ(next_limited_restrictions, restrictions_listener_.restrictions());
+
+  // Delete `resource_` for cleanup.
+  resource_ = nullptr;
+}
+
+TEST_F(ResourceAdaptationProcessorTest,
+       RemovingMostLimitedResourceSetsNextLimitationsInDisabled) {
+  video_stream_adapter_->SetDegradationPreference(
+      DegradationPreference::MAINTAIN_FRAMERATE);
+  SetInputStates(true, kDefaultFrameRate, kDefaultFrameSize);
+
+  other_resource_->SetUsageState(ResourceUsageState::kOveruse);
+  RestrictSource(restrictions_listener_.restrictions());
+  VideoSourceRestrictions next_limited_restrictions =
+      restrictions_listener_.restrictions();
+  VideoAdaptationCounters next_limited_counters =
+      restrictions_listener_.adaptation_counters();
+  EXPECT_EQ(1, restrictions_listener_.adaptation_counters().Total());
+  resource_->SetUsageState(ResourceUsageState::kOveruse);
+  RestrictSource(restrictions_listener_.restrictions());
+  EXPECT_EQ(2, restrictions_listener_.adaptation_counters().Total());
+
+  video_stream_adapter_->SetDegradationPreference(
+      DegradationPreference::DISABLED);
+
+  // Revert to `other_resource_` when removing `resource_` even though the
+  // current degradataion preference is disabled.
+  processor_->RemoveResource(resource_);
+
+  // After switching back to MAINTAIN_FRAMERATE, the next most limited settings
+  // are restored.
+  video_stream_adapter_->SetDegradationPreference(
+      DegradationPreference::MAINTAIN_FRAMERATE);
+  EXPECT_EQ(next_limited_restrictions, restrictions_listener_.restrictions());
+  EXPECT_EQ(next_limited_counters,
+            restrictions_listener_.adaptation_counters());
+
+  // Delete `resource_` for cleanup.
+  resource_ = nullptr;
+}
+
+TEST_F(ResourceAdaptationProcessorTest,
+       RemovedResourceSignalsIgnoredByProcessor) {
+  video_stream_adapter_->SetDegradationPreference(
+      DegradationPreference::MAINTAIN_FRAMERATE);
+  SetInputStates(true, kDefaultFrameRate, kDefaultFrameSize);
+
+  processor_->RemoveResource(resource_);
+  resource_->SetUsageState(ResourceUsageState::kOveruse);
+  EXPECT_EQ(0u, restrictions_listener_.restrictions_updated_count());
+
+  // Delete `resource_` for cleanup.
+  resource_ = nullptr;
+}
+
+TEST_F(ResourceAdaptationProcessorTest,
+       RemovingResourceWhenMultipleMostLimtedHasNoEffect) {
+  video_stream_adapter_->SetDegradationPreference(
+      DegradationPreference::MAINTAIN_FRAMERATE);
+  SetInputStates(true, kDefaultFrameRate, kDefaultFrameSize);
+
+  other_resource_->SetUsageState(ResourceUsageState::kOveruse);
+  RestrictSource(restrictions_listener_.restrictions());
+  EXPECT_EQ(1, restrictions_listener_.adaptation_counters().Total());
+  // Adapt `resource_` up and then down so that both resource's are most
+  // limited at 1 adaptation.
+  resource_->SetUsageState(ResourceUsageState::kOveruse);
+  RestrictSource(restrictions_listener_.restrictions());
+  resource_->SetUsageState(ResourceUsageState::kUnderuse);
+  RestrictSource(restrictions_listener_.restrictions());
+  EXPECT_EQ(1, restrictions_listener_.adaptation_counters().Total());
+
+  // Removing `resource_` has no effect since both `resource_` and
+  // `other_resource_` are most limited.
+  processor_->RemoveResource(resource_);
+  EXPECT_EQ(1, restrictions_listener_.adaptation_counters().Total());
+
+  // Delete `resource_` for cleanup.
+  resource_ = nullptr;
+}
+
+TEST_F(ResourceAdaptationProcessorTest,
+       ResourceOverusedAtLimitReachedWillShareMostLimited) {
+  video_stream_adapter_->SetDegradationPreference(
+      DegradationPreference::MAINTAIN_FRAMERATE);
+  SetInputStates(true, kDefaultFrameRate, kDefaultFrameSize);
+
+  bool has_reached_min_pixels = false;
+  ON_CALL(frame_rate_provider_, OnMinPixelLimitReached())
+      .WillByDefault(testing::Assign(&has_reached_min_pixels, true));
+
+  // Adapt 10 times, which should make us hit the limit.
+  for (int i = 0; i < 10; ++i) {
+    resource_->SetUsageState(ResourceUsageState::kOveruse);
+    RestrictSource(restrictions_listener_.restrictions());
+  }
+  EXPECT_TRUE(has_reached_min_pixels);
+  auto last_update_count = restrictions_listener_.restrictions_updated_count();
+  other_resource_->SetUsageState(ResourceUsageState::kOveruse);
+  // Now both `resource_` and `other_resource_` are most limited. Underuse of
+  // `resource_` will not adapt up.
+  resource_->SetUsageState(ResourceUsageState::kUnderuse);
+  EXPECT_EQ(last_update_count,
+            restrictions_listener_.restrictions_updated_count());
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/adaptation/resource_unittest.cc b/third_party/libwebrtc/call/adaptation/resource_unittest.cc
new file mode 100644
index 0000000000..a2291dfdce
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/resource_unittest.cc
@@ -0,0 +1,55 @@
+/*
+ *  Copyright 2020 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "api/adaptation/resource.h"
+
+#include <memory>
+
+#include "api/scoped_refptr.h"
+#include "call/adaptation/test/fake_resource.h"
+#include "call/adaptation/test/mock_resource_listener.h"
+#include "test/gmock.h"
+#include "test/gtest.h"
+
+namespace webrtc {
+
+using ::testing::_;
+using ::testing::StrictMock;
+
+class ResourceTest : public ::testing::Test {
+ public:
+  ResourceTest() : fake_resource_(FakeResource::Create("FakeResource")) {}
+
+ protected:
+  rtc::scoped_refptr<FakeResource> fake_resource_;
+};
+
+TEST_F(ResourceTest, RegisteringListenerReceivesCallbacks) {
+  StrictMock<MockResourceListener> resource_listener;
+  fake_resource_->SetResourceListener(&resource_listener);
+  EXPECT_CALL(resource_listener, OnResourceUsageStateMeasured(_, _))
+      .Times(1)
+      .WillOnce([](rtc::scoped_refptr<Resource> resource,
+                   ResourceUsageState usage_state) {
+        EXPECT_EQ(ResourceUsageState::kOveruse, usage_state);
+      });
+  fake_resource_->SetUsageState(ResourceUsageState::kOveruse);
+  fake_resource_->SetResourceListener(nullptr);
+}
+
+TEST_F(ResourceTest, UnregisteringListenerStopsCallbacks) {
+  StrictMock<MockResourceListener> resource_listener;
+  fake_resource_->SetResourceListener(&resource_listener);
+  fake_resource_->SetResourceListener(nullptr);
+  EXPECT_CALL(resource_listener, OnResourceUsageStateMeasured(_, _)).Times(0);
+  fake_resource_->SetUsageState(ResourceUsageState::kOveruse);
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/adaptation/test/fake_adaptation_constraint.cc b/third_party/libwebrtc/call/adaptation/test/fake_adaptation_constraint.cc
new file mode 100644
index 0000000000..dbb31f0d3b
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/test/fake_adaptation_constraint.cc
@@ -0,0 +1,40 @@
+/*
+ *  Copyright 2020 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/adaptation/test/fake_adaptation_constraint.h"
+
+#include <utility>
+
+#include "absl/strings/string_view.h"
+
+namespace webrtc {
+
+FakeAdaptationConstraint::FakeAdaptationConstraint(absl::string_view name)
+    : name_(name), is_adaptation_up_allowed_(true) {}
+
+FakeAdaptationConstraint::~FakeAdaptationConstraint() = default;
+
+void FakeAdaptationConstraint::set_is_adaptation_up_allowed(
+    bool is_adaptation_up_allowed) {
+  is_adaptation_up_allowed_ = is_adaptation_up_allowed;
+}
+
+std::string FakeAdaptationConstraint::Name() const {
+  return name_;
+}
+
+bool FakeAdaptationConstraint::IsAdaptationUpAllowed(
+    const VideoStreamInputState& input_state,
+    const VideoSourceRestrictions& restrictions_before,
+    const VideoSourceRestrictions& restrictions_after) const {
+  return is_adaptation_up_allowed_;
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/adaptation/test/fake_adaptation_constraint.h b/third_party/libwebrtc/call/adaptation/test/fake_adaptation_constraint.h
new file mode 100644
index 0000000000..5c684335f2
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/test/fake_adaptation_constraint.h
@@ -0,0 +1,42 @@
+/*
+ *  Copyright 2020 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_ADAPTATION_TEST_FAKE_ADAPTATION_CONSTRAINT_H_
+#define CALL_ADAPTATION_TEST_FAKE_ADAPTATION_CONSTRAINT_H_
+
+#include <string>
+
+#include "absl/strings/string_view.h"
+#include "call/adaptation/adaptation_constraint.h"
+
+namespace webrtc {
+
+class FakeAdaptationConstraint : public AdaptationConstraint {
+ public:
+  explicit FakeAdaptationConstraint(absl::string_view name);
+  ~FakeAdaptationConstraint() override;
+
+  void set_is_adaptation_up_allowed(bool is_adaptation_up_allowed);
+
+  // AdaptationConstraint implementation.
+  std::string Name() const override;
+  bool IsAdaptationUpAllowed(
+      const VideoStreamInputState& input_state,
+      const VideoSourceRestrictions& restrictions_before,
+      const VideoSourceRestrictions& restrictions_after) const override;
+
+ private:
+  const std::string name_;
+  bool is_adaptation_up_allowed_;
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_ADAPTATION_TEST_FAKE_ADAPTATION_CONSTRAINT_H_
diff --git a/third_party/libwebrtc/call/adaptation/test/fake_frame_rate_provider.cc b/third_party/libwebrtc/call/adaptation/test/fake_frame_rate_provider.cc
new file mode 100644
index 0000000000..65fee6a7ba
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/test/fake_frame_rate_provider.cc
@@ -0,0 +1,27 @@
+/*
+ *  Copyright (c) 2020 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/adaptation/test/fake_frame_rate_provider.h"
+
+#include "test/gmock.h"
+
+using ::testing::Return;
+
+namespace webrtc {
+
+FakeFrameRateProvider::FakeFrameRateProvider() {
+  set_fps(0);
+}
+
+void FakeFrameRateProvider::set_fps(int fps) {
+  EXPECT_CALL(*this, GetInputFrameRate()).WillRepeatedly(Return(fps));
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/adaptation/test/fake_frame_rate_provider.h b/third_party/libwebrtc/call/adaptation/test/fake_frame_rate_provider.h
new file mode 100644
index 0000000000..b8815f592a
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/test/fake_frame_rate_provider.h
@@ -0,0 +1,69 @@
+/*
+ *  Copyright (c) 2020 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_ADAPTATION_TEST_FAKE_FRAME_RATE_PROVIDER_H_
+#define CALL_ADAPTATION_TEST_FAKE_FRAME_RATE_PROVIDER_H_
+
+#include <string>
+#include <vector>
+
+#include "test/gmock.h"
+#include "video/video_stream_encoder_observer.h"
+
+namespace webrtc {
+
+class MockVideoStreamEncoderObserver : public VideoStreamEncoderObserver {
+ public:
+  MOCK_METHOD(void, OnEncodedFrameTimeMeasured, (int, int), (override));
+  MOCK_METHOD(void, OnIncomingFrame, (int, int), (override));
+  MOCK_METHOD(void,
+              OnSendEncodedImage,
+              (const EncodedImage&, const CodecSpecificInfo*),
+              (override));
+  MOCK_METHOD(void,
+              OnEncoderImplementationChanged,
+              (EncoderImplementation),
+              (override));
+  MOCK_METHOD(void, OnFrameDropped, (DropReason), (override));
+  MOCK_METHOD(void,
+              OnEncoderReconfigured,
+              (const VideoEncoderConfig&, const std::vector<VideoStream>&),
+              (override));
+  MOCK_METHOD(void,
+              OnAdaptationChanged,
+              (VideoAdaptationReason,
+               const VideoAdaptationCounters&,
+               const VideoAdaptationCounters&),
+              (override));
+  MOCK_METHOD(void, ClearAdaptationStats, (), (override));
+  MOCK_METHOD(void,
+              UpdateAdaptationSettings,
+              (AdaptationSettings, AdaptationSettings),
+              (override));
+  MOCK_METHOD(void, OnMinPixelLimitReached, (), (override));
+  MOCK_METHOD(void, OnInitialQualityResolutionAdaptDown, (), (override));
+  MOCK_METHOD(void, OnSuspendChange, (bool), (override));
+  MOCK_METHOD(void,
+              OnBitrateAllocationUpdated,
+              (const VideoCodec&, const VideoBitrateAllocation&),
+              (override));
+  MOCK_METHOD(void, OnEncoderInternalScalerUpdate, (bool), (override));
+  MOCK_METHOD(int, GetInputFrameRate, (), (const, override));
+};
+
+class FakeFrameRateProvider : public MockVideoStreamEncoderObserver {
+ public:
+  FakeFrameRateProvider();
+  void set_fps(int fps);
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_ADAPTATION_TEST_FAKE_FRAME_RATE_PROVIDER_H_
diff --git a/third_party/libwebrtc/call/adaptation/test/fake_resource.cc b/third_party/libwebrtc/call/adaptation/test/fake_resource.cc
new file mode 100644
index 0000000000..48b4768550
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/test/fake_resource.cc
@@ -0,0 +1,46 @@
+/*
+ *  Copyright 2019 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/adaptation/test/fake_resource.h"
+
+#include <algorithm>
+#include <utility>
+
+#include "absl/strings/string_view.h"
+#include "api/make_ref_counted.h"
+
+namespace webrtc {
+
+// static
+rtc::scoped_refptr<FakeResource> FakeResource::Create(absl::string_view name) {
+  return rtc::make_ref_counted<FakeResource>(name);
+}
+
+FakeResource::FakeResource(absl::string_view name)
+    : Resource(), name_(name), listener_(nullptr) {}
+
+FakeResource::~FakeResource() {}
+
+void FakeResource::SetUsageState(ResourceUsageState usage_state) {
+  if (listener_) {
+    listener_->OnResourceUsageStateMeasured(rtc::scoped_refptr<Resource>(this),
+                                            usage_state);
+  }
+}
+
+std::string FakeResource::Name() const {
+  return name_;
+}
+
+void FakeResource::SetResourceListener(ResourceListener* listener) {
+  listener_ = listener;
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/adaptation/test/fake_resource.h b/third_party/libwebrtc/call/adaptation/test/fake_resource.h
new file mode 100644
index 0000000000..1119a9614f
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/test/fake_resource.h
@@ -0,0 +1,45 @@
+/*
+ *  Copyright 2019 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_ADAPTATION_TEST_FAKE_RESOURCE_H_
+#define CALL_ADAPTATION_TEST_FAKE_RESOURCE_H_
+
+#include <string>
+#include <vector>
+
+#include "absl/strings/string_view.h"
+#include "absl/types/optional.h"
+#include "api/adaptation/resource.h"
+#include "api/scoped_refptr.h"
+
+namespace webrtc {
+
+// Fake resource used for testing.
+class FakeResource : public Resource {
+ public:
+  static rtc::scoped_refptr<FakeResource> Create(absl::string_view name);
+
+  explicit FakeResource(absl::string_view name);
+  ~FakeResource() override;
+
+  void SetUsageState(ResourceUsageState usage_state);
+
+  // Resource implementation.
+  std::string Name() const override;
+  void SetResourceListener(ResourceListener* listener) override;
+
+ private:
+  const std::string name_;
+  ResourceListener* listener_;
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_ADAPTATION_TEST_FAKE_RESOURCE_H_
diff --git a/third_party/libwebrtc/call/adaptation/test/fake_video_stream_input_state_provider.cc b/third_party/libwebrtc/call/adaptation/test/fake_video_stream_input_state_provider.cc
new file mode 100644
index 0000000000..ce92dfb204
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/test/fake_video_stream_input_state_provider.cc
@@ -0,0 +1,35 @@
+/*
+ *  Copyright 2020 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/adaptation/test/fake_video_stream_input_state_provider.h"
+
+namespace webrtc {
+
+FakeVideoStreamInputStateProvider::FakeVideoStreamInputStateProvider()
+    : VideoStreamInputStateProvider(nullptr) {}
+
+FakeVideoStreamInputStateProvider::~FakeVideoStreamInputStateProvider() =
+    default;
+
+void FakeVideoStreamInputStateProvider::SetInputState(
+    int input_pixels,
+    int input_fps,
+    int min_pixels_per_frame) {
+  fake_input_state_.set_has_input(true);
+  fake_input_state_.set_frame_size_pixels(input_pixels);
+  fake_input_state_.set_frames_per_second(input_fps);
+  fake_input_state_.set_min_pixels_per_frame(min_pixels_per_frame);
+}
+
+VideoStreamInputState FakeVideoStreamInputStateProvider::InputState() {
+  return fake_input_state_;
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/adaptation/test/fake_video_stream_input_state_provider.h b/third_party/libwebrtc/call/adaptation/test/fake_video_stream_input_state_provider.h
new file mode 100644
index 0000000000..93f7dba7e6
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/test/fake_video_stream_input_state_provider.h
@@ -0,0 +1,32 @@
+/*
+ *  Copyright 2020 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_ADAPTATION_TEST_FAKE_VIDEO_STREAM_INPUT_STATE_PROVIDER_H_
+#define CALL_ADAPTATION_TEST_FAKE_VIDEO_STREAM_INPUT_STATE_PROVIDER_H_
+
+#include "call/adaptation/video_stream_input_state_provider.h"
+
+namespace webrtc {
+
+class FakeVideoStreamInputStateProvider : public VideoStreamInputStateProvider {
+ public:
+  FakeVideoStreamInputStateProvider();
+  virtual ~FakeVideoStreamInputStateProvider();
+
+  void SetInputState(int input_pixels, int input_fps, int min_pixels_per_frame);
+  VideoStreamInputState InputState() override;
+
+ private:
+  VideoStreamInputState fake_input_state_;
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_ADAPTATION_TEST_FAKE_VIDEO_STREAM_INPUT_STATE_PROVIDER_H_
diff --git a/third_party/libwebrtc/call/adaptation/test/mock_resource_listener.h b/third_party/libwebrtc/call/adaptation/test/mock_resource_listener.h
new file mode 100644
index 0000000000..f0f998f2e3
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/test/mock_resource_listener.h
@@ -0,0 +1,31 @@
+/*
+ *  Copyright 2020 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_ADAPTATION_TEST_MOCK_RESOURCE_LISTENER_H_
+#define CALL_ADAPTATION_TEST_MOCK_RESOURCE_LISTENER_H_
+
+#include "api/adaptation/resource.h"
+
+#include "test/gmock.h"
+
+namespace webrtc {
+
+class MockResourceListener : public ResourceListener {
+ public:
+  MOCK_METHOD(void,
+              OnResourceUsageStateMeasured,
+              (rtc::scoped_refptr<Resource> resource,
+               ResourceUsageState usage_state),
+              (override));
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_ADAPTATION_TEST_MOCK_RESOURCE_LISTENER_H_
diff --git a/third_party/libwebrtc/call/adaptation/video_source_restrictions.cc b/third_party/libwebrtc/call/adaptation/video_source_restrictions.cc
new file mode 100644
index 0000000000..719bc53278
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/video_source_restrictions.cc
@@ -0,0 +1,173 @@
+/*
+ *  Copyright 2020 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/adaptation/video_source_restrictions.h"
+
+#include <algorithm>
+#include <limits>
+
+#include "rtc_base/checks.h"
+#include "rtc_base/strings/string_builder.h"
+
+namespace webrtc {
+
+VideoSourceRestrictions::VideoSourceRestrictions()
+    : max_pixels_per_frame_(absl::nullopt),
+      target_pixels_per_frame_(absl::nullopt),
+      max_frame_rate_(absl::nullopt) {}
+
+VideoSourceRestrictions::VideoSourceRestrictions(
+    absl::optional<size_t> max_pixels_per_frame,
+    absl::optional<size_t> target_pixels_per_frame,
+    absl::optional<double> max_frame_rate)
+    : max_pixels_per_frame_(std::move(max_pixels_per_frame)),
+      target_pixels_per_frame_(std::move(target_pixels_per_frame)),
+      max_frame_rate_(std::move(max_frame_rate)) {
+  RTC_DCHECK(!max_pixels_per_frame_.has_value() ||
+             max_pixels_per_frame_.value() <
+                 static_cast<size_t>(std::numeric_limits<int>::max()));
+  RTC_DCHECK(!max_frame_rate_.has_value() ||
+             max_frame_rate_.value() < std::numeric_limits<int>::max());
+  RTC_DCHECK(!max_frame_rate_.has_value() || max_frame_rate_.value() > 0.0);
+}
+
+std::string VideoSourceRestrictions::ToString() const {
+  rtc::StringBuilder ss;
+  ss << "{";
+  if (max_frame_rate_)
+    ss << " max_fps=" << max_frame_rate_.value();
+  if (max_pixels_per_frame_)
+    ss << " max_pixels_per_frame=" << max_pixels_per_frame_.value();
+  if (target_pixels_per_frame_)
+    ss << " target_pixels_per_frame=" << target_pixels_per_frame_.value();
+  ss << " }";
+  return ss.Release();
+}
+
+const absl::optional<size_t>& VideoSourceRestrictions::max_pixels_per_frame()
+    const {
+  return max_pixels_per_frame_;
+}
+
+const absl::optional<size_t>& VideoSourceRestrictions::target_pixels_per_frame()
+    const {
+  return target_pixels_per_frame_;
+}
+
+const absl::optional<double>& VideoSourceRestrictions::max_frame_rate() const {
+  return max_frame_rate_;
+}
+
+void VideoSourceRestrictions::set_max_pixels_per_frame(
+    absl::optional<size_t> max_pixels_per_frame) {
+  max_pixels_per_frame_ = std::move(max_pixels_per_frame);
+}
+
+void VideoSourceRestrictions::set_target_pixels_per_frame(
+    absl::optional<size_t> target_pixels_per_frame) {
+  target_pixels_per_frame_ = std::move(target_pixels_per_frame);
+}
+
+void VideoSourceRestrictions::set_max_frame_rate(
+    absl::optional<double> max_frame_rate) {
+  max_frame_rate_ = std::move(max_frame_rate);
+}
+
+void VideoSourceRestrictions::UpdateMin(const VideoSourceRestrictions& other) {
+  if (max_pixels_per_frame_.has_value()) {
+    max_pixels_per_frame_ = std::min(*max_pixels_per_frame_,
+                                     other.max_pixels_per_frame().value_or(
+                                         std::numeric_limits<size_t>::max()));
+  } else {
+    max_pixels_per_frame_ = other.max_pixels_per_frame();
+  }
+  if (target_pixels_per_frame_.has_value()) {
+    target_pixels_per_frame_ = std::min(
+        *target_pixels_per_frame_, other.target_pixels_per_frame().value_or(
+                                       std::numeric_limits<size_t>::max()));
+  } else {
+    target_pixels_per_frame_ = other.target_pixels_per_frame();
+  }
+  if (max_frame_rate_.has_value()) {
+    max_frame_rate_ = std::min(
+        *max_frame_rate_,
+        other.max_frame_rate().value_or(std::numeric_limits<double>::max()));
+  } else {
+    max_frame_rate_ = other.max_frame_rate();
+  }
+}
+
+bool DidRestrictionsIncrease(VideoSourceRestrictions before,
+                             VideoSourceRestrictions after) {
+  bool decreased_resolution = DidDecreaseResolution(before, after);
+  bool decreased_framerate = DidDecreaseFrameRate(before, after);
+  bool same_resolution =
+      before.max_pixels_per_frame() == after.max_pixels_per_frame();
+  bool same_framerate = before.max_frame_rate() == after.max_frame_rate();
+
+  return (decreased_resolution && decreased_framerate) ||
+         (decreased_resolution && same_framerate) ||
+         (same_resolution && decreased_framerate);
+}
+
+bool DidRestrictionsDecrease(VideoSourceRestrictions before,
+                             VideoSourceRestrictions after) {
+  bool increased_resolution = DidIncreaseResolution(before, after);
+  bool increased_framerate = DidIncreaseFrameRate(before, after);
+  bool same_resolution =
+      before.max_pixels_per_frame() == after.max_pixels_per_frame();
+  bool same_framerate = before.max_frame_rate() == after.max_frame_rate();
+
+  return (increased_resolution && increased_framerate) ||
+         (increased_resolution && same_framerate) ||
+         (same_resolution && increased_framerate);
+}
+
+bool DidIncreaseResolution(VideoSourceRestrictions restrictions_before,
+                           VideoSourceRestrictions restrictions_after) {
+  if (!restrictions_before.max_pixels_per_frame().has_value())
+    return false;
+  if (!restrictions_after.max_pixels_per_frame().has_value())
+    return true;
+  return restrictions_after.max_pixels_per_frame().value() >
+         restrictions_before.max_pixels_per_frame().value();
+}
+
+bool DidDecreaseResolution(VideoSourceRestrictions restrictions_before,
+                           VideoSourceRestrictions restrictions_after) {
+  if (!restrictions_after.max_pixels_per_frame().has_value())
+    return false;
+  if (!restrictions_before.max_pixels_per_frame().has_value())
+    return true;
+  return restrictions_after.max_pixels_per_frame().value() <
+         restrictions_before.max_pixels_per_frame().value();
+}
+
+bool DidIncreaseFrameRate(VideoSourceRestrictions restrictions_before,
+                          VideoSourceRestrictions restrictions_after) {
+  if (!restrictions_before.max_frame_rate().has_value())
+    return false;
+  if (!restrictions_after.max_frame_rate().has_value())
+    return true;
+  return restrictions_after.max_frame_rate().value() >
+         restrictions_before.max_frame_rate().value();
+}
+
+bool DidDecreaseFrameRate(VideoSourceRestrictions restrictions_before,
+                          VideoSourceRestrictions restrictions_after) {
+  if (!restrictions_after.max_frame_rate().has_value())
+    return false;
+  if (!restrictions_before.max_frame_rate().has_value())
+    return true;
+  return restrictions_after.max_frame_rate().value() <
+         restrictions_before.max_frame_rate().value();
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/adaptation/video_source_restrictions.h b/third_party/libwebrtc/call/adaptation/video_source_restrictions.h
new file mode 100644
index 0000000000..be8520a385
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/video_source_restrictions.h
@@ -0,0 +1,89 @@
+/*
+ *  Copyright 2020 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_ADAPTATION_VIDEO_SOURCE_RESTRICTIONS_H_
+#define CALL_ADAPTATION_VIDEO_SOURCE_RESTRICTIONS_H_
+
+#include <string>
+#include <utility>
+
+#include "absl/types/optional.h"
+
+namespace webrtc {
+
+// Describes optional restrictions to the resolution and frame rate of a video
+// source.
+class VideoSourceRestrictions {
+ public:
+  // Constructs without any restrictions.
+  VideoSourceRestrictions();
+  // All values must be positive or nullopt.
+  // TODO(hbos): Support expressing "disable this stream"?
+  VideoSourceRestrictions(absl::optional<size_t> max_pixels_per_frame,
+                          absl::optional<size_t> target_pixels_per_frame,
+                          absl::optional<double> max_frame_rate);
+
+  bool operator==(const VideoSourceRestrictions& rhs) const {
+    return max_pixels_per_frame_ == rhs.max_pixels_per_frame_ &&
+           target_pixels_per_frame_ == rhs.target_pixels_per_frame_ &&
+           max_frame_rate_ == rhs.max_frame_rate_;
+  }
+  bool operator!=(const VideoSourceRestrictions& rhs) const {
+    return !(*this == rhs);
+  }
+
+  std::string ToString() const;
+
+  // The source must produce a resolution less than or equal to
+  // max_pixels_per_frame().
+  const absl::optional<size_t>& max_pixels_per_frame() const;
+  // The source should produce a resolution as close to the
+  // target_pixels_per_frame() as possible, provided this does not exceed
+  // max_pixels_per_frame().
+  // The actual pixel count selected depends on the capabilities of the source.
+  // TODO(hbos): Clarify how "target" is used. One possible implementation: open
+  // the camera in the smallest resolution that is greater than or equal to the
+  // target and scale it down to the target if it is greater. Is this an
+  // accurate description of what this does today, or do we do something else?
+  const absl::optional<size_t>& target_pixels_per_frame() const;
+  const absl::optional<double>& max_frame_rate() const;
+
+  void set_max_pixels_per_frame(absl::optional<size_t> max_pixels_per_frame);
+  void set_target_pixels_per_frame(
+      absl::optional<size_t> target_pixels_per_frame);
+  void set_max_frame_rate(absl::optional<double> max_frame_rate);
+
+  // Update `this` with min(`this`, `other`).
+  void UpdateMin(const VideoSourceRestrictions& other);
+
+ private:
+  // These map to rtc::VideoSinkWants's `max_pixel_count` and
+  // `target_pixel_count`.
+  absl::optional<size_t> max_pixels_per_frame_;
+  absl::optional<size_t> target_pixels_per_frame_;
+  absl::optional<double> max_frame_rate_;
+};
+
+bool DidRestrictionsIncrease(VideoSourceRestrictions before,
+                             VideoSourceRestrictions after);
+bool DidRestrictionsDecrease(VideoSourceRestrictions before,
+                             VideoSourceRestrictions after);
+bool DidIncreaseResolution(VideoSourceRestrictions restrictions_before,
+                           VideoSourceRestrictions restrictions_after);
+bool DidDecreaseResolution(VideoSourceRestrictions restrictions_before,
+                           VideoSourceRestrictions restrictions_after);
+bool DidIncreaseFrameRate(VideoSourceRestrictions restrictions_before,
+                          VideoSourceRestrictions restrictions_after);
+bool DidDecreaseFrameRate(VideoSourceRestrictions restrictions_before,
+                          VideoSourceRestrictions restrictions_after);
+
+}  // namespace webrtc
+
+#endif  // CALL_ADAPTATION_VIDEO_SOURCE_RESTRICTIONS_H_
diff --git a/third_party/libwebrtc/call/adaptation/video_source_restrictions_unittest.cc b/third_party/libwebrtc/call/adaptation/video_source_restrictions_unittest.cc
new file mode 100644
index 0000000000..8c1ae4c896
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/video_source_restrictions_unittest.cc
@@ -0,0 +1,146 @@
+/*
+ *  Copyright (c) 2020 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/adaptation/video_source_restrictions.h"
+
+#include "test/gtest.h"
+
+namespace webrtc {
+
+namespace {
+
+const size_t kHdPixels = 1280 * 720;
+
+const VideoSourceRestrictions kUnlimited;
+const VideoSourceRestrictions k15fps(absl::nullopt, absl::nullopt, 15.0);
+const VideoSourceRestrictions kHd(kHdPixels, kHdPixels, absl::nullopt);
+const VideoSourceRestrictions kHd15fps(kHdPixels, kHdPixels, 15.0);
+const VideoSourceRestrictions kVga7fps(kHdPixels / 2, kHdPixels / 2, 7.0);
+
+VideoSourceRestrictions RestrictionsFromMaxPixelsPerFrame(
+    size_t max_pixels_per_frame) {
+  return VideoSourceRestrictions(max_pixels_per_frame, absl::nullopt,
+                                 absl::nullopt);
+}
+
+VideoSourceRestrictions RestrictionsFromMaxFrameRate(double max_frame_rate) {
+  return VideoSourceRestrictions(absl::nullopt, absl::nullopt, max_frame_rate);
+}
+
+}  // namespace
+
+TEST(VideoSourceRestrictionsTest, DidIncreaseResolution) {
+  // smaller restrictions -> larger restrictions
+  EXPECT_TRUE(DidIncreaseResolution(RestrictionsFromMaxPixelsPerFrame(10),
+                                    RestrictionsFromMaxPixelsPerFrame(11)));
+  // unrestricted -> restricted
+  EXPECT_FALSE(DidIncreaseResolution(VideoSourceRestrictions(),
+                                     RestrictionsFromMaxPixelsPerFrame(10)));
+  // restricted -> unrestricted
+  EXPECT_TRUE(DidIncreaseResolution(RestrictionsFromMaxPixelsPerFrame(10),
+                                    VideoSourceRestrictions()));
+  // restricted -> equally restricted
+  EXPECT_FALSE(DidIncreaseResolution(RestrictionsFromMaxPixelsPerFrame(10),
+                                     RestrictionsFromMaxPixelsPerFrame(10)));
+  // unrestricted -> unrestricted
+  EXPECT_FALSE(DidIncreaseResolution(VideoSourceRestrictions(),
+                                     VideoSourceRestrictions()));
+  // larger restrictions -> smaller restrictions
+  EXPECT_FALSE(DidIncreaseResolution(RestrictionsFromMaxPixelsPerFrame(10),
+                                     RestrictionsFromMaxPixelsPerFrame(9)));
+}
+
+TEST(VideoSourceRestrictionsTest, DidDecreaseFrameRate) {
+  // samller restrictions -> larger restrictions
+  EXPECT_FALSE(DidDecreaseFrameRate(RestrictionsFromMaxFrameRate(10),
+                                    RestrictionsFromMaxFrameRate(11)));
+  // unrestricted -> restricted
+  EXPECT_TRUE(DidDecreaseFrameRate(VideoSourceRestrictions(),
+                                   RestrictionsFromMaxFrameRate(10)));
+  // restricted -> unrestricted
+  EXPECT_FALSE(DidDecreaseFrameRate(RestrictionsFromMaxFrameRate(10),
+                                    VideoSourceRestrictions()));
+  // restricted -> equally restricted
+  EXPECT_FALSE(DidDecreaseFrameRate(RestrictionsFromMaxFrameRate(10),
+                                    RestrictionsFromMaxFrameRate(10)));
+  // unrestricted -> unrestricted
+  EXPECT_FALSE(DidDecreaseFrameRate(VideoSourceRestrictions(),
+                                    VideoSourceRestrictions()));
+  // larger restrictions -> samller restrictions
+  EXPECT_TRUE(DidDecreaseFrameRate(RestrictionsFromMaxFrameRate(10),
+                                   RestrictionsFromMaxFrameRate(9)));
+}
+
+TEST(VideoSourceRestrictionsTest, DidRestrictionsChangeFalseForSame) {
+  EXPECT_FALSE(DidRestrictionsDecrease(kUnlimited, kUnlimited));
+  EXPECT_FALSE(DidRestrictionsIncrease(kUnlimited, kUnlimited));
+
+  // Both resolution and fps restricted.
+  EXPECT_FALSE(DidRestrictionsDecrease(kHd15fps, kHd15fps));
+  EXPECT_FALSE(DidRestrictionsIncrease(kHd15fps, kHd15fps));
+}
+
+TEST(VideoSourceRestrictions,
+     DidRestrictionsIncreaseTrueWhenPixelsOrFrameRateDecreased) {
+  // Unlimited > Limited resolution.
+  EXPECT_TRUE(DidRestrictionsIncrease(kUnlimited, kHd));
+  // Unlimited > limited fps.
+  EXPECT_TRUE(DidRestrictionsIncrease(kUnlimited, k15fps));
+  // Unlimited > limited resolution + limited fps.
+  EXPECT_TRUE(DidRestrictionsIncrease(kUnlimited, kHd15fps));
+  // Limited resolution > limited resolution + limited fps.
+  EXPECT_TRUE(DidRestrictionsIncrease(kHd, kHd15fps));
+  // Limited fps > limited resolution + limited fps.
+  EXPECT_TRUE(DidRestrictionsIncrease(k15fps, kHd15fps));
+  // Limited resolution + fps > More limited resolution + more limited fps
+  EXPECT_TRUE(DidRestrictionsIncrease(kHd15fps, kVga7fps));
+}
+
+TEST(VideoSourceRestrictions,
+     DidRestrictionsDecreaseTrueWhenPixelsOrFrameRateIncreased) {
+  // Limited resolution < Unlimited.
+  EXPECT_TRUE(DidRestrictionsDecrease(kHd, kUnlimited));
+  // Limited fps < Unlimited.
+  EXPECT_TRUE(DidRestrictionsDecrease(k15fps, kUnlimited));
+  // Limited resolution + limited fps < unlimited.
+  EXPECT_TRUE(DidRestrictionsDecrease(kHd15fps, kUnlimited));
+  // Limited resolution + limited fps < limited resolution.
+  EXPECT_TRUE(DidRestrictionsDecrease(kHd15fps, kHd));
+  // Limited resolution + limited fps < limited fps.
+  EXPECT_TRUE(DidRestrictionsDecrease(kHd15fps, k15fps));
+  // More limited resolution + more limited fps < limited resolution + fps
+  EXPECT_TRUE(DidRestrictionsDecrease(kVga7fps, kHd15fps));
+}
+
+TEST(VideoSourceRestrictions,
+     DidRestrictionsChangeFalseWhenFrameRateAndPixelsChangeDifferently) {
+  // One changed framerate, the other resolution; not an increase or decrease.
+  EXPECT_FALSE(DidRestrictionsIncrease(kHd, k15fps));
+  EXPECT_FALSE(DidRestrictionsDecrease(kHd, k15fps));
+}
+
+TEST(VideoSourceRestrictions, UpdateMin) {
+  VideoSourceRestrictions one(kHdPixels / 2, kHdPixels, 7.0);
+  VideoSourceRestrictions two(kHdPixels, kHdPixels / 3, 15.0);
+
+  one.UpdateMin(two);
+
+  EXPECT_EQ(one.max_pixels_per_frame(), kHdPixels / 2);
+  EXPECT_EQ(one.target_pixels_per_frame(), kHdPixels / 3);
+  EXPECT_EQ(one.max_frame_rate(), 7.0);
+
+  two.UpdateMin(one);
+
+  EXPECT_EQ(two.max_pixels_per_frame(), kHdPixels / 2);
+  EXPECT_EQ(two.target_pixels_per_frame(), kHdPixels / 3);
+  EXPECT_EQ(two.max_frame_rate(), 7.0);
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/adaptation/video_stream_adapter.cc b/third_party/libwebrtc/call/adaptation/video_stream_adapter.cc
new file mode 100644
index 0000000000..f30a4d7abb
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/video_stream_adapter.cc
@@ -0,0 +1,742 @@
+/*
+ *  Copyright 2020 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/adaptation/video_stream_adapter.h"
+
+#include <algorithm>
+#include <limits>
+#include <utility>
+
+#include "absl/types/optional.h"
+#include "absl/types/variant.h"
+#include "api/sequence_checker.h"
+#include "api/video/video_adaptation_counters.h"
+#include "api/video/video_adaptation_reason.h"
+#include "api/video_codecs/video_encoder.h"
+#include "call/adaptation/video_source_restrictions.h"
+#include "call/adaptation/video_stream_input_state.h"
+#include "rtc_base/checks.h"
+#include "rtc_base/logging.h"
+#include "rtc_base/numerics/safe_conversions.h"
+
+namespace webrtc {
+
+const int kMinFrameRateFps = 2;
+
+namespace {
+
+// For frame rate, the steps we take are 2/3 (down) and 3/2 (up).
+int GetLowerFrameRateThan(int fps) {
+  RTC_DCHECK(fps != std::numeric_limits<int>::max());
+  return (fps * 2) / 3;
+}
+// TODO(hbos): Use absl::optional<> instead?
+int GetHigherFrameRateThan(int fps) {
+  return fps != std::numeric_limits<int>::max()
+             ? (fps * 3) / 2
+             : std::numeric_limits<int>::max();
+}
+
+int GetIncreasedMaxPixelsWanted(int target_pixels) {
+  if (target_pixels == std::numeric_limits<int>::max())
+    return std::numeric_limits<int>::max();
+  // When we decrease resolution, we go down to at most 3/5 of current pixels.
+  // Thus to increase resolution, we need 3/5 to get back to where we started.
+  // When going up, the desired max_pixels_per_frame() has to be significantly
+  // higher than the target because the source's native resolutions might not
+  // match the target. We pick 12/5 of the target.
+  //
+  // (This value was historically 4 times the old target, which is (3/5)*4 of
+  // the new target - or 12/5 - assuming the target is adjusted according to
+  // the above steps.)
+  RTC_DCHECK(target_pixels != std::numeric_limits<int>::max());
+  return (target_pixels * 12) / 5;
+}
+
+bool CanDecreaseResolutionTo(int target_pixels,
+                             int target_pixels_min,
+                             const VideoStreamInputState& input_state,
+                             const VideoSourceRestrictions& restrictions) {
+  int max_pixels_per_frame =
+      rtc::dchecked_cast<int>(restrictions.max_pixels_per_frame().value_or(
+          std::numeric_limits<int>::max()));
+  return target_pixels < max_pixels_per_frame &&
+         target_pixels_min >= input_state.min_pixels_per_frame();
+}
+
+bool CanIncreaseResolutionTo(int target_pixels,
+                             const VideoSourceRestrictions& restrictions) {
+  int max_pixels_wanted = GetIncreasedMaxPixelsWanted(target_pixels);
+  int max_pixels_per_frame =
+      rtc::dchecked_cast<int>(restrictions.max_pixels_per_frame().value_or(
+          std::numeric_limits<int>::max()));
+  return max_pixels_wanted > max_pixels_per_frame;
+}
+
+bool CanDecreaseFrameRateTo(int max_frame_rate,
+                            const VideoSourceRestrictions& restrictions) {
+  const int fps_wanted = std::max(kMinFrameRateFps, max_frame_rate);
+  return fps_wanted <
+         rtc::dchecked_cast<int>(restrictions.max_frame_rate().value_or(
+             std::numeric_limits<int>::max()));
+}
+
+bool CanIncreaseFrameRateTo(int max_frame_rate,
+                            const VideoSourceRestrictions& restrictions) {
+  return max_frame_rate >
+         rtc::dchecked_cast<int>(restrictions.max_frame_rate().value_or(
+             std::numeric_limits<int>::max()));
+}
+
+bool MinPixelLimitReached(const VideoStreamInputState& input_state) {
+  if (input_state.single_active_stream_pixels().has_value()) {
+    return GetLowerResolutionThan(
+               input_state.single_active_stream_pixels().value()) <
+           input_state.min_pixels_per_frame();
+  }
+  return input_state.frame_size_pixels().has_value() &&
+         GetLowerResolutionThan(input_state.frame_size_pixels().value()) <
+             input_state.min_pixels_per_frame();
+}
+
+}  // namespace
+
+VideoSourceRestrictionsListener::~VideoSourceRestrictionsListener() = default;
+
+VideoSourceRestrictions FilterRestrictionsByDegradationPreference(
+    VideoSourceRestrictions source_restrictions,
+    DegradationPreference degradation_preference) {
+  switch (degradation_preference) {
+    case DegradationPreference::BALANCED:
+      break;
+    case DegradationPreference::MAINTAIN_FRAMERATE:
+      source_restrictions.set_max_frame_rate(absl::nullopt);
+      break;
+    case DegradationPreference::MAINTAIN_RESOLUTION:
+      source_restrictions.set_max_pixels_per_frame(absl::nullopt);
+      source_restrictions.set_target_pixels_per_frame(absl::nullopt);
+      break;
+    case DegradationPreference::DISABLED:
+      source_restrictions.set_max_pixels_per_frame(absl::nullopt);
+      source_restrictions.set_target_pixels_per_frame(absl::nullopt);
+      source_restrictions.set_max_frame_rate(absl::nullopt);
+  }
+  return source_restrictions;
+}
+
+// For resolution, the steps we take are 3/5 (down) and 5/3 (up).
+// Notice the asymmetry of which restriction property is set depending on if
+// we are adapting up or down:
+// - VideoSourceRestrictor::DecreaseResolution() sets the max_pixels_per_frame()
+//   to the desired target and target_pixels_per_frame() to null.
+// - VideoSourceRestrictor::IncreaseResolutionTo() sets the
+//   target_pixels_per_frame() to the desired target, and max_pixels_per_frame()
+//   is set according to VideoSourceRestrictor::GetIncreasedMaxPixelsWanted().
+int GetLowerResolutionThan(int pixel_count) {
+  RTC_DCHECK(pixel_count != std::numeric_limits<int>::max());
+  return (pixel_count * 3) / 5;
+}
+
+// TODO(hbos): Use absl::optional<> instead?
+int GetHigherResolutionThan(int pixel_count) {
+  return pixel_count != std::numeric_limits<int>::max()
+             ? (pixel_count * 5) / 3
+             : std::numeric_limits<int>::max();
+}
+
+// static
+const char* Adaptation::StatusToString(Adaptation::Status status) {
+  switch (status) {
+    case Adaptation::Status::kValid:
+      return "kValid";
+    case Adaptation::Status::kLimitReached:
+      return "kLimitReached";
+    case Adaptation::Status::kAwaitingPreviousAdaptation:
+      return "kAwaitingPreviousAdaptation";
+    case Status::kInsufficientInput:
+      return "kInsufficientInput";
+    case Status::kAdaptationDisabled:
+      return "kAdaptationDisabled";
+    case Status::kRejectedByConstraint:
+      return "kRejectedByConstraint";
+  }
+  RTC_CHECK_NOTREACHED();
+}
+
+Adaptation::Adaptation(int validation_id,
+                       VideoSourceRestrictions restrictions,
+                       VideoAdaptationCounters counters,
+                       VideoStreamInputState input_state)
+    : validation_id_(validation_id),
+      status_(Status::kValid),
+      input_state_(std::move(input_state)),
+      restrictions_(std::move(restrictions)),
+      counters_(std::move(counters)) {}
+
+Adaptation::Adaptation(int validation_id, Status invalid_status)
+    : validation_id_(validation_id), status_(invalid_status) {
+  RTC_DCHECK_NE(status_, Status::kValid);
+}
+
+Adaptation::Status Adaptation::status() const {
+  return status_;
+}
+
+const VideoStreamInputState& Adaptation::input_state() const {
+  return input_state_;
+}
+
+const VideoSourceRestrictions& Adaptation::restrictions() const {
+  return restrictions_;
+}
+
+const VideoAdaptationCounters& Adaptation::counters() const {
+  return counters_;
+}
+
+VideoStreamAdapter::VideoStreamAdapter(
+    VideoStreamInputStateProvider* input_state_provider,
+    VideoStreamEncoderObserver* encoder_stats_observer,
+    const FieldTrialsView& field_trials)
+    : input_state_provider_(input_state_provider),
+      encoder_stats_observer_(encoder_stats_observer),
+      balanced_settings_(field_trials),
+      adaptation_validation_id_(0),
+      degradation_preference_(DegradationPreference::DISABLED),
+      awaiting_frame_size_change_(absl::nullopt) {
+  sequence_checker_.Detach();
+  RTC_DCHECK(input_state_provider_);
+  RTC_DCHECK(encoder_stats_observer_);
+}
+
+VideoStreamAdapter::~VideoStreamAdapter() {
+  RTC_DCHECK(adaptation_constraints_.empty())
+      << "There are constaint(s) attached to a VideoStreamAdapter being "
+         "destroyed.";
+}
+
+VideoSourceRestrictions VideoStreamAdapter::source_restrictions() const {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  return current_restrictions_.restrictions;
+}
+
+const VideoAdaptationCounters& VideoStreamAdapter::adaptation_counters() const {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  return current_restrictions_.counters;
+}
+
+void VideoStreamAdapter::ClearRestrictions() {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  // Invalidate any previously returned Adaptation.
+  RTC_LOG(LS_INFO) << "Resetting restrictions";
+  ++adaptation_validation_id_;
+  current_restrictions_ = {VideoSourceRestrictions(),
+                           VideoAdaptationCounters()};
+  awaiting_frame_size_change_ = absl::nullopt;
+  BroadcastVideoRestrictionsUpdate(input_state_provider_->InputState(),
+                                   nullptr);
+}
+
+void VideoStreamAdapter::AddRestrictionsListener(
+    VideoSourceRestrictionsListener* restrictions_listener) {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  RTC_DCHECK(std::find(restrictions_listeners_.begin(),
+                       restrictions_listeners_.end(),
+                       restrictions_listener) == restrictions_listeners_.end());
+  restrictions_listeners_.push_back(restrictions_listener);
+}
+
+void VideoStreamAdapter::RemoveRestrictionsListener(
+    VideoSourceRestrictionsListener* restrictions_listener) {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  auto it = std::find(restrictions_listeners_.begin(),
+                      restrictions_listeners_.end(), restrictions_listener);
+  RTC_DCHECK(it != restrictions_listeners_.end());
+  restrictions_listeners_.erase(it);
+}
+
+void VideoStreamAdapter::AddAdaptationConstraint(
+    AdaptationConstraint* adaptation_constraint) {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  RTC_DCHECK(std::find(adaptation_constraints_.begin(),
+                       adaptation_constraints_.end(),
+                       adaptation_constraint) == adaptation_constraints_.end());
+  adaptation_constraints_.push_back(adaptation_constraint);
+}
+
+void VideoStreamAdapter::RemoveAdaptationConstraint(
+    AdaptationConstraint* adaptation_constraint) {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  auto it = std::find(adaptation_constraints_.begin(),
+                      adaptation_constraints_.end(), adaptation_constraint);
+  RTC_DCHECK(it != adaptation_constraints_.end());
+  adaptation_constraints_.erase(it);
+}
+
+void VideoStreamAdapter::SetDegradationPreference(
+    DegradationPreference degradation_preference) {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  if (degradation_preference_ == degradation_preference)
+    return;
+  // Invalidate any previously returned Adaptation.
+  ++adaptation_validation_id_;
+  bool balanced_switch =
+      degradation_preference == DegradationPreference::BALANCED ||
+      degradation_preference_ == DegradationPreference::BALANCED;
+  degradation_preference_ = degradation_preference;
+  if (balanced_switch) {
+    // ClearRestrictions() calls BroadcastVideoRestrictionsUpdate(nullptr).
+    ClearRestrictions();
+  } else {
+    BroadcastVideoRestrictionsUpdate(input_state_provider_->InputState(),
+                                     nullptr);
+  }
+}
+
+struct VideoStreamAdapter::RestrictionsOrStateVisitor {
+  Adaptation operator()(const RestrictionsWithCounters& r) const {
+    return Adaptation(adaptation_validation_id, r.restrictions, r.counters,
+                      input_state);
+  }
+  Adaptation operator()(const Adaptation::Status& status) const {
+    RTC_DCHECK_NE(status, Adaptation::Status::kValid);
+    return Adaptation(adaptation_validation_id, status);
+  }
+
+  const int adaptation_validation_id;
+  const VideoStreamInputState& input_state;
+};
+
+Adaptation VideoStreamAdapter::RestrictionsOrStateToAdaptation(
+    VideoStreamAdapter::RestrictionsOrState step_or_state,
+    const VideoStreamInputState& input_state) const {
+  RTC_DCHECK(!step_or_state.valueless_by_exception());
+  return absl::visit(
+      RestrictionsOrStateVisitor{adaptation_validation_id_, input_state},
+      step_or_state);
+}
+
+Adaptation VideoStreamAdapter::GetAdaptationUp(
+    const VideoStreamInputState& input_state) const {
+  RestrictionsOrState step = GetAdaptationUpStep(input_state);
+  // If an adaptation proposed, check with the constraints that it is ok.
+  if (absl::holds_alternative<RestrictionsWithCounters>(step)) {
+    RestrictionsWithCounters restrictions =
+        absl::get<RestrictionsWithCounters>(step);
+    for (const auto* constraint : adaptation_constraints_) {
+      if (!constraint->IsAdaptationUpAllowed(input_state,
+                                             current_restrictions_.restrictions,
+                                             restrictions.restrictions)) {
+        RTC_LOG(LS_INFO) << "Not adapting up because constraint \""
+                         << constraint->Name() << "\" disallowed it";
+        step = Adaptation::Status::kRejectedByConstraint;
+      }
+    }
+  }
+  return RestrictionsOrStateToAdaptation(step, input_state);
+}
+
+Adaptation VideoStreamAdapter::GetAdaptationUp() {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  VideoStreamInputState input_state = input_state_provider_->InputState();
+  ++adaptation_validation_id_;
+  Adaptation adaptation = GetAdaptationUp(input_state);
+  return adaptation;
+}
+
+VideoStreamAdapter::RestrictionsOrState VideoStreamAdapter::GetAdaptationUpStep(
+    const VideoStreamInputState& input_state) const {
+  if (!HasSufficientInputForAdaptation(input_state)) {
+    return Adaptation::Status::kInsufficientInput;
+  }
+  // Don't adapt if we're awaiting a previous adaptation to have an effect.
+  if (awaiting_frame_size_change_ &&
+      awaiting_frame_size_change_->pixels_increased &&
+      degradation_preference_ == DegradationPreference::MAINTAIN_FRAMERATE &&
+      input_state.frame_size_pixels().value() <=
+          awaiting_frame_size_change_->frame_size_pixels) {
+    return Adaptation::Status::kAwaitingPreviousAdaptation;
+  }
+
+  // Maybe propose targets based on degradation preference.
+  switch (degradation_preference_) {
+    case DegradationPreference::BALANCED: {
+      // Attempt to increase target frame rate.
+      RestrictionsOrState increase_frame_rate =
+          IncreaseFramerate(input_state, current_restrictions_);
+      if (absl::holds_alternative<RestrictionsWithCounters>(
+              increase_frame_rate)) {
+        return increase_frame_rate;
+      }
+      // else, increase resolution.
+      [[fallthrough]];
+    }
+    case DegradationPreference::MAINTAIN_FRAMERATE: {
+      // Attempt to increase pixel count.
+      return IncreaseResolution(input_state, current_restrictions_);
+    }
+    case DegradationPreference::MAINTAIN_RESOLUTION: {
+      // Scale up framerate.
+      return IncreaseFramerate(input_state, current_restrictions_);
+    }
+    case DegradationPreference::DISABLED:
+      return Adaptation::Status::kAdaptationDisabled;
+  }
+  RTC_CHECK_NOTREACHED();
+}
+
+Adaptation VideoStreamAdapter::GetAdaptationDown() {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  VideoStreamInputState input_state = input_state_provider_->InputState();
+  ++adaptation_validation_id_;
+  RestrictionsOrState restrictions_or_state =
+      GetAdaptationDownStep(input_state, current_restrictions_);
+  if (MinPixelLimitReached(input_state)) {
+    encoder_stats_observer_->OnMinPixelLimitReached();
+  }
+  // Check for min_fps
+  if (degradation_preference_ == DegradationPreference::BALANCED &&
+      absl::holds_alternative<RestrictionsWithCounters>(
+          restrictions_or_state)) {
+    restrictions_or_state = AdaptIfFpsDiffInsufficient(
+        input_state,
+        absl::get<RestrictionsWithCounters>(restrictions_or_state));
+  }
+  return RestrictionsOrStateToAdaptation(restrictions_or_state, input_state);
+}
+
+VideoStreamAdapter::RestrictionsOrState
+VideoStreamAdapter::AdaptIfFpsDiffInsufficient(
+    const VideoStreamInputState& input_state,
+    const RestrictionsWithCounters& restrictions) const {
+  RTC_DCHECK_EQ(degradation_preference_, DegradationPreference::BALANCED);
+  int frame_size_pixels = input_state.single_active_stream_pixels().value_or(
+      input_state.frame_size_pixels().value());
+  absl::optional<int> min_fps_diff =
+      balanced_settings_.MinFpsDiff(frame_size_pixels);
+  if (current_restrictions_.counters.fps_adaptations <
+          restrictions.counters.fps_adaptations &&
+      min_fps_diff && input_state.frames_per_second() > 0) {
+    int fps_diff = input_state.frames_per_second() -
+                   restrictions.restrictions.max_frame_rate().value();
+    if (fps_diff < min_fps_diff.value()) {
+      return GetAdaptationDownStep(input_state, restrictions);
+    }
+  }
+  return restrictions;
+}
+
+VideoStreamAdapter::RestrictionsOrState
+VideoStreamAdapter::GetAdaptationDownStep(
+    const VideoStreamInputState& input_state,
+    const RestrictionsWithCounters& current_restrictions) const {
+  if (!HasSufficientInputForAdaptation(input_state)) {
+    return Adaptation::Status::kInsufficientInput;
+  }
+  // Don't adapt if we're awaiting a previous adaptation to have an effect or
+  // if we switched degradation preference.
+  if (awaiting_frame_size_change_ &&
+      !awaiting_frame_size_change_->pixels_increased &&
+      degradation_preference_ == DegradationPreference::MAINTAIN_FRAMERATE &&
+      input_state.frame_size_pixels().value() >=
+          awaiting_frame_size_change_->frame_size_pixels) {
+    return Adaptation::Status::kAwaitingPreviousAdaptation;
+  }
+  // Maybe propose targets based on degradation preference.
+  switch (degradation_preference_) {
+    case DegradationPreference::BALANCED: {
+      // Try scale down framerate, if lower.
+      RestrictionsOrState decrease_frame_rate =
+          DecreaseFramerate(input_state, current_restrictions);
+      if (absl::holds_alternative<RestrictionsWithCounters>(
+              decrease_frame_rate)) {
+        return decrease_frame_rate;
+      }
+      // else, decrease resolution.
+      [[fallthrough]];
+    }
+    case DegradationPreference::MAINTAIN_FRAMERATE: {
+      return DecreaseResolution(input_state, current_restrictions);
+    }
+    case DegradationPreference::MAINTAIN_RESOLUTION: {
+      return DecreaseFramerate(input_state, current_restrictions);
+    }
+    case DegradationPreference::DISABLED:
+      return Adaptation::Status::kAdaptationDisabled;
+  }
+  RTC_CHECK_NOTREACHED();
+}
+
+VideoStreamAdapter::RestrictionsOrState VideoStreamAdapter::DecreaseResolution(
+    const VideoStreamInputState& input_state,
+    const RestrictionsWithCounters& current_restrictions) {
+  int target_pixels =
+      GetLowerResolutionThan(input_state.frame_size_pixels().value());
+  // Use single active stream if set, this stream could be lower than the input.
+  int target_pixels_min =
+      GetLowerResolutionThan(input_state.single_active_stream_pixels().value_or(
+          input_state.frame_size_pixels().value()));
+  if (!CanDecreaseResolutionTo(target_pixels, target_pixels_min, input_state,
+                               current_restrictions.restrictions)) {
+    return Adaptation::Status::kLimitReached;
+  }
+  RestrictionsWithCounters new_restrictions = current_restrictions;
+  RTC_LOG(LS_INFO) << "Scaling down resolution, max pixels: " << target_pixels;
+  new_restrictions.restrictions.set_max_pixels_per_frame(
+      target_pixels != std::numeric_limits<int>::max()
+          ? absl::optional<size_t>(target_pixels)
+          : absl::nullopt);
+  new_restrictions.restrictions.set_target_pixels_per_frame(absl::nullopt);
+  ++new_restrictions.counters.resolution_adaptations;
+  return new_restrictions;
+}
+
+VideoStreamAdapter::RestrictionsOrState VideoStreamAdapter::DecreaseFramerate(
+    const VideoStreamInputState& input_state,
+    const RestrictionsWithCounters& current_restrictions) const {
+  int max_frame_rate;
+  if (degradation_preference_ == DegradationPreference::MAINTAIN_RESOLUTION) {
+    max_frame_rate = GetLowerFrameRateThan(input_state.frames_per_second());
+  } else if (degradation_preference_ == DegradationPreference::BALANCED) {
+    int frame_size_pixels = input_state.single_active_stream_pixels().value_or(
+        input_state.frame_size_pixels().value());
+    max_frame_rate = balanced_settings_.MinFps(input_state.video_codec_type(),
+                                               frame_size_pixels);
+  } else {
+    RTC_DCHECK_NOTREACHED();
+    max_frame_rate = GetLowerFrameRateThan(input_state.frames_per_second());
+  }
+  if (!CanDecreaseFrameRateTo(max_frame_rate,
+                              current_restrictions.restrictions)) {
+    return Adaptation::Status::kLimitReached;
+  }
+  RestrictionsWithCounters new_restrictions = current_restrictions;
+  max_frame_rate = std::max(kMinFrameRateFps, max_frame_rate);
+  RTC_LOG(LS_INFO) << "Scaling down framerate: " << max_frame_rate;
+  new_restrictions.restrictions.set_max_frame_rate(
+      max_frame_rate != std::numeric_limits<int>::max()
+          ? absl::optional<double>(max_frame_rate)
+          : absl::nullopt);
+  ++new_restrictions.counters.fps_adaptations;
+  return new_restrictions;
+}
+
+VideoStreamAdapter::RestrictionsOrState VideoStreamAdapter::IncreaseResolution(
+    const VideoStreamInputState& input_state,
+    const RestrictionsWithCounters& current_restrictions) {
+  int target_pixels = input_state.frame_size_pixels().value();
+  if (current_restrictions.counters.resolution_adaptations == 1) {
+    RTC_LOG(LS_INFO) << "Removing resolution down-scaling setting.";
+    target_pixels = std::numeric_limits<int>::max();
+  }
+  target_pixels = GetHigherResolutionThan(target_pixels);
+  if (!CanIncreaseResolutionTo(target_pixels,
+                               current_restrictions.restrictions)) {
+    return Adaptation::Status::kLimitReached;
+  }
+  int max_pixels_wanted = GetIncreasedMaxPixelsWanted(target_pixels);
+  RestrictionsWithCounters new_restrictions = current_restrictions;
+  RTC_LOG(LS_INFO) << "Scaling up resolution, max pixels: "
+                   << max_pixels_wanted;
+  new_restrictions.restrictions.set_max_pixels_per_frame(
+      max_pixels_wanted != std::numeric_limits<int>::max()
+          ? absl::optional<size_t>(max_pixels_wanted)
+          : absl::nullopt);
+  new_restrictions.restrictions.set_target_pixels_per_frame(
+      max_pixels_wanted != std::numeric_limits<int>::max()
+          ? absl::optional<size_t>(target_pixels)
+          : absl::nullopt);
+  --new_restrictions.counters.resolution_adaptations;
+  RTC_DCHECK_GE(new_restrictions.counters.resolution_adaptations, 0);
+  return new_restrictions;
+}
+
+VideoStreamAdapter::RestrictionsOrState VideoStreamAdapter::IncreaseFramerate(
+    const VideoStreamInputState& input_state,
+    const RestrictionsWithCounters& current_restrictions) const {
+  int max_frame_rate;
+  if (degradation_preference_ == DegradationPreference::MAINTAIN_RESOLUTION) {
+    max_frame_rate = GetHigherFrameRateThan(input_state.frames_per_second());
+  } else if (degradation_preference_ == DegradationPreference::BALANCED) {
+    int frame_size_pixels = input_state.single_active_stream_pixels().value_or(
+        input_state.frame_size_pixels().value());
+    max_frame_rate = balanced_settings_.MaxFps(input_state.video_codec_type(),
+                                               frame_size_pixels);
+    // Temporary fix for cases when there are fewer framerate adaptation steps
+    // up than down. Make number of down/up steps equal.
+    if (max_frame_rate == std::numeric_limits<int>::max() &&
+        current_restrictions.counters.fps_adaptations > 1) {
+      // Do not unrestrict framerate to allow additional adaptation up steps.
+      RTC_LOG(LS_INFO) << "Modifying framerate due to remaining fps count.";
+      max_frame_rate -= current_restrictions.counters.fps_adaptations;
+    }
+    // In BALANCED, the max_frame_rate must be checked before proceeding. This
+    // is because the MaxFps might be the current Fps and so the balanced
+    // settings may want to scale up the resolution.
+    if (!CanIncreaseFrameRateTo(max_frame_rate,
+                                current_restrictions.restrictions)) {
+      return Adaptation::Status::kLimitReached;
+    }
+  } else {
+    RTC_DCHECK_NOTREACHED();
+    max_frame_rate = GetHigherFrameRateThan(input_state.frames_per_second());
+  }
+  if (current_restrictions.counters.fps_adaptations == 1) {
+    RTC_LOG(LS_INFO) << "Removing framerate down-scaling setting.";
+    max_frame_rate = std::numeric_limits<int>::max();
+  }
+  if (!CanIncreaseFrameRateTo(max_frame_rate,
+                              current_restrictions.restrictions)) {
+    return Adaptation::Status::kLimitReached;
+  }
+  RTC_LOG(LS_INFO) << "Scaling up framerate: " << max_frame_rate;
+  RestrictionsWithCounters new_restrictions = current_restrictions;
+  new_restrictions.restrictions.set_max_frame_rate(
+      max_frame_rate != std::numeric_limits<int>::max()
+          ? absl::optional<double>(max_frame_rate)
+          : absl::nullopt);
+  --new_restrictions.counters.fps_adaptations;
+  RTC_DCHECK_GE(new_restrictions.counters.fps_adaptations, 0);
+  return new_restrictions;
+}
+
+Adaptation VideoStreamAdapter::GetAdaptDownResolution() {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  VideoStreamInputState input_state = input_state_provider_->InputState();
+  switch (degradation_preference_) {
+    case DegradationPreference::DISABLED:
+      return RestrictionsOrStateToAdaptation(
+          Adaptation::Status::kAdaptationDisabled, input_state);
+    case DegradationPreference::MAINTAIN_RESOLUTION:
+      return RestrictionsOrStateToAdaptation(Adaptation::Status::kLimitReached,
+                                             input_state);
+    case DegradationPreference::MAINTAIN_FRAMERATE:
+      return GetAdaptationDown();
+    case DegradationPreference::BALANCED: {
+      return RestrictionsOrStateToAdaptation(
+          GetAdaptDownResolutionStepForBalanced(input_state), input_state);
+    }
+  }
+  RTC_CHECK_NOTREACHED();
+}
+
+VideoStreamAdapter::RestrictionsOrState
+VideoStreamAdapter::GetAdaptDownResolutionStepForBalanced(
+    const VideoStreamInputState& input_state) const {
+  // Adapt twice if the first adaptation did not decrease resolution.
+  auto first_step = GetAdaptationDownStep(input_state, current_restrictions_);
+  if (!absl::holds_alternative<RestrictionsWithCounters>(first_step)) {
+    return first_step;
+  }
+  auto first_restrictions = absl::get<RestrictionsWithCounters>(first_step);
+  if (first_restrictions.counters.resolution_adaptations >
+      current_restrictions_.counters.resolution_adaptations) {
+    return first_step;
+  }
+  // We didn't decrease resolution so force it; amend a resolution resuction
+  // to the existing framerate reduction in `first_restrictions`.
+  auto second_step = DecreaseResolution(input_state, first_restrictions);
+  if (absl::holds_alternative<RestrictionsWithCounters>(second_step)) {
+    return second_step;
+  }
+  // If the second step was not successful then settle for the first one.
+  return first_step;
+}
+
+void VideoStreamAdapter::ApplyAdaptation(
+    const Adaptation& adaptation,
+    rtc::scoped_refptr<Resource> resource) {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  RTC_DCHECK_EQ(adaptation.validation_id_, adaptation_validation_id_);
+  if (adaptation.status() != Adaptation::Status::kValid)
+    return;
+  // Remember the input pixels and fps of this adaptation. Used to avoid
+  // adapting again before this adaptation has had an effect.
+  if (DidIncreaseResolution(current_restrictions_.restrictions,
+                            adaptation.restrictions())) {
+    awaiting_frame_size_change_.emplace(
+        true, adaptation.input_state().frame_size_pixels().value());
+  } else if (DidDecreaseResolution(current_restrictions_.restrictions,
+                                   adaptation.restrictions())) {
+    awaiting_frame_size_change_.emplace(
+        false, adaptation.input_state().frame_size_pixels().value());
+  } else {
+    awaiting_frame_size_change_ = absl::nullopt;
+  }
+  current_restrictions_ = {adaptation.restrictions(), adaptation.counters()};
+  BroadcastVideoRestrictionsUpdate(adaptation.input_state(), resource);
+}
+
+Adaptation VideoStreamAdapter::GetAdaptationTo(
+    const VideoAdaptationCounters& counters,
+    const VideoSourceRestrictions& restrictions) {
+  // Adapts up/down from the current levels so counters are equal.
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  VideoStreamInputState input_state = input_state_provider_->InputState();
+  return Adaptation(adaptation_validation_id_, restrictions, counters,
+                    input_state);
+}
+
+void VideoStreamAdapter::BroadcastVideoRestrictionsUpdate(
+    const VideoStreamInputState& input_state,
+    const rtc::scoped_refptr<Resource>& resource) {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  VideoSourceRestrictions filtered = FilterRestrictionsByDegradationPreference(
+      source_restrictions(), degradation_preference_);
+  if (last_filtered_restrictions_ == filtered) {
+    return;
+  }
+  for (auto* restrictions_listener : restrictions_listeners_) {
+    restrictions_listener->OnVideoSourceRestrictionsUpdated(
+        filtered, current_restrictions_.counters, resource,
+        source_restrictions());
+  }
+  last_video_source_restrictions_ = current_restrictions_.restrictions;
+  last_filtered_restrictions_ = filtered;
+}
+
+bool VideoStreamAdapter::HasSufficientInputForAdaptation(
+    const VideoStreamInputState& input_state) const {
+  return input_state.HasInputFrameSizeAndFramesPerSecond() &&
+         (degradation_preference_ !=
+              DegradationPreference::MAINTAIN_RESOLUTION ||
+          input_state.frames_per_second() >= kMinFrameRateFps);
+}
+
+VideoStreamAdapter::AwaitingFrameSizeChange::AwaitingFrameSizeChange(
+    bool pixels_increased,
+    int frame_size_pixels)
+    : pixels_increased(pixels_increased),
+      frame_size_pixels(frame_size_pixels) {}
+
+absl::optional<uint32_t> VideoStreamAdapter::GetSingleActiveLayerPixels(
+    const VideoCodec& codec) {
+  int num_active = 0;
+  absl::optional<uint32_t> pixels;
+  if (codec.codecType == VideoCodecType::kVideoCodecVP9) {
+    for (int i = 0; i < codec.VP9().numberOfSpatialLayers; ++i) {
+      if (codec.spatialLayers[i].active) {
+        ++num_active;
+        pixels = codec.spatialLayers[i].width * codec.spatialLayers[i].height;
+      }
+    }
+  } else {
+    for (int i = 0; i < codec.numberOfSimulcastStreams; ++i) {
+      if (codec.simulcastStream[i].active) {
+        ++num_active;
+        pixels =
+            codec.simulcastStream[i].width * codec.simulcastStream[i].height;
+      }
+    }
+  }
+  return (num_active > 1) ? absl::nullopt : pixels;
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/adaptation/video_stream_adapter.h b/third_party/libwebrtc/call/adaptation/video_stream_adapter.h
new file mode 100644
index 0000000000..5c174178e4
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/video_stream_adapter.h
@@ -0,0 +1,271 @@
+/*
+ *  Copyright 2020 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_ADAPTATION_VIDEO_STREAM_ADAPTER_H_
+#define CALL_ADAPTATION_VIDEO_STREAM_ADAPTER_H_
+
+#include <memory>
+#include <utility>
+#include <vector>
+
+#include "absl/types/optional.h"
+#include "absl/types/variant.h"
+#include "api/adaptation/resource.h"
+#include "api/field_trials_view.h"
+#include "api/rtp_parameters.h"
+#include "api/video/video_adaptation_counters.h"
+#include "call/adaptation/adaptation_constraint.h"
+#include "call/adaptation/degradation_preference_provider.h"
+#include "call/adaptation/video_source_restrictions.h"
+#include "call/adaptation/video_stream_input_state.h"
+#include "call/adaptation/video_stream_input_state_provider.h"
+#include "modules/video_coding/utility/quality_scaler.h"
+#include "rtc_base/experiments/balanced_degradation_settings.h"
+#include "rtc_base/system/no_unique_address.h"
+#include "rtc_base/thread_annotations.h"
+#include "video/video_stream_encoder_observer.h"
+
+namespace webrtc {
+
+// The listener is responsible for carrying out the reconfiguration of the video
+// source such that the VideoSourceRestrictions are fulfilled.
+class VideoSourceRestrictionsListener {
+ public:
+  virtual ~VideoSourceRestrictionsListener();
+
+  // The `restrictions` are filtered by degradation preference but not the
+  // `adaptation_counters`, which are currently only reported for legacy stats
+  // calculation purposes.
+  virtual void OnVideoSourceRestrictionsUpdated(
+      VideoSourceRestrictions restrictions,
+      const VideoAdaptationCounters& adaptation_counters,
+      rtc::scoped_refptr<Resource> reason,
+      const VideoSourceRestrictions& unfiltered_restrictions) = 0;
+};
+
+class VideoStreamAdapter;
+
+extern const int kMinFrameRateFps;
+
+VideoSourceRestrictions FilterRestrictionsByDegradationPreference(
+    VideoSourceRestrictions source_restrictions,
+    DegradationPreference degradation_preference);
+
+int GetLowerResolutionThan(int pixel_count);
+int GetHigherResolutionThan(int pixel_count);
+
+// Either represents the next VideoSourceRestrictions the VideoStreamAdapter
+// will take, or provides a Status code indicating the reason for not adapting
+// if the adaptation is not valid.
+class Adaptation final {
+ public:
+  enum class Status {
+    // Applying this adaptation will have an effect. All other Status codes
+    // indicate that adaptation is not possible and why.
+    kValid,
+    // Cannot adapt. The minimum or maximum adaptation has already been reached.
+    // There are no more steps to take.
+    kLimitReached,
+    // Cannot adapt. The resolution or frame rate requested by a recent
+    // adaptation has not yet been reflected in the input resolution or frame
+    // rate; adaptation is refused to avoid "double-adapting".
+    kAwaitingPreviousAdaptation,
+    // Not enough input.
+    kInsufficientInput,
+    // Adaptation disabled via degradation preference.
+    kAdaptationDisabled,
+    // Adaptation up was rejected by a VideoAdaptationConstraint.
+    kRejectedByConstraint,
+  };
+
+  static const char* StatusToString(Status status);
+
+  Status status() const;
+  const VideoStreamInputState& input_state() const;
+  const VideoSourceRestrictions& restrictions() const;
+  const VideoAdaptationCounters& counters() const;
+
+ private:
+  friend class VideoStreamAdapter;
+
+  // Constructs with a valid adaptation. Status is kValid.
+  Adaptation(int validation_id,
+             VideoSourceRestrictions restrictions,
+             VideoAdaptationCounters counters,
+             VideoStreamInputState input_state);
+  // Constructor when adaptation is not valid. Status MUST NOT be kValid.
+  Adaptation(int validation_id, Status invalid_status);
+
+  // An Adaptation can become invalidated if the state of VideoStreamAdapter is
+  // modified before the Adaptation is applied. To guard against this, this ID
+  // has to match VideoStreamAdapter::adaptation_validation_id_ when applied.
+  // TODO(https://crbug.com/webrtc/11700): Remove the validation_id_.
+  const int validation_id_;
+  const Status status_;
+  // Input state when adaptation was made.
+  const VideoStreamInputState input_state_;
+  const VideoSourceRestrictions restrictions_;
+  const VideoAdaptationCounters counters_;
+};
+
+// Owns the VideoSourceRestriction for a single stream and is responsible for
+// adapting it up or down when told to do so. This class serves the following
+// purposes:
+// 1. Keep track of a stream's restrictions.
+// 2. Provide valid ways to adapt up or down the stream's restrictions.
+// 3. Modify the stream's restrictions in one of the valid ways.
+class VideoStreamAdapter {
+ public:
+  VideoStreamAdapter(VideoStreamInputStateProvider* input_state_provider,
+                     VideoStreamEncoderObserver* encoder_stats_observer,
+                     const FieldTrialsView& field_trials);
+  ~VideoStreamAdapter();
+
+  VideoSourceRestrictions source_restrictions() const;
+  const VideoAdaptationCounters& adaptation_counters() const;
+  void ClearRestrictions();
+
+  void AddRestrictionsListener(
+      VideoSourceRestrictionsListener* restrictions_listener);
+  void RemoveRestrictionsListener(
+      VideoSourceRestrictionsListener* restrictions_listener);
+  void AddAdaptationConstraint(AdaptationConstraint* adaptation_constraint);
+  void RemoveAdaptationConstraint(AdaptationConstraint* adaptation_constraint);
+
+  // TODO(hbos): Setting the degradation preference should not clear
+  // restrictions! This is not defined in the spec and is unexpected, there is a
+  // tiny risk that people would discover and rely on this behavior.
+  void SetDegradationPreference(DegradationPreference degradation_preference);
+
+  // Returns an adaptation that we are guaranteed to be able to apply, or a
+  // status code indicating the reason why we cannot adapt.
+  Adaptation GetAdaptationUp();
+  Adaptation GetAdaptationDown();
+  Adaptation GetAdaptationTo(const VideoAdaptationCounters& counters,
+                             const VideoSourceRestrictions& restrictions);
+  // Tries to adapt the resolution one step. This is used for initial frame
+  // dropping. Does nothing if the degradation preference is not BALANCED or
+  // MAINTAIN_FRAMERATE. In the case of BALANCED, it will try twice to reduce
+  // the resolution. If it fails twice it gives up.
+  Adaptation GetAdaptDownResolution();
+
+  // Updates source_restrictions() the Adaptation.
+  void ApplyAdaptation(const Adaptation& adaptation,
+                       rtc::scoped_refptr<Resource> resource);
+
+  struct RestrictionsWithCounters {
+    VideoSourceRestrictions restrictions;
+    VideoAdaptationCounters counters;
+  };
+
+  static absl::optional<uint32_t> GetSingleActiveLayerPixels(
+      const VideoCodec& codec);
+
+ private:
+  void BroadcastVideoRestrictionsUpdate(
+      const VideoStreamInputState& input_state,
+      const rtc::scoped_refptr<Resource>& resource);
+
+  bool HasSufficientInputForAdaptation(const VideoStreamInputState& input_state)
+      const RTC_RUN_ON(&sequence_checker_);
+
+  using RestrictionsOrState =
+      absl::variant<RestrictionsWithCounters, Adaptation::Status>;
+  RestrictionsOrState GetAdaptationUpStep(
+      const VideoStreamInputState& input_state) const
+      RTC_RUN_ON(&sequence_checker_);
+  RestrictionsOrState GetAdaptationDownStep(
+      const VideoStreamInputState& input_state,
+      const RestrictionsWithCounters& current_restrictions) const
+      RTC_RUN_ON(&sequence_checker_);
+  RestrictionsOrState GetAdaptDownResolutionStepForBalanced(
+      const VideoStreamInputState& input_state) const
+      RTC_RUN_ON(&sequence_checker_);
+  RestrictionsOrState AdaptIfFpsDiffInsufficient(
+      const VideoStreamInputState& input_state,
+      const RestrictionsWithCounters& restrictions) const
+      RTC_RUN_ON(&sequence_checker_);
+
+  Adaptation GetAdaptationUp(const VideoStreamInputState& input_state) const
+      RTC_RUN_ON(&sequence_checker_);
+  Adaptation GetAdaptationDown(const VideoStreamInputState& input_state) const
+      RTC_RUN_ON(&sequence_checker_);
+
+  static RestrictionsOrState DecreaseResolution(
+      const VideoStreamInputState& input_state,
+      const RestrictionsWithCounters& current_restrictions);
+  static RestrictionsOrState IncreaseResolution(
+      const VideoStreamInputState& input_state,
+      const RestrictionsWithCounters& current_restrictions);
+  // Framerate methods are member functions because they need internal state
+  // if the degradation preference is BALANCED.
+  RestrictionsOrState DecreaseFramerate(
+      const VideoStreamInputState& input_state,
+      const RestrictionsWithCounters& current_restrictions) const
+      RTC_RUN_ON(&sequence_checker_);
+  RestrictionsOrState IncreaseFramerate(
+      const VideoStreamInputState& input_state,
+      const RestrictionsWithCounters& current_restrictions) const
+      RTC_RUN_ON(&sequence_checker_);
+
+  struct RestrictionsOrStateVisitor;
+  Adaptation RestrictionsOrStateToAdaptation(
+      RestrictionsOrState step_or_state,
+      const VideoStreamInputState& input_state) const
+      RTC_RUN_ON(&sequence_checker_);
+
+  RTC_NO_UNIQUE_ADDRESS SequenceChecker sequence_checker_
+      RTC_GUARDED_BY(&sequence_checker_);
+  // Gets the input state which is the basis of all adaptations.
+  // Thread safe.
+  VideoStreamInputStateProvider* input_state_provider_;
+  // Used to signal when min pixel limit has been reached.
+  VideoStreamEncoderObserver* const encoder_stats_observer_;
+  // Decides the next adaptation target in DegradationPreference::BALANCED.
+  const BalancedDegradationSettings balanced_settings_;
+  // To guard against applying adaptations that have become invalidated, an
+  // Adaptation that is applied has to have a matching validation ID.
+  int adaptation_validation_id_ RTC_GUARDED_BY(&sequence_checker_);
+  // When deciding the next target up or down, different strategies are used
+  // depending on the DegradationPreference.
+  // https://w3c.github.io/mst-content-hint/#dom-rtcdegradationpreference
+  DegradationPreference degradation_preference_
+      RTC_GUARDED_BY(&sequence_checker_);
+  // Used to avoid adapting twice. Stores the resolution at the time of the last
+  // adaptation.
+  // TODO(hbos): Can we implement a more general "cooldown" mechanism of
+  // resources intead? If we already have adapted it seems like we should wait
+  // a while before adapting again, so that we are not acting on usage
+  // measurements that are made obsolete/unreliable by an "ongoing" adaptation.
+  struct AwaitingFrameSizeChange {
+    AwaitingFrameSizeChange(bool pixels_increased, int frame_size);
+    const bool pixels_increased;
+    const int frame_size_pixels;
+  };
+  absl::optional<AwaitingFrameSizeChange> awaiting_frame_size_change_
+      RTC_GUARDED_BY(&sequence_checker_);
+  // The previous restrictions value. Starts as unrestricted.
+  VideoSourceRestrictions last_video_source_restrictions_
+      RTC_GUARDED_BY(&sequence_checker_);
+  VideoSourceRestrictions last_filtered_restrictions_
+      RTC_GUARDED_BY(&sequence_checker_);
+
+  std::vector<VideoSourceRestrictionsListener*> restrictions_listeners_
+      RTC_GUARDED_BY(&sequence_checker_);
+  std::vector<AdaptationConstraint*> adaptation_constraints_
+      RTC_GUARDED_BY(&sequence_checker_);
+
+  RestrictionsWithCounters current_restrictions_
+      RTC_GUARDED_BY(&sequence_checker_);
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_ADAPTATION_VIDEO_STREAM_ADAPTER_H_
diff --git a/third_party/libwebrtc/call/adaptation/video_stream_adapter_unittest.cc b/third_party/libwebrtc/call/adaptation/video_stream_adapter_unittest.cc
new file mode 100644
index 0000000000..d4bc650856
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/video_stream_adapter_unittest.cc
@@ -0,0 +1,951 @@
+/*
+ *  Copyright (c) 2020 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/adaptation/video_stream_adapter.h"
+
+#include <string>
+#include <utility>
+
+#include "absl/types/optional.h"
+#include "api/scoped_refptr.h"
+#include "api/video/video_adaptation_reason.h"
+#include "api/video_codecs/video_codec.h"
+#include "api/video_codecs/video_encoder.h"
+#include "call/adaptation/adaptation_constraint.h"
+#include "call/adaptation/encoder_settings.h"
+#include "call/adaptation/test/fake_frame_rate_provider.h"
+#include "call/adaptation/test/fake_resource.h"
+#include "call/adaptation/test/fake_video_stream_input_state_provider.h"
+#include "call/adaptation/video_source_restrictions.h"
+#include "call/adaptation/video_stream_input_state.h"
+#include "rtc_base/string_encode.h"
+#include "test/gmock.h"
+#include "test/gtest.h"
+#include "test/scoped_key_value_config.h"
+#include "test/testsupport/rtc_expect_death.h"
+#include "video/config/video_encoder_config.h"
+
+namespace webrtc {
+
+using ::testing::_;
+using ::testing::DoAll;
+using ::testing::Return;
+using ::testing::SaveArg;
+
+namespace {
+
+const int kBalancedHighResolutionPixels = 1280 * 720;
+const int kBalancedHighFrameRateFps = 30;
+
+const int kBalancedMediumResolutionPixels = 640 * 480;
+const int kBalancedMediumFrameRateFps = 20;
+
+const int kBalancedLowResolutionPixels = 320 * 240;
+const int kBalancedLowFrameRateFps = 10;
+
+std::string BalancedFieldTrialConfig() {
+  return "WebRTC-Video-BalancedDegradationSettings/pixels:" +
+         rtc::ToString(kBalancedLowResolutionPixels) + "|" +
+         rtc::ToString(kBalancedMediumResolutionPixels) + "|" +
+         rtc::ToString(kBalancedHighResolutionPixels) +
+         ",fps:" + rtc::ToString(kBalancedLowFrameRateFps) + "|" +
+         rtc::ToString(kBalancedMediumFrameRateFps) + "|" +
+         rtc::ToString(kBalancedHighFrameRateFps) + "/";
+}
+
+// Responsible for adjusting the inputs to VideoStreamAdapter (SetInput), such
+// as pixels and frame rate, according to the most recent source restrictions.
+// This helps tests that apply adaptations multiple times: if the input is not
+// adjusted between adaptations, the subsequent adaptations fail with
+// kAwaitingPreviousAdaptation.
+class FakeVideoStream {
+ public:
+  FakeVideoStream(VideoStreamAdapter* adapter,
+                  FakeVideoStreamInputStateProvider* provider,
+                  int input_pixels,
+                  int input_fps,
+                  int min_pixels_per_frame)
+      : adapter_(adapter),
+        provider_(provider),
+        input_pixels_(input_pixels),
+        input_fps_(input_fps),
+        min_pixels_per_frame_(min_pixels_per_frame) {
+    provider_->SetInputState(input_pixels_, input_fps_, min_pixels_per_frame_);
+  }
+
+  int input_pixels() const { return input_pixels_; }
+  int input_fps() const { return input_fps_; }
+
+  // Performs ApplyAdaptation() followed by SetInput() with input pixels and
+  // frame rate adjusted according to the resulting restrictions.
+  void ApplyAdaptation(Adaptation adaptation) {
+    adapter_->ApplyAdaptation(adaptation, nullptr);
+    // Update input pixels and fps according to the resulting restrictions.
+    auto restrictions = adapter_->source_restrictions();
+    if (restrictions.target_pixels_per_frame().has_value()) {
+      RTC_DCHECK(!restrictions.max_pixels_per_frame().has_value() ||
+                 restrictions.max_pixels_per_frame().value() >=
+                     restrictions.target_pixels_per_frame().value());
+      input_pixels_ = restrictions.target_pixels_per_frame().value();
+    } else if (restrictions.max_pixels_per_frame().has_value()) {
+      input_pixels_ = restrictions.max_pixels_per_frame().value();
+    }
+    if (restrictions.max_frame_rate().has_value()) {
+      input_fps_ = restrictions.max_frame_rate().value();
+    }
+    provider_->SetInputState(input_pixels_, input_fps_, min_pixels_per_frame_);
+  }
+
+ private:
+  VideoStreamAdapter* adapter_;
+  FakeVideoStreamInputStateProvider* provider_;
+  int input_pixels_;
+  int input_fps_;
+  int min_pixels_per_frame_;
+};
+
+class FakeVideoStreamAdapterListner : public VideoSourceRestrictionsListener {
+ public:
+  void OnVideoSourceRestrictionsUpdated(
+      VideoSourceRestrictions restrictions,
+      const VideoAdaptationCounters& adaptation_counters,
+      rtc::scoped_refptr<Resource> reason,
+      const VideoSourceRestrictions& unfiltered_restrictions) override {
+    calls_++;
+    last_restrictions_ = unfiltered_restrictions;
+  }
+
+  int calls() const { return calls_; }
+
+  VideoSourceRestrictions last_restrictions() const {
+    return last_restrictions_;
+  }
+
+ private:
+  int calls_ = 0;
+  VideoSourceRestrictions last_restrictions_;
+};
+
+class MockAdaptationConstraint : public AdaptationConstraint {
+ public:
+  MOCK_METHOD(bool,
+              IsAdaptationUpAllowed,
+              (const VideoStreamInputState& input_state,
+               const VideoSourceRestrictions& restrictions_before,
+               const VideoSourceRestrictions& restrictions_after),
+              (const, override));
+
+  // MOCK_METHOD(std::string, Name, (), (const, override));
+  std::string Name() const override { return "MockAdaptationConstraint"; }
+};
+
+}  // namespace
+
+class VideoStreamAdapterTest : public ::testing::Test {
+ public:
+  VideoStreamAdapterTest()
+      : field_trials_(BalancedFieldTrialConfig()),
+        resource_(FakeResource::Create("FakeResource")),
+        adapter_(&input_state_provider_,
+                 &encoder_stats_observer_,
+                 field_trials_) {}
+
+ protected:
+  webrtc::test::ScopedKeyValueConfig field_trials_;
+  FakeVideoStreamInputStateProvider input_state_provider_;
+  rtc::scoped_refptr<Resource> resource_;
+  testing::StrictMock<MockVideoStreamEncoderObserver> encoder_stats_observer_;
+  VideoStreamAdapter adapter_;
+};
+
+TEST_F(VideoStreamAdapterTest, NoRestrictionsByDefault) {
+  EXPECT_EQ(VideoSourceRestrictions(), adapter_.source_restrictions());
+  EXPECT_EQ(0, adapter_.adaptation_counters().Total());
+}
+
+TEST_F(VideoStreamAdapterTest, MaintainFramerate_DecreasesPixelsToThreeFifths) {
+  const int kInputPixels = 1280 * 720;
+  adapter_.SetDegradationPreference(DegradationPreference::MAINTAIN_FRAMERATE);
+  input_state_provider_.SetInputState(kInputPixels, 30,
+                                      kDefaultMinPixelsPerFrame);
+  Adaptation adaptation = adapter_.GetAdaptationDown();
+  EXPECT_EQ(Adaptation::Status::kValid, adaptation.status());
+  adapter_.ApplyAdaptation(adaptation, nullptr);
+  EXPECT_EQ(static_cast<size_t>((kInputPixels * 3) / 5),
+            adapter_.source_restrictions().max_pixels_per_frame());
+  EXPECT_EQ(absl::nullopt,
+            adapter_.source_restrictions().target_pixels_per_frame());
+  EXPECT_EQ(absl::nullopt, adapter_.source_restrictions().max_frame_rate());
+  EXPECT_EQ(1, adapter_.adaptation_counters().resolution_adaptations);
+}
+
+TEST_F(VideoStreamAdapterTest,
+       MaintainFramerate_DecreasesPixelsToLimitReached) {
+  const int kMinPixelsPerFrame = 640 * 480;
+
+  adapter_.SetDegradationPreference(DegradationPreference::MAINTAIN_FRAMERATE);
+  input_state_provider_.SetInputState(kMinPixelsPerFrame + 1, 30,
+                                      kMinPixelsPerFrame);
+  EXPECT_CALL(encoder_stats_observer_, OnMinPixelLimitReached());
+  // Even though we are above kMinPixelsPerFrame, because adapting down would
+  // have exceeded the limit, we are said to have reached the limit already.
+  // This differs from the frame rate adaptation logic, which would have clamped
+  // to the limit in the first step and reported kLimitReached in the second
+  // step.
+  Adaptation adaptation = adapter_.GetAdaptationDown();
+  EXPECT_EQ(Adaptation::Status::kLimitReached, adaptation.status());
+}
+
+TEST_F(VideoStreamAdapterTest, MaintainFramerate_IncreasePixelsToFiveThirds) {
+  adapter_.SetDegradationPreference(DegradationPreference::MAINTAIN_FRAMERATE);
+  FakeVideoStream fake_stream(&adapter_, &input_state_provider_, 1280 * 720, 30,
+                              kDefaultMinPixelsPerFrame);
+  // Go down twice, ensuring going back up is still a restricted resolution.
+  fake_stream.ApplyAdaptation(adapter_.GetAdaptationDown());
+  fake_stream.ApplyAdaptation(adapter_.GetAdaptationDown());
+  EXPECT_EQ(2, adapter_.adaptation_counters().resolution_adaptations);
+  int input_pixels = fake_stream.input_pixels();
+  // Go up once. The target is 5/3 and the max is 12/5 of the target.
+  const int target = (input_pixels * 5) / 3;
+  fake_stream.ApplyAdaptation(adapter_.GetAdaptationUp());
+  EXPECT_EQ(static_cast<size_t>((target * 12) / 5),
+            adapter_.source_restrictions().max_pixels_per_frame());
+  EXPECT_EQ(static_cast<size_t>(target),
+            adapter_.source_restrictions().target_pixels_per_frame());
+  EXPECT_EQ(absl::nullopt, adapter_.source_restrictions().max_frame_rate());
+  EXPECT_EQ(1, adapter_.adaptation_counters().resolution_adaptations);
+}
+
+TEST_F(VideoStreamAdapterTest, MaintainFramerate_IncreasePixelsToUnrestricted) {
+  adapter_.SetDegradationPreference(DegradationPreference::MAINTAIN_FRAMERATE);
+  FakeVideoStream fake_stream(&adapter_, &input_state_provider_, 1280 * 720, 30,
+                              kDefaultMinPixelsPerFrame);
+  // We are unrestricted by default and should not be able to adapt up.
+  EXPECT_EQ(Adaptation::Status::kLimitReached,
+            adapter_.GetAdaptationUp().status());
+  // If we go down once and then back up we should not have any restrictions.
+  fake_stream.ApplyAdaptation(adapter_.GetAdaptationDown());
+  EXPECT_EQ(1, adapter_.adaptation_counters().resolution_adaptations);
+  fake_stream.ApplyAdaptation(adapter_.GetAdaptationUp());
+  EXPECT_EQ(VideoSourceRestrictions(), adapter_.source_restrictions());
+  EXPECT_EQ(0, adapter_.adaptation_counters().Total());
+}
+
+TEST_F(VideoStreamAdapterTest, MaintainResolution_DecreasesFpsToTwoThirds) {
+  const int kInputFps = 30;
+
+  adapter_.SetDegradationPreference(DegradationPreference::MAINTAIN_RESOLUTION);
+  input_state_provider_.SetInputState(1280 * 720, kInputFps,
+                                      kDefaultMinPixelsPerFrame);
+  Adaptation adaptation = adapter_.GetAdaptationDown();
+  EXPECT_EQ(Adaptation::Status::kValid, adaptation.status());
+  adapter_.ApplyAdaptation(adaptation, nullptr);
+  EXPECT_EQ(absl::nullopt,
+            adapter_.source_restrictions().max_pixels_per_frame());
+  EXPECT_EQ(absl::nullopt,
+            adapter_.source_restrictions().target_pixels_per_frame());
+  EXPECT_EQ(static_cast<double>((kInputFps * 2) / 3),
+            adapter_.source_restrictions().max_frame_rate());
+  EXPECT_EQ(1, adapter_.adaptation_counters().fps_adaptations);
+}
+
+TEST_F(VideoStreamAdapterTest, MaintainResolution_DecreasesFpsToLimitReached) {
+  adapter_.SetDegradationPreference(DegradationPreference::MAINTAIN_RESOLUTION);
+  FakeVideoStream fake_stream(&adapter_, &input_state_provider_, 1280 * 720,
+                              kMinFrameRateFps + 1, kDefaultMinPixelsPerFrame);
+  // If we are not yet at the limit and the next step would exceed it, the step
+  // is clamped such that we end up exactly on the limit.
+  Adaptation adaptation = adapter_.GetAdaptationDown();
+  EXPECT_EQ(Adaptation::Status::kValid, adaptation.status());
+  fake_stream.ApplyAdaptation(adaptation);
+  EXPECT_EQ(static_cast<double>(kMinFrameRateFps),
+            adapter_.source_restrictions().max_frame_rate());
+  EXPECT_EQ(1, adapter_.adaptation_counters().fps_adaptations);
+  // Having reached the limit, the next adaptation down is not valid.
+  EXPECT_EQ(Adaptation::Status::kLimitReached,
+            adapter_.GetAdaptationDown().status());
+}
+
+TEST_F(VideoStreamAdapterTest, MaintainResolution_IncreaseFpsToThreeHalves) {
+  adapter_.SetDegradationPreference(DegradationPreference::MAINTAIN_RESOLUTION);
+  FakeVideoStream fake_stream(&adapter_, &input_state_provider_, 1280 * 720, 30,
+                              kDefaultMinPixelsPerFrame);
+  // Go down twice, ensuring going back up is still a restricted frame rate.
+  fake_stream.ApplyAdaptation(adapter_.GetAdaptationDown());
+  fake_stream.ApplyAdaptation(adapter_.GetAdaptationDown());
+  EXPECT_EQ(2, adapter_.adaptation_counters().fps_adaptations);
+  int input_fps = fake_stream.input_fps();
+  // Go up once. The target is 3/2 of the input.
+  Adaptation adaptation = adapter_.GetAdaptationUp();
+  EXPECT_EQ(Adaptation::Status::kValid, adaptation.status());
+  fake_stream.ApplyAdaptation(adaptation);
+  EXPECT_EQ(absl::nullopt,
+            adapter_.source_restrictions().max_pixels_per_frame());
+  EXPECT_EQ(absl::nullopt,
+            adapter_.source_restrictions().target_pixels_per_frame());
+  EXPECT_EQ(static_cast<double>((input_fps * 3) / 2),
+            adapter_.source_restrictions().max_frame_rate());
+  EXPECT_EQ(1, adapter_.adaptation_counters().fps_adaptations);
+}
+
+TEST_F(VideoStreamAdapterTest, MaintainResolution_IncreaseFpsToUnrestricted) {
+  adapter_.SetDegradationPreference(DegradationPreference::MAINTAIN_RESOLUTION);
+  FakeVideoStream fake_stream(&adapter_, &input_state_provider_, 1280 * 720, 30,
+                              kDefaultMinPixelsPerFrame);
+  // We are unrestricted by default and should not be able to adapt up.
+  EXPECT_EQ(Adaptation::Status::kLimitReached,
+            adapter_.GetAdaptationUp().status());
+  // If we go down once and then back up we should not have any restrictions.
+  fake_stream.ApplyAdaptation(adapter_.GetAdaptationDown());
+  EXPECT_EQ(1, adapter_.adaptation_counters().fps_adaptations);
+  fake_stream.ApplyAdaptation(adapter_.GetAdaptationUp());
+  EXPECT_EQ(VideoSourceRestrictions(), adapter_.source_restrictions());
+  EXPECT_EQ(0, adapter_.adaptation_counters().Total());
+}
+
+TEST_F(VideoStreamAdapterTest, Balanced_DecreaseFrameRate) {
+  adapter_.SetDegradationPreference(DegradationPreference::BALANCED);
+  input_state_provider_.SetInputState(kBalancedMediumResolutionPixels,
+                                      kBalancedHighFrameRateFps,
+                                      kDefaultMinPixelsPerFrame);
+  // If our frame rate is higher than the frame rate associated with our
+  // resolution we should try to adapt to the frame rate associated with our
+  // resolution: kBalancedMediumFrameRateFps.
+  Adaptation adaptation = adapter_.GetAdaptationDown();
+  EXPECT_EQ(Adaptation::Status::kValid, adaptation.status());
+  adapter_.ApplyAdaptation(adaptation, nullptr);
+  EXPECT_EQ(absl::nullopt,
+            adapter_.source_restrictions().max_pixels_per_frame());
+  EXPECT_EQ(absl::nullopt,
+            adapter_.source_restrictions().target_pixels_per_frame());
+  EXPECT_EQ(static_cast<double>(kBalancedMediumFrameRateFps),
+            adapter_.source_restrictions().max_frame_rate());
+  EXPECT_EQ(0, adapter_.adaptation_counters().resolution_adaptations);
+  EXPECT_EQ(1, adapter_.adaptation_counters().fps_adaptations);
+}
+
+TEST_F(VideoStreamAdapterTest, Balanced_DecreaseResolution) {
+  adapter_.SetDegradationPreference(DegradationPreference::BALANCED);
+  FakeVideoStream fake_stream(
+      &adapter_, &input_state_provider_, kBalancedHighResolutionPixels,
+      kBalancedHighFrameRateFps, kDefaultMinPixelsPerFrame);
+  // If we are not below the current resolution's frame rate limit, we should
+  // adapt resolution according to "maintain-framerate" logic (three fifths).
+  //
+  // However, since we are unlimited at the start and input frame rate is not
+  // below kBalancedHighFrameRateFps, we first restrict the frame rate to
+  // kBalancedHighFrameRateFps even though that is our current frame rate. This
+  // does prevent the source from going higher, though, so it's technically not
+  // a NO-OP.
+  {
+    Adaptation adaptation = adapter_.GetAdaptationDown();
+    EXPECT_EQ(Adaptation::Status::kValid, adaptation.status());
+    fake_stream.ApplyAdaptation(adaptation);
+  }
+  EXPECT_EQ(absl::nullopt,
+            adapter_.source_restrictions().max_pixels_per_frame());
+  EXPECT_EQ(absl::nullopt,
+            adapter_.source_restrictions().target_pixels_per_frame());
+  EXPECT_EQ(static_cast<double>(kBalancedHighFrameRateFps),
+            adapter_.source_restrictions().max_frame_rate());
+  EXPECT_EQ(0, adapter_.adaptation_counters().resolution_adaptations);
+  EXPECT_EQ(1, adapter_.adaptation_counters().fps_adaptations);
+  // Verify "maintain-framerate" logic the second time we adapt: Frame rate
+  // restrictions remains the same and resolution goes down.
+  {
+    Adaptation adaptation = adapter_.GetAdaptationDown();
+    EXPECT_EQ(Adaptation::Status::kValid, adaptation.status());
+    fake_stream.ApplyAdaptation(adaptation);
+  }
+  constexpr size_t kReducedPixelsFirstStep =
+      static_cast<size_t>((kBalancedHighResolutionPixels * 3) / 5);
+  EXPECT_EQ(kReducedPixelsFirstStep,
+            adapter_.source_restrictions().max_pixels_per_frame());
+  EXPECT_EQ(absl::nullopt,
+            adapter_.source_restrictions().target_pixels_per_frame());
+  EXPECT_EQ(static_cast<double>(kBalancedHighFrameRateFps),
+            adapter_.source_restrictions().max_frame_rate());
+  EXPECT_EQ(1, adapter_.adaptation_counters().resolution_adaptations);
+  EXPECT_EQ(1, adapter_.adaptation_counters().fps_adaptations);
+  // If we adapt again, because the balanced settings' proposed frame rate is
+  // still kBalancedHighFrameRateFps, "maintain-framerate" will trigger again.
+  static_assert(kReducedPixelsFirstStep > kBalancedMediumResolutionPixels,
+                "The reduced resolution is still greater than the next lower "
+                "balanced setting resolution");
+  constexpr size_t kReducedPixelsSecondStep = (kReducedPixelsFirstStep * 3) / 5;
+  {
+    Adaptation adaptation = adapter_.GetAdaptationDown();
+    EXPECT_EQ(Adaptation::Status::kValid, adaptation.status());
+    fake_stream.ApplyAdaptation(adaptation);
+  }
+  EXPECT_EQ(kReducedPixelsSecondStep,
+            adapter_.source_restrictions().max_pixels_per_frame());
+  EXPECT_EQ(absl::nullopt,
+            adapter_.source_restrictions().target_pixels_per_frame());
+  EXPECT_EQ(static_cast<double>(kBalancedHighFrameRateFps),
+            adapter_.source_restrictions().max_frame_rate());
+  EXPECT_EQ(2, adapter_.adaptation_counters().resolution_adaptations);
+  EXPECT_EQ(1, adapter_.adaptation_counters().fps_adaptations);
+}
+
+// Testing when to adapt frame rate and when to adapt resolution is quite
+// entangled, so this test covers both cases.
+//
+// There is an asymmetry: When we adapt down we do it in one order, but when we
+// adapt up we don't do it in the reverse order. Instead we always try to adapt
+// frame rate first according to balanced settings' configs and only when the
+// frame rate is already achieved do we adjust the resolution.
+TEST_F(VideoStreamAdapterTest, Balanced_IncreaseFrameRateAndResolution) {
+  adapter_.SetDegradationPreference(DegradationPreference::BALANCED);
+  FakeVideoStream fake_stream(
+      &adapter_, &input_state_provider_, kBalancedHighResolutionPixels,
+      kBalancedHighFrameRateFps, kDefaultMinPixelsPerFrame);
+  // The desired starting point of this test is having adapted frame rate twice.
+  // This requires performing a number of adaptations.
+  constexpr size_t kReducedPixelsFirstStep =
+      static_cast<size_t>((kBalancedHighResolutionPixels * 3) / 5);
+  constexpr size_t kReducedPixelsSecondStep = (kReducedPixelsFirstStep * 3) / 5;
+  constexpr size_t kReducedPixelsThirdStep = (kReducedPixelsSecondStep * 3) / 5;
+  static_assert(kReducedPixelsFirstStep > kBalancedMediumResolutionPixels,
+                "The first pixel reduction is greater than the balanced "
+                "settings' medium pixel configuration");
+  static_assert(kReducedPixelsSecondStep > kBalancedMediumResolutionPixels,
+                "The second pixel reduction is greater than the balanced "
+                "settings' medium pixel configuration");
+  static_assert(kReducedPixelsThirdStep <= kBalancedMediumResolutionPixels,
+                "The third pixel reduction is NOT greater than the balanced "
+                "settings' medium pixel configuration");
+  // The first adaptation should affect the frame rate: See
+  // Balanced_DecreaseResolution for explanation why.
+  fake_stream.ApplyAdaptation(adapter_.GetAdaptationDown());
+  EXPECT_EQ(static_cast<double>(kBalancedHighFrameRateFps),
+            adapter_.source_restrictions().max_frame_rate());
+  // The next three adaptations affects the resolution, because we have to reach
+  // kBalancedMediumResolutionPixels before a lower frame rate is considered by
+  // BalancedDegradationSettings. The number three is derived from the
+  // static_asserts above.
+  fake_stream.ApplyAdaptation(adapter_.GetAdaptationDown());
+  EXPECT_EQ(kReducedPixelsFirstStep,
+            adapter_.source_restrictions().max_pixels_per_frame());
+  fake_stream.ApplyAdaptation(adapter_.GetAdaptationDown());
+  EXPECT_EQ(kReducedPixelsSecondStep,
+            adapter_.source_restrictions().max_pixels_per_frame());
+  fake_stream.ApplyAdaptation(adapter_.GetAdaptationDown());
+  EXPECT_EQ(kReducedPixelsThirdStep,
+            adapter_.source_restrictions().max_pixels_per_frame());
+  // Thus, the next adaptation will reduce frame rate to
+  // kBalancedMediumFrameRateFps.
+  fake_stream.ApplyAdaptation(adapter_.GetAdaptationDown());
+  EXPECT_EQ(static_cast<double>(kBalancedMediumFrameRateFps),
+            adapter_.source_restrictions().max_frame_rate());
+  EXPECT_EQ(3, adapter_.adaptation_counters().resolution_adaptations);
+  EXPECT_EQ(2, adapter_.adaptation_counters().fps_adaptations);
+  // Adapt up!
+  // While our resolution is in the medium-range, the frame rate associated with
+  // the next resolution configuration up ("high") is kBalancedHighFrameRateFps
+  // and "balanced" prefers adapting frame rate if not already applied.
+  {
+    Adaptation adaptation = adapter_.GetAdaptationUp();
+    EXPECT_EQ(Adaptation::Status::kValid, adaptation.status());
+    fake_stream.ApplyAdaptation(adaptation);
+    EXPECT_EQ(static_cast<double>(kBalancedHighFrameRateFps),
+              adapter_.source_restrictions().max_frame_rate());
+    EXPECT_EQ(3, adapter_.adaptation_counters().resolution_adaptations);
+    EXPECT_EQ(1, adapter_.adaptation_counters().fps_adaptations);
+  }
+  // Now that we have already achieved the next frame rate up, we act according
+  // to "maintain-framerate". We go back up in resolution. Due to rounding
+  // errors we don't end up back at kReducedPixelsSecondStep. Rather we get to
+  // kReducedPixelsSecondStepUp, which is off by one compared to
+  // kReducedPixelsSecondStep.
+  constexpr size_t kReducedPixelsSecondStepUp =
+      (kReducedPixelsThirdStep * 5) / 3;
+  {
+    Adaptation adaptation = adapter_.GetAdaptationUp();
+    EXPECT_EQ(Adaptation::Status::kValid, adaptation.status());
+    fake_stream.ApplyAdaptation(adaptation);
+    EXPECT_EQ(kReducedPixelsSecondStepUp,
+              adapter_.source_restrictions().target_pixels_per_frame());
+    EXPECT_EQ(2, adapter_.adaptation_counters().resolution_adaptations);
+    EXPECT_EQ(1, adapter_.adaptation_counters().fps_adaptations);
+  }
+  // Now that our resolution is back in the high-range, the next frame rate to
+  // try out is "unlimited".
+  {
+    Adaptation adaptation = adapter_.GetAdaptationUp();
+    EXPECT_EQ(Adaptation::Status::kValid, adaptation.status());
+    fake_stream.ApplyAdaptation(adaptation);
+    EXPECT_EQ(absl::nullopt, adapter_.source_restrictions().max_frame_rate());
+    EXPECT_EQ(2, adapter_.adaptation_counters().resolution_adaptations);
+    EXPECT_EQ(0, adapter_.adaptation_counters().fps_adaptations);
+  }
+  // Now only adapting resolution remains.
+  constexpr size_t kReducedPixelsFirstStepUp =
+      (kReducedPixelsSecondStepUp * 5) / 3;
+  {
+    Adaptation adaptation = adapter_.GetAdaptationUp();
+    EXPECT_EQ(Adaptation::Status::kValid, adaptation.status());
+    fake_stream.ApplyAdaptation(adaptation);
+    EXPECT_EQ(kReducedPixelsFirstStepUp,
+              adapter_.source_restrictions().target_pixels_per_frame());
+    EXPECT_EQ(1, adapter_.adaptation_counters().resolution_adaptations);
+    EXPECT_EQ(0, adapter_.adaptation_counters().fps_adaptations);
+  }
+  // The last step up should make us entirely unrestricted.
+  {
+    Adaptation adaptation = adapter_.GetAdaptationUp();
+    EXPECT_EQ(Adaptation::Status::kValid, adaptation.status());
+    fake_stream.ApplyAdaptation(adaptation);
+    EXPECT_EQ(VideoSourceRestrictions(), adapter_.source_restrictions());
+    EXPECT_EQ(0, adapter_.adaptation_counters().Total());
+  }
+}
+
+TEST_F(VideoStreamAdapterTest, Balanced_LimitReached) {
+  adapter_.SetDegradationPreference(DegradationPreference::BALANCED);
+  FakeVideoStream fake_stream(
+      &adapter_, &input_state_provider_, kBalancedLowResolutionPixels,
+      kBalancedLowFrameRateFps, kDefaultMinPixelsPerFrame);
+  // Attempting to adapt up while unrestricted should result in kLimitReached.
+  EXPECT_EQ(Adaptation::Status::kLimitReached,
+            adapter_.GetAdaptationUp().status());
+  // Adapting down once result in restricted frame rate, in this case we reach
+  // the lowest possible frame rate immediately: kBalancedLowFrameRateFps.
+  EXPECT_CALL(encoder_stats_observer_, OnMinPixelLimitReached()).Times(2);
+  fake_stream.ApplyAdaptation(adapter_.GetAdaptationDown());
+  EXPECT_EQ(static_cast<double>(kBalancedLowFrameRateFps),
+            adapter_.source_restrictions().max_frame_rate());
+  EXPECT_EQ(1, adapter_.adaptation_counters().fps_adaptations);
+  // Any further adaptation must follow "maintain-framerate" rules (these are
+  // covered in more depth by the MaintainFramerate tests). This test does not
+  // assert exactly how resolution is adjusted, only that resolution always
+  // decreases and that we eventually reach kLimitReached.
+  size_t previous_resolution = kBalancedLowResolutionPixels;
+  bool did_reach_limit = false;
+  // If we have not reached the limit within 5 adaptations something is wrong...
+  for (int i = 0; i < 5; i++) {
+    Adaptation adaptation = adapter_.GetAdaptationDown();
+    if (adaptation.status() == Adaptation::Status::kLimitReached) {
+      did_reach_limit = true;
+      break;
+    }
+    EXPECT_EQ(Adaptation::Status::kValid, adaptation.status());
+    fake_stream.ApplyAdaptation(adaptation);
+    EXPECT_LT(adapter_.source_restrictions().max_pixels_per_frame().value(),
+              previous_resolution);
+    previous_resolution =
+        adapter_.source_restrictions().max_pixels_per_frame().value();
+  }
+  EXPECT_TRUE(did_reach_limit);
+  // Frame rate restrictions are the same as before.
+  EXPECT_EQ(static_cast<double>(kBalancedLowFrameRateFps),
+            adapter_.source_restrictions().max_frame_rate());
+  EXPECT_EQ(1, adapter_.adaptation_counters().fps_adaptations);
+}
+
+// kAwaitingPreviousAdaptation is only supported in "maintain-framerate".
+TEST_F(VideoStreamAdapterTest,
+       MaintainFramerate_AwaitingPreviousAdaptationDown) {
+  adapter_.SetDegradationPreference(DegradationPreference::MAINTAIN_FRAMERATE);
+  input_state_provider_.SetInputState(1280 * 720, 30,
+                                      kDefaultMinPixelsPerFrame);
+  // Adapt down once, but don't update the input.
+  adapter_.ApplyAdaptation(adapter_.GetAdaptationDown(), nullptr);
+  EXPECT_EQ(1, adapter_.adaptation_counters().resolution_adaptations);
+  {
+    // Having performed the adaptation, but not updated the input based on the
+    // new restrictions, adapting again in the same direction will not work.
+    Adaptation adaptation = adapter_.GetAdaptationDown();
+    EXPECT_EQ(Adaptation::Status::kAwaitingPreviousAdaptation,
+              adaptation.status());
+  }
+}
+
+// kAwaitingPreviousAdaptation is only supported in "maintain-framerate".
+TEST_F(VideoStreamAdapterTest, MaintainFramerate_AwaitingPreviousAdaptationUp) {
+  adapter_.SetDegradationPreference(DegradationPreference::MAINTAIN_FRAMERATE);
+  FakeVideoStream fake_stream(&adapter_, &input_state_provider_, 1280 * 720, 30,
+                              kDefaultMinPixelsPerFrame);
+  // Perform two adaptation down so that adapting up twice is possible.
+  fake_stream.ApplyAdaptation(adapter_.GetAdaptationDown());
+  fake_stream.ApplyAdaptation(adapter_.GetAdaptationDown());
+  EXPECT_EQ(2, adapter_.adaptation_counters().resolution_adaptations);
+  // Adapt up once, but don't update the input.
+  adapter_.ApplyAdaptation(adapter_.GetAdaptationUp(), nullptr);
+  EXPECT_EQ(1, adapter_.adaptation_counters().resolution_adaptations);
+  {
+    // Having performed the adaptation, but not updated the input based on the
+    // new restrictions, adapting again in the same direction will not work.
+    Adaptation adaptation = adapter_.GetAdaptationUp();
+    EXPECT_EQ(Adaptation::Status::kAwaitingPreviousAdaptation,
+              adaptation.status());
+  }
+}
+
+TEST_F(VideoStreamAdapterTest,
+       MaintainResolution_AdaptsUpAfterSwitchingDegradationPreference) {
+  adapter_.SetDegradationPreference(DegradationPreference::MAINTAIN_RESOLUTION);
+  FakeVideoStream fake_stream(&adapter_, &input_state_provider_, 1280 * 720, 30,
+                              kDefaultMinPixelsPerFrame);
+  // Adapt down in fps for later.
+  fake_stream.ApplyAdaptation(adapter_.GetAdaptationDown());
+  EXPECT_EQ(1, adapter_.adaptation_counters().fps_adaptations);
+
+  adapter_.SetDegradationPreference(DegradationPreference::MAINTAIN_FRAMERATE);
+  fake_stream.ApplyAdaptation(adapter_.GetAdaptationDown());
+  fake_stream.ApplyAdaptation(adapter_.GetAdaptationUp());
+  EXPECT_EQ(1, adapter_.adaptation_counters().fps_adaptations);
+  EXPECT_EQ(0, adapter_.adaptation_counters().resolution_adaptations);
+
+  // We should be able to adapt in framerate one last time after the change of
+  // degradation preference.
+  adapter_.SetDegradationPreference(DegradationPreference::MAINTAIN_RESOLUTION);
+  Adaptation adaptation = adapter_.GetAdaptationUp();
+  EXPECT_EQ(Adaptation::Status::kValid, adaptation.status());
+  fake_stream.ApplyAdaptation(adapter_.GetAdaptationUp());
+  EXPECT_EQ(0, adapter_.adaptation_counters().fps_adaptations);
+}
+
+TEST_F(VideoStreamAdapterTest,
+       MaintainFramerate_AdaptsUpAfterSwitchingDegradationPreference) {
+  adapter_.SetDegradationPreference(DegradationPreference::MAINTAIN_FRAMERATE);
+  FakeVideoStream fake_stream(&adapter_, &input_state_provider_, 1280 * 720, 30,
+                              kDefaultMinPixelsPerFrame);
+  // Adapt down in resolution for later.
+  fake_stream.ApplyAdaptation(adapter_.GetAdaptationDown());
+  EXPECT_EQ(1, adapter_.adaptation_counters().resolution_adaptations);
+
+  adapter_.SetDegradationPreference(DegradationPreference::MAINTAIN_RESOLUTION);
+  fake_stream.ApplyAdaptation(adapter_.GetAdaptationDown());
+  fake_stream.ApplyAdaptation(adapter_.GetAdaptationUp());
+  EXPECT_EQ(1, adapter_.adaptation_counters().resolution_adaptations);
+  EXPECT_EQ(0, adapter_.adaptation_counters().fps_adaptations);
+
+  // We should be able to adapt in framerate one last time after the change of
+  // degradation preference.
+  adapter_.SetDegradationPreference(DegradationPreference::MAINTAIN_FRAMERATE);
+  Adaptation adaptation = adapter_.GetAdaptationUp();
+  EXPECT_EQ(Adaptation::Status::kValid, adaptation.status());
+  fake_stream.ApplyAdaptation(adapter_.GetAdaptationUp());
+  EXPECT_EQ(0, adapter_.adaptation_counters().resolution_adaptations);
+}
+
+TEST_F(VideoStreamAdapterTest,
+       PendingResolutionIncreaseAllowsAdaptUpAfterSwitchToMaintainResolution) {
+  adapter_.SetDegradationPreference(DegradationPreference::MAINTAIN_RESOLUTION);
+  FakeVideoStream fake_stream(&adapter_, &input_state_provider_, 1280 * 720, 30,
+                              kDefaultMinPixelsPerFrame);
+  // Adapt fps down so we can adapt up later in the test.
+  fake_stream.ApplyAdaptation(adapter_.GetAdaptationDown());
+
+  adapter_.SetDegradationPreference(DegradationPreference::MAINTAIN_FRAMERATE);
+  fake_stream.ApplyAdaptation(adapter_.GetAdaptationDown());
+  // Apply adaptation up but don't update input.
+  adapter_.ApplyAdaptation(adapter_.GetAdaptationUp(), nullptr);
+  EXPECT_EQ(Adaptation::Status::kAwaitingPreviousAdaptation,
+            adapter_.GetAdaptationUp().status());
+
+  adapter_.SetDegradationPreference(DegradationPreference::MAINTAIN_RESOLUTION);
+  Adaptation adaptation = adapter_.GetAdaptationUp();
+  EXPECT_EQ(Adaptation::Status::kValid, adaptation.status());
+}
+
+TEST_F(VideoStreamAdapterTest,
+       MaintainFramerate_AdaptsDownAfterSwitchingDegradationPreference) {
+  adapter_.SetDegradationPreference(DegradationPreference::MAINTAIN_RESOLUTION);
+  FakeVideoStream fake_stream(&adapter_, &input_state_provider_, 1280 * 720, 30,
+                              kDefaultMinPixelsPerFrame);
+  // Adapt down once, should change FPS.
+  fake_stream.ApplyAdaptation(adapter_.GetAdaptationDown());
+  EXPECT_EQ(1, adapter_.adaptation_counters().fps_adaptations);
+
+  adapter_.SetDegradationPreference(DegradationPreference::MAINTAIN_FRAMERATE);
+  // Adaptation down should apply after the degradation prefs change.
+  Adaptation adaptation = adapter_.GetAdaptationDown();
+  EXPECT_EQ(Adaptation::Status::kValid, adaptation.status());
+  fake_stream.ApplyAdaptation(adaptation);
+  EXPECT_EQ(1, adapter_.adaptation_counters().fps_adaptations);
+  EXPECT_EQ(1, adapter_.adaptation_counters().resolution_adaptations);
+}
+
+TEST_F(VideoStreamAdapterTest,
+       MaintainResolution_AdaptsDownAfterSwitchingDegradationPreference) {
+  adapter_.SetDegradationPreference(DegradationPreference::MAINTAIN_FRAMERATE);
+  FakeVideoStream fake_stream(&adapter_, &input_state_provider_, 1280 * 720, 30,
+                              kDefaultMinPixelsPerFrame);
+  // Adapt down once, should change FPS.
+  fake_stream.ApplyAdaptation(adapter_.GetAdaptationDown());
+  EXPECT_EQ(1, adapter_.adaptation_counters().resolution_adaptations);
+
+  adapter_.SetDegradationPreference(DegradationPreference::MAINTAIN_RESOLUTION);
+  Adaptation adaptation = adapter_.GetAdaptationDown();
+  EXPECT_EQ(Adaptation::Status::kValid, adaptation.status());
+  fake_stream.ApplyAdaptation(adaptation);
+
+  EXPECT_EQ(1, adapter_.adaptation_counters().fps_adaptations);
+  EXPECT_EQ(1, adapter_.adaptation_counters().resolution_adaptations);
+}
+
+TEST_F(
+    VideoStreamAdapterTest,
+    PendingResolutionDecreaseAllowsAdaptDownAfterSwitchToMaintainResolution) {
+  adapter_.SetDegradationPreference(DegradationPreference::MAINTAIN_FRAMERATE);
+  FakeVideoStream fake_stream(&adapter_, &input_state_provider_, 1280 * 720, 30,
+                              kDefaultMinPixelsPerFrame);
+  // Apply adaptation but don't update the input.
+  adapter_.ApplyAdaptation(adapter_.GetAdaptationDown(), nullptr);
+  EXPECT_EQ(Adaptation::Status::kAwaitingPreviousAdaptation,
+            adapter_.GetAdaptationDown().status());
+  adapter_.SetDegradationPreference(DegradationPreference::MAINTAIN_RESOLUTION);
+  Adaptation adaptation = adapter_.GetAdaptationDown();
+  EXPECT_EQ(Adaptation::Status::kValid, adaptation.status());
+}
+
+TEST_F(VideoStreamAdapterTest, RestrictionBroadcasted) {
+  FakeVideoStreamAdapterListner listener;
+  adapter_.AddRestrictionsListener(&listener);
+  adapter_.SetDegradationPreference(DegradationPreference::MAINTAIN_FRAMERATE);
+  FakeVideoStream fake_stream(&adapter_, &input_state_provider_, 1280 * 720, 30,
+                              kDefaultMinPixelsPerFrame);
+  // Not broadcast on invalid ApplyAdaptation.
+  {
+    Adaptation adaptation = adapter_.GetAdaptationUp();
+    adapter_.ApplyAdaptation(adaptation, nullptr);
+    EXPECT_EQ(0, listener.calls());
+  }
+
+  // Broadcast on ApplyAdaptation.
+  {
+    Adaptation adaptation = adapter_.GetAdaptationDown();
+    fake_stream.ApplyAdaptation(adaptation);
+    EXPECT_EQ(1, listener.calls());
+    EXPECT_EQ(adaptation.restrictions(), listener.last_restrictions());
+  }
+
+  // Broadcast on ClearRestrictions().
+  adapter_.ClearRestrictions();
+  EXPECT_EQ(2, listener.calls());
+  EXPECT_EQ(VideoSourceRestrictions(), listener.last_restrictions());
+}
+
+TEST_F(VideoStreamAdapterTest, AdaptationHasNextRestrcitions) {
+  // Any non-disabled DegradationPreference will do.
+  adapter_.SetDegradationPreference(DegradationPreference::MAINTAIN_FRAMERATE);
+  FakeVideoStream fake_stream(&adapter_, &input_state_provider_, 1280 * 720, 30,
+                              kDefaultMinPixelsPerFrame);
+  // When adaptation is not possible.
+  {
+    Adaptation adaptation = adapter_.GetAdaptationUp();
+    EXPECT_EQ(Adaptation::Status::kLimitReached, adaptation.status());
+    EXPECT_EQ(adaptation.restrictions(), adapter_.source_restrictions());
+    EXPECT_EQ(0, adaptation.counters().Total());
+  }
+  // When we adapt down.
+  {
+    Adaptation adaptation = adapter_.GetAdaptationDown();
+    EXPECT_EQ(Adaptation::Status::kValid, adaptation.status());
+    fake_stream.ApplyAdaptation(adaptation);
+    EXPECT_EQ(adaptation.restrictions(), adapter_.source_restrictions());
+    EXPECT_EQ(adaptation.counters(), adapter_.adaptation_counters());
+  }
+  // When we adapt up.
+  {
+    Adaptation adaptation = adapter_.GetAdaptationUp();
+    EXPECT_EQ(Adaptation::Status::kValid, adaptation.status());
+    fake_stream.ApplyAdaptation(adaptation);
+    EXPECT_EQ(adaptation.restrictions(), adapter_.source_restrictions());
+    EXPECT_EQ(adaptation.counters(), adapter_.adaptation_counters());
+  }
+}
+
+TEST_F(VideoStreamAdapterTest,
+       SetDegradationPreferenceToOrFromBalancedClearsRestrictions) {
+  adapter_.SetDegradationPreference(DegradationPreference::MAINTAIN_FRAMERATE);
+  input_state_provider_.SetInputState(1280 * 720, 30,
+                                      kDefaultMinPixelsPerFrame);
+  adapter_.ApplyAdaptation(adapter_.GetAdaptationDown(), nullptr);
+  EXPECT_NE(VideoSourceRestrictions(), adapter_.source_restrictions());
+  EXPECT_NE(0, adapter_.adaptation_counters().Total());
+  // Changing from non-balanced to balanced clears the restrictions.
+  adapter_.SetDegradationPreference(DegradationPreference::BALANCED);
+  EXPECT_EQ(VideoSourceRestrictions(), adapter_.source_restrictions());
+  EXPECT_EQ(0, adapter_.adaptation_counters().Total());
+  // Apply adaptation again.
+  adapter_.ApplyAdaptation(adapter_.GetAdaptationDown(), nullptr);
+  EXPECT_NE(VideoSourceRestrictions(), adapter_.source_restrictions());
+  EXPECT_NE(0, adapter_.adaptation_counters().Total());
+  // Changing from balanced to non-balanced clears the restrictions.
+  adapter_.SetDegradationPreference(DegradationPreference::MAINTAIN_RESOLUTION);
+  EXPECT_EQ(VideoSourceRestrictions(), adapter_.source_restrictions());
+  EXPECT_EQ(0, adapter_.adaptation_counters().Total());
+}
+
+TEST_F(VideoStreamAdapterTest,
+       GetAdaptDownResolutionAdaptsResolutionInMaintainFramerate) {
+  adapter_.SetDegradationPreference(DegradationPreference::MAINTAIN_FRAMERATE);
+  input_state_provider_.SetInputState(1280 * 720, 30,
+                                      kDefaultMinPixelsPerFrame);
+
+  auto adaptation = adapter_.GetAdaptDownResolution();
+  EXPECT_EQ(Adaptation::Status::kValid, adaptation.status());
+  EXPECT_EQ(1, adaptation.counters().resolution_adaptations);
+  EXPECT_EQ(0, adaptation.counters().fps_adaptations);
+}
+
+TEST_F(VideoStreamAdapterTest,
+       GetAdaptDownResolutionReturnsWithStatusInDisabledAndMaintainResolution) {
+  adapter_.SetDegradationPreference(DegradationPreference::DISABLED);
+  input_state_provider_.SetInputState(1280 * 720, 30,
+                                      kDefaultMinPixelsPerFrame);
+  EXPECT_EQ(Adaptation::Status::kAdaptationDisabled,
+            adapter_.GetAdaptDownResolution().status());
+  adapter_.SetDegradationPreference(DegradationPreference::MAINTAIN_RESOLUTION);
+  EXPECT_EQ(Adaptation::Status::kLimitReached,
+            adapter_.GetAdaptDownResolution().status());
+}
+
+TEST_F(VideoStreamAdapterTest,
+       GetAdaptDownResolutionAdaptsFpsAndResolutionInBalanced) {
+  // Note: This test depends on BALANCED implementation, but with current
+  // implementation and input state settings, BALANCED will adapt resolution and
+  // frame rate once.
+  adapter_.SetDegradationPreference(DegradationPreference::BALANCED);
+  input_state_provider_.SetInputState(1280 * 720, 30,
+                                      kDefaultMinPixelsPerFrame);
+
+  auto adaptation = adapter_.GetAdaptDownResolution();
+  EXPECT_EQ(Adaptation::Status::kValid, adaptation.status());
+  EXPECT_EQ(1, adaptation.counters().resolution_adaptations);
+  EXPECT_EQ(1, adaptation.counters().fps_adaptations);
+}
+
+TEST_F(
+    VideoStreamAdapterTest,
+    GetAdaptDownResolutionAdaptsOnlyResolutionIfFpsAlreadyAdapterInBalanced) {
+  // Note: This test depends on BALANCED implementation, but with current
+  // implementation and input state settings, BALANCED will adapt resolution
+  // only.
+  adapter_.SetDegradationPreference(DegradationPreference::BALANCED);
+  input_state_provider_.SetInputState(1280 * 720, 5, kDefaultMinPixelsPerFrame);
+  FakeVideoStream fake_stream(&adapter_, &input_state_provider_, 1280 * 720, 30,
+                              kDefaultMinPixelsPerFrame);
+
+  auto first_adaptation = adapter_.GetAdaptationDown();
+  fake_stream.ApplyAdaptation(first_adaptation);
+
+  auto adaptation = adapter_.GetAdaptDownResolution();
+  EXPECT_EQ(Adaptation::Status::kValid, adaptation.status());
+  EXPECT_EQ(1, adaptation.counters().resolution_adaptations);
+  EXPECT_EQ(first_adaptation.counters().fps_adaptations,
+            adaptation.counters().fps_adaptations);
+}
+
+TEST_F(VideoStreamAdapterTest,
+       GetAdaptDownResolutionAdaptsOnlyFpsIfResolutionLowInBalanced) {
+  // Note: This test depends on BALANCED implementation, but with current
+  // implementation and input state settings, BALANCED will adapt resolution
+  // only.
+  adapter_.SetDegradationPreference(DegradationPreference::BALANCED);
+  input_state_provider_.SetInputState(kDefaultMinPixelsPerFrame, 30,
+                                      kDefaultMinPixelsPerFrame);
+
+  auto adaptation = adapter_.GetAdaptDownResolution();
+  EXPECT_EQ(Adaptation::Status::kValid, adaptation.status());
+  EXPECT_EQ(0, adaptation.counters().resolution_adaptations);
+  EXPECT_EQ(1, adaptation.counters().fps_adaptations);
+}
+
+TEST_F(VideoStreamAdapterTest,
+       AdaptationDisabledStatusAlwaysWhenDegradationPreferenceDisabled) {
+  adapter_.SetDegradationPreference(DegradationPreference::DISABLED);
+  input_state_provider_.SetInputState(1280 * 720, 30,
+                                      kDefaultMinPixelsPerFrame);
+  EXPECT_EQ(Adaptation::Status::kAdaptationDisabled,
+            adapter_.GetAdaptationDown().status());
+  EXPECT_EQ(Adaptation::Status::kAdaptationDisabled,
+            adapter_.GetAdaptationUp().status());
+  EXPECT_EQ(Adaptation::Status::kAdaptationDisabled,
+            adapter_.GetAdaptDownResolution().status());
+}
+
+TEST_F(VideoStreamAdapterTest, AdaptationConstraintAllowsAdaptationsUp) {
+  testing::StrictMock<MockAdaptationConstraint> adaptation_constraint;
+  adapter_.SetDegradationPreference(DegradationPreference::MAINTAIN_FRAMERATE);
+  adapter_.AddAdaptationConstraint(&adaptation_constraint);
+  input_state_provider_.SetInputState(1280 * 720, 30,
+                                      kDefaultMinPixelsPerFrame);
+  FakeVideoStream fake_stream(&adapter_, &input_state_provider_, 1280 * 720, 30,
+                              kDefaultMinPixelsPerFrame);
+  // Adapt down once so we can adapt up later.
+  auto first_adaptation = adapter_.GetAdaptationDown();
+  fake_stream.ApplyAdaptation(first_adaptation);
+
+  EXPECT_CALL(adaptation_constraint,
+              IsAdaptationUpAllowed(_, first_adaptation.restrictions(), _))
+      .WillOnce(Return(true));
+  EXPECT_EQ(Adaptation::Status::kValid, adapter_.GetAdaptationUp().status());
+  adapter_.RemoveAdaptationConstraint(&adaptation_constraint);
+}
+
+TEST_F(VideoStreamAdapterTest, AdaptationConstraintDisallowsAdaptationsUp) {
+  testing::StrictMock<MockAdaptationConstraint> adaptation_constraint;
+  adapter_.SetDegradationPreference(DegradationPreference::MAINTAIN_FRAMERATE);
+  adapter_.AddAdaptationConstraint(&adaptation_constraint);
+  input_state_provider_.SetInputState(1280 * 720, 30,
+                                      kDefaultMinPixelsPerFrame);
+  FakeVideoStream fake_stream(&adapter_, &input_state_provider_, 1280 * 720, 30,
+                              kDefaultMinPixelsPerFrame);
+  // Adapt down once so we can adapt up later.
+  auto first_adaptation = adapter_.GetAdaptationDown();
+  fake_stream.ApplyAdaptation(first_adaptation);
+
+  EXPECT_CALL(adaptation_constraint,
+              IsAdaptationUpAllowed(_, first_adaptation.restrictions(), _))
+      .WillOnce(Return(false));
+  EXPECT_EQ(Adaptation::Status::kRejectedByConstraint,
+            adapter_.GetAdaptationUp().status());
+  adapter_.RemoveAdaptationConstraint(&adaptation_constraint);
+}
+
+// Death tests.
+// Disabled on Android because death tests misbehave on Android, see
+// base/test/gtest_util.h.
+#if RTC_DCHECK_IS_ON && GTEST_HAS_DEATH_TEST && !defined(WEBRTC_ANDROID)
+
+TEST(VideoStreamAdapterDeathTest,
+     SetDegradationPreferenceInvalidatesAdaptations) {
+  webrtc::test::ScopedKeyValueConfig field_trials;
+  FakeVideoStreamInputStateProvider input_state_provider;
+  testing::StrictMock<MockVideoStreamEncoderObserver> encoder_stats_observer_;
+  VideoStreamAdapter adapter(&input_state_provider, &encoder_stats_observer_,
+                             field_trials);
+  adapter.SetDegradationPreference(DegradationPreference::MAINTAIN_FRAMERATE);
+  input_state_provider.SetInputState(1280 * 720, 30, kDefaultMinPixelsPerFrame);
+  Adaptation adaptation = adapter.GetAdaptationDown();
+  adapter.SetDegradationPreference(DegradationPreference::MAINTAIN_RESOLUTION);
+  EXPECT_DEATH(adapter.ApplyAdaptation(adaptation, nullptr), "");
+}
+
+TEST(VideoStreamAdapterDeathTest, AdaptDownInvalidatesAdaptations) {
+  webrtc::test::ScopedKeyValueConfig field_trials;
+  FakeVideoStreamInputStateProvider input_state_provider;
+  testing::StrictMock<MockVideoStreamEncoderObserver> encoder_stats_observer_;
+  VideoStreamAdapter adapter(&input_state_provider, &encoder_stats_observer_,
+                             field_trials);
+  adapter.SetDegradationPreference(DegradationPreference::MAINTAIN_RESOLUTION);
+  input_state_provider.SetInputState(1280 * 720, 30, kDefaultMinPixelsPerFrame);
+  Adaptation adaptation = adapter.GetAdaptationDown();
+  adapter.GetAdaptationDown();
+  EXPECT_DEATH(adapter.ApplyAdaptation(adaptation, nullptr), "");
+}
+
+#endif  // RTC_DCHECK_IS_ON && GTEST_HAS_DEATH_TEST && !defined(WEBRTC_ANDROID)
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/adaptation/video_stream_input_state.cc b/third_party/libwebrtc/call/adaptation/video_stream_input_state.cc
new file mode 100644
index 0000000000..9c0d475902
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/video_stream_input_state.cc
@@ -0,0 +1,80 @@
+/*
+ *  Copyright 2020 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/adaptation/video_stream_input_state.h"
+
+#include "api/video_codecs/video_encoder.h"
+
+namespace webrtc {
+
+VideoStreamInputState::VideoStreamInputState()
+    : has_input_(false),
+      frame_size_pixels_(absl::nullopt),
+      frames_per_second_(0),
+      video_codec_type_(VideoCodecType::kVideoCodecGeneric),
+      min_pixels_per_frame_(kDefaultMinPixelsPerFrame),
+      single_active_stream_pixels_(absl::nullopt) {}
+
+void VideoStreamInputState::set_has_input(bool has_input) {
+  has_input_ = has_input;
+}
+
+void VideoStreamInputState::set_frame_size_pixels(
+    absl::optional<int> frame_size_pixels) {
+  frame_size_pixels_ = frame_size_pixels;
+}
+
+void VideoStreamInputState::set_frames_per_second(int frames_per_second) {
+  frames_per_second_ = frames_per_second;
+}
+
+void VideoStreamInputState::set_video_codec_type(
+    VideoCodecType video_codec_type) {
+  video_codec_type_ = video_codec_type;
+}
+
+void VideoStreamInputState::set_min_pixels_per_frame(int min_pixels_per_frame) {
+  min_pixels_per_frame_ = min_pixels_per_frame;
+}
+
+void VideoStreamInputState::set_single_active_stream_pixels(
+    absl::optional<int> single_active_stream_pixels) {
+  single_active_stream_pixels_ = single_active_stream_pixels;
+}
+
+bool VideoStreamInputState::has_input() const {
+  return has_input_;
+}
+
+absl::optional<int> VideoStreamInputState::frame_size_pixels() const {
+  return frame_size_pixels_;
+}
+
+int VideoStreamInputState::frames_per_second() const {
+  return frames_per_second_;
+}
+
+VideoCodecType VideoStreamInputState::video_codec_type() const {
+  return video_codec_type_;
+}
+
+int VideoStreamInputState::min_pixels_per_frame() const {
+  return min_pixels_per_frame_;
+}
+
+absl::optional<int> VideoStreamInputState::single_active_stream_pixels() const {
+  return single_active_stream_pixels_;
+}
+
+bool VideoStreamInputState::HasInputFrameSizeAndFramesPerSecond() const {
+  return has_input_ && frame_size_pixels_.has_value();
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/adaptation/video_stream_input_state.h b/third_party/libwebrtc/call/adaptation/video_stream_input_state.h
new file mode 100644
index 0000000000..191e22386a
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/video_stream_input_state.h
@@ -0,0 +1,53 @@
+/*
+ *  Copyright 2020 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_ADAPTATION_VIDEO_STREAM_INPUT_STATE_H_
+#define CALL_ADAPTATION_VIDEO_STREAM_INPUT_STATE_H_
+
+#include "absl/types/optional.h"
+#include "api/video/video_codec_type.h"
+
+namespace webrtc {
+
+// The source resolution, frame rate and other properties of a
+// VideoStreamEncoder.
+class VideoStreamInputState {
+ public:
+  VideoStreamInputState();
+
+  void set_has_input(bool has_input);
+  void set_frame_size_pixels(absl::optional<int> frame_size_pixels);
+  void set_frames_per_second(int frames_per_second);
+  void set_video_codec_type(VideoCodecType video_codec_type);
+  void set_min_pixels_per_frame(int min_pixels_per_frame);
+  void set_single_active_stream_pixels(
+      absl::optional<int> single_active_stream_pixels);
+
+  bool has_input() const;
+  absl::optional<int> frame_size_pixels() const;
+  int frames_per_second() const;
+  VideoCodecType video_codec_type() const;
+  int min_pixels_per_frame() const;
+  absl::optional<int> single_active_stream_pixels() const;
+
+  bool HasInputFrameSizeAndFramesPerSecond() const;
+
+ private:
+  bool has_input_;
+  absl::optional<int> frame_size_pixels_;
+  int frames_per_second_;
+  VideoCodecType video_codec_type_;
+  int min_pixels_per_frame_;
+  absl::optional<int> single_active_stream_pixels_;
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_ADAPTATION_VIDEO_STREAM_INPUT_STATE_H_
diff --git a/third_party/libwebrtc/call/adaptation/video_stream_input_state_provider.cc b/third_party/libwebrtc/call/adaptation/video_stream_input_state_provider.cc
new file mode 100644
index 0000000000..3261af39ea
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/video_stream_input_state_provider.cc
@@ -0,0 +1,54 @@
+/*
+ *  Copyright 2020 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/adaptation/video_stream_input_state_provider.h"
+
+#include "call/adaptation/video_stream_adapter.h"
+
+namespace webrtc {
+
+VideoStreamInputStateProvider::VideoStreamInputStateProvider(
+    VideoStreamEncoderObserver* frame_rate_provider)
+    : frame_rate_provider_(frame_rate_provider) {}
+
+VideoStreamInputStateProvider::~VideoStreamInputStateProvider() {}
+
+void VideoStreamInputStateProvider::OnHasInputChanged(bool has_input) {
+  MutexLock lock(&mutex_);
+  input_state_.set_has_input(has_input);
+}
+
+void VideoStreamInputStateProvider::OnFrameSizeObserved(int frame_size_pixels) {
+  RTC_DCHECK_GT(frame_size_pixels, 0);
+  MutexLock lock(&mutex_);
+  input_state_.set_frame_size_pixels(frame_size_pixels);
+}
+
+void VideoStreamInputStateProvider::OnEncoderSettingsChanged(
+    EncoderSettings encoder_settings) {
+  MutexLock lock(&mutex_);
+  input_state_.set_video_codec_type(
+      encoder_settings.encoder_config().codec_type);
+  input_state_.set_min_pixels_per_frame(
+      encoder_settings.encoder_info().scaling_settings.min_pixels_per_frame);
+  input_state_.set_single_active_stream_pixels(
+      VideoStreamAdapter::GetSingleActiveLayerPixels(
+          encoder_settings.video_codec()));
+}
+
+VideoStreamInputState VideoStreamInputStateProvider::InputState() {
+  // GetInputFrameRate() is thread-safe.
+  int input_fps = frame_rate_provider_->GetInputFrameRate();
+  MutexLock lock(&mutex_);
+  input_state_.set_frames_per_second(input_fps);
+  return input_state_;
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/adaptation/video_stream_input_state_provider.h b/third_party/libwebrtc/call/adaptation/video_stream_input_state_provider.h
new file mode 100644
index 0000000000..81996e6eb9
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/video_stream_input_state_provider.h
@@ -0,0 +1,41 @@
+/*
+ *  Copyright 2020 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_ADAPTATION_VIDEO_STREAM_INPUT_STATE_PROVIDER_H_
+#define CALL_ADAPTATION_VIDEO_STREAM_INPUT_STATE_PROVIDER_H_
+
+#include "call/adaptation/encoder_settings.h"
+#include "call/adaptation/video_stream_input_state.h"
+#include "rtc_base/synchronization/mutex.h"
+#include "video/video_stream_encoder_observer.h"
+
+namespace webrtc {
+
+class VideoStreamInputStateProvider {
+ public:
+  VideoStreamInputStateProvider(
+      VideoStreamEncoderObserver* frame_rate_provider);
+  virtual ~VideoStreamInputStateProvider();
+
+  void OnHasInputChanged(bool has_input);
+  void OnFrameSizeObserved(int frame_size_pixels);
+  void OnEncoderSettingsChanged(EncoderSettings encoder_settings);
+
+  virtual VideoStreamInputState InputState();
+
+ private:
+  Mutex mutex_;
+  VideoStreamEncoderObserver* const frame_rate_provider_;
+  VideoStreamInputState input_state_ RTC_GUARDED_BY(mutex_);
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_ADAPTATION_VIDEO_STREAM_INPUT_STATE_PROVIDER_H_
diff --git a/third_party/libwebrtc/call/adaptation/video_stream_input_state_provider_unittest.cc b/third_party/libwebrtc/call/adaptation/video_stream_input_state_provider_unittest.cc
new file mode 100644
index 0000000000..5da2ef21cd
--- /dev/null
+++ b/third_party/libwebrtc/call/adaptation/video_stream_input_state_provider_unittest.cc
@@ -0,0 +1,62 @@
+/*
+ *  Copyright (c) 2020 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/adaptation/video_stream_input_state_provider.h"
+
+#include <utility>
+
+#include "api/video_codecs/video_encoder.h"
+#include "call/adaptation/encoder_settings.h"
+#include "call/adaptation/test/fake_frame_rate_provider.h"
+#include "test/gtest.h"
+
+namespace webrtc {
+
+TEST(VideoStreamInputStateProviderTest, DefaultValues) {
+  FakeFrameRateProvider frame_rate_provider;
+  VideoStreamInputStateProvider input_state_provider(&frame_rate_provider);
+  VideoStreamInputState input_state = input_state_provider.InputState();
+  EXPECT_EQ(false, input_state.has_input());
+  EXPECT_EQ(absl::nullopt, input_state.frame_size_pixels());
+  EXPECT_EQ(0, input_state.frames_per_second());
+  EXPECT_EQ(VideoCodecType::kVideoCodecGeneric, input_state.video_codec_type());
+  EXPECT_EQ(kDefaultMinPixelsPerFrame, input_state.min_pixels_per_frame());
+  EXPECT_EQ(absl::nullopt, input_state.single_active_stream_pixels());
+}
+
+TEST(VideoStreamInputStateProviderTest, ValuesSet) {
+  FakeFrameRateProvider frame_rate_provider;
+  VideoStreamInputStateProvider input_state_provider(&frame_rate_provider);
+  input_state_provider.OnHasInputChanged(true);
+  input_state_provider.OnFrameSizeObserved(42);
+  frame_rate_provider.set_fps(123);
+  VideoEncoder::EncoderInfo encoder_info;
+  encoder_info.scaling_settings.min_pixels_per_frame = 1337;
+  VideoEncoderConfig encoder_config;
+  encoder_config.codec_type = VideoCodecType::kVideoCodecVP9;
+  VideoCodec video_codec;
+  video_codec.codecType = VideoCodecType::kVideoCodecVP8;
+  video_codec.numberOfSimulcastStreams = 2;
+  video_codec.simulcastStream[0].active = false;
+  video_codec.simulcastStream[1].active = true;
+  video_codec.simulcastStream[1].width = 111;
+  video_codec.simulcastStream[1].height = 222;
+  input_state_provider.OnEncoderSettingsChanged(EncoderSettings(
+      std::move(encoder_info), std::move(encoder_config), video_codec));
+  VideoStreamInputState input_state = input_state_provider.InputState();
+  EXPECT_EQ(true, input_state.has_input());
+  EXPECT_EQ(42, input_state.frame_size_pixels());
+  EXPECT_EQ(123, input_state.frames_per_second());
+  EXPECT_EQ(VideoCodecType::kVideoCodecVP9, input_state.video_codec_type());
+  EXPECT_EQ(1337, input_state.min_pixels_per_frame());
+  EXPECT_EQ(111 * 222, input_state.single_active_stream_pixels());
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/audio_receive_stream.cc b/third_party/libwebrtc/call/audio_receive_stream.cc
new file mode 100644
index 0000000000..0766eb6bbb
--- /dev/null
+++ b/third_party/libwebrtc/call/audio_receive_stream.cc
@@ -0,0 +1,24 @@
+/*
+ *  Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/audio_receive_stream.h"
+
+namespace webrtc {
+
+AudioReceiveStreamInterface::Stats::Stats() = default;
+AudioReceiveStreamInterface::Stats::~Stats() = default;
+
+AudioReceiveStreamInterface::Config::Config() = default;
+AudioReceiveStreamInterface::Config::~Config() = default;
+
+AudioReceiveStreamInterface::Config::Rtp::Rtp() = default;
+AudioReceiveStreamInterface::Config::Rtp::~Rtp() = default;
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/audio_receive_stream.h b/third_party/libwebrtc/call/audio_receive_stream.h
new file mode 100644
index 0000000000..6fc93b2d9a
--- /dev/null
+++ b/third_party/libwebrtc/call/audio_receive_stream.h
@@ -0,0 +1,210 @@
+/*
+ *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_AUDIO_RECEIVE_STREAM_H_
+#define CALL_AUDIO_RECEIVE_STREAM_H_
+
+#include <map>
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "absl/types/optional.h"
+#include "api/audio_codecs/audio_decoder_factory.h"
+#include "api/call/transport.h"
+#include "modules/rtp_rtcp/include/rtp_rtcp_defines.h"
+#include "api/crypto/crypto_options.h"
+#include "api/rtp_parameters.h"
+#include "call/receive_stream.h"
+#include "call/rtp_config.h"
+
+namespace webrtc {
+class AudioSinkInterface;
+
+class AudioReceiveStreamInterface : public MediaReceiveStreamInterface {
+ public:
+  struct Stats {
+    Stats();
+    ~Stats();
+    uint32_t remote_ssrc = 0;
+    int64_t payload_bytes_rcvd = 0;
+    int64_t header_and_padding_bytes_rcvd = 0;
+    uint32_t packets_rcvd = 0;
+    uint64_t fec_packets_received = 0;
+    uint64_t fec_packets_discarded = 0;
+    int32_t packets_lost = 0;
+    uint64_t packets_discarded = 0;
+    uint32_t nacks_sent = 0;
+    std::string codec_name;
+    absl::optional<int> codec_payload_type;
+    uint32_t jitter_ms = 0;
+    uint32_t jitter_buffer_ms = 0;
+    uint32_t jitter_buffer_preferred_ms = 0;
+    uint32_t delay_estimate_ms = 0;
+    int32_t audio_level = -1;
+    // Stats below correspond to similarly-named fields in the WebRTC stats
+    // spec. https://w3c.github.io/webrtc-stats/#dom-rtcmediastreamtrackstats
+    double total_output_energy = 0.0;
+    uint64_t total_samples_received = 0;
+    double total_output_duration = 0.0;
+    uint64_t concealed_samples = 0;
+    uint64_t silent_concealed_samples = 0;
+    uint64_t concealment_events = 0;
+    double jitter_buffer_delay_seconds = 0.0;
+    uint64_t jitter_buffer_emitted_count = 0;
+    double jitter_buffer_target_delay_seconds = 0.0;
+    double jitter_buffer_minimum_delay_seconds = 0.0;
+    uint64_t inserted_samples_for_deceleration = 0;
+    uint64_t removed_samples_for_acceleration = 0;
+    // Stats below DO NOT correspond directly to anything in the WebRTC stats
+    float expand_rate = 0.0f;
+    float speech_expand_rate = 0.0f;
+    float secondary_decoded_rate = 0.0f;
+    float secondary_discarded_rate = 0.0f;
+    float accelerate_rate = 0.0f;
+    float preemptive_expand_rate = 0.0f;
+    uint64_t delayed_packet_outage_samples = 0;
+    int32_t decoding_calls_to_silence_generator = 0;
+    int32_t decoding_calls_to_neteq = 0;
+    int32_t decoding_normal = 0;
+    // TODO(alexnarest): Consider decoding_neteq_plc for consistency
+    int32_t decoding_plc = 0;
+    int32_t decoding_codec_plc = 0;
+    int32_t decoding_cng = 0;
+    int32_t decoding_plc_cng = 0;
+    int32_t decoding_muted_output = 0;
+    int64_t capture_start_ntp_time_ms = 0;
+    // The timestamp at which the last packet was received, i.e. the time of the
+    // local clock when it was received - not the RTP timestamp of that packet.
+    // https://w3c.github.io/webrtc-stats/#dom-rtcinboundrtpstreamstats-lastpacketreceivedtimestamp
+    absl::optional<int64_t> last_packet_received_timestamp_ms;
+    uint64_t jitter_buffer_flushes = 0;
+    double relative_packet_arrival_delay_seconds = 0.0;
+    int32_t interruption_count = 0;
+    int32_t total_interruption_duration_ms = 0;
+    // https://w3c.github.io/webrtc-stats/#dom-rtcinboundrtpstreamstats-estimatedplayouttimestamp
+    absl::optional<int64_t> estimated_playout_ntp_timestamp_ms;
+    // Remote outbound stats derived by the received RTCP sender reports.
+    // https://w3c.github.io/webrtc-stats/#remoteoutboundrtpstats-dict*
+    absl::optional<int64_t> last_sender_report_timestamp_ms;
+    absl::optional<int64_t> last_sender_report_remote_timestamp_ms;
+    uint32_t sender_reports_packets_sent = 0;
+    uint64_t sender_reports_bytes_sent = 0;
+    uint64_t sender_reports_reports_count = 0;
+    absl::optional<TimeDelta> round_trip_time;
+    TimeDelta total_round_trip_time = TimeDelta::Zero();
+    int round_trip_time_measurements;
+  };
+
+  struct Config {
+    Config();
+    ~Config();
+
+    std::string ToString() const;
+
+    // Receive-stream specific RTP settings.
+    struct Rtp : public ReceiveStreamRtpConfig {
+      Rtp();
+      ~Rtp();
+
+      std::string ToString() const;
+
+      // See NackConfig for description.
+      NackConfig nack;
+
+      RtcpEventObserver* rtcp_event_observer = nullptr;
+    } rtp;
+
+    // Receive-side RTT.
+    bool enable_non_sender_rtt = false;
+
+    Transport* rtcp_send_transport = nullptr;
+
+    // NetEq settings.
+    size_t jitter_buffer_max_packets = 200;
+    bool jitter_buffer_fast_accelerate = false;
+    int jitter_buffer_min_delay_ms = 0;
+
+    // Identifier for an A/V synchronization group. Empty string to disable.
+    // TODO(pbos): Synchronize streams in a sync group, not just one video
+    // stream to one audio stream. Tracked by issue webrtc:4762.
+    std::string sync_group;
+
+    // Decoder specifications for every payload type that we can receive.
+    std::map<int, SdpAudioFormat> decoder_map;
+
+    rtc::scoped_refptr<AudioDecoderFactory> decoder_factory;
+
+    absl::optional<AudioCodecPairId> codec_pair_id;
+
+    // Per PeerConnection crypto options.
+    webrtc::CryptoOptions crypto_options;
+
+    // An optional custom frame decryptor that allows the entire frame to be
+    // decrypted in whatever way the caller choses. This is not required by
+    // default.
+    // TODO(tommi): Remove this member variable from the struct. It's not
+    // a part of the AudioReceiveStreamInterface state but rather a pass through
+    // variable.
+    rtc::scoped_refptr<webrtc::FrameDecryptorInterface> frame_decryptor;
+
+    // An optional frame transformer used by insertable streams to transform
+    // encoded frames.
+    // TODO(tommi): Remove this member variable from the struct. It's not
+    // a part of the AudioReceiveStreamInterface state but rather a pass through
+    // variable.
+    rtc::scoped_refptr<webrtc::FrameTransformerInterface> frame_transformer;
+  };
+
+  // Methods that support reconfiguring the stream post initialization.
+  virtual void SetDecoderMap(std::map<int, SdpAudioFormat> decoder_map) = 0;
+  virtual void SetNackHistory(int history_ms) = 0;
+  virtual void SetNonSenderRttMeasurement(bool enabled) = 0;
+
+  // Returns true if the stream has been started.
+  virtual bool IsRunning() const = 0;
+
+  virtual Stats GetStats(bool get_and_clear_legacy_stats) const = 0;
+  Stats GetStats() { return GetStats(/*get_and_clear_legacy_stats=*/true); }
+
+  // Sets an audio sink that receives unmixed audio from the receive stream.
+  // Ownership of the sink is managed by the caller.
+  // Only one sink can be set and passing a null sink clears an existing one.
+  // NOTE: Audio must still somehow be pulled through AudioTransport for audio
+  // to stream through this sink. In practice, this happens if mixed audio
+  // is being pulled+rendered and/or if audio is being pulled for the purposes
+  // of feeding to the AEC.
+  virtual void SetSink(AudioSinkInterface* sink) = 0;
+
+  // Sets playback gain of the stream, applied when mixing, and thus after it
+  // is potentially forwarded to any attached AudioSinkInterface implementation.
+  virtual void SetGain(float gain) = 0;
+
+  // Sets a base minimum for the playout delay. Base minimum delay sets lower
+  // bound on minimum delay value determining lower bound on playout delay.
+  //
+  // Returns true if value was successfully set, false overwise.
+  virtual bool SetBaseMinimumPlayoutDelayMs(int delay_ms) = 0;
+
+  // Returns current value of base minimum delay in milliseconds.
+  virtual int GetBaseMinimumPlayoutDelayMs() const = 0;
+
+  // Synchronization source (stream identifier) to be received.
+  // This member will not change mid-stream and can be assumed to be const
+  // post initialization.
+  virtual uint32_t remote_ssrc() const = 0;
+
+ protected:
+  virtual ~AudioReceiveStreamInterface() {}
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_AUDIO_RECEIVE_STREAM_H_
diff --git a/third_party/libwebrtc/call/audio_send_stream.cc b/third_party/libwebrtc/call/audio_send_stream.cc
new file mode 100644
index 0000000000..a36050a9f7
--- /dev/null
+++ b/third_party/libwebrtc/call/audio_send_stream.cc
@@ -0,0 +1,108 @@
+/*
+ *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/audio_send_stream.h"
+
+#include <stddef.h>
+
+#include "rtc_base/strings/audio_format_to_string.h"
+#include "rtc_base/strings/string_builder.h"
+
+namespace webrtc {
+
+AudioSendStream::Stats::Stats() = default;
+AudioSendStream::Stats::~Stats() = default;
+
+AudioSendStream::Config::Config(Transport* send_transport)
+    : send_transport(send_transport) {}
+
+AudioSendStream::Config::~Config() = default;
+
+std::string AudioSendStream::Config::ToString() const {
+  rtc::StringBuilder ss;
+  ss << "{rtp: " << rtp.ToString();
+  ss << ", rtcp_report_interval_ms: " << rtcp_report_interval_ms;
+  ss << ", send_transport: " << (send_transport ? "(Transport)" : "null");
+  ss << ", min_bitrate_bps: " << min_bitrate_bps;
+  ss << ", max_bitrate_bps: " << max_bitrate_bps;
+  ss << ", has audio_network_adaptor_config: "
+     << (audio_network_adaptor_config ? "true" : "false");
+  ss << ", has_dscp: " << (has_dscp ? "true" : "false");
+  ss << ", send_codec_spec: "
+     << (send_codec_spec ? send_codec_spec->ToString() : "<unset>");
+  ss << "}";
+  return ss.Release();
+}
+
+AudioSendStream::Config::Rtp::Rtp() = default;
+
+AudioSendStream::Config::Rtp::~Rtp() = default;
+
+std::string AudioSendStream::Config::Rtp::ToString() const {
+  char buf[1024];
+  rtc::SimpleStringBuilder ss(buf);
+  ss << "{ssrc: " << ssrc;
+  if (!rid.empty()) {
+    ss << ", rid: " << rid;
+  }
+  if (!mid.empty()) {
+    ss << ", mid: " << mid;
+  }
+  ss << ", extmap-allow-mixed: " << (extmap_allow_mixed ? "true" : "false");
+  ss << ", extensions: [";
+  for (size_t i = 0; i < extensions.size(); ++i) {
+    ss << extensions[i].ToString();
+    if (i != extensions.size() - 1) {
+      ss << ", ";
+    }
+  }
+  ss << ']';
+  ss << ", c_name: " << c_name;
+  ss << '}';
+  return ss.str();
+}
+
+AudioSendStream::Config::SendCodecSpec::SendCodecSpec(
+    int payload_type,
+    const SdpAudioFormat& format)
+    : payload_type(payload_type), format(format) {}
+AudioSendStream::Config::SendCodecSpec::~SendCodecSpec() = default;
+
+std::string AudioSendStream::Config::SendCodecSpec::ToString() const {
+  char buf[1024];
+  rtc::SimpleStringBuilder ss(buf);
+  ss << "{nack_enabled: " << (nack_enabled ? "true" : "false");
+  ss << ", transport_cc_enabled: " << (transport_cc_enabled ? "true" : "false");
+  ss << ", enable_non_sender_rtt: "
+     << (enable_non_sender_rtt ? "true" : "false");
+  ss << ", cng_payload_type: "
+     << (cng_payload_type ? rtc::ToString(*cng_payload_type) : "<unset>");
+  ss << ", red_payload_type: "
+     << (red_payload_type ? rtc::ToString(*red_payload_type) : "<unset>");
+  ss << ", payload_type: " << payload_type;
+  ss << ", format: " << rtc::ToString(format);
+  ss << '}';
+  return ss.str();
+}
+
+bool AudioSendStream::Config::SendCodecSpec::operator==(
+    const AudioSendStream::Config::SendCodecSpec& rhs) const {
+  if (nack_enabled == rhs.nack_enabled &&
+      transport_cc_enabled == rhs.transport_cc_enabled &&
+      enable_non_sender_rtt == rhs.enable_non_sender_rtt &&
+      cng_payload_type == rhs.cng_payload_type &&
+      red_payload_type == rhs.red_payload_type &&
+      payload_type == rhs.payload_type && format == rhs.format &&
+      target_bitrate_bps == rhs.target_bitrate_bps) {
+    return true;
+  }
+  return false;
+}
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/audio_send_stream.h b/third_party/libwebrtc/call/audio_send_stream.h
new file mode 100644
index 0000000000..187ec65ed8
--- /dev/null
+++ b/third_party/libwebrtc/call/audio_send_stream.h
@@ -0,0 +1,203 @@
+/*
+ *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_AUDIO_SEND_STREAM_H_
+#define CALL_AUDIO_SEND_STREAM_H_
+
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "absl/types/optional.h"
+#include "api/audio_codecs/audio_codec_pair_id.h"
+#include "api/audio_codecs/audio_encoder.h"
+#include "api/audio_codecs/audio_encoder_factory.h"
+#include "api/audio_codecs/audio_format.h"
+#include "api/call/transport.h"
+#include "api/crypto/crypto_options.h"
+#include "api/crypto/frame_encryptor_interface.h"
+#include "api/frame_transformer_interface.h"
+#include "api/rtp_parameters.h"
+#include "api/rtp_sender_setparameters_callback.h"
+#include "api/scoped_refptr.h"
+#include "call/audio_sender.h"
+#include "call/rtp_config.h"
+#include "modules/audio_processing/include/audio_processing_statistics.h"
+#include "modules/rtp_rtcp/include/report_block_data.h"
+#include "modules/rtp_rtcp/include/rtcp_statistics.h"
+
+namespace webrtc {
+
+class AudioSendStream : public AudioSender {
+ public:
+  struct Stats {
+    Stats();
+    ~Stats();
+
+    // TODO(solenberg): Harmonize naming and defaults with receive stream stats.
+    uint32_t local_ssrc = 0;
+    int64_t payload_bytes_sent = 0;
+    int64_t header_and_padding_bytes_sent = 0;
+    // https://w3c.github.io/webrtc-stats/#dom-rtcoutboundrtpstreamstats-retransmittedbytessent
+    uint64_t retransmitted_bytes_sent = 0;
+    int32_t packets_sent = 0;
+    // https://w3c.github.io/webrtc-stats/#dom-rtcoutboundrtpstreamstats-totalpacketsenddelay
+    TimeDelta total_packet_send_delay = TimeDelta::Zero();
+    // https://w3c.github.io/webrtc-stats/#dom-rtcoutboundrtpstreamstats-retransmittedpacketssent
+    uint64_t retransmitted_packets_sent = 0;
+    int32_t packets_lost = -1;
+    float fraction_lost = -1.0f;
+    std::string codec_name;
+    absl::optional<int> codec_payload_type;
+    int32_t jitter_ms = -1;
+    int64_t rtt_ms = -1;
+    int16_t audio_level = 0;
+    // See description of "totalAudioEnergy" in the WebRTC stats spec:
+    // https://w3c.github.io/webrtc-stats/#dom-rtcmediastreamtrackstats-totalaudioenergy
+    double total_input_energy = 0.0;
+    double total_input_duration = 0.0;
+
+    ANAStats ana_statistics;
+    AudioProcessingStats apm_statistics;
+    RtcpPacketTypeCounter rtcp_packet_type_counts;
+
+    int64_t target_bitrate_bps = 0;
+    // A snapshot of Report Blocks with additional data of interest to
+    // statistics. Within this list, the sender-source SSRC pair is unique and
+    // per-pair the ReportBlockData represents the latest Report Block that was
+    // received for that pair.
+    std::vector<ReportBlockData> report_block_datas;
+    uint32_t nacks_rcvd = 0;
+  };
+
+  struct Config {
+    Config() = delete;
+    explicit Config(Transport* send_transport);
+    ~Config();
+    std::string ToString() const;
+
+    // Send-stream specific RTP settings.
+    struct Rtp {
+      Rtp();
+      ~Rtp();
+      std::string ToString() const;
+
+      // Sender SSRC.
+      uint32_t ssrc = 0;
+
+      // The value to send in the RID RTP header extension if the extension is
+      // included in the list of extensions.
+      std::string rid;
+
+      // The value to send in the MID RTP header extension if the extension is
+      // included in the list of extensions.
+      std::string mid;
+
+      // Corresponds to the SDP attribute extmap-allow-mixed.
+      bool extmap_allow_mixed = false;
+
+      // RTP header extensions used for the sent stream.
+      std::vector<RtpExtension> extensions;
+
+      // RTCP CNAME, see RFC 3550.
+      std::string c_name;
+    } rtp;
+
+    // Time interval between RTCP report for audio
+    int rtcp_report_interval_ms = 5000;
+
+    // Transport for outgoing packets. The transport is expected to exist for
+    // the entire life of the AudioSendStream and is owned by the API client.
+    Transport* send_transport = nullptr;
+
+    // Bitrate limits used for variable audio bitrate streams. Set both to -1 to
+    // disable audio bitrate adaptation.
+    // Note: This is still an experimental feature and not ready for real usage.
+    int min_bitrate_bps = -1;
+    int max_bitrate_bps = -1;
+
+    double bitrate_priority = 1.0;
+    bool has_dscp = false;
+
+    // Defines whether to turn on audio network adaptor, and defines its config
+    // string.
+    absl::optional<std::string> audio_network_adaptor_config;
+
+    struct SendCodecSpec {
+      SendCodecSpec(int payload_type, const SdpAudioFormat& format);
+      ~SendCodecSpec();
+      std::string ToString() const;
+
+      bool operator==(const SendCodecSpec& rhs) const;
+      bool operator!=(const SendCodecSpec& rhs) const {
+        return !(*this == rhs);
+      }
+
+      int payload_type;
+      SdpAudioFormat format;
+      bool nack_enabled = false;
+      bool transport_cc_enabled = false;
+      bool enable_non_sender_rtt = false;
+      absl::optional<int> cng_payload_type;
+      absl::optional<int> red_payload_type;
+      // If unset, use the encoder's default target bitrate.
+      absl::optional<int> target_bitrate_bps;
+    };
+
+    absl::optional<SendCodecSpec> send_codec_spec;
+    rtc::scoped_refptr<AudioEncoderFactory> encoder_factory;
+    absl::optional<AudioCodecPairId> codec_pair_id;
+
+    // Track ID as specified during track creation.
+    std::string track_id;
+
+    // Per PeerConnection crypto options.
+    webrtc::CryptoOptions crypto_options;
+
+    // An optional custom frame encryptor that allows the entire frame to be
+    // encryptor in whatever way the caller choses. This is not required by
+    // default.
+    rtc::scoped_refptr<webrtc::FrameEncryptorInterface> frame_encryptor;
+
+    // An optional frame transformer used by insertable streams to transform
+    // encoded frames.
+    rtc::scoped_refptr<webrtc::FrameTransformerInterface> frame_transformer;
+  };
+
+  virtual ~AudioSendStream() = default;
+
+  virtual const webrtc::AudioSendStream::Config& GetConfig() const = 0;
+
+  // Reconfigure the stream according to the Configuration.
+  virtual void Reconfigure(const Config& config,
+                           SetParametersCallback callback) = 0;
+
+  // Starts stream activity.
+  // When a stream is active, it can receive, process and deliver packets.
+  virtual void Start() = 0;
+  // Stops stream activity.
+  // When a stream is stopped, it can't receive, process or deliver packets.
+  virtual void Stop() = 0;
+
+  // TODO(solenberg): Make payload_type a config property instead.
+  virtual bool SendTelephoneEvent(int payload_type,
+                                  int payload_frequency,
+                                  int event,
+                                  int duration_ms) = 0;
+
+  virtual void SetMuted(bool muted) = 0;
+
+  virtual Stats GetStats() const = 0;
+  virtual Stats GetStats(bool has_remote_tracks) const = 0;
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_AUDIO_SEND_STREAM_H_
diff --git a/third_party/libwebrtc/call/audio_sender.h b/third_party/libwebrtc/call/audio_sender.h
new file mode 100644
index 0000000000..daab070879
--- /dev/null
+++ b/third_party/libwebrtc/call/audio_sender.h
@@ -0,0 +1,30 @@
+/*
+ *  Copyright (c) 2020 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_AUDIO_SENDER_H_
+#define CALL_AUDIO_SENDER_H_
+
+#include <memory>
+
+#include "api/audio/audio_frame.h"
+
+namespace webrtc {
+
+class AudioSender {
+ public:
+  // Encode and send audio.
+  virtual void SendAudioData(std::unique_ptr<AudioFrame> audio_frame) = 0;
+
+  virtual ~AudioSender() = default;
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_AUDIO_SENDER_H_
diff --git a/third_party/libwebrtc/call/audio_sender_interface_gn/moz.build b/third_party/libwebrtc/call/audio_sender_interface_gn/moz.build
new file mode 100644
index 0000000000..6779dfa7cc
--- /dev/null
+++ b/third_party/libwebrtc/call/audio_sender_interface_gn/moz.build
@@ -0,0 +1,209 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+  ### This moz.build was AUTOMATICALLY GENERATED from a GN config,  ###
+  ### DO NOT edit it by hand.                                       ###
+
+COMPILE_FLAGS["OS_INCLUDES"] = []
+AllowCompilerWarnings()
+
+DEFINES["ABSL_ALLOCATOR_NOTHROW"] = "1"
+DEFINES["RTC_DAV1D_IN_INTERNAL_DECODER_FACTORY"] = True
+DEFINES["RTC_ENABLE_VP9"] = True
+DEFINES["WEBRTC_ENABLE_PROTOBUF"] = "0"
+DEFINES["WEBRTC_LIBRARY_IMPL"] = True
+DEFINES["WEBRTC_MOZILLA_BUILD"] = True
+DEFINES["WEBRTC_NON_STATIC_TRACE_EVENT_HANDLERS"] = "0"
+DEFINES["WEBRTC_STRICT_FIELD_TRIALS"] = "0"
+
+FINAL_LIBRARY = "webrtc"
+
+
+LOCAL_INCLUDES += [
+    "!/ipc/ipdl/_ipdlheaders",
+    "!/third_party/libwebrtc/gen",
+    "/ipc/chromium/src",
+    "/third_party/libwebrtc/",
+    "/third_party/libwebrtc/third_party/abseil-cpp/",
+    "/tools/profiler/public"
+]
+
+if not CONFIG["MOZ_DEBUG"]:
+
+    DEFINES["DYNAMIC_ANNOTATIONS_ENABLED"] = "0"
+    DEFINES["NDEBUG"] = True
+    DEFINES["NVALGRIND"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1":
+
+    DEFINES["DYNAMIC_ANNOTATIONS_ENABLED"] = "1"
+
+if CONFIG["OS_TARGET"] == "Android":
+
+    DEFINES["ANDROID"] = True
+    DEFINES["ANDROID_NDK_VERSION_ROLL"] = "r22_1"
+    DEFINES["HAVE_SYS_UIO_H"] = True
+    DEFINES["WEBRTC_ANDROID"] = True
+    DEFINES["WEBRTC_ANDROID_OPENSLES"] = True
+    DEFINES["WEBRTC_LINUX"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_GNU_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+    OS_LIBS += [
+        "log"
+    ]
+
+if CONFIG["OS_TARGET"] == "Darwin":
+
+    DEFINES["WEBRTC_MAC"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_LIBCPP_HAS_NO_ALIGNED_ALLOCATION"] = True
+    DEFINES["__ASSERT_MACROS_DEFINE_VERSIONS_WITHOUT_UNDERSCORES"] = "0"
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+if CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["USE_AURA"] = "1"
+    DEFINES["USE_GLIB"] = "1"
+    DEFINES["USE_NSS_CERTS"] = "1"
+    DEFINES["USE_OZONE"] = "1"
+    DEFINES["USE_UDEV"] = True
+    DEFINES["WEBRTC_LINUX"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_FILE_OFFSET_BITS"] = "64"
+    DEFINES["_LARGEFILE64_SOURCE"] = True
+    DEFINES["_LARGEFILE_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+if CONFIG["OS_TARGET"] == "OpenBSD":
+
+    DEFINES["USE_GLIB"] = "1"
+    DEFINES["USE_OZONE"] = "1"
+    DEFINES["USE_X11"] = "1"
+    DEFINES["WEBRTC_BSD"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_FILE_OFFSET_BITS"] = "64"
+    DEFINES["_LARGEFILE64_SOURCE"] = True
+    DEFINES["_LARGEFILE_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+if CONFIG["OS_TARGET"] == "WINNT":
+
+    DEFINES["CERT_CHAIN_PARA_HAS_EXTRA_FIELDS"] = True
+    DEFINES["NOMINMAX"] = True
+    DEFINES["NTDDI_VERSION"] = "0x0A000000"
+    DEFINES["PSAPI_VERSION"] = "2"
+    DEFINES["UNICODE"] = True
+    DEFINES["USE_AURA"] = "1"
+    DEFINES["WEBRTC_WIN"] = True
+    DEFINES["WIN32"] = True
+    DEFINES["WIN32_LEAN_AND_MEAN"] = True
+    DEFINES["WINAPI_FAMILY"] = "WINAPI_FAMILY_DESKTOP_APP"
+    DEFINES["WINVER"] = "0x0A00"
+    DEFINES["_ATL_NO_OPENGL"] = True
+    DEFINES["_CRT_RAND_S"] = True
+    DEFINES["_CRT_SECURE_NO_DEPRECATE"] = True
+    DEFINES["_ENABLE_EXTENDED_ALIGNED_STORAGE"] = True
+    DEFINES["_HAS_EXCEPTIONS"] = "0"
+    DEFINES["_HAS_NODISCARD"] = True
+    DEFINES["_SCL_SECURE_NO_DEPRECATE"] = True
+    DEFINES["_SECURE_ATL"] = True
+    DEFINES["_UNICODE"] = True
+    DEFINES["_WIN32_WINNT"] = "0x0A00"
+    DEFINES["_WINDOWS"] = True
+    DEFINES["__STD_C"] = True
+
+    OS_LIBS += [
+        "winmm"
+    ]
+
+if CONFIG["CPU_ARCH"] == "aarch64":
+
+    DEFINES["WEBRTC_ARCH_ARM64"] = True
+    DEFINES["WEBRTC_HAS_NEON"] = True
+
+if CONFIG["CPU_ARCH"] == "arm":
+
+    DEFINES["WEBRTC_ARCH_ARM"] = True
+    DEFINES["WEBRTC_ARCH_ARM_V7"] = True
+    DEFINES["WEBRTC_HAS_NEON"] = True
+
+if CONFIG["CPU_ARCH"] == "mips32":
+
+    DEFINES["MIPS32_LE"] = True
+    DEFINES["MIPS_FPU_LE"] = True
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "mips64":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86":
+
+    DEFINES["WEBRTC_ENABLE_AVX2"] = True
+
+if CONFIG["CPU_ARCH"] == "x86_64":
+
+    DEFINES["WEBRTC_ENABLE_AVX2"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Android":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Darwin":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "OpenBSD":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "WINNT":
+
+    DEFINES["_HAS_ITERATOR_DEBUGGING"] = "0"
+
+if CONFIG["MOZ_X11"] == "1" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["USE_X11"] = "1"
+
+if CONFIG["CPU_ARCH"] == "arm" and CONFIG["OS_TARGET"] == "Android":
+
+    OS_LIBS += [
+        "android_support",
+        "unwind"
+    ]
+
+if CONFIG["CPU_ARCH"] == "x86" and CONFIG["OS_TARGET"] == "Android":
+
+    OS_LIBS += [
+        "android_support"
+    ]
+
+if CONFIG["CPU_ARCH"] == "aarch64" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "arm" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86_64" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+Library("audio_sender_interface_gn")
diff --git a/third_party/libwebrtc/call/audio_state.cc b/third_party/libwebrtc/call/audio_state.cc
new file mode 100644
index 0000000000..725d27f423
--- /dev/null
+++ b/third_party/libwebrtc/call/audio_state.cc
@@ -0,0 +1,18 @@
+/*
+ *  Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/audio_state.h"
+
+namespace webrtc {
+
+AudioState::Config::Config() = default;
+AudioState::Config::~Config() = default;
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/audio_state.h b/third_party/libwebrtc/call/audio_state.h
new file mode 100644
index 0000000000..79fb5cf981
--- /dev/null
+++ b/third_party/libwebrtc/call/audio_state.h
@@ -0,0 +1,69 @@
+/*
+ *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+#ifndef CALL_AUDIO_STATE_H_
+#define CALL_AUDIO_STATE_H_
+
+#include "api/audio/audio_mixer.h"
+#include "api/scoped_refptr.h"
+#include "modules/async_audio_processing/async_audio_processing.h"
+#include "modules/audio_device/include/audio_device.h"
+#include "modules/audio_processing/include/audio_processing.h"
+#include "rtc_base/ref_count.h"
+
+namespace webrtc {
+
+class AudioTransport;
+
+// AudioState holds the state which must be shared between multiple instances of
+// webrtc::Call for audio processing purposes.
+class AudioState : public rtc::RefCountInterface {
+ public:
+  struct Config {
+    Config();
+    ~Config();
+
+    // The audio mixer connected to active receive streams. One per
+    // AudioState.
+    rtc::scoped_refptr<AudioMixer> audio_mixer;
+
+    // The audio processing module.
+    rtc::scoped_refptr<webrtc::AudioProcessing> audio_processing;
+
+    // TODO(solenberg): Temporary: audio device module.
+    rtc::scoped_refptr<webrtc::AudioDeviceModule> audio_device_module;
+
+    rtc::scoped_refptr<AsyncAudioProcessing::Factory>
+        async_audio_processing_factory;
+  };
+
+  virtual AudioProcessing* audio_processing() = 0;
+  virtual AudioTransport* audio_transport() = 0;
+
+  // Enable/disable playout of the audio channels. Enabled by default.
+  // This will stop playout of the underlying audio device but start a task
+  // which will poll for audio data every 10ms to ensure that audio processing
+  // happens and the audio stats are updated.
+  virtual void SetPlayout(bool enabled) = 0;
+
+  // Enable/disable recording of the audio channels. Enabled by default.
+  // This will stop recording of the underlying audio device and no audio
+  // packets will be encoded or transmitted.
+  virtual void SetRecording(bool enabled) = 0;
+
+  virtual void SetStereoChannelSwapping(bool enable) = 0;
+
+  static rtc::scoped_refptr<AudioState> Create(
+      const AudioState::Config& config);
+
+  ~AudioState() override {}
+};
+}  // namespace webrtc
+
+#endif  // CALL_AUDIO_STATE_H_
diff --git a/third_party/libwebrtc/call/bitrate_allocator.cc b/third_party/libwebrtc/call/bitrate_allocator.cc
new file mode 100644
index 0000000000..2684a1650e
--- /dev/null
+++ b/third_party/libwebrtc/call/bitrate_allocator.cc
@@ -0,0 +1,593 @@
+/*
+ *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ *
+ */
+
+#include "call/bitrate_allocator.h"
+
+#include <algorithm>
+#include <cmath>
+#include <memory>
+#include <utility>
+
+#include "absl/algorithm/container.h"
+#include "api/units/data_rate.h"
+#include "api/units/time_delta.h"
+#include "rtc_base/checks.h"
+#include "rtc_base/logging.h"
+#include "rtc_base/numerics/safe_minmax.h"
+#include "system_wrappers/include/clock.h"
+#include "system_wrappers/include/metrics.h"
+
+namespace webrtc {
+
+namespace {
+using bitrate_allocator_impl::AllocatableTrack;
+
+// Allow packets to be transmitted in up to 2 times max video bitrate if the
+// bandwidth estimate allows it.
+const uint8_t kTransmissionMaxBitrateMultiplier = 2;
+const int kDefaultBitrateBps = 300000;
+
+// Require a bitrate increase of max(10%, 20kbps) to resume paused streams.
+const double kToggleFactor = 0.1;
+const uint32_t kMinToggleBitrateBps = 20000;
+
+const int64_t kBweLogIntervalMs = 5000;
+
+double MediaRatio(uint32_t allocated_bitrate, uint32_t protection_bitrate) {
+  RTC_DCHECK_GT(allocated_bitrate, 0);
+  if (protection_bitrate == 0)
+    return 1.0;
+
+  uint32_t media_bitrate = allocated_bitrate - protection_bitrate;
+  return media_bitrate / static_cast<double>(allocated_bitrate);
+}
+
+bool EnoughBitrateForAllObservers(
+    const std::vector<AllocatableTrack>& allocatable_tracks,
+    uint32_t bitrate,
+    uint32_t sum_min_bitrates) {
+  if (bitrate < sum_min_bitrates)
+    return false;
+
+  uint32_t extra_bitrate_per_observer =
+      (bitrate - sum_min_bitrates) /
+      static_cast<uint32_t>(allocatable_tracks.size());
+  for (const auto& observer_config : allocatable_tracks) {
+    if (observer_config.config.min_bitrate_bps + extra_bitrate_per_observer <
+        observer_config.MinBitrateWithHysteresis()) {
+      return false;
+    }
+  }
+  return true;
+}
+
+// Splits `bitrate` evenly to observers already in `allocation`.
+// `include_zero_allocations` decides if zero allocations should be part of
+// the distribution or not. The allowed max bitrate is `max_multiplier` x
+// observer max bitrate.
+void DistributeBitrateEvenly(
+    const std::vector<AllocatableTrack>& allocatable_tracks,
+    uint32_t bitrate,
+    bool include_zero_allocations,
+    int max_multiplier,
+    std::map<BitrateAllocatorObserver*, int>* allocation) {
+  RTC_DCHECK_EQ(allocation->size(), allocatable_tracks.size());
+
+  std::multimap<uint32_t, const AllocatableTrack*> list_max_bitrates;
+  for (const auto& observer_config : allocatable_tracks) {
+    if (include_zero_allocations ||
+        allocation->at(observer_config.observer) != 0) {
+      list_max_bitrates.insert(
+          {observer_config.config.max_bitrate_bps, &observer_config});
+    }
+  }
+  auto it = list_max_bitrates.begin();
+  while (it != list_max_bitrates.end()) {
+    RTC_DCHECK_GT(bitrate, 0);
+    uint32_t extra_allocation =
+        bitrate / static_cast<uint32_t>(list_max_bitrates.size());
+    uint32_t total_allocation =
+        extra_allocation + allocation->at(it->second->observer);
+    bitrate -= extra_allocation;
+    if (total_allocation > max_multiplier * it->first) {
+      // There is more than we can fit for this observer, carry over to the
+      // remaining observers.
+      bitrate += total_allocation - max_multiplier * it->first;
+      total_allocation = max_multiplier * it->first;
+    }
+    // Finally, update the allocation for this observer.
+    allocation->at(it->second->observer) = total_allocation;
+    it = list_max_bitrates.erase(it);
+  }
+}
+
+// From the available `bitrate`, each observer will be allocated a
+// proportional amount based upon its bitrate priority. If that amount is
+// more than the observer's capacity, it will be allocated its capacity, and
+// the excess bitrate is still allocated proportionally to other observers.
+// Allocating the proportional amount means an observer with twice the
+// bitrate_priority of another will be allocated twice the bitrate.
+void DistributeBitrateRelatively(
+    const std::vector<AllocatableTrack>& allocatable_tracks,
+    uint32_t remaining_bitrate,
+    const std::map<BitrateAllocatorObserver*, int>& observers_capacities,
+    std::map<BitrateAllocatorObserver*, int>* allocation) {
+  RTC_DCHECK_EQ(allocation->size(), allocatable_tracks.size());
+  RTC_DCHECK_EQ(observers_capacities.size(), allocatable_tracks.size());
+
+  struct PriorityRateObserverConfig {
+    BitrateAllocatorObserver* allocation_key;
+    // The amount of bitrate bps that can be allocated to this observer.
+    int capacity_bps;
+    double bitrate_priority;
+  };
+
+  double bitrate_priority_sum = 0;
+  std::vector<PriorityRateObserverConfig> priority_rate_observers;
+  for (const auto& observer_config : allocatable_tracks) {
+    priority_rate_observers.push_back(PriorityRateObserverConfig{
+        observer_config.observer,
+        observers_capacities.at(observer_config.observer),
+        observer_config.config.bitrate_priority});
+    bitrate_priority_sum += observer_config.config.bitrate_priority;
+  }
+
+  // Iterate in the order observers can be allocated their full capacity.
+
+  // We want to sort by which observers will be allocated their full capacity
+  // first. By dividing each observer's capacity by its bitrate priority we
+  // are "normalizing" the capacity of an observer by the rate it will be
+  // filled. This is because the amount allocated is based upon bitrate
+  // priority. We allocate twice as much bitrate to an observer with twice the
+  // bitrate priority of another.
+  absl::c_sort(priority_rate_observers, [](const auto& a, const auto& b) {
+    return a.capacity_bps / a.bitrate_priority <
+           b.capacity_bps / b.bitrate_priority;
+  });
+  size_t i;
+  for (i = 0; i < priority_rate_observers.size(); ++i) {
+    const auto& priority_rate_observer = priority_rate_observers[i];
+    // We allocate the full capacity to an observer only if its relative
+    // portion from the remaining bitrate is sufficient to allocate its full
+    // capacity. This means we aren't greedily allocating the full capacity, but
+    // that it is only done when there is also enough bitrate to allocate the
+    // proportional amounts to all other observers.
+    double observer_share =
+        priority_rate_observer.bitrate_priority / bitrate_priority_sum;
+    double allocation_bps = observer_share * remaining_bitrate;
+    bool enough_bitrate = allocation_bps >= priority_rate_observer.capacity_bps;
+    if (!enough_bitrate)
+      break;
+    allocation->at(priority_rate_observer.allocation_key) +=
+        priority_rate_observer.capacity_bps;
+    remaining_bitrate -= priority_rate_observer.capacity_bps;
+    bitrate_priority_sum -= priority_rate_observer.bitrate_priority;
+  }
+
+  // From the remaining bitrate, allocate the proportional amounts to the
+  // observers that aren't allocated their max capacity.
+  for (; i < priority_rate_observers.size(); ++i) {
+    const auto& priority_rate_observer = priority_rate_observers[i];
+    double fraction_allocated =
+        priority_rate_observer.bitrate_priority / bitrate_priority_sum;
+    allocation->at(priority_rate_observer.allocation_key) +=
+        fraction_allocated * remaining_bitrate;
+  }
+}
+
+// Allocates bitrate to observers when there isn't enough to allocate the
+// minimum to all observers.
+std::map<BitrateAllocatorObserver*, int> LowRateAllocation(
+    const std::vector<AllocatableTrack>& allocatable_tracks,
+    uint32_t bitrate) {
+  std::map<BitrateAllocatorObserver*, int> allocation;
+  // Start by allocating bitrate to observers enforcing a min bitrate, hence
+  // remaining_bitrate might turn negative.
+  int64_t remaining_bitrate = bitrate;
+  for (const auto& observer_config : allocatable_tracks) {
+    int32_t allocated_bitrate = 0;
+    if (observer_config.config.enforce_min_bitrate)
+      allocated_bitrate = observer_config.config.min_bitrate_bps;
+
+    allocation[observer_config.observer] = allocated_bitrate;
+    remaining_bitrate -= allocated_bitrate;
+  }
+
+  // Allocate bitrate to all previously active streams.
+  if (remaining_bitrate > 0) {
+    for (const auto& observer_config : allocatable_tracks) {
+      if (observer_config.config.enforce_min_bitrate ||
+          observer_config.LastAllocatedBitrate() == 0)
+        continue;
+
+      uint32_t required_bitrate = observer_config.MinBitrateWithHysteresis();
+      if (remaining_bitrate >= required_bitrate) {
+        allocation[observer_config.observer] = required_bitrate;
+        remaining_bitrate -= required_bitrate;
+      }
+    }
+  }
+
+  // Allocate bitrate to previously paused streams.
+  if (remaining_bitrate > 0) {
+    for (const auto& observer_config : allocatable_tracks) {
+      if (observer_config.LastAllocatedBitrate() != 0)
+        continue;
+
+      // Add a hysteresis to avoid toggling.
+      uint32_t required_bitrate = observer_config.MinBitrateWithHysteresis();
+      if (remaining_bitrate >= required_bitrate) {
+        allocation[observer_config.observer] = required_bitrate;
+        remaining_bitrate -= required_bitrate;
+      }
+    }
+  }
+
+  // Split a possible remainder evenly on all streams with an allocation.
+  if (remaining_bitrate > 0)
+    DistributeBitrateEvenly(allocatable_tracks, remaining_bitrate, false, 1,
+                            &allocation);
+
+  RTC_DCHECK_EQ(allocation.size(), allocatable_tracks.size());
+  return allocation;
+}
+
+// Allocates bitrate to all observers when the available bandwidth is enough
+// to allocate the minimum to all observers but not enough to allocate the
+// max bitrate of each observer.
+
+// Allocates the bitrate based on the bitrate priority of each observer. This
+// bitrate priority defines the priority for bitrate to be allocated to that
+// observer in relation to other observers. For example with two observers, if
+// observer 1 had a bitrate_priority = 1.0, and observer 2 has a
+// bitrate_priority = 2.0, the expected behavior is that observer 2 will be
+// allocated twice the bitrate as observer 1 above the each observer's
+// min_bitrate_bps values, until one of the observers hits its max_bitrate_bps.
+std::map<BitrateAllocatorObserver*, int> NormalRateAllocation(
+    const std::vector<AllocatableTrack>& allocatable_tracks,
+    uint32_t bitrate,
+    uint32_t sum_min_bitrates) {
+  std::map<BitrateAllocatorObserver*, int> allocation;
+  std::map<BitrateAllocatorObserver*, int> observers_capacities;
+  for (const auto& observer_config : allocatable_tracks) {
+    allocation[observer_config.observer] =
+        observer_config.config.min_bitrate_bps;
+    observers_capacities[observer_config.observer] =
+        observer_config.config.max_bitrate_bps -
+        observer_config.config.min_bitrate_bps;
+  }
+
+  bitrate -= sum_min_bitrates;
+
+  // TODO(srte): Implement fair sharing between prioritized streams, currently
+  // they are treated on a first come first serve basis.
+  for (const auto& observer_config : allocatable_tracks) {
+    int64_t priority_margin = observer_config.config.priority_bitrate_bps -
+                              allocation[observer_config.observer];
+    if (priority_margin > 0 && bitrate > 0) {
+      int64_t extra_bitrate = std::min<int64_t>(priority_margin, bitrate);
+      allocation[observer_config.observer] +=
+          rtc::dchecked_cast<int>(extra_bitrate);
+      observers_capacities[observer_config.observer] -= extra_bitrate;
+      bitrate -= extra_bitrate;
+    }
+  }
+
+  // From the remaining bitrate, allocate a proportional amount to each observer
+  // above the min bitrate already allocated.
+  if (bitrate > 0)
+    DistributeBitrateRelatively(allocatable_tracks, bitrate,
+                                observers_capacities, &allocation);
+
+  return allocation;
+}
+
+// Allocates bitrate to observers when there is enough available bandwidth
+// for all observers to be allocated their max bitrate.
+std::map<BitrateAllocatorObserver*, int> MaxRateAllocation(
+    const std::vector<AllocatableTrack>& allocatable_tracks,
+    uint32_t bitrate,
+    uint32_t sum_max_bitrates) {
+  std::map<BitrateAllocatorObserver*, int> allocation;
+
+  for (const auto& observer_config : allocatable_tracks) {
+    allocation[observer_config.observer] =
+        observer_config.config.max_bitrate_bps;
+    bitrate -= observer_config.config.max_bitrate_bps;
+  }
+  DistributeBitrateEvenly(allocatable_tracks, bitrate, true,
+                          kTransmissionMaxBitrateMultiplier, &allocation);
+  return allocation;
+}
+
+// Allocates zero bitrate to all observers.
+std::map<BitrateAllocatorObserver*, int> ZeroRateAllocation(
+    const std::vector<AllocatableTrack>& allocatable_tracks) {
+  std::map<BitrateAllocatorObserver*, int> allocation;
+  for (const auto& observer_config : allocatable_tracks)
+    allocation[observer_config.observer] = 0;
+  return allocation;
+}
+
+std::map<BitrateAllocatorObserver*, int> AllocateBitrates(
+    const std::vector<AllocatableTrack>& allocatable_tracks,
+    uint32_t bitrate) {
+  if (allocatable_tracks.empty())
+    return std::map<BitrateAllocatorObserver*, int>();
+
+  if (bitrate == 0)
+    return ZeroRateAllocation(allocatable_tracks);
+
+  uint32_t sum_min_bitrates = 0;
+  uint32_t sum_max_bitrates = 0;
+  for (const auto& observer_config : allocatable_tracks) {
+    sum_min_bitrates += observer_config.config.min_bitrate_bps;
+    sum_max_bitrates += observer_config.config.max_bitrate_bps;
+  }
+
+  // Not enough for all observers to get an allocation, allocate according to:
+  // enforced min bitrate -> allocated bitrate previous round -> restart paused
+  // streams.
+  if (!EnoughBitrateForAllObservers(allocatable_tracks, bitrate,
+                                    sum_min_bitrates))
+    return LowRateAllocation(allocatable_tracks, bitrate);
+
+  // All observers will get their min bitrate plus a share of the rest. This
+  // share is allocated to each observer based on its bitrate_priority.
+  if (bitrate <= sum_max_bitrates)
+    return NormalRateAllocation(allocatable_tracks, bitrate, sum_min_bitrates);
+
+  // All observers will get up to transmission_max_bitrate_multiplier_ x max.
+  return MaxRateAllocation(allocatable_tracks, bitrate, sum_max_bitrates);
+}
+
+}  // namespace
+
+BitrateAllocator::BitrateAllocator(LimitObserver* limit_observer)
+    : limit_observer_(limit_observer),
+      last_target_bps_(0),
+      last_stable_target_bps_(0),
+      last_non_zero_bitrate_bps_(kDefaultBitrateBps),
+      last_fraction_loss_(0),
+      last_rtt_(0),
+      last_bwe_period_ms_(1000),
+      num_pause_events_(0),
+      last_bwe_log_time_(0) {
+  sequenced_checker_.Detach();
+}
+
+BitrateAllocator::~BitrateAllocator() {
+  RTC_HISTOGRAM_COUNTS_100("WebRTC.Call.NumberOfPauseEvents",
+                           num_pause_events_);
+}
+
+void BitrateAllocator::UpdateStartRate(uint32_t start_rate_bps) {
+  RTC_DCHECK_RUN_ON(&sequenced_checker_);
+  last_non_zero_bitrate_bps_ = start_rate_bps;
+}
+
+void BitrateAllocator::OnNetworkEstimateChanged(TargetTransferRate msg) {
+  RTC_DCHECK_RUN_ON(&sequenced_checker_);
+  last_target_bps_ = msg.target_rate.bps();
+  last_stable_target_bps_ = msg.stable_target_rate.bps();
+  last_non_zero_bitrate_bps_ =
+      last_target_bps_ > 0 ? last_target_bps_ : last_non_zero_bitrate_bps_;
+
+  int loss_ratio_255 = msg.network_estimate.loss_rate_ratio * 255;
+  last_fraction_loss_ =
+      rtc::dchecked_cast<uint8_t>(rtc::SafeClamp(loss_ratio_255, 0, 255));
+  last_rtt_ = msg.network_estimate.round_trip_time.ms();
+  last_bwe_period_ms_ = msg.network_estimate.bwe_period.ms();
+
+  // Periodically log the incoming BWE.
+  int64_t now = msg.at_time.ms();
+  if (now > last_bwe_log_time_ + kBweLogIntervalMs) {
+    RTC_LOG(LS_INFO) << "Current BWE " << last_target_bps_;
+    last_bwe_log_time_ = now;
+  }
+
+  auto allocation = AllocateBitrates(allocatable_tracks_, last_target_bps_);
+  auto stable_bitrate_allocation =
+      AllocateBitrates(allocatable_tracks_, last_stable_target_bps_);
+
+  for (auto& config : allocatable_tracks_) {
+    uint32_t allocated_bitrate = allocation[config.observer];
+    uint32_t allocated_stable_target_rate =
+        stable_bitrate_allocation[config.observer];
+    BitrateAllocationUpdate update;
+    update.target_bitrate = DataRate::BitsPerSec(allocated_bitrate);
+    update.stable_target_bitrate =
+        DataRate::BitsPerSec(allocated_stable_target_rate);
+    update.packet_loss_ratio = last_fraction_loss_ / 256.0;
+    update.round_trip_time = TimeDelta::Millis(last_rtt_);
+    update.bwe_period = TimeDelta::Millis(last_bwe_period_ms_);
+    update.cwnd_reduce_ratio = msg.cwnd_reduce_ratio;
+    uint32_t protection_bitrate = config.observer->OnBitrateUpdated(update);
+
+    if (allocated_bitrate == 0 && config.allocated_bitrate_bps > 0) {
+      if (last_target_bps_ > 0)
+        ++num_pause_events_;
+      // The protection bitrate is an estimate based on the ratio between media
+      // and protection used before this observer was muted.
+      uint32_t predicted_protection_bps =
+          (1.0 - config.media_ratio) * config.config.min_bitrate_bps;
+      RTC_LOG(LS_INFO) << "Pausing observer " << config.observer
+                       << " with configured min bitrate "
+                       << config.config.min_bitrate_bps
+                       << " and current estimate of " << last_target_bps_
+                       << " and protection bitrate "
+                       << predicted_protection_bps;
+    } else if (allocated_bitrate > 0 && config.allocated_bitrate_bps == 0) {
+      if (last_target_bps_ > 0)
+        ++num_pause_events_;
+      RTC_LOG(LS_INFO) << "Resuming observer " << config.observer
+                       << ", configured min bitrate "
+                       << config.config.min_bitrate_bps
+                       << ", current allocation " << allocated_bitrate
+                       << " and protection bitrate " << protection_bitrate;
+    }
+
+    // Only update the media ratio if the observer got an allocation.
+    if (allocated_bitrate > 0)
+      config.media_ratio = MediaRatio(allocated_bitrate, protection_bitrate);
+    config.allocated_bitrate_bps = allocated_bitrate;
+  }
+  UpdateAllocationLimits();
+}
+
+void BitrateAllocator::AddObserver(BitrateAllocatorObserver* observer,
+                                   MediaStreamAllocationConfig config) {
+  RTC_DCHECK_RUN_ON(&sequenced_checker_);
+  RTC_DCHECK_GT(config.bitrate_priority, 0);
+  RTC_DCHECK(std::isnormal(config.bitrate_priority));
+  auto it = absl::c_find_if(
+      allocatable_tracks_,
+      [observer](const auto& config) { return config.observer == observer; });
+  // Update settings if the observer already exists, create a new one otherwise.
+  if (it != allocatable_tracks_.end()) {
+    it->config = config;
+  } else {
+    allocatable_tracks_.push_back(AllocatableTrack(observer, config));
+  }
+
+  if (last_target_bps_ > 0) {
+    // Calculate a new allocation and update all observers.
+
+    auto allocation = AllocateBitrates(allocatable_tracks_, last_target_bps_);
+    auto stable_bitrate_allocation =
+        AllocateBitrates(allocatable_tracks_, last_stable_target_bps_);
+    for (auto& config : allocatable_tracks_) {
+      uint32_t allocated_bitrate = allocation[config.observer];
+      uint32_t allocated_stable_bitrate =
+          stable_bitrate_allocation[config.observer];
+      BitrateAllocationUpdate update;
+      update.target_bitrate = DataRate::BitsPerSec(allocated_bitrate);
+      update.stable_target_bitrate =
+          DataRate::BitsPerSec(allocated_stable_bitrate);
+      update.packet_loss_ratio = last_fraction_loss_ / 256.0;
+      update.round_trip_time = TimeDelta::Millis(last_rtt_);
+      update.bwe_period = TimeDelta::Millis(last_bwe_period_ms_);
+      uint32_t protection_bitrate = config.observer->OnBitrateUpdated(update);
+      config.allocated_bitrate_bps = allocated_bitrate;
+      if (allocated_bitrate > 0)
+        config.media_ratio = MediaRatio(allocated_bitrate, protection_bitrate);
+    }
+  } else {
+    // Currently, an encoder is not allowed to produce frames.
+    // But we still have to return the initial config bitrate + let the
+    // observer know that it can not produce frames.
+
+    BitrateAllocationUpdate update;
+    update.target_bitrate = DataRate::Zero();
+    update.stable_target_bitrate = DataRate::Zero();
+    update.packet_loss_ratio = last_fraction_loss_ / 256.0;
+    update.round_trip_time = TimeDelta::Millis(last_rtt_);
+    update.bwe_period = TimeDelta::Millis(last_bwe_period_ms_);
+    observer->OnBitrateUpdated(update);
+  }
+  UpdateAllocationLimits();
+}
+
+void BitrateAllocator::UpdateAllocationLimits() {
+  BitrateAllocationLimits limits;
+  for (const auto& config : allocatable_tracks_) {
+    uint32_t stream_padding = config.config.pad_up_bitrate_bps;
+    if (config.config.enforce_min_bitrate) {
+      limits.min_allocatable_rate +=
+          DataRate::BitsPerSec(config.config.min_bitrate_bps);
+    } else if (config.allocated_bitrate_bps == 0) {
+      stream_padding =
+          std::max(config.MinBitrateWithHysteresis(), stream_padding);
+    }
+    limits.max_padding_rate += DataRate::BitsPerSec(stream_padding);
+    limits.max_allocatable_rate +=
+        DataRate::BitsPerSec(config.config.max_bitrate_bps);
+  }
+
+  if (limits.min_allocatable_rate == current_limits_.min_allocatable_rate &&
+      limits.max_allocatable_rate == current_limits_.max_allocatable_rate &&
+      limits.max_padding_rate == current_limits_.max_padding_rate) {
+    return;
+  }
+  current_limits_ = limits;
+
+  RTC_LOG(LS_INFO) << "UpdateAllocationLimits : total_requested_min_bitrate: "
+                   << ToString(limits.min_allocatable_rate)
+                   << ", total_requested_padding_bitrate: "
+                   << ToString(limits.max_padding_rate)
+                   << ", total_requested_max_bitrate: "
+                   << ToString(limits.max_allocatable_rate);
+
+  limit_observer_->OnAllocationLimitsChanged(limits);
+}
+
+void BitrateAllocator::RemoveObserver(BitrateAllocatorObserver* observer) {
+  RTC_DCHECK_RUN_ON(&sequenced_checker_);
+  for (auto it = allocatable_tracks_.begin(); it != allocatable_tracks_.end();
+       ++it) {
+    if (it->observer == observer) {
+      allocatable_tracks_.erase(it);
+      break;
+    }
+  }
+
+  UpdateAllocationLimits();
+}
+
+int BitrateAllocator::GetStartBitrate(
+    BitrateAllocatorObserver* observer) const {
+  RTC_DCHECK_RUN_ON(&sequenced_checker_);
+  auto it = absl::c_find_if(
+      allocatable_tracks_,
+      [observer](const auto& config) { return config.observer == observer; });
+  if (it == allocatable_tracks_.end()) {
+    // This observer hasn't been added yet, just give it its fair share.
+    return last_non_zero_bitrate_bps_ /
+           static_cast<int>((allocatable_tracks_.size() + 1));
+  } else if (it->allocated_bitrate_bps == -1) {
+    // This observer hasn't received an allocation yet, so do the same.
+    return last_non_zero_bitrate_bps_ /
+           static_cast<int>(allocatable_tracks_.size());
+  } else {
+    // This observer already has an allocation.
+    return it->allocated_bitrate_bps;
+  }
+}
+
+uint32_t bitrate_allocator_impl::AllocatableTrack::LastAllocatedBitrate()
+    const {
+  // Return the configured minimum bitrate for newly added observers, to avoid
+  // requiring an extra high bitrate for the observer to get an allocated
+  // bitrate.
+  return allocated_bitrate_bps == -1 ? config.min_bitrate_bps
+                                     : allocated_bitrate_bps;
+}
+
+uint32_t bitrate_allocator_impl::AllocatableTrack::MinBitrateWithHysteresis()
+    const {
+  uint32_t min_bitrate = config.min_bitrate_bps;
+  if (LastAllocatedBitrate() == 0) {
+    min_bitrate += std::max(static_cast<uint32_t>(kToggleFactor * min_bitrate),
+                            kMinToggleBitrateBps);
+  }
+  // Account for protection bitrate used by this observer in the previous
+  // allocation.
+  // Note: the ratio will only be updated when the stream is active, meaning a
+  // paused stream won't get any ratio updates. This might lead to waiting a bit
+  // longer than necessary if the network condition improves, but this is to
+  // avoid too much toggling.
+  if (media_ratio > 0.0 && media_ratio < 1.0)
+    min_bitrate += min_bitrate * (1.0 - media_ratio);
+
+  return min_bitrate;
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/bitrate_allocator.h b/third_party/libwebrtc/call/bitrate_allocator.h
new file mode 100644
index 0000000000..204fc6f94d
--- /dev/null
+++ b/third_party/libwebrtc/call/bitrate_allocator.h
@@ -0,0 +1,170 @@
+/*
+ *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_BITRATE_ALLOCATOR_H_
+#define CALL_BITRATE_ALLOCATOR_H_
+
+#include <stdint.h>
+
+#include <map>
+#include <memory>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "api/call/bitrate_allocation.h"
+#include "api/sequence_checker.h"
+#include "api/transport/network_types.h"
+#include "rtc_base/system/no_unique_address.h"
+
+namespace webrtc {
+
+class Clock;
+
+// Used by all send streams with adaptive bitrate, to get the currently
+// allocated bitrate for the send stream. The current network properties are
+// given at the same time, to let the send stream decide about possible loss
+// protection.
+class BitrateAllocatorObserver {
+ public:
+  // Returns the amount of protection used by the BitrateAllocatorObserver
+  // implementation, as bitrate in bps.
+  virtual uint32_t OnBitrateUpdated(BitrateAllocationUpdate update) = 0;
+
+ protected:
+  virtual ~BitrateAllocatorObserver() {}
+};
+
+// Struct describing parameters for how a media stream should get bitrate
+// allocated to it.
+
+struct MediaStreamAllocationConfig {
+  // Minimum bitrate supported by track. 0 equals no min bitrate.
+  uint32_t min_bitrate_bps;
+  // Maximum bitrate supported by track. 0 equals no max bitrate.
+  uint32_t max_bitrate_bps;
+  uint32_t pad_up_bitrate_bps;
+  int64_t priority_bitrate_bps;
+  // True means track may not be paused by allocating 0 bitrate will allocate at
+  // least `min_bitrate_bps` for this observer, even if the BWE is too low,
+  // false will allocate 0 to the observer if BWE doesn't allow
+  // `min_bitrate_bps`.
+  bool enforce_min_bitrate;
+  // The amount of bitrate allocated to this observer relative to all other
+  // observers. If an observer has twice the bitrate_priority of other
+  // observers, it should be allocated twice the bitrate above its min.
+  double bitrate_priority;
+};
+
+// Interface used for mocking
+class BitrateAllocatorInterface {
+ public:
+  virtual void AddObserver(BitrateAllocatorObserver* observer,
+                           MediaStreamAllocationConfig config) = 0;
+  virtual void RemoveObserver(BitrateAllocatorObserver* observer) = 0;
+  virtual int GetStartBitrate(BitrateAllocatorObserver* observer) const = 0;
+
+ protected:
+  virtual ~BitrateAllocatorInterface() = default;
+};
+
+namespace bitrate_allocator_impl {
+struct AllocatableTrack {
+  AllocatableTrack(BitrateAllocatorObserver* observer,
+                   MediaStreamAllocationConfig allocation_config)
+      : observer(observer),
+        config(allocation_config),
+        allocated_bitrate_bps(-1),
+        media_ratio(1.0) {}
+  BitrateAllocatorObserver* observer;
+  MediaStreamAllocationConfig config;
+  int64_t allocated_bitrate_bps;
+  double media_ratio;  // Part of the total bitrate used for media [0.0, 1.0].
+
+  uint32_t LastAllocatedBitrate() const;
+  // The minimum bitrate required by this observer, including
+  // enable-hysteresis if the observer is in a paused state.
+  uint32_t MinBitrateWithHysteresis() const;
+};
+}  // namespace bitrate_allocator_impl
+
+// Usage: this class will register multiple RtcpBitrateObserver's one at each
+// RTCP module. It will aggregate the results and run one bandwidth estimation
+// and push the result to the encoders via BitrateAllocatorObserver(s).
+class BitrateAllocator : public BitrateAllocatorInterface {
+ public:
+  // Used to get notified when send stream limits such as the minimum send
+  // bitrate and max padding bitrate is changed.
+  class LimitObserver {
+   public:
+    virtual void OnAllocationLimitsChanged(BitrateAllocationLimits limits) = 0;
+
+   protected:
+    virtual ~LimitObserver() = default;
+  };
+
+  explicit BitrateAllocator(LimitObserver* limit_observer);
+  ~BitrateAllocator() override;
+
+  void UpdateStartRate(uint32_t start_rate_bps);
+
+  // Allocate target_bitrate across the registered BitrateAllocatorObservers.
+  void OnNetworkEstimateChanged(TargetTransferRate msg);
+
+  // Set the configuration used by the bandwidth management.
+  // `observer` updates bitrates if already in use.
+  // `config` is the configuration to use for allocation.
+  // Note that `observer`->OnBitrateUpdated() will be called
+  // within the scope of this method with the current rtt, fraction_loss and
+  // available bitrate and that the bitrate in OnBitrateUpdated will be zero if
+  // the `observer` is currently not allowed to send data.
+  void AddObserver(BitrateAllocatorObserver* observer,
+                   MediaStreamAllocationConfig config) override;
+
+  // Removes a previously added observer, but will not trigger a new bitrate
+  // allocation.
+  void RemoveObserver(BitrateAllocatorObserver* observer) override;
+
+  // Returns initial bitrate allocated for `observer`. If `observer` is not in
+  // the list of added observers, a best guess is returned.
+  int GetStartBitrate(BitrateAllocatorObserver* observer) const override;
+
+ private:
+  using AllocatableTrack = bitrate_allocator_impl::AllocatableTrack;
+
+  // Calculates the minimum requested send bitrate and max padding bitrate and
+  // calls LimitObserver::OnAllocationLimitsChanged.
+  void UpdateAllocationLimits() RTC_RUN_ON(&sequenced_checker_);
+
+  // Allow packets to be transmitted in up to 2 times max video bitrate if the
+  // bandwidth estimate allows it.
+  // TODO(bugs.webrtc.org/8541): May be worth to refactor to keep this logic in
+  // video send stream.
+  static uint8_t GetTransmissionMaxBitrateMultiplier();
+
+  RTC_NO_UNIQUE_ADDRESS SequenceChecker sequenced_checker_;
+  LimitObserver* const limit_observer_ RTC_GUARDED_BY(&sequenced_checker_);
+  // Stored in a list to keep track of the insertion order.
+  std::vector<AllocatableTrack> allocatable_tracks_
+      RTC_GUARDED_BY(&sequenced_checker_);
+  uint32_t last_target_bps_ RTC_GUARDED_BY(&sequenced_checker_);
+  uint32_t last_stable_target_bps_ RTC_GUARDED_BY(&sequenced_checker_);
+  uint32_t last_non_zero_bitrate_bps_ RTC_GUARDED_BY(&sequenced_checker_);
+  uint8_t last_fraction_loss_ RTC_GUARDED_BY(&sequenced_checker_);
+  int64_t last_rtt_ RTC_GUARDED_BY(&sequenced_checker_);
+  int64_t last_bwe_period_ms_ RTC_GUARDED_BY(&sequenced_checker_);
+  // Number of mute events based on too low BWE, not network up/down.
+  int num_pause_events_ RTC_GUARDED_BY(&sequenced_checker_);
+  int64_t last_bwe_log_time_ RTC_GUARDED_BY(&sequenced_checker_);
+  BitrateAllocationLimits current_limits_ RTC_GUARDED_BY(&sequenced_checker_);
+};
+
+}  // namespace webrtc
+#endif  // CALL_BITRATE_ALLOCATOR_H_
diff --git a/third_party/libwebrtc/call/bitrate_allocator_gn/moz.build b/third_party/libwebrtc/call/bitrate_allocator_gn/moz.build
new file mode 100644
index 0000000000..ef48a850a4
--- /dev/null
+++ b/third_party/libwebrtc/call/bitrate_allocator_gn/moz.build
@@ -0,0 +1,232 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+  ### This moz.build was AUTOMATICALLY GENERATED from a GN config,  ###
+  ### DO NOT edit it by hand.                                       ###
+
+COMPILE_FLAGS["OS_INCLUDES"] = []
+AllowCompilerWarnings()
+
+DEFINES["ABSL_ALLOCATOR_NOTHROW"] = "1"
+DEFINES["RTC_DAV1D_IN_INTERNAL_DECODER_FACTORY"] = True
+DEFINES["RTC_ENABLE_VP9"] = True
+DEFINES["WEBRTC_ENABLE_PROTOBUF"] = "0"
+DEFINES["WEBRTC_LIBRARY_IMPL"] = True
+DEFINES["WEBRTC_MOZILLA_BUILD"] = True
+DEFINES["WEBRTC_NON_STATIC_TRACE_EVENT_HANDLERS"] = "0"
+DEFINES["WEBRTC_STRICT_FIELD_TRIALS"] = "0"
+
+FINAL_LIBRARY = "webrtc"
+
+
+LOCAL_INCLUDES += [
+    "!/ipc/ipdl/_ipdlheaders",
+    "!/third_party/libwebrtc/gen",
+    "/ipc/chromium/src",
+    "/third_party/libwebrtc/",
+    "/third_party/libwebrtc/third_party/abseil-cpp/",
+    "/tools/profiler/public"
+]
+
+UNIFIED_SOURCES += [
+    "/third_party/libwebrtc/call/bitrate_allocator.cc"
+]
+
+if not CONFIG["MOZ_DEBUG"]:
+
+    DEFINES["DYNAMIC_ANNOTATIONS_ENABLED"] = "0"
+    DEFINES["NDEBUG"] = True
+    DEFINES["NVALGRIND"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1":
+
+    DEFINES["DYNAMIC_ANNOTATIONS_ENABLED"] = "1"
+
+if CONFIG["OS_TARGET"] == "Android":
+
+    DEFINES["ANDROID"] = True
+    DEFINES["ANDROID_NDK_VERSION_ROLL"] = "r22_1"
+    DEFINES["HAVE_SYS_UIO_H"] = True
+    DEFINES["WEBRTC_ANDROID"] = True
+    DEFINES["WEBRTC_ANDROID_OPENSLES"] = True
+    DEFINES["WEBRTC_LINUX"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_GNU_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+    OS_LIBS += [
+        "log"
+    ]
+
+if CONFIG["OS_TARGET"] == "Darwin":
+
+    DEFINES["WEBRTC_MAC"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_LIBCPP_HAS_NO_ALIGNED_ALLOCATION"] = True
+    DEFINES["__ASSERT_MACROS_DEFINE_VERSIONS_WITHOUT_UNDERSCORES"] = "0"
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+if CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["USE_AURA"] = "1"
+    DEFINES["USE_GLIB"] = "1"
+    DEFINES["USE_NSS_CERTS"] = "1"
+    DEFINES["USE_OZONE"] = "1"
+    DEFINES["USE_UDEV"] = True
+    DEFINES["WEBRTC_LINUX"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_FILE_OFFSET_BITS"] = "64"
+    DEFINES["_LARGEFILE64_SOURCE"] = True
+    DEFINES["_LARGEFILE_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+    OS_LIBS += [
+        "rt"
+    ]
+
+if CONFIG["OS_TARGET"] == "OpenBSD":
+
+    DEFINES["USE_GLIB"] = "1"
+    DEFINES["USE_OZONE"] = "1"
+    DEFINES["USE_X11"] = "1"
+    DEFINES["WEBRTC_BSD"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_FILE_OFFSET_BITS"] = "64"
+    DEFINES["_LARGEFILE64_SOURCE"] = True
+    DEFINES["_LARGEFILE_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+if CONFIG["OS_TARGET"] == "WINNT":
+
+    DEFINES["CERT_CHAIN_PARA_HAS_EXTRA_FIELDS"] = True
+    DEFINES["NOMINMAX"] = True
+    DEFINES["NTDDI_VERSION"] = "0x0A000000"
+    DEFINES["PSAPI_VERSION"] = "2"
+    DEFINES["UNICODE"] = True
+    DEFINES["USE_AURA"] = "1"
+    DEFINES["WEBRTC_WIN"] = True
+    DEFINES["WIN32"] = True
+    DEFINES["WIN32_LEAN_AND_MEAN"] = True
+    DEFINES["WINAPI_FAMILY"] = "WINAPI_FAMILY_DESKTOP_APP"
+    DEFINES["WINVER"] = "0x0A00"
+    DEFINES["_ATL_NO_OPENGL"] = True
+    DEFINES["_CRT_RAND_S"] = True
+    DEFINES["_CRT_SECURE_NO_DEPRECATE"] = True
+    DEFINES["_ENABLE_EXTENDED_ALIGNED_STORAGE"] = True
+    DEFINES["_HAS_EXCEPTIONS"] = "0"
+    DEFINES["_HAS_NODISCARD"] = True
+    DEFINES["_SCL_SECURE_NO_DEPRECATE"] = True
+    DEFINES["_SECURE_ATL"] = True
+    DEFINES["_UNICODE"] = True
+    DEFINES["_WIN32_WINNT"] = "0x0A00"
+    DEFINES["_WINDOWS"] = True
+    DEFINES["__STD_C"] = True
+
+    OS_LIBS += [
+        "crypt32",
+        "iphlpapi",
+        "secur32",
+        "winmm"
+    ]
+
+if CONFIG["CPU_ARCH"] == "aarch64":
+
+    DEFINES["WEBRTC_ARCH_ARM64"] = True
+    DEFINES["WEBRTC_HAS_NEON"] = True
+
+if CONFIG["CPU_ARCH"] == "arm":
+
+    CXXFLAGS += [
+        "-mfpu=neon"
+    ]
+
+    DEFINES["WEBRTC_ARCH_ARM"] = True
+    DEFINES["WEBRTC_ARCH_ARM_V7"] = True
+    DEFINES["WEBRTC_HAS_NEON"] = True
+
+if CONFIG["CPU_ARCH"] == "mips32":
+
+    DEFINES["MIPS32_LE"] = True
+    DEFINES["MIPS_FPU_LE"] = True
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "mips64":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86":
+
+    DEFINES["WEBRTC_ENABLE_AVX2"] = True
+
+if CONFIG["CPU_ARCH"] == "x86_64":
+
+    DEFINES["WEBRTC_ENABLE_AVX2"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Android":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Darwin":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "OpenBSD":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "WINNT":
+
+    DEFINES["_HAS_ITERATOR_DEBUGGING"] = "0"
+
+if CONFIG["MOZ_X11"] == "1" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["USE_X11"] = "1"
+
+if CONFIG["CPU_ARCH"] == "arm" and CONFIG["OS_TARGET"] == "Android":
+
+    OS_LIBS += [
+        "android_support",
+        "unwind"
+    ]
+
+if CONFIG["CPU_ARCH"] == "x86" and CONFIG["OS_TARGET"] == "Android":
+
+    CXXFLAGS += [
+        "-msse2"
+    ]
+
+    OS_LIBS += [
+        "android_support"
+    ]
+
+if CONFIG["CPU_ARCH"] == "aarch64" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "arm" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86" and CONFIG["OS_TARGET"] == "Linux":
+
+    CXXFLAGS += [
+        "-msse2"
+    ]
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86_64" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+Library("bitrate_allocator_gn")
diff --git a/third_party/libwebrtc/call/bitrate_allocator_unittest.cc b/third_party/libwebrtc/call/bitrate_allocator_unittest.cc
new file mode 100644
index 0000000000..69bdd83397
--- /dev/null
+++ b/third_party/libwebrtc/call/bitrate_allocator_unittest.cc
@@ -0,0 +1,1037 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/bitrate_allocator.h"
+
+#include <algorithm>
+#include <memory>
+#include <vector>
+
+#include "absl/strings/string_view.h"
+#include "system_wrappers/include/clock.h"
+#include "test/gmock.h"
+#include "test/gtest.h"
+
+using ::testing::_;
+using ::testing::AllOf;
+using ::testing::Field;
+using ::testing::NiceMock;
+
+namespace webrtc {
+
+namespace {
+auto AllocationLimitsEq(uint32_t min_allocatable_rate_bps,
+                        uint32_t max_padding_rate_bps,
+                        uint32_t max_allocatable_rate_bps) {
+  return AllOf(Field(&BitrateAllocationLimits::min_allocatable_rate,
+                     DataRate::BitsPerSec(min_allocatable_rate_bps)),
+               Field(&BitrateAllocationLimits::max_allocatable_rate,
+                     DataRate::BitsPerSec(max_allocatable_rate_bps)),
+               Field(&BitrateAllocationLimits::max_padding_rate,
+                     DataRate::BitsPerSec(max_padding_rate_bps)));
+}
+
+auto AllocationLimitsEq(uint32_t min_allocatable_rate_bps,
+                        uint32_t max_padding_rate_bps) {
+  return AllOf(Field(&BitrateAllocationLimits::min_allocatable_rate,
+                     DataRate::BitsPerSec(min_allocatable_rate_bps)),
+               Field(&BitrateAllocationLimits::max_padding_rate,
+                     DataRate::BitsPerSec(max_padding_rate_bps)));
+}
+
+class MockLimitObserver : public BitrateAllocator::LimitObserver {
+ public:
+  MOCK_METHOD(void,
+              OnAllocationLimitsChanged,
+              (BitrateAllocationLimits),
+              (override));
+};
+
+class TestBitrateObserver : public BitrateAllocatorObserver {
+ public:
+  TestBitrateObserver()
+      : last_bitrate_bps_(0),
+        last_fraction_loss_(0),
+        last_rtt_ms_(0),
+        last_probing_interval_ms_(0),
+        protection_ratio_(0.0) {}
+
+  void SetBitrateProtectionRatio(double protection_ratio) {
+    protection_ratio_ = protection_ratio;
+  }
+
+  uint32_t OnBitrateUpdated(BitrateAllocationUpdate update) override {
+    last_bitrate_bps_ = update.target_bitrate.bps();
+    last_fraction_loss_ =
+        rtc::dchecked_cast<uint8_t>(update.packet_loss_ratio * 256);
+    last_rtt_ms_ = update.round_trip_time.ms();
+    last_probing_interval_ms_ = update.bwe_period.ms();
+    return update.target_bitrate.bps() * protection_ratio_;
+  }
+  uint32_t last_bitrate_bps_;
+  uint8_t last_fraction_loss_;
+  int64_t last_rtt_ms_;
+  int last_probing_interval_ms_;
+  double protection_ratio_;
+};
+
+constexpr int64_t kDefaultProbingIntervalMs = 3000;
+const double kDefaultBitratePriority = 1.0;
+
+TargetTransferRate CreateTargetRateMessage(uint32_t target_bitrate_bps,
+                                           uint8_t fraction_loss,
+                                           int64_t rtt_ms,
+                                           int64_t bwe_period_ms) {
+  TargetTransferRate msg;
+  // The timestamp is just for log output, keeping it fixed just means fewer log
+  // messages in the test.
+  msg.at_time = Timestamp::Seconds(10000);
+  msg.target_rate = DataRate::BitsPerSec(target_bitrate_bps);
+  msg.stable_target_rate = msg.target_rate;
+  msg.network_estimate.bandwidth = msg.target_rate;
+  msg.network_estimate.loss_rate_ratio = fraction_loss / 255.0;
+  msg.network_estimate.round_trip_time = TimeDelta::Millis(rtt_ms);
+  msg.network_estimate.bwe_period = TimeDelta::Millis(bwe_period_ms);
+  return msg;
+}
+}  // namespace
+
+class BitrateAllocatorTest : public ::testing::Test {
+ protected:
+  BitrateAllocatorTest() : allocator_(new BitrateAllocator(&limit_observer_)) {
+    allocator_->OnNetworkEstimateChanged(
+        CreateTargetRateMessage(300000u, 0, 0, kDefaultProbingIntervalMs));
+  }
+  ~BitrateAllocatorTest() {}
+  void AddObserver(BitrateAllocatorObserver* observer,
+                   uint32_t min_bitrate_bps,
+                   uint32_t max_bitrate_bps,
+                   uint32_t pad_up_bitrate_bps,
+                   bool enforce_min_bitrate,
+                   double bitrate_priority) {
+    allocator_->AddObserver(
+        observer,
+        {min_bitrate_bps, max_bitrate_bps, pad_up_bitrate_bps,
+         /* priority_bitrate */ 0, enforce_min_bitrate, bitrate_priority});
+  }
+  MediaStreamAllocationConfig DefaultConfig() const {
+    MediaStreamAllocationConfig default_config;
+    default_config.min_bitrate_bps = 0;
+    default_config.max_bitrate_bps = 1500000;
+    default_config.pad_up_bitrate_bps = 0;
+    default_config.priority_bitrate_bps = 0;
+    default_config.enforce_min_bitrate = true;
+    default_config.bitrate_priority = kDefaultBitratePriority;
+    return default_config;
+  }
+
+  NiceMock<MockLimitObserver> limit_observer_;
+  std::unique_ptr<BitrateAllocator> allocator_;
+};
+
+TEST_F(BitrateAllocatorTest, RespectsPriorityBitrate) {
+  TestBitrateObserver stream_a;
+  auto config_a = DefaultConfig();
+  config_a.min_bitrate_bps = 100000;
+  config_a.priority_bitrate_bps = 0;
+  allocator_->AddObserver(&stream_a, config_a);
+
+  TestBitrateObserver stream_b;
+  auto config_b = DefaultConfig();
+  config_b.min_bitrate_bps = 100000;
+  config_b.max_bitrate_bps = 300000;
+  config_b.priority_bitrate_bps = 300000;
+  allocator_->AddObserver(&stream_b, config_b);
+
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(100000, 0, 0, 0));
+  EXPECT_EQ(stream_a.last_bitrate_bps_, 100000u);
+  EXPECT_EQ(stream_b.last_bitrate_bps_, 100000u);
+
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(200000, 0, 0, 0));
+  EXPECT_EQ(stream_a.last_bitrate_bps_, 100000u);
+  EXPECT_EQ(stream_b.last_bitrate_bps_, 100000u);
+
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(300000, 0, 0, 0));
+  EXPECT_EQ(stream_a.last_bitrate_bps_, 100000u);
+  EXPECT_EQ(stream_b.last_bitrate_bps_, 200000u);
+
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(400000, 0, 0, 0));
+  EXPECT_EQ(stream_a.last_bitrate_bps_, 100000u);
+  EXPECT_EQ(stream_b.last_bitrate_bps_, 300000u);
+
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(800000, 0, 0, 0));
+  EXPECT_EQ(stream_a.last_bitrate_bps_, 500000u);
+  EXPECT_EQ(stream_b.last_bitrate_bps_, 300000u);
+}
+
+TEST_F(BitrateAllocatorTest, UpdatingBitrateObserver) {
+  TestBitrateObserver bitrate_observer;
+  const uint32_t kMinSendBitrateBps = 100000;
+  const uint32_t kPadUpToBitrateBps = 50000;
+  const uint32_t kMaxBitrateBps = 1500000;
+
+  EXPECT_CALL(limit_observer_,
+              OnAllocationLimitsChanged(AllocationLimitsEq(
+                  kMinSendBitrateBps, kPadUpToBitrateBps, kMaxBitrateBps)));
+  AddObserver(&bitrate_observer, kMinSendBitrateBps, kMaxBitrateBps,
+              kPadUpToBitrateBps, true, kDefaultBitratePriority);
+  EXPECT_EQ(300000, allocator_->GetStartBitrate(&bitrate_observer));
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(200000, 0, 0, kDefaultProbingIntervalMs));
+  EXPECT_EQ(200000, allocator_->GetStartBitrate(&bitrate_observer));
+
+  // TODO(pbos): Expect capping to 1.5M instead of 3M when not boosting the max
+  // bitrate for FEC/retransmissions (see todo in BitrateAllocator).
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(4000000, 0, 0, kDefaultProbingIntervalMs));
+  EXPECT_EQ(3000000, allocator_->GetStartBitrate(&bitrate_observer));
+
+  // Expect `max_padding_bitrate_bps` to change to 0 if the observer is updated.
+  EXPECT_CALL(limit_observer_, OnAllocationLimitsChanged(
+                                   AllocationLimitsEq(kMinSendBitrateBps, 0)));
+  AddObserver(&bitrate_observer, kMinSendBitrateBps, 4000000, 0, true,
+              kDefaultBitratePriority);
+  EXPECT_CALL(limit_observer_, OnAllocationLimitsChanged(
+                                   AllocationLimitsEq(kMinSendBitrateBps, 0)));
+  EXPECT_EQ(4000000, allocator_->GetStartBitrate(&bitrate_observer));
+
+  AddObserver(&bitrate_observer, kMinSendBitrateBps, kMaxBitrateBps, 0, true,
+              kDefaultBitratePriority);
+  EXPECT_EQ(3000000, allocator_->GetStartBitrate(&bitrate_observer));
+  EXPECT_EQ(3000000u, bitrate_observer.last_bitrate_bps_);
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(kMaxBitrateBps, 0, 0, kDefaultProbingIntervalMs));
+  EXPECT_EQ(1500000u, bitrate_observer.last_bitrate_bps_);
+}
+
+TEST_F(BitrateAllocatorTest, TwoBitrateObserversOneRtcpObserver) {
+  TestBitrateObserver bitrate_observer_1;
+  TestBitrateObserver bitrate_observer_2;
+  const uint32_t kObs1StartBitrateBps = 100000;
+  const uint32_t kObs2StartBitrateBps = 200000;
+  const uint32_t kObs1MaxBitrateBps = 300000;
+  const uint32_t kObs2MaxBitrateBps = 300000;
+
+  EXPECT_CALL(limit_observer_,
+              OnAllocationLimitsChanged(AllocationLimitsEq(
+                  kObs1StartBitrateBps, 0, kObs1MaxBitrateBps)));
+  AddObserver(&bitrate_observer_1, kObs1StartBitrateBps, kObs1MaxBitrateBps, 0,
+              true, kDefaultBitratePriority);
+  EXPECT_EQ(static_cast<int>(kObs1MaxBitrateBps),
+            allocator_->GetStartBitrate(&bitrate_observer_1));
+  EXPECT_CALL(limit_observer_,
+              OnAllocationLimitsChanged(AllocationLimitsEq(
+                  kObs1StartBitrateBps + kObs2StartBitrateBps, 0,
+                  kObs1MaxBitrateBps + kObs2MaxBitrateBps)));
+  AddObserver(&bitrate_observer_2, kObs2StartBitrateBps, kObs2MaxBitrateBps, 0,
+              true, kDefaultBitratePriority);
+  EXPECT_EQ(static_cast<int>(kObs2StartBitrateBps),
+            allocator_->GetStartBitrate(&bitrate_observer_2));
+
+  // Test too low start bitrate, hence lower than sum of min. Min bitrates
+  // will
+  // be allocated to all observers.
+  allocator_->OnNetworkEstimateChanged(CreateTargetRateMessage(
+      kObs2StartBitrateBps, 0, 50, kDefaultProbingIntervalMs));
+  EXPECT_EQ(100000u, bitrate_observer_1.last_bitrate_bps_);
+  EXPECT_EQ(0, bitrate_observer_1.last_fraction_loss_);
+  EXPECT_EQ(50, bitrate_observer_1.last_rtt_ms_);
+  EXPECT_EQ(200000u, bitrate_observer_2.last_bitrate_bps_);
+  EXPECT_EQ(0, bitrate_observer_2.last_fraction_loss_);
+  EXPECT_EQ(50, bitrate_observer_2.last_rtt_ms_);
+
+  // Test a bitrate which should be distributed equally.
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(500000, 0, 50, kDefaultProbingIntervalMs));
+  const uint32_t kBitrateToShare =
+      500000 - kObs2StartBitrateBps - kObs1StartBitrateBps;
+  EXPECT_EQ(100000u + kBitrateToShare / 2,
+            bitrate_observer_1.last_bitrate_bps_);
+  EXPECT_EQ(200000u + kBitrateToShare / 2,
+            bitrate_observer_2.last_bitrate_bps_);
+
+  // Limited by 2x max bitrates since we leave room for FEC and
+  // retransmissions.
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(1500000, 0, 50, kDefaultProbingIntervalMs));
+  EXPECT_EQ(600000u, bitrate_observer_1.last_bitrate_bps_);
+  EXPECT_EQ(600000u, bitrate_observer_2.last_bitrate_bps_);
+
+  // Verify that if the bandwidth estimate is set to zero, the allocated
+  // rate is
+  // zero.
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(0, 0, 50, kDefaultProbingIntervalMs));
+  EXPECT_EQ(0u, bitrate_observer_1.last_bitrate_bps_);
+  EXPECT_EQ(0u, bitrate_observer_2.last_bitrate_bps_);
+}
+
+TEST_F(BitrateAllocatorTest, RemoveObserverTriggersLimitObserver) {
+  TestBitrateObserver bitrate_observer;
+  const uint32_t kMinSendBitrateBps = 100000;
+  const uint32_t kPadUpToBitrateBps = 50000;
+  const uint32_t kMaxBitrateBps = 1500000;
+
+  EXPECT_CALL(limit_observer_,
+              OnAllocationLimitsChanged(AllocationLimitsEq(
+                  kMinSendBitrateBps, kPadUpToBitrateBps, kMaxBitrateBps)));
+  AddObserver(&bitrate_observer, kMinSendBitrateBps, kMaxBitrateBps,
+              kPadUpToBitrateBps, true, kDefaultBitratePriority);
+  EXPECT_CALL(limit_observer_,
+              OnAllocationLimitsChanged(AllocationLimitsEq(0, 0)));
+  allocator_->RemoveObserver(&bitrate_observer);
+}
+
+class BitrateAllocatorTestNoEnforceMin : public ::testing::Test {
+ protected:
+  BitrateAllocatorTestNoEnforceMin()
+      : allocator_(new BitrateAllocator(&limit_observer_)) {
+    allocator_->OnNetworkEstimateChanged(
+        CreateTargetRateMessage(300000u, 0, 0, kDefaultProbingIntervalMs));
+  }
+  ~BitrateAllocatorTestNoEnforceMin() {}
+  void AddObserver(BitrateAllocatorObserver* observer,
+                   uint32_t min_bitrate_bps,
+                   uint32_t max_bitrate_bps,
+                   uint32_t pad_up_bitrate_bps,
+                   bool enforce_min_bitrate,
+                   absl::string_view track_id,
+                   double bitrate_priority) {
+    allocator_->AddObserver(
+        observer, {min_bitrate_bps, max_bitrate_bps, pad_up_bitrate_bps, 0,
+                   enforce_min_bitrate, bitrate_priority});
+  }
+  NiceMock<MockLimitObserver> limit_observer_;
+  std::unique_ptr<BitrateAllocator> allocator_;
+};
+
+// The following three tests verify enforcing a minimum bitrate works as
+// intended.
+TEST_F(BitrateAllocatorTestNoEnforceMin, OneBitrateObserver) {
+  TestBitrateObserver bitrate_observer_1;
+  // Expect OnAllocationLimitsChanged with `min_send_bitrate_bps` = 0 since
+  // AddObserver is called with `enforce_min_bitrate` = false.
+  EXPECT_CALL(limit_observer_,
+              OnAllocationLimitsChanged(AllocationLimitsEq(0, 0)));
+  EXPECT_CALL(limit_observer_,
+              OnAllocationLimitsChanged(AllocationLimitsEq(0, 120000)));
+  AddObserver(&bitrate_observer_1, 100000, 400000, 0, false, "",
+              kDefaultBitratePriority);
+  EXPECT_EQ(300000, allocator_->GetStartBitrate(&bitrate_observer_1));
+
+  // High BWE.
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(150000, 0, 0, kDefaultProbingIntervalMs));
+  EXPECT_EQ(150000u, bitrate_observer_1.last_bitrate_bps_);
+
+  // Low BWE.
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(10000, 0, 0, kDefaultProbingIntervalMs));
+  EXPECT_EQ(0u, bitrate_observer_1.last_bitrate_bps_);
+
+  EXPECT_CALL(limit_observer_,
+              OnAllocationLimitsChanged(AllocationLimitsEq(0, 0)));
+  allocator_->RemoveObserver(&bitrate_observer_1);
+}
+
+TEST_F(BitrateAllocatorTestNoEnforceMin, ThreeBitrateObservers) {
+  TestBitrateObserver bitrate_observer_1;
+  TestBitrateObserver bitrate_observer_2;
+  TestBitrateObserver bitrate_observer_3;
+  // Set up the observers with min bitrates at 100000, 200000, and 300000.
+  AddObserver(&bitrate_observer_1, 100000, 400000, 0, false, "",
+              kDefaultBitratePriority);
+  EXPECT_EQ(300000, allocator_->GetStartBitrate(&bitrate_observer_1));
+
+  AddObserver(&bitrate_observer_2, 200000, 400000, 0, false, "",
+              kDefaultBitratePriority);
+  EXPECT_EQ(200000, allocator_->GetStartBitrate(&bitrate_observer_2));
+  EXPECT_EQ(100000u, bitrate_observer_1.last_bitrate_bps_);
+
+  AddObserver(&bitrate_observer_3, 300000, 400000, 0, false, "",
+              kDefaultBitratePriority);
+  EXPECT_EQ(0, allocator_->GetStartBitrate(&bitrate_observer_3));
+  EXPECT_EQ(100000u, bitrate_observer_1.last_bitrate_bps_);
+  EXPECT_EQ(200000u, bitrate_observer_2.last_bitrate_bps_);
+
+  // High BWE. Make sure the controllers get a fair share of the surplus (i.e.,
+  // what is left after each controller gets its min rate).
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(690000, 0, 0, kDefaultProbingIntervalMs));
+  // Verify that each observer gets its min rate (sum of min rates is 600000),
+  // and that the remaining 90000 is divided equally among the three.
+  uint32_t bitrate_to_share = 690000u - 100000u - 200000u - 300000u;
+  EXPECT_EQ(100000u + bitrate_to_share / 3,
+            bitrate_observer_1.last_bitrate_bps_);
+  EXPECT_EQ(200000u + bitrate_to_share / 3,
+            bitrate_observer_2.last_bitrate_bps_);
+  EXPECT_EQ(300000u + bitrate_to_share / 3,
+            bitrate_observer_3.last_bitrate_bps_);
+
+  // BWE below the sum of observer's min bitrate.
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(300000, 0, 0, kDefaultProbingIntervalMs));
+  EXPECT_EQ(100000u, bitrate_observer_1.last_bitrate_bps_);  // Min bitrate.
+  EXPECT_EQ(200000u, bitrate_observer_2.last_bitrate_bps_);  // Min bitrate.
+  EXPECT_EQ(0u, bitrate_observer_3.last_bitrate_bps_);       // Nothing.
+
+  // Increased BWE, but still below the sum of configured min bitrates for all
+  // observers and too little for observer 3. 1 and 2 will share the rest.
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(500000, 0, 0, kDefaultProbingIntervalMs));
+  EXPECT_EQ(200000u, bitrate_observer_1.last_bitrate_bps_);  // Min + split.
+  EXPECT_EQ(300000u, bitrate_observer_2.last_bitrate_bps_);  // Min + split.
+  EXPECT_EQ(0u, bitrate_observer_3.last_bitrate_bps_);       // Nothing.
+
+  // Below min for all.
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(10000, 0, 0, kDefaultProbingIntervalMs));
+  EXPECT_EQ(0u, bitrate_observer_1.last_bitrate_bps_);
+  EXPECT_EQ(0u, bitrate_observer_2.last_bitrate_bps_);
+  EXPECT_EQ(0u, bitrate_observer_3.last_bitrate_bps_);
+
+  // Verify that zero estimated bandwidth, means that that all gets zero,
+  // regardless of set min bitrate.
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(0, 0, 0, kDefaultProbingIntervalMs));
+  EXPECT_EQ(0u, bitrate_observer_1.last_bitrate_bps_);
+  EXPECT_EQ(0u, bitrate_observer_2.last_bitrate_bps_);
+  EXPECT_EQ(0u, bitrate_observer_3.last_bitrate_bps_);
+
+  allocator_->RemoveObserver(&bitrate_observer_1);
+  allocator_->RemoveObserver(&bitrate_observer_2);
+  allocator_->RemoveObserver(&bitrate_observer_3);
+}
+
+TEST_F(BitrateAllocatorTestNoEnforceMin, OneBitrateObserverWithPacketLoss) {
+  const uint32_t kMinBitrateBps = 100000;
+  const uint32_t kMaxBitrateBps = 400000;
+  // Hysteresis adds another 10% or 20kbps to min bitrate.
+  const uint32_t kMinStartBitrateBps =
+      kMinBitrateBps + std::max(20000u, kMinBitrateBps / 10);
+
+  // Expect OnAllocationLimitsChanged with `min_send_bitrate_bps` = 0 since
+  // AddObserver is called with `enforce_min_bitrate` = false.
+  TestBitrateObserver bitrate_observer;
+  EXPECT_CALL(limit_observer_, OnAllocationLimitsChanged(
+                                   AllocationLimitsEq(0, 0, kMaxBitrateBps)));
+  AddObserver(&bitrate_observer, kMinBitrateBps, kMaxBitrateBps, 0, false, "",
+              kDefaultBitratePriority);
+  EXPECT_EQ(300000, allocator_->GetStartBitrate(&bitrate_observer));
+
+  // High BWE.
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(150000, 0, 0, kDefaultProbingIntervalMs));
+  EXPECT_EQ(150000u, bitrate_observer.last_bitrate_bps_);
+
+  // Add loss and use a part of the bitrate for protection.
+  const double kProtectionRatio = 0.4;
+  const uint8_t fraction_loss = kProtectionRatio * 256;
+  bitrate_observer.SetBitrateProtectionRatio(kProtectionRatio);
+  allocator_->OnNetworkEstimateChanged(CreateTargetRateMessage(
+      200000, 0, fraction_loss, kDefaultProbingIntervalMs));
+  EXPECT_EQ(200000u, bitrate_observer.last_bitrate_bps_);
+
+  // Above the min threshold, but not enough given the protection used.
+  // Limits changed, as we will video is now off and we need to pad up to the
+  // start bitrate.
+  // Verify the hysteresis is added for the protection.
+  const uint32_t kMinStartBitrateWithProtectionBps =
+      static_cast<uint32_t>(kMinStartBitrateBps * (1 + kProtectionRatio));
+  EXPECT_CALL(limit_observer_,
+              OnAllocationLimitsChanged(AllocationLimitsEq(
+                  0, kMinStartBitrateWithProtectionBps, kMaxBitrateBps)));
+  allocator_->OnNetworkEstimateChanged(CreateTargetRateMessage(
+      kMinStartBitrateBps + 1000, 0, fraction_loss, kDefaultProbingIntervalMs));
+  EXPECT_EQ(0u, bitrate_observer.last_bitrate_bps_);
+
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(kMinStartBitrateWithProtectionBps - 1000, 0,
+                              fraction_loss, kDefaultProbingIntervalMs));
+  EXPECT_EQ(0u, bitrate_observer.last_bitrate_bps_);
+
+  // Just enough to enable video again.
+  EXPECT_CALL(limit_observer_, OnAllocationLimitsChanged(
+                                   AllocationLimitsEq(0, 0, kMaxBitrateBps)));
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(kMinStartBitrateWithProtectionBps, 0,
+                              fraction_loss, kDefaultProbingIntervalMs));
+  EXPECT_EQ(kMinStartBitrateWithProtectionBps,
+            bitrate_observer.last_bitrate_bps_);
+
+  // Remove all protection and make sure video is not paused as earlier.
+  bitrate_observer.SetBitrateProtectionRatio(0.0);
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(kMinStartBitrateWithProtectionBps - 1000, 0, 0,
+                              kDefaultProbingIntervalMs));
+  EXPECT_EQ(kMinStartBitrateWithProtectionBps - 1000,
+            bitrate_observer.last_bitrate_bps_);
+
+  allocator_->OnNetworkEstimateChanged(CreateTargetRateMessage(
+      kMinStartBitrateBps, 0, 0, kDefaultProbingIntervalMs));
+  EXPECT_EQ(kMinStartBitrateBps, bitrate_observer.last_bitrate_bps_);
+
+  EXPECT_CALL(limit_observer_,
+              OnAllocationLimitsChanged(AllocationLimitsEq(0, 0, 0)));
+  allocator_->RemoveObserver(&bitrate_observer);
+}
+
+TEST_F(BitrateAllocatorTest,
+       TotalAllocationLimitsAreUnaffectedByProtectionRatio) {
+  TestBitrateObserver bitrate_observer;
+
+  const uint32_t kMinBitrateBps = 100000;
+  const uint32_t kMaxBitrateBps = 400000;
+
+  // Register `bitrate_observer` and expect total allocation limits to change.
+  EXPECT_CALL(limit_observer_, OnAllocationLimitsChanged(AllocationLimitsEq(
+                                   kMinBitrateBps, 0, kMaxBitrateBps)))
+      .Times(1);
+  MediaStreamAllocationConfig allocation_config = DefaultConfig();
+  allocation_config.min_bitrate_bps = kMinBitrateBps;
+  allocation_config.max_bitrate_bps = kMaxBitrateBps;
+  allocator_->AddObserver(&bitrate_observer, allocation_config);
+
+  // Observer uses 20% of it's allocated bitrate for protection.
+  bitrate_observer.SetBitrateProtectionRatio(/*protection_ratio=*/0.2);
+  // Total allocation limits are unaffected by the protection rate change.
+  EXPECT_CALL(limit_observer_, OnAllocationLimitsChanged(_)).Times(0);
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(200000u, 0, 100, kDefaultProbingIntervalMs));
+
+  // Observer uses 0% of it's allocated bitrate for protection.
+  bitrate_observer.SetBitrateProtectionRatio(/*protection_ratio=*/0.0);
+  // Total allocation limits are unaffected by the protection rate change.
+  EXPECT_CALL(limit_observer_, OnAllocationLimitsChanged(_)).Times(0);
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(200000u, 0, 100, kDefaultProbingIntervalMs));
+
+  // Observer again uses 20% of it's allocated bitrate for protection.
+  bitrate_observer.SetBitrateProtectionRatio(/*protection_ratio=*/0.2);
+  // Total allocation limits are unaffected by the protection rate change.
+  EXPECT_CALL(limit_observer_, OnAllocationLimitsChanged(_)).Times(0);
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(200000u, 0, 100, kDefaultProbingIntervalMs));
+}
+
+TEST_F(BitrateAllocatorTestNoEnforceMin, TwoBitrateObserverWithPacketLoss) {
+  TestBitrateObserver bitrate_observer_1;
+  TestBitrateObserver bitrate_observer_2;
+
+  AddObserver(&bitrate_observer_1, 100000, 400000, 0, false, "",
+              kDefaultBitratePriority);
+  EXPECT_EQ(300000, allocator_->GetStartBitrate(&bitrate_observer_1));
+  AddObserver(&bitrate_observer_2, 200000, 400000, 0, false, "",
+              kDefaultBitratePriority);
+  EXPECT_EQ(200000, allocator_->GetStartBitrate(&bitrate_observer_2));
+  EXPECT_EQ(100000u, bitrate_observer_1.last_bitrate_bps_);
+
+  // Enough bitrate for both.
+  bitrate_observer_2.SetBitrateProtectionRatio(0.5);
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(300000, 0, 0, kDefaultProbingIntervalMs));
+  EXPECT_EQ(100000u, bitrate_observer_1.last_bitrate_bps_);
+  EXPECT_EQ(200000u, bitrate_observer_2.last_bitrate_bps_);
+
+  // Above min for observer 2, but too little given the protection used.
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(330000, 0, 0, kDefaultProbingIntervalMs));
+  EXPECT_EQ(330000u, bitrate_observer_1.last_bitrate_bps_);
+  EXPECT_EQ(0u, bitrate_observer_2.last_bitrate_bps_);
+
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(100000, 0, 0, kDefaultProbingIntervalMs));
+  EXPECT_EQ(100000u, bitrate_observer_1.last_bitrate_bps_);
+  EXPECT_EQ(0u, bitrate_observer_2.last_bitrate_bps_);
+
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(99999, 0, 0, kDefaultProbingIntervalMs));
+  EXPECT_EQ(0u, bitrate_observer_1.last_bitrate_bps_);
+  EXPECT_EQ(0u, bitrate_observer_2.last_bitrate_bps_);
+
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(119000, 0, 0, kDefaultProbingIntervalMs));
+  EXPECT_EQ(0u, bitrate_observer_1.last_bitrate_bps_);
+  EXPECT_EQ(0u, bitrate_observer_2.last_bitrate_bps_);
+
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(120000, 0, 0, kDefaultProbingIntervalMs));
+  EXPECT_EQ(120000u, bitrate_observer_1.last_bitrate_bps_);
+  EXPECT_EQ(0u, bitrate_observer_2.last_bitrate_bps_);
+
+  // Verify the protection is accounted for before resuming observer 2.
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(429000, 0, 0, kDefaultProbingIntervalMs));
+  EXPECT_EQ(400000u, bitrate_observer_1.last_bitrate_bps_);
+  EXPECT_EQ(0u, bitrate_observer_2.last_bitrate_bps_);
+
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(430000, 0, 0, kDefaultProbingIntervalMs));
+  EXPECT_EQ(100000u, bitrate_observer_1.last_bitrate_bps_);
+  EXPECT_EQ(330000u, bitrate_observer_2.last_bitrate_bps_);
+
+  allocator_->RemoveObserver(&bitrate_observer_1);
+  allocator_->RemoveObserver(&bitrate_observer_2);
+}
+
+TEST_F(BitrateAllocatorTest, ThreeBitrateObserversLowBweEnforceMin) {
+  TestBitrateObserver bitrate_observer_1;
+  TestBitrateObserver bitrate_observer_2;
+  TestBitrateObserver bitrate_observer_3;
+
+  AddObserver(&bitrate_observer_1, 100000, 400000, 0, true,
+              kDefaultBitratePriority);
+  EXPECT_EQ(300000, allocator_->GetStartBitrate(&bitrate_observer_1));
+
+  AddObserver(&bitrate_observer_2, 200000, 400000, 0, true,
+              kDefaultBitratePriority);
+  EXPECT_EQ(200000, allocator_->GetStartBitrate(&bitrate_observer_2));
+  EXPECT_EQ(100000u, bitrate_observer_1.last_bitrate_bps_);
+
+  AddObserver(&bitrate_observer_3, 300000, 400000, 0, true,
+              kDefaultBitratePriority);
+  EXPECT_EQ(300000, allocator_->GetStartBitrate(&bitrate_observer_3));
+  EXPECT_EQ(100000, static_cast<int>(bitrate_observer_1.last_bitrate_bps_));
+  EXPECT_EQ(200000, static_cast<int>(bitrate_observer_2.last_bitrate_bps_));
+
+  // Low BWE. Verify that all observers still get their respective min
+  // bitrate.
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(1000, 0, 0, kDefaultProbingIntervalMs));
+  EXPECT_EQ(100000u, bitrate_observer_1.last_bitrate_bps_);  // Min cap.
+  EXPECT_EQ(200000u, bitrate_observer_2.last_bitrate_bps_);  // Min cap.
+  EXPECT_EQ(300000u, bitrate_observer_3.last_bitrate_bps_);  // Min cap.
+
+  allocator_->RemoveObserver(&bitrate_observer_1);
+  allocator_->RemoveObserver(&bitrate_observer_2);
+  allocator_->RemoveObserver(&bitrate_observer_3);
+}
+
+TEST_F(BitrateAllocatorTest, AddObserverWhileNetworkDown) {
+  TestBitrateObserver bitrate_observer_1;
+  EXPECT_CALL(limit_observer_,
+              OnAllocationLimitsChanged(AllocationLimitsEq(50000, 0)));
+
+  AddObserver(&bitrate_observer_1, 50000, 400000, 0, true,
+              kDefaultBitratePriority);
+  EXPECT_EQ(300000, allocator_->GetStartBitrate(&bitrate_observer_1));
+
+  // Set network down, ie, no available bitrate.
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(0, 0, 0, kDefaultProbingIntervalMs));
+
+  EXPECT_EQ(0u, bitrate_observer_1.last_bitrate_bps_);
+
+  TestBitrateObserver bitrate_observer_2;
+  // Adding an observer while the network is down should not affect the limits.
+  EXPECT_CALL(limit_observer_,
+              OnAllocationLimitsChanged(AllocationLimitsEq(50000 + 50000, 0)));
+  AddObserver(&bitrate_observer_2, 50000, 400000, 0, true,
+              kDefaultBitratePriority);
+
+  // Expect the start_bitrate to be set as if the network was still up but that
+  // the new observer have been notified that the network is down.
+  EXPECT_EQ(300000 / 2, allocator_->GetStartBitrate(&bitrate_observer_2));
+  EXPECT_EQ(0u, bitrate_observer_1.last_bitrate_bps_);
+  EXPECT_EQ(0u, bitrate_observer_2.last_bitrate_bps_);
+
+  // Set network back up.
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(1500000, 0, 50, kDefaultProbingIntervalMs));
+  EXPECT_EQ(750000u, bitrate_observer_1.last_bitrate_bps_);
+  EXPECT_EQ(750000u, bitrate_observer_2.last_bitrate_bps_);
+}
+
+TEST_F(BitrateAllocatorTest, MixedEnforecedConfigs) {
+  TestBitrateObserver enforced_observer;
+  AddObserver(&enforced_observer, 6000, 30000, 0, true,
+              kDefaultBitratePriority);
+  EXPECT_EQ(60000, allocator_->GetStartBitrate(&enforced_observer));
+
+  TestBitrateObserver not_enforced_observer;
+  AddObserver(&not_enforced_observer, 30000, 2500000, 0, false,
+              kDefaultBitratePriority);
+  EXPECT_EQ(270000, allocator_->GetStartBitrate(&not_enforced_observer));
+  EXPECT_EQ(30000u, enforced_observer.last_bitrate_bps_);
+
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(36000, 0, 50, kDefaultProbingIntervalMs));
+  EXPECT_EQ(6000u, enforced_observer.last_bitrate_bps_);
+  EXPECT_EQ(30000u, not_enforced_observer.last_bitrate_bps_);
+
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(35000, 0, 50, kDefaultProbingIntervalMs));
+  EXPECT_EQ(30000u, enforced_observer.last_bitrate_bps_);
+  EXPECT_EQ(0u, not_enforced_observer.last_bitrate_bps_);
+
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(5000, 0, 50, kDefaultProbingIntervalMs));
+  EXPECT_EQ(6000u, enforced_observer.last_bitrate_bps_);
+  EXPECT_EQ(0u, not_enforced_observer.last_bitrate_bps_);
+
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(36000, 0, 50, kDefaultProbingIntervalMs));
+  EXPECT_EQ(30000u, enforced_observer.last_bitrate_bps_);
+  EXPECT_EQ(0u, not_enforced_observer.last_bitrate_bps_);
+
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(55000, 0, 50, kDefaultProbingIntervalMs));
+  EXPECT_EQ(30000u, enforced_observer.last_bitrate_bps_);
+  EXPECT_EQ(0u, not_enforced_observer.last_bitrate_bps_);
+
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(56000, 0, 50, kDefaultProbingIntervalMs));
+  EXPECT_EQ(6000u, enforced_observer.last_bitrate_bps_);
+  EXPECT_EQ(50000u, not_enforced_observer.last_bitrate_bps_);
+
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(56000, 0, 50, kDefaultProbingIntervalMs));
+  EXPECT_EQ(16000u, enforced_observer.last_bitrate_bps_);
+  EXPECT_EQ(40000u, not_enforced_observer.last_bitrate_bps_);
+
+  allocator_->RemoveObserver(&enforced_observer);
+  allocator_->RemoveObserver(&not_enforced_observer);
+}
+
+TEST_F(BitrateAllocatorTest, AvoidToggleAbsolute) {
+  TestBitrateObserver observer;
+  AddObserver(&observer, 30000, 300000, 0, false, kDefaultBitratePriority);
+  EXPECT_EQ(300000, allocator_->GetStartBitrate(&observer));
+
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(30000, 0, 50, kDefaultProbingIntervalMs));
+  EXPECT_EQ(30000u, observer.last_bitrate_bps_);
+
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(20000, 0, 50, kDefaultProbingIntervalMs));
+  EXPECT_EQ(0u, observer.last_bitrate_bps_);
+
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(30000, 0, 50, kDefaultProbingIntervalMs));
+  EXPECT_EQ(0u, observer.last_bitrate_bps_);
+
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(49000, 0, 50, kDefaultProbingIntervalMs));
+  EXPECT_EQ(0u, observer.last_bitrate_bps_);
+
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(50000, 0, 50, kDefaultProbingIntervalMs));
+  EXPECT_EQ(50000u, observer.last_bitrate_bps_);
+
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(30000, 0, 50, kDefaultProbingIntervalMs));
+  EXPECT_EQ(30000u, observer.last_bitrate_bps_);
+
+  allocator_->RemoveObserver(&observer);
+}
+
+TEST_F(BitrateAllocatorTest, AvoidTogglePercent) {
+  TestBitrateObserver observer;
+  AddObserver(&observer, 300000, 600000, 0, false, kDefaultBitratePriority);
+  EXPECT_EQ(300000, allocator_->GetStartBitrate(&observer));
+
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(300000, 0, 50, kDefaultProbingIntervalMs));
+  EXPECT_EQ(300000u, observer.last_bitrate_bps_);
+
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(200000, 0, 50, kDefaultProbingIntervalMs));
+  EXPECT_EQ(0u, observer.last_bitrate_bps_);
+
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(300000, 0, 50, kDefaultProbingIntervalMs));
+  EXPECT_EQ(0u, observer.last_bitrate_bps_);
+
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(329000, 0, 50, kDefaultProbingIntervalMs));
+  EXPECT_EQ(0u, observer.last_bitrate_bps_);
+
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(330000, 0, 50, kDefaultProbingIntervalMs));
+  EXPECT_EQ(330000u, observer.last_bitrate_bps_);
+
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(300000, 0, 50, kDefaultProbingIntervalMs));
+  EXPECT_EQ(300000u, observer.last_bitrate_bps_);
+
+  allocator_->RemoveObserver(&observer);
+}
+
+TEST_F(BitrateAllocatorTest, PassProbingInterval) {
+  TestBitrateObserver observer;
+  AddObserver(&observer, 300000, 600000, 0, false, kDefaultBitratePriority);
+  EXPECT_EQ(300000, allocator_->GetStartBitrate(&observer));
+
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(300000, 0, 50, 5000));
+  EXPECT_EQ(5000, observer.last_probing_interval_ms_);
+
+  allocator_->RemoveObserver(&observer);
+}
+
+TEST_F(BitrateAllocatorTest, PriorityRateOneObserverBasic) {
+  TestBitrateObserver observer;
+  const uint32_t kMinSendBitrateBps = 10;
+  const uint32_t kMaxSendBitrateBps = 60;
+  const uint32_t kNetworkBandwidthBps = 30;
+
+  AddObserver(&observer, kMinSendBitrateBps, kMaxSendBitrateBps, 0, true, 2.0);
+  allocator_->OnNetworkEstimateChanged(CreateTargetRateMessage(
+      kNetworkBandwidthBps, 0, 0, kDefaultProbingIntervalMs));
+
+  EXPECT_EQ(kNetworkBandwidthBps, observer.last_bitrate_bps_);
+
+  allocator_->RemoveObserver(&observer);
+}
+
+// Tests that two observers with the same bitrate priority are allocated
+// their bitrate evenly.
+TEST_F(BitrateAllocatorTest, PriorityRateTwoObserversBasic) {
+  TestBitrateObserver observer_low_1;
+  TestBitrateObserver observer_low_2;
+  const uint32_t kMinSendBitrateBps = 10;
+  const uint32_t kMaxSendBitrateBps = 60;
+  const uint32_t kNetworkBandwidthBps = 60;
+  AddObserver(&observer_low_1, kMinSendBitrateBps, kMaxSendBitrateBps, 0, false,
+              2.0);
+  AddObserver(&observer_low_2, kMinSendBitrateBps, kMaxSendBitrateBps, 0, false,
+              2.0);
+  allocator_->OnNetworkEstimateChanged(CreateTargetRateMessage(
+      kNetworkBandwidthBps, 0, 0, kDefaultProbingIntervalMs));
+
+  EXPECT_EQ(kNetworkBandwidthBps / 2, observer_low_1.last_bitrate_bps_);
+  EXPECT_EQ(kNetworkBandwidthBps / 2, observer_low_2.last_bitrate_bps_);
+
+  allocator_->RemoveObserver(&observer_low_1);
+  allocator_->RemoveObserver(&observer_low_2);
+}
+
+// Tests that there is no difference in functionality when the min bitrate is
+// enforced.
+TEST_F(BitrateAllocatorTest, PriorityRateTwoObserversBasicMinEnforced) {
+  TestBitrateObserver observer_low_1;
+  TestBitrateObserver observer_low_2;
+  const uint32_t kMinSendBitrateBps = 0;
+  const uint32_t kMaxSendBitrateBps = 60;
+  const uint32_t kNetworkBandwidthBps = 60;
+  AddObserver(&observer_low_1, kMinSendBitrateBps, kMaxSendBitrateBps, 0, true,
+              2.0);
+  AddObserver(&observer_low_2, kMinSendBitrateBps, kMaxSendBitrateBps, 0, true,
+              2.0);
+  allocator_->OnNetworkEstimateChanged(CreateTargetRateMessage(
+      kNetworkBandwidthBps, 0, 0, kDefaultProbingIntervalMs));
+
+  EXPECT_EQ(kNetworkBandwidthBps / 2, observer_low_1.last_bitrate_bps_);
+  EXPECT_EQ(kNetworkBandwidthBps / 2, observer_low_2.last_bitrate_bps_);
+
+  allocator_->RemoveObserver(&observer_low_1);
+  allocator_->RemoveObserver(&observer_low_2);
+}
+
+// Tests that if the available bandwidth is the sum of the max bitrate
+// of all observers, they will be allocated their max.
+TEST_F(BitrateAllocatorTest, PriorityRateTwoObserversBothAllocatedMax) {
+  TestBitrateObserver observer_low;
+  TestBitrateObserver observer_mid;
+  const uint32_t kMinSendBitrateBps = 0;
+  const uint32_t kMaxSendBitrateBps = 60;
+  const uint32_t kNetworkBandwidthBps = kMaxSendBitrateBps * 2;
+  AddObserver(&observer_low, kMinSendBitrateBps, kMaxSendBitrateBps, 0, true,
+              2.0);
+  AddObserver(&observer_mid, kMinSendBitrateBps, kMaxSendBitrateBps, 0, true,
+              4.0);
+  allocator_->OnNetworkEstimateChanged(CreateTargetRateMessage(
+      kNetworkBandwidthBps, 0, 0, kDefaultProbingIntervalMs));
+
+  EXPECT_EQ(kMaxSendBitrateBps, observer_low.last_bitrate_bps_);
+  EXPECT_EQ(kMaxSendBitrateBps, observer_mid.last_bitrate_bps_);
+
+  allocator_->RemoveObserver(&observer_low);
+  allocator_->RemoveObserver(&observer_mid);
+}
+
+// Tests that after a higher bitrate priority observer has been allocated its
+// max bitrate the lower priority observer will then be allocated the remaining
+// bitrate.
+TEST_F(BitrateAllocatorTest, PriorityRateTwoObserversOneAllocatedToMax) {
+  TestBitrateObserver observer_low;
+  TestBitrateObserver observer_mid;
+  AddObserver(&observer_low, 10, 50, 0, false, 2.0);
+  AddObserver(&observer_mid, 10, 50, 0, false, 4.0);
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(90, 0, 0, kDefaultProbingIntervalMs));
+
+  EXPECT_EQ(40u, observer_low.last_bitrate_bps_);
+  EXPECT_EQ(50u, observer_mid.last_bitrate_bps_);
+
+  allocator_->RemoveObserver(&observer_low);
+  allocator_->RemoveObserver(&observer_mid);
+}
+
+// Tests that three observers with three different bitrate priorities will all
+// be allocated bitrate according to their relative bitrate priority.
+TEST_F(BitrateAllocatorTest,
+       PriorityRateThreeObserversAllocatedRelativeAmounts) {
+  TestBitrateObserver observer_low;
+  TestBitrateObserver observer_mid;
+  TestBitrateObserver observer_high;
+  const uint32_t kMaxBitrate = 100;
+  // Not enough bandwidth to fill any observer's max bitrate.
+  const uint32_t kNetworkBandwidthBps = 70;
+  const double kLowBitratePriority = 2.0;
+  const double kMidBitratePriority = 4.0;
+  const double kHighBitratePriority = 8.0;
+  const double kTotalBitratePriority =
+      kLowBitratePriority + kMidBitratePriority + kHighBitratePriority;
+  AddObserver(&observer_low, 0, kMaxBitrate, 0, false, kLowBitratePriority);
+  AddObserver(&observer_mid, 0, kMaxBitrate, 0, false, kMidBitratePriority);
+  AddObserver(&observer_high, 0, kMaxBitrate, 0, false, kHighBitratePriority);
+  allocator_->OnNetworkEstimateChanged(CreateTargetRateMessage(
+      kNetworkBandwidthBps, 0, 0, kDefaultProbingIntervalMs));
+
+  const double kLowFractionAllocated =
+      kLowBitratePriority / kTotalBitratePriority;
+  const double kMidFractionAllocated =
+      kMidBitratePriority / kTotalBitratePriority;
+  const double kHighFractionAllocated =
+      kHighBitratePriority / kTotalBitratePriority;
+  EXPECT_EQ(kLowFractionAllocated * kNetworkBandwidthBps,
+            observer_low.last_bitrate_bps_);
+  EXPECT_EQ(kMidFractionAllocated * kNetworkBandwidthBps,
+            observer_mid.last_bitrate_bps_);
+  EXPECT_EQ(kHighFractionAllocated * kNetworkBandwidthBps,
+            observer_high.last_bitrate_bps_);
+
+  allocator_->RemoveObserver(&observer_low);
+  allocator_->RemoveObserver(&observer_mid);
+  allocator_->RemoveObserver(&observer_high);
+}
+
+// Tests that after the high priority observer has been allocated its maximum
+// bitrate, the other two observers are still allocated bitrate according to
+// their relative bitrate priority.
+TEST_F(BitrateAllocatorTest, PriorityRateThreeObserversHighAllocatedToMax) {
+  TestBitrateObserver observer_low;
+  const double kLowBitratePriority = 2.0;
+  TestBitrateObserver observer_mid;
+  const double kMidBitratePriority = 4.0;
+  TestBitrateObserver observer_high;
+  const double kHighBitratePriority = 8.0;
+
+  const uint32_t kAvailableBitrate = 90;
+  const uint32_t kMaxBitrate = 40;
+  const uint32_t kMinBitrate = 10;
+  // Remaining bitrate after allocating to all mins and knowing that the high
+  // priority observer will have its max bitrate allocated.
+  const uint32_t kRemainingBitrate =
+      kAvailableBitrate - kMaxBitrate - (2 * kMinBitrate);
+
+  AddObserver(&observer_low, kMinBitrate, kMaxBitrate, 0, false,
+              kLowBitratePriority);
+  AddObserver(&observer_mid, kMinBitrate, kMaxBitrate, 0, false,
+              kMidBitratePriority);
+  AddObserver(&observer_high, kMinBitrate, kMaxBitrate, 0, false,
+              kHighBitratePriority);
+  allocator_->OnNetworkEstimateChanged(CreateTargetRateMessage(
+      kAvailableBitrate, 0, 0, kDefaultProbingIntervalMs));
+
+  const double kLowFractionAllocated =
+      kLowBitratePriority / (kLowBitratePriority + kMidBitratePriority);
+  const double kMidFractionAllocated =
+      kMidBitratePriority / (kLowBitratePriority + kMidBitratePriority);
+  EXPECT_EQ(kMinBitrate + (kRemainingBitrate * kLowFractionAllocated),
+            observer_low.last_bitrate_bps_);
+  EXPECT_EQ(kMinBitrate + (kRemainingBitrate * kMidFractionAllocated),
+            observer_mid.last_bitrate_bps_);
+  EXPECT_EQ(40u, observer_high.last_bitrate_bps_);
+
+  allocator_->RemoveObserver(&observer_low);
+  allocator_->RemoveObserver(&observer_mid);
+  allocator_->RemoveObserver(&observer_high);
+}
+
+// Tests that after the low priority observer has been allocated its maximum
+// bitrate, the other two observers are still allocated bitrate according to
+// their relative bitrate priority.
+TEST_F(BitrateAllocatorTest, PriorityRateThreeObserversLowAllocatedToMax) {
+  TestBitrateObserver observer_low;
+  const double kLowBitratePriority = 2.0;
+  const uint32_t kLowMaxBitrate = 10;
+  TestBitrateObserver observer_mid;
+  const double kMidBitratePriority = 4.0;
+  TestBitrateObserver observer_high;
+  const double kHighBitratePriority = 8.0;
+
+  const uint32_t kMinBitrate = 0;
+  const uint32_t kMaxBitrate = 60;
+  const uint32_t kAvailableBitrate = 100;
+  // Remaining bitrate knowing that the low priority observer is allocated its
+  // max bitrate. We know this because it is allocated 2.0/14.0 (1/7) of the
+  // available bitrate, so 70 bps would be sufficient network bandwidth.
+  const uint32_t kRemainingBitrate = kAvailableBitrate - kLowMaxBitrate;
+
+  AddObserver(&observer_low, kMinBitrate, kLowMaxBitrate, 0, false,
+              kLowBitratePriority);
+  AddObserver(&observer_mid, kMinBitrate, kMaxBitrate, 0, false,
+              kMidBitratePriority);
+  AddObserver(&observer_high, kMinBitrate, kMaxBitrate, 0, false,
+              kHighBitratePriority);
+  allocator_->OnNetworkEstimateChanged(CreateTargetRateMessage(
+      kAvailableBitrate, 0, 0, kDefaultProbingIntervalMs));
+
+  const double kMidFractionAllocated =
+      kMidBitratePriority / (kMidBitratePriority + kHighBitratePriority);
+  const double kHighFractionAllocated =
+      kHighBitratePriority / (kMidBitratePriority + kHighBitratePriority);
+  EXPECT_EQ(kLowMaxBitrate, observer_low.last_bitrate_bps_);
+  EXPECT_EQ(kMinBitrate + (kRemainingBitrate * kMidFractionAllocated),
+            observer_mid.last_bitrate_bps_);
+  EXPECT_EQ(kMinBitrate + (kRemainingBitrate * kHighFractionAllocated),
+            observer_high.last_bitrate_bps_);
+
+  allocator_->RemoveObserver(&observer_low);
+  allocator_->RemoveObserver(&observer_mid);
+  allocator_->RemoveObserver(&observer_high);
+}
+
+// Tests that after two observers are allocated bitrate to their max, the
+// the remaining observer is allocated what's left appropriately. This test
+// handles an edge case where the medium and high observer reach their
+// "relative" max allocation  at the same time. The high has 40 to allocate
+// above its min, and the mid has 20 to allocate above its min, which scaled
+// by their bitrate priority is the same for each.
+TEST_F(BitrateAllocatorTest, PriorityRateThreeObserversTwoAllocatedToMax) {
+  TestBitrateObserver observer_low;
+  TestBitrateObserver observer_mid;
+  TestBitrateObserver observer_high;
+  AddObserver(&observer_low, 10, 40, 0, false, 2.0);
+  // Scaled allocation above the min allocation is the same for these two,
+  // meaning they will get allocated  their max at the same time.
+  // Scaled (target allocation) = (max - min) / bitrate priority
+  AddObserver(&observer_mid, 10, 30, 0, false, 4.0);
+  AddObserver(&observer_high, 10, 50, 0, false, 8.0);
+  allocator_->OnNetworkEstimateChanged(
+      CreateTargetRateMessage(110, 0, 0, kDefaultProbingIntervalMs));
+
+  EXPECT_EQ(30u, observer_low.last_bitrate_bps_);
+  EXPECT_EQ(30u, observer_mid.last_bitrate_bps_);
+  EXPECT_EQ(50u, observer_high.last_bitrate_bps_);
+
+  allocator_->RemoveObserver(&observer_low);
+  allocator_->RemoveObserver(&observer_mid);
+  allocator_->RemoveObserver(&observer_high);
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/bitrate_configurator_gn/moz.build b/third_party/libwebrtc/call/bitrate_configurator_gn/moz.build
new file mode 100644
index 0000000000..b70008b548
--- /dev/null
+++ b/third_party/libwebrtc/call/bitrate_configurator_gn/moz.build
@@ -0,0 +1,232 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+  ### This moz.build was AUTOMATICALLY GENERATED from a GN config,  ###
+  ### DO NOT edit it by hand.                                       ###
+
+COMPILE_FLAGS["OS_INCLUDES"] = []
+AllowCompilerWarnings()
+
+DEFINES["ABSL_ALLOCATOR_NOTHROW"] = "1"
+DEFINES["RTC_DAV1D_IN_INTERNAL_DECODER_FACTORY"] = True
+DEFINES["RTC_ENABLE_VP9"] = True
+DEFINES["WEBRTC_ENABLE_PROTOBUF"] = "0"
+DEFINES["WEBRTC_LIBRARY_IMPL"] = True
+DEFINES["WEBRTC_MOZILLA_BUILD"] = True
+DEFINES["WEBRTC_NON_STATIC_TRACE_EVENT_HANDLERS"] = "0"
+DEFINES["WEBRTC_STRICT_FIELD_TRIALS"] = "0"
+
+FINAL_LIBRARY = "webrtc"
+
+
+LOCAL_INCLUDES += [
+    "!/ipc/ipdl/_ipdlheaders",
+    "!/third_party/libwebrtc/gen",
+    "/ipc/chromium/src",
+    "/third_party/libwebrtc/",
+    "/third_party/libwebrtc/third_party/abseil-cpp/",
+    "/tools/profiler/public"
+]
+
+UNIFIED_SOURCES += [
+    "/third_party/libwebrtc/call/rtp_bitrate_configurator.cc"
+]
+
+if not CONFIG["MOZ_DEBUG"]:
+
+    DEFINES["DYNAMIC_ANNOTATIONS_ENABLED"] = "0"
+    DEFINES["NDEBUG"] = True
+    DEFINES["NVALGRIND"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1":
+
+    DEFINES["DYNAMIC_ANNOTATIONS_ENABLED"] = "1"
+
+if CONFIG["OS_TARGET"] == "Android":
+
+    DEFINES["ANDROID"] = True
+    DEFINES["ANDROID_NDK_VERSION_ROLL"] = "r22_1"
+    DEFINES["HAVE_SYS_UIO_H"] = True
+    DEFINES["WEBRTC_ANDROID"] = True
+    DEFINES["WEBRTC_ANDROID_OPENSLES"] = True
+    DEFINES["WEBRTC_LINUX"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_GNU_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+    OS_LIBS += [
+        "log"
+    ]
+
+if CONFIG["OS_TARGET"] == "Darwin":
+
+    DEFINES["WEBRTC_MAC"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_LIBCPP_HAS_NO_ALIGNED_ALLOCATION"] = True
+    DEFINES["__ASSERT_MACROS_DEFINE_VERSIONS_WITHOUT_UNDERSCORES"] = "0"
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+if CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["USE_AURA"] = "1"
+    DEFINES["USE_GLIB"] = "1"
+    DEFINES["USE_NSS_CERTS"] = "1"
+    DEFINES["USE_OZONE"] = "1"
+    DEFINES["USE_UDEV"] = True
+    DEFINES["WEBRTC_LINUX"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_FILE_OFFSET_BITS"] = "64"
+    DEFINES["_LARGEFILE64_SOURCE"] = True
+    DEFINES["_LARGEFILE_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+    OS_LIBS += [
+        "rt"
+    ]
+
+if CONFIG["OS_TARGET"] == "OpenBSD":
+
+    DEFINES["USE_GLIB"] = "1"
+    DEFINES["USE_OZONE"] = "1"
+    DEFINES["USE_X11"] = "1"
+    DEFINES["WEBRTC_BSD"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_FILE_OFFSET_BITS"] = "64"
+    DEFINES["_LARGEFILE64_SOURCE"] = True
+    DEFINES["_LARGEFILE_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+if CONFIG["OS_TARGET"] == "WINNT":
+
+    DEFINES["CERT_CHAIN_PARA_HAS_EXTRA_FIELDS"] = True
+    DEFINES["NOMINMAX"] = True
+    DEFINES["NTDDI_VERSION"] = "0x0A000000"
+    DEFINES["PSAPI_VERSION"] = "2"
+    DEFINES["UNICODE"] = True
+    DEFINES["USE_AURA"] = "1"
+    DEFINES["WEBRTC_WIN"] = True
+    DEFINES["WIN32"] = True
+    DEFINES["WIN32_LEAN_AND_MEAN"] = True
+    DEFINES["WINAPI_FAMILY"] = "WINAPI_FAMILY_DESKTOP_APP"
+    DEFINES["WINVER"] = "0x0A00"
+    DEFINES["_ATL_NO_OPENGL"] = True
+    DEFINES["_CRT_RAND_S"] = True
+    DEFINES["_CRT_SECURE_NO_DEPRECATE"] = True
+    DEFINES["_ENABLE_EXTENDED_ALIGNED_STORAGE"] = True
+    DEFINES["_HAS_EXCEPTIONS"] = "0"
+    DEFINES["_HAS_NODISCARD"] = True
+    DEFINES["_SCL_SECURE_NO_DEPRECATE"] = True
+    DEFINES["_SECURE_ATL"] = True
+    DEFINES["_UNICODE"] = True
+    DEFINES["_WIN32_WINNT"] = "0x0A00"
+    DEFINES["_WINDOWS"] = True
+    DEFINES["__STD_C"] = True
+
+    OS_LIBS += [
+        "crypt32",
+        "iphlpapi",
+        "secur32",
+        "winmm"
+    ]
+
+if CONFIG["CPU_ARCH"] == "aarch64":
+
+    DEFINES["WEBRTC_ARCH_ARM64"] = True
+    DEFINES["WEBRTC_HAS_NEON"] = True
+
+if CONFIG["CPU_ARCH"] == "arm":
+
+    CXXFLAGS += [
+        "-mfpu=neon"
+    ]
+
+    DEFINES["WEBRTC_ARCH_ARM"] = True
+    DEFINES["WEBRTC_ARCH_ARM_V7"] = True
+    DEFINES["WEBRTC_HAS_NEON"] = True
+
+if CONFIG["CPU_ARCH"] == "mips32":
+
+    DEFINES["MIPS32_LE"] = True
+    DEFINES["MIPS_FPU_LE"] = True
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "mips64":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86":
+
+    DEFINES["WEBRTC_ENABLE_AVX2"] = True
+
+if CONFIG["CPU_ARCH"] == "x86_64":
+
+    DEFINES["WEBRTC_ENABLE_AVX2"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Android":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Darwin":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "OpenBSD":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "WINNT":
+
+    DEFINES["_HAS_ITERATOR_DEBUGGING"] = "0"
+
+if CONFIG["MOZ_X11"] == "1" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["USE_X11"] = "1"
+
+if CONFIG["CPU_ARCH"] == "arm" and CONFIG["OS_TARGET"] == "Android":
+
+    OS_LIBS += [
+        "android_support",
+        "unwind"
+    ]
+
+if CONFIG["CPU_ARCH"] == "x86" and CONFIG["OS_TARGET"] == "Android":
+
+    CXXFLAGS += [
+        "-msse2"
+    ]
+
+    OS_LIBS += [
+        "android_support"
+    ]
+
+if CONFIG["CPU_ARCH"] == "aarch64" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "arm" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86" and CONFIG["OS_TARGET"] == "Linux":
+
+    CXXFLAGS += [
+        "-msse2"
+    ]
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86_64" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+Library("bitrate_configurator_gn")
diff --git a/third_party/libwebrtc/call/bitrate_estimator_tests.cc b/third_party/libwebrtc/call/bitrate_estimator_tests.cc
new file mode 100644
index 0000000000..6dedc59059
--- /dev/null
+++ b/third_party/libwebrtc/call/bitrate_estimator_tests.cc
@@ -0,0 +1,323 @@
+/*
+ *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+#include <cstddef>
+#include <functional>
+#include <list>
+#include <memory>
+#include <string>
+
+#include "absl/strings/string_view.h"
+#include "api/test/create_frame_generator.h"
+#include "call/call.h"
+#include "call/simulated_network.h"
+#include "rtc_base/checks.h"
+#include "rtc_base/event.h"
+#include "rtc_base/logging.h"
+#include "rtc_base/synchronization/mutex.h"
+#include "rtc_base/task_queue_for_test.h"
+#include "rtc_base/thread_annotations.h"
+#include "test/call_test.h"
+#include "test/encoder_settings.h"
+#include "test/fake_decoder.h"
+#include "test/fake_encoder.h"
+#include "test/frame_generator_capturer.h"
+#include "test/gtest.h"
+
+namespace webrtc {
+namespace {
+// Note: If you consider to re-use this class, think twice and instead consider
+// writing tests that don't depend on the logging system.
+class LogObserver {
+ public:
+  LogObserver() { rtc::LogMessage::AddLogToStream(&callback_, rtc::LS_INFO); }
+
+  ~LogObserver() { rtc::LogMessage::RemoveLogToStream(&callback_); }
+
+  void PushExpectedLogLine(absl::string_view expected_log_line) {
+    callback_.PushExpectedLogLine(expected_log_line);
+  }
+
+  bool Wait() { return callback_.Wait(); }
+
+ private:
+  class Callback : public rtc::LogSink {
+   public:
+    void OnLogMessage(const std::string& message) override {
+      OnLogMessage(absl::string_view(message));
+    }
+
+    void OnLogMessage(absl::string_view message) override {
+      MutexLock lock(&mutex_);
+      // Ignore log lines that are due to missing AST extensions, these are
+      // logged when we switch back from AST to TOF until the wrapping bitrate
+      // estimator gives up on using AST.
+      if (message.find("BitrateEstimator") != absl::string_view::npos &&
+          message.find("packet is missing") == absl::string_view::npos) {
+        received_log_lines_.push_back(std::string(message));
+      }
+
+      int num_popped = 0;
+      while (!received_log_lines_.empty() && !expected_log_lines_.empty()) {
+        std::string a = received_log_lines_.front();
+        std::string b = expected_log_lines_.front();
+        received_log_lines_.pop_front();
+        expected_log_lines_.pop_front();
+        num_popped++;
+        EXPECT_TRUE(a.find(b) != absl::string_view::npos) << a << " != " << b;
+      }
+      if (expected_log_lines_.empty()) {
+        if (num_popped > 0) {
+          done_.Set();
+        }
+        return;
+      }
+    }
+
+    bool Wait() { return done_.Wait(test::CallTest::kDefaultTimeout); }
+
+    void PushExpectedLogLine(absl::string_view expected_log_line) {
+      MutexLock lock(&mutex_);
+      expected_log_lines_.emplace_back(expected_log_line);
+    }
+
+   private:
+    typedef std::list<std::string> Strings;
+    Mutex mutex_;
+    Strings received_log_lines_ RTC_GUARDED_BY(mutex_);
+    Strings expected_log_lines_ RTC_GUARDED_BY(mutex_);
+    rtc::Event done_;
+  };
+
+  Callback callback_;
+};
+}  // namespace
+
+static const int kTOFExtensionId = 4;
+static const int kASTExtensionId = 5;
+
+class BitrateEstimatorTest : public test::CallTest {
+ public:
+  BitrateEstimatorTest() : receive_config_(nullptr) {}
+
+  virtual ~BitrateEstimatorTest() { EXPECT_TRUE(streams_.empty()); }
+
+  virtual void SetUp() {
+    SendTask(task_queue(), [this]() {
+      RegisterRtpExtension(
+          RtpExtension(RtpExtension::kTimestampOffsetUri, kTOFExtensionId));
+      RegisterRtpExtension(
+          RtpExtension(RtpExtension::kAbsSendTimeUri, kASTExtensionId));
+
+      CreateCalls();
+
+      CreateSendTransport(BuiltInNetworkBehaviorConfig(), /*observer=*/nullptr);
+      CreateReceiveTransport(BuiltInNetworkBehaviorConfig(),
+                             /*observer=*/nullptr);
+
+      VideoSendStream::Config video_send_config(send_transport_.get());
+      video_send_config.rtp.ssrcs.push_back(kVideoSendSsrcs[0]);
+      video_send_config.encoder_settings.encoder_factory =
+          &fake_encoder_factory_;
+      video_send_config.encoder_settings.bitrate_allocator_factory =
+          bitrate_allocator_factory_.get();
+      video_send_config.rtp.payload_name = "FAKE";
+      video_send_config.rtp.payload_type = kFakeVideoSendPayloadType;
+      SetVideoSendConfig(video_send_config);
+      VideoEncoderConfig video_encoder_config;
+      test::FillEncoderConfiguration(kVideoCodecVP8, 1, &video_encoder_config);
+      SetVideoEncoderConfig(video_encoder_config);
+
+      receive_config_ =
+          VideoReceiveStreamInterface::Config(receive_transport_.get());
+      // receive_config_.decoders will be set by every stream separately.
+      receive_config_.rtp.remote_ssrc = GetVideoSendConfig()->rtp.ssrcs[0];
+      receive_config_.rtp.local_ssrc = kReceiverLocalVideoSsrc;
+      receive_config_.rtp.extensions.push_back(
+          RtpExtension(RtpExtension::kTimestampOffsetUri, kTOFExtensionId));
+      receive_config_.rtp.extensions.push_back(
+          RtpExtension(RtpExtension::kAbsSendTimeUri, kASTExtensionId));
+    });
+  }
+
+  virtual void TearDown() {
+    SendTask(task_queue(), [this]() {
+      for (auto* stream : streams_) {
+        stream->StopSending();
+        delete stream;
+      }
+      streams_.clear();
+      DestroyCalls();
+    });
+  }
+
+ protected:
+  friend class Stream;
+
+  class Stream {
+   public:
+    explicit Stream(BitrateEstimatorTest* test)
+        : test_(test),
+          is_sending_receiving_(false),
+          send_stream_(nullptr),
+          frame_generator_capturer_(),
+          decoder_factory_(
+              []() { return std::make_unique<test::FakeDecoder>(); }) {
+      test_->GetVideoSendConfig()->rtp.ssrcs[0]++;
+      send_stream_ = test_->sender_call_->CreateVideoSendStream(
+          test_->GetVideoSendConfig()->Copy(),
+          test_->GetVideoEncoderConfig()->Copy());
+      RTC_DCHECK_EQ(1, test_->GetVideoEncoderConfig()->number_of_streams);
+      frame_generator_capturer_ =
+          std::make_unique<test::FrameGeneratorCapturer>(
+              test->clock_,
+              test::CreateSquareFrameGenerator(kDefaultWidth, kDefaultHeight,
+                                               absl::nullopt, absl::nullopt),
+              kDefaultFramerate, *test->task_queue_factory_);
+      frame_generator_capturer_->Init();
+      send_stream_->SetSource(frame_generator_capturer_.get(),
+                              DegradationPreference::MAINTAIN_FRAMERATE);
+      send_stream_->Start();
+
+      VideoReceiveStreamInterface::Decoder decoder;
+      test_->receive_config_.decoder_factory = &decoder_factory_;
+      decoder.payload_type = test_->GetVideoSendConfig()->rtp.payload_type;
+      decoder.video_format =
+          SdpVideoFormat(test_->GetVideoSendConfig()->rtp.payload_name);
+      test_->receive_config_.decoders.clear();
+      test_->receive_config_.decoders.push_back(decoder);
+      test_->receive_config_.rtp.remote_ssrc =
+          test_->GetVideoSendConfig()->rtp.ssrcs[0];
+      test_->receive_config_.rtp.local_ssrc++;
+      test_->receive_config_.renderer = &test->fake_renderer_;
+      video_receive_stream_ = test_->receiver_call_->CreateVideoReceiveStream(
+          test_->receive_config_.Copy());
+      video_receive_stream_->Start();
+      is_sending_receiving_ = true;
+    }
+
+    ~Stream() {
+      EXPECT_FALSE(is_sending_receiving_);
+      test_->sender_call_->DestroyVideoSendStream(send_stream_);
+      frame_generator_capturer_.reset(nullptr);
+      send_stream_ = nullptr;
+      if (video_receive_stream_) {
+        test_->receiver_call_->DestroyVideoReceiveStream(video_receive_stream_);
+        video_receive_stream_ = nullptr;
+      }
+    }
+
+    void StopSending() {
+      if (is_sending_receiving_) {
+        send_stream_->Stop();
+        if (video_receive_stream_) {
+          video_receive_stream_->Stop();
+        }
+        is_sending_receiving_ = false;
+      }
+    }
+
+   private:
+    BitrateEstimatorTest* test_;
+    bool is_sending_receiving_;
+    VideoSendStream* send_stream_;
+    VideoReceiveStreamInterface* video_receive_stream_;
+    std::unique_ptr<test::FrameGeneratorCapturer> frame_generator_capturer_;
+
+    test::FunctionVideoDecoderFactory decoder_factory_;
+  };
+
+  LogObserver receiver_log_;
+  VideoReceiveStreamInterface::Config receive_config_;
+  std::vector<Stream*> streams_;
+};
+
+static const char* kAbsSendTimeLog =
+    "RemoteBitrateEstimatorAbsSendTime: Instantiating.";
+static const char* kSingleStreamLog =
+    "RemoteBitrateEstimatorSingleStream: Instantiating.";
+
+TEST_F(BitrateEstimatorTest, InstantiatesTOFPerDefaultForVideo) {
+  SendTask(task_queue(), [this]() {
+    GetVideoSendConfig()->rtp.extensions.push_back(
+        RtpExtension(RtpExtension::kTimestampOffsetUri, kTOFExtensionId));
+    receiver_log_.PushExpectedLogLine(kSingleStreamLog);
+    receiver_log_.PushExpectedLogLine(kSingleStreamLog);
+    streams_.push_back(new Stream(this));
+  });
+  EXPECT_TRUE(receiver_log_.Wait());
+}
+
+TEST_F(BitrateEstimatorTest, ImmediatelySwitchToASTForVideo) {
+  SendTask(task_queue(), [this]() {
+    GetVideoSendConfig()->rtp.extensions.push_back(
+        RtpExtension(RtpExtension::kAbsSendTimeUri, kASTExtensionId));
+    receiver_log_.PushExpectedLogLine(kSingleStreamLog);
+    receiver_log_.PushExpectedLogLine(kSingleStreamLog);
+    receiver_log_.PushExpectedLogLine("Switching to absolute send time RBE.");
+    receiver_log_.PushExpectedLogLine(kAbsSendTimeLog);
+    streams_.push_back(new Stream(this));
+  });
+  EXPECT_TRUE(receiver_log_.Wait());
+}
+
+TEST_F(BitrateEstimatorTest, SwitchesToASTForVideo) {
+  SendTask(task_queue(), [this]() {
+    GetVideoSendConfig()->rtp.extensions.push_back(
+        RtpExtension(RtpExtension::kTimestampOffsetUri, kTOFExtensionId));
+    receiver_log_.PushExpectedLogLine(kSingleStreamLog);
+    receiver_log_.PushExpectedLogLine(kSingleStreamLog);
+    streams_.push_back(new Stream(this));
+  });
+  EXPECT_TRUE(receiver_log_.Wait());
+
+  SendTask(task_queue(), [this]() {
+    GetVideoSendConfig()->rtp.extensions[0] =
+        RtpExtension(RtpExtension::kAbsSendTimeUri, kASTExtensionId);
+    receiver_log_.PushExpectedLogLine("Switching to absolute send time RBE.");
+    receiver_log_.PushExpectedLogLine(kAbsSendTimeLog);
+    streams_.push_back(new Stream(this));
+  });
+  EXPECT_TRUE(receiver_log_.Wait());
+}
+
+// This test is flaky. See webrtc:5790.
+TEST_F(BitrateEstimatorTest, DISABLED_SwitchesToASTThenBackToTOFForVideo) {
+  SendTask(task_queue(), [this]() {
+    GetVideoSendConfig()->rtp.extensions.push_back(
+        RtpExtension(RtpExtension::kTimestampOffsetUri, kTOFExtensionId));
+    receiver_log_.PushExpectedLogLine(kSingleStreamLog);
+    receiver_log_.PushExpectedLogLine(kAbsSendTimeLog);
+    receiver_log_.PushExpectedLogLine(kSingleStreamLog);
+    streams_.push_back(new Stream(this));
+  });
+  EXPECT_TRUE(receiver_log_.Wait());
+
+  SendTask(task_queue(), [this]() {
+    GetVideoSendConfig()->rtp.extensions[0] =
+        RtpExtension(RtpExtension::kAbsSendTimeUri, kASTExtensionId);
+    receiver_log_.PushExpectedLogLine(kAbsSendTimeLog);
+    receiver_log_.PushExpectedLogLine("Switching to absolute send time RBE.");
+    streams_.push_back(new Stream(this));
+  });
+  EXPECT_TRUE(receiver_log_.Wait());
+
+  SendTask(task_queue(), [this]() {
+    GetVideoSendConfig()->rtp.extensions[0] =
+        RtpExtension(RtpExtension::kTimestampOffsetUri, kTOFExtensionId);
+    receiver_log_.PushExpectedLogLine(kAbsSendTimeLog);
+    receiver_log_.PushExpectedLogLine(
+        "WrappingBitrateEstimator: Switching to transmission time offset RBE.");
+    streams_.push_back(new Stream(this));
+    streams_[0]->StopSending();
+    streams_[1]->StopSending();
+  });
+  EXPECT_TRUE(receiver_log_.Wait());
+}
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/call.cc b/third_party/libwebrtc/call/call.cc
new file mode 100644
index 0000000000..4c3f4b63fc
--- /dev/null
+++ b/third_party/libwebrtc/call/call.cc
@@ -0,0 +1,1503 @@
+/*
+ *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/call.h"
+
+#include <string.h>
+
+#include <algorithm>
+#include <atomic>
+#include <map>
+#include <memory>
+#include <set>
+#include <utility>
+#include <vector>
+
+#include "absl/functional/bind_front.h"
+#include "absl/strings/string_view.h"
+#include "absl/types/optional.h"
+#include "api/media_types.h"
+#include "api/rtc_event_log/rtc_event_log.h"
+#include "api/sequence_checker.h"
+#include "api/task_queue/pending_task_safety_flag.h"
+#include "api/transport/network_control.h"
+#include "audio/audio_receive_stream.h"
+#include "audio/audio_send_stream.h"
+#include "audio/audio_state.h"
+#include "call/adaptation/broadcast_resource_listener.h"
+#include "call/bitrate_allocator.h"
+#include "call/flexfec_receive_stream_impl.h"
+#include "call/packet_receiver.h"
+#include "call/receive_time_calculator.h"
+#include "call/rtp_stream_receiver_controller.h"
+#include "call/rtp_transport_controller_send.h"
+#include "call/rtp_transport_controller_send_factory.h"
+#include "call/version.h"
+#include "logging/rtc_event_log/events/rtc_event_audio_receive_stream_config.h"
+#include "logging/rtc_event_log/events/rtc_event_rtcp_packet_incoming.h"
+#include "logging/rtc_event_log/events/rtc_event_rtp_packet_incoming.h"
+#include "logging/rtc_event_log/events/rtc_event_video_receive_stream_config.h"
+#include "logging/rtc_event_log/events/rtc_event_video_send_stream_config.h"
+#include "logging/rtc_event_log/rtc_stream_config.h"
+#include "modules/congestion_controller/include/receive_side_congestion_controller.h"
+#include "modules/rtp_rtcp/include/flexfec_receiver.h"
+#include "modules/rtp_rtcp/include/rtp_header_extension_map.h"
+#include "modules/rtp_rtcp/source/byte_io.h"
+#include "modules/rtp_rtcp/source/rtp_packet_received.h"
+#include "modules/rtp_rtcp/source/rtp_util.h"
+#include "modules/video_coding/fec_controller_default.h"
+#include "rtc_base/checks.h"
+#include "rtc_base/logging.h"
+#include "rtc_base/strings/string_builder.h"
+#include "rtc_base/system/no_unique_address.h"
+#include "rtc_base/task_utils/repeating_task.h"
+#include "rtc_base/thread_annotations.h"
+#include "rtc_base/time_utils.h"
+#include "rtc_base/trace_event.h"
+#include "system_wrappers/include/clock.h"
+#include "system_wrappers/include/cpu_info.h"
+#include "system_wrappers/include/metrics.h"
+#include "video/call_stats2.h"
+#include "video/send_delay_stats.h"
+#include "video/stats_counter.h"
+#include "video/video_receive_stream2.h"
+#include "video/video_send_stream.h"
+
+namespace webrtc {
+
+namespace {
+bool SendPeriodicFeedback(const std::vector<RtpExtension>& extensions) {
+  for (const auto& extension : extensions) {
+    if (extension.uri == RtpExtension::kTransportSequenceNumberV2Uri)
+      return false;
+  }
+  return true;
+}
+
+const int* FindKeyByValue(const std::map<int, int>& m, int v) {
+  for (const auto& kv : m) {
+    if (kv.second == v)
+      return &kv.first;
+  }
+  return nullptr;
+}
+
+std::unique_ptr<rtclog::StreamConfig> CreateRtcLogStreamConfig(
+    const VideoReceiveStreamInterface::Config& config) {
+  auto rtclog_config = std::make_unique<rtclog::StreamConfig>();
+  rtclog_config->remote_ssrc = config.rtp.remote_ssrc;
+  rtclog_config->local_ssrc = config.rtp.local_ssrc;
+  rtclog_config->rtx_ssrc = config.rtp.rtx_ssrc;
+  rtclog_config->rtcp_mode = config.rtp.rtcp_mode;
+  rtclog_config->rtp_extensions = config.rtp.extensions;
+
+  for (const auto& d : config.decoders) {
+    const int* search =
+        FindKeyByValue(config.rtp.rtx_associated_payload_types, d.payload_type);
+    rtclog_config->codecs.emplace_back(d.video_format.name, d.payload_type,
+                                       search ? *search : 0);
+  }
+  return rtclog_config;
+}
+
+std::unique_ptr<rtclog::StreamConfig> CreateRtcLogStreamConfig(
+    const VideoSendStream::Config& config,
+    size_t ssrc_index) {
+  auto rtclog_config = std::make_unique<rtclog::StreamConfig>();
+  rtclog_config->local_ssrc = config.rtp.ssrcs[ssrc_index];
+  if (ssrc_index < config.rtp.rtx.ssrcs.size()) {
+    rtclog_config->rtx_ssrc = config.rtp.rtx.ssrcs[ssrc_index];
+  }
+  rtclog_config->rtcp_mode = config.rtp.rtcp_mode;
+  rtclog_config->rtp_extensions = config.rtp.extensions;
+
+  rtclog_config->codecs.emplace_back(config.rtp.payload_name,
+                                     config.rtp.payload_type,
+                                     config.rtp.rtx.payload_type);
+  return rtclog_config;
+}
+
+std::unique_ptr<rtclog::StreamConfig> CreateRtcLogStreamConfig(
+    const AudioReceiveStreamInterface::Config& config) {
+  auto rtclog_config = std::make_unique<rtclog::StreamConfig>();
+  rtclog_config->remote_ssrc = config.rtp.remote_ssrc;
+  rtclog_config->local_ssrc = config.rtp.local_ssrc;
+  rtclog_config->rtp_extensions = config.rtp.extensions;
+  return rtclog_config;
+}
+
+TaskQueueBase* GetCurrentTaskQueueOrThread() {
+  TaskQueueBase* current = TaskQueueBase::Current();
+  if (!current)
+    current = rtc::ThreadManager::Instance()->CurrentThread();
+  return current;
+}
+
+}  // namespace
+
+namespace internal {
+
+// Wraps an injected resource in a BroadcastResourceListener and handles adding
+// and removing adapter resources to individual VideoSendStreams.
+class ResourceVideoSendStreamForwarder {
+ public:
+  ResourceVideoSendStreamForwarder(
+      rtc::scoped_refptr<webrtc::Resource> resource)
+      : broadcast_resource_listener_(resource) {
+    broadcast_resource_listener_.StartListening();
+  }
+  ~ResourceVideoSendStreamForwarder() {
+    RTC_DCHECK(adapter_resources_.empty());
+    broadcast_resource_listener_.StopListening();
+  }
+
+  rtc::scoped_refptr<webrtc::Resource> Resource() const {
+    return broadcast_resource_listener_.SourceResource();
+  }
+
+  void OnCreateVideoSendStream(VideoSendStream* video_send_stream) {
+    RTC_DCHECK(adapter_resources_.find(video_send_stream) ==
+               adapter_resources_.end());
+    auto adapter_resource =
+        broadcast_resource_listener_.CreateAdapterResource();
+    video_send_stream->AddAdaptationResource(adapter_resource);
+    adapter_resources_.insert(
+        std::make_pair(video_send_stream, adapter_resource));
+  }
+
+  void OnDestroyVideoSendStream(VideoSendStream* video_send_stream) {
+    auto it = adapter_resources_.find(video_send_stream);
+    RTC_DCHECK(it != adapter_resources_.end());
+    broadcast_resource_listener_.RemoveAdapterResource(it->second);
+    adapter_resources_.erase(it);
+  }
+
+ private:
+  BroadcastResourceListener broadcast_resource_listener_;
+  std::map<VideoSendStream*, rtc::scoped_refptr<webrtc::Resource>>
+      adapter_resources_;
+};
+
+class Call final : public webrtc::Call,
+                   public PacketReceiver,
+                   public TargetTransferRateObserver,
+                   public BitrateAllocator::LimitObserver {
+ public:
+  Call(Clock* clock,
+       const Call::Config& config,
+       std::unique_ptr<RtpTransportControllerSendInterface> transport_send,
+       TaskQueueFactory* task_queue_factory);
+  ~Call() override;
+
+  Call(const Call&) = delete;
+  Call& operator=(const Call&) = delete;
+
+  // Implements webrtc::Call.
+  PacketReceiver* Receiver() override;
+
+  webrtc::AudioSendStream* CreateAudioSendStream(
+      const webrtc::AudioSendStream::Config& config) override;
+  void DestroyAudioSendStream(webrtc::AudioSendStream* send_stream) override;
+
+  webrtc::AudioReceiveStreamInterface* CreateAudioReceiveStream(
+      const webrtc::AudioReceiveStreamInterface::Config& config) override;
+  void DestroyAudioReceiveStream(
+      webrtc::AudioReceiveStreamInterface* receive_stream) override;
+
+  webrtc::VideoSendStream* CreateVideoSendStream(
+      webrtc::VideoSendStream::Config config,
+      VideoEncoderConfig encoder_config) override;
+  webrtc::VideoSendStream* CreateVideoSendStream(
+      webrtc::VideoSendStream::Config config,
+      VideoEncoderConfig encoder_config,
+      std::unique_ptr<FecController> fec_controller) override;
+  void DestroyVideoSendStream(webrtc::VideoSendStream* send_stream) override;
+
+  webrtc::VideoReceiveStreamInterface* CreateVideoReceiveStream(
+      webrtc::VideoReceiveStreamInterface::Config configuration) override;
+  void DestroyVideoReceiveStream(
+      webrtc::VideoReceiveStreamInterface* receive_stream) override;
+
+  FlexfecReceiveStream* CreateFlexfecReceiveStream(
+      const FlexfecReceiveStream::Config config) override;
+  void DestroyFlexfecReceiveStream(
+      FlexfecReceiveStream* receive_stream) override;
+
+  void AddAdaptationResource(rtc::scoped_refptr<Resource> resource) override;
+
+  RtpTransportControllerSendInterface* GetTransportControllerSend() override;
+
+  Stats GetStats() const override;
+
+  const FieldTrialsView& trials() const override;
+
+  TaskQueueBase* network_thread() const override;
+  TaskQueueBase* worker_thread() const override;
+
+  void DeliverRtcpPacket(rtc::CopyOnWriteBuffer packet) override;
+
+  void DeliverRtpPacket(
+      MediaType media_type,
+      RtpPacketReceived packet,
+      OnUndemuxablePacketHandler undemuxable_packet_handler) override;
+
+  void SignalChannelNetworkState(MediaType media, NetworkState state) override;
+
+  void OnAudioTransportOverheadChanged(
+      int transport_overhead_per_packet) override;
+
+  void OnLocalSsrcUpdated(webrtc::AudioReceiveStreamInterface& stream,
+                          uint32_t local_ssrc) override;
+  void OnLocalSsrcUpdated(VideoReceiveStreamInterface& stream,
+                          uint32_t local_ssrc) override;
+  void OnLocalSsrcUpdated(FlexfecReceiveStream& stream,
+                          uint32_t local_ssrc) override;
+
+  void OnUpdateSyncGroup(webrtc::AudioReceiveStreamInterface& stream,
+                         absl::string_view sync_group) override;
+
+  void OnSentPacket(const rtc::SentPacket& sent_packet) override;
+
+  // Implements TargetTransferRateObserver,
+  void OnTargetTransferRate(TargetTransferRate msg) override;
+  void OnStartRateUpdate(DataRate start_rate) override;
+
+  // Implements BitrateAllocator::LimitObserver.
+  void OnAllocationLimitsChanged(BitrateAllocationLimits limits) override;
+
+  void SetClientBitratePreferences(const BitrateSettings& preferences) override;
+
+ private:
+  // Thread-compatible class that collects received packet stats and exposes
+  // them as UMA histograms on destruction.
+  class ReceiveStats {
+   public:
+    explicit ReceiveStats(Clock* clock);
+    ~ReceiveStats();
+
+    void AddReceivedRtcpBytes(int bytes);
+    void AddReceivedAudioBytes(int bytes, webrtc::Timestamp arrival_time);
+    void AddReceivedVideoBytes(int bytes, webrtc::Timestamp arrival_time);
+
+   private:
+    RTC_NO_UNIQUE_ADDRESS SequenceChecker sequence_checker_;
+    RateCounter received_bytes_per_second_counter_
+        RTC_GUARDED_BY(sequence_checker_);
+    RateCounter received_audio_bytes_per_second_counter_
+        RTC_GUARDED_BY(sequence_checker_);
+    RateCounter received_video_bytes_per_second_counter_
+        RTC_GUARDED_BY(sequence_checker_);
+    RateCounter received_rtcp_bytes_per_second_counter_
+        RTC_GUARDED_BY(sequence_checker_);
+    absl::optional<Timestamp> first_received_rtp_audio_timestamp_
+        RTC_GUARDED_BY(sequence_checker_);
+    absl::optional<Timestamp> last_received_rtp_audio_timestamp_
+        RTC_GUARDED_BY(sequence_checker_);
+    absl::optional<Timestamp> first_received_rtp_video_timestamp_
+        RTC_GUARDED_BY(sequence_checker_);
+    absl::optional<Timestamp> last_received_rtp_video_timestamp_
+        RTC_GUARDED_BY(sequence_checker_);
+  };
+
+  // Thread-compatible class that collects sent packet stats and exposes
+  // them as UMA histograms on destruction, provided SetFirstPacketTime was
+  // called with a non-empty packet timestamp before the destructor.
+  class SendStats {
+   public:
+    explicit SendStats(Clock* clock);
+    ~SendStats();
+
+    void SetFirstPacketTime(absl::optional<Timestamp> first_sent_packet_time);
+    void PauseSendAndPacerBitrateCounters();
+    void AddTargetBitrateSample(uint32_t target_bitrate_bps);
+    void SetMinAllocatableRate(BitrateAllocationLimits limits);
+
+   private:
+    RTC_NO_UNIQUE_ADDRESS SequenceChecker destructor_sequence_checker_;
+    RTC_NO_UNIQUE_ADDRESS SequenceChecker sequence_checker_;
+    Clock* const clock_ RTC_GUARDED_BY(destructor_sequence_checker_);
+    AvgCounter estimated_send_bitrate_kbps_counter_
+        RTC_GUARDED_BY(sequence_checker_);
+    AvgCounter pacer_bitrate_kbps_counter_ RTC_GUARDED_BY(sequence_checker_);
+    uint32_t min_allocated_send_bitrate_bps_ RTC_GUARDED_BY(sequence_checker_){
+        0};
+    absl::optional<Timestamp> first_sent_packet_time_
+        RTC_GUARDED_BY(destructor_sequence_checker_);
+  };
+
+  void DeliverRtcp(MediaType media_type, rtc::CopyOnWriteBuffer packet)
+      RTC_RUN_ON(network_thread_);
+
+  AudioReceiveStreamImpl* FindAudioStreamForSyncGroup(
+      absl::string_view sync_group) RTC_RUN_ON(worker_thread_);
+  void ConfigureSync(absl::string_view sync_group) RTC_RUN_ON(worker_thread_);
+
+  void NotifyBweOfReceivedPacket(const RtpPacketReceived& packet,
+                                 MediaType media_type)
+      RTC_RUN_ON(worker_thread_);
+
+  bool RegisterReceiveStream(uint32_t ssrc, ReceiveStreamInterface* stream);
+  bool UnregisterReceiveStream(uint32_t ssrc);
+
+  void UpdateAggregateNetworkState();
+
+  // Ensure that necessary process threads are started, and any required
+  // callbacks have been registered.
+  void EnsureStarted() RTC_RUN_ON(worker_thread_);
+
+  Clock* const clock_;
+  TaskQueueFactory* const task_queue_factory_;
+  TaskQueueBase* const worker_thread_;
+  TaskQueueBase* const network_thread_;
+  const std::unique_ptr<DecodeSynchronizer> decode_sync_;
+  RTC_NO_UNIQUE_ADDRESS SequenceChecker send_transport_sequence_checker_;
+
+  const int num_cpu_cores_;
+  const std::unique_ptr<CallStats> call_stats_;
+  const std::unique_ptr<BitrateAllocator> bitrate_allocator_;
+  const Call::Config config_ RTC_GUARDED_BY(worker_thread_);
+  // Maps to config_.trials, can be used from any thread via `trials()`.
+  const FieldTrialsView& trials_;
+
+  NetworkState audio_network_state_ RTC_GUARDED_BY(worker_thread_);
+  NetworkState video_network_state_ RTC_GUARDED_BY(worker_thread_);
+  // TODO(bugs.webrtc.org/11993): Move aggregate_network_up_ over to the
+  // network thread.
+  bool aggregate_network_up_ RTC_GUARDED_BY(worker_thread_);
+
+  // Schedules nack periodic processing on behalf of all streams.
+  NackPeriodicProcessor nack_periodic_processor_;
+
+  // Audio, Video, and FlexFEC receive streams are owned by the client that
+  // creates them.
+  // TODO(bugs.webrtc.org/11993): Move audio_receive_streams_,
+  // video_receive_streams_ over to the network thread.
+  std::set<AudioReceiveStreamImpl*> audio_receive_streams_
+      RTC_GUARDED_BY(worker_thread_);
+  std::set<VideoReceiveStream2*> video_receive_streams_
+      RTC_GUARDED_BY(worker_thread_);
+  // TODO(bugs.webrtc.org/7135, bugs.webrtc.org/9719): Should eventually be
+  // injected at creation, with a single object in the bundled case.
+  RtpStreamReceiverController audio_receiver_controller_
+      RTC_GUARDED_BY(worker_thread_);
+  RtpStreamReceiverController video_receiver_controller_
+      RTC_GUARDED_BY(worker_thread_);
+
+  // This extra map is used for receive processing which is
+  // independent of media type.
+
+  RTC_NO_UNIQUE_ADDRESS SequenceChecker receive_11993_checker_;
+
+  // TODO(bugs.webrtc.org/11993): Move receive_rtp_config_ over to the
+  // network thread.
+  std::map<uint32_t, ReceiveStreamInterface*> receive_rtp_config_
+      RTC_GUARDED_BY(&receive_11993_checker_);
+
+  // Audio and Video send streams are owned by the client that creates them.
+  // TODO(bugs.webrtc.org/11993): `audio_send_ssrcs_` and `video_send_ssrcs_`
+  // should be accessed on the network thread.
+  std::map<uint32_t, AudioSendStream*> audio_send_ssrcs_
+      RTC_GUARDED_BY(worker_thread_);
+  std::map<uint32_t, VideoSendStream*> video_send_ssrcs_
+      RTC_GUARDED_BY(worker_thread_);
+  std::set<VideoSendStream*> video_send_streams_ RTC_GUARDED_BY(worker_thread_);
+  // True if `video_send_streams_` is empty, false if not. The atomic variable
+  // is used to decide UMA send statistics behavior and enables avoiding a
+  // PostTask().
+  std::atomic<bool> video_send_streams_empty_{true};
+
+  // Each forwarder wraps an adaptation resource that was added to the call.
+  std::vector<std::unique_ptr<ResourceVideoSendStreamForwarder>>
+      adaptation_resource_forwarders_ RTC_GUARDED_BY(worker_thread_);
+
+  using RtpStateMap = std::map<uint32_t, RtpState>;
+  RtpStateMap suspended_audio_send_ssrcs_ RTC_GUARDED_BY(worker_thread_);
+  RtpStateMap suspended_video_send_ssrcs_ RTC_GUARDED_BY(worker_thread_);
+
+  using RtpPayloadStateMap = std::map<uint32_t, RtpPayloadState>;
+  RtpPayloadStateMap suspended_video_payload_states_
+      RTC_GUARDED_BY(worker_thread_);
+
+  webrtc::RtcEventLog* const event_log_;
+
+  // TODO(bugs.webrtc.org/11993) ready to move stats access to the network
+  // thread.
+  ReceiveStats receive_stats_ RTC_GUARDED_BY(worker_thread_);
+  SendStats send_stats_ RTC_GUARDED_BY(send_transport_sequence_checker_);
+  // `last_bandwidth_bps_` and `configured_max_padding_bitrate_bps_` being
+  // atomic avoids a PostTask. The variables are used for stats gathering.
+  std::atomic<uint32_t> last_bandwidth_bps_{0};
+  std::atomic<uint32_t> configured_max_padding_bitrate_bps_{0};
+
+  ReceiveSideCongestionController receive_side_cc_;
+  RepeatingTaskHandle receive_side_cc_periodic_task_;
+
+  const std::unique_ptr<ReceiveTimeCalculator> receive_time_calculator_;
+
+  const std::unique_ptr<SendDelayStats> video_send_delay_stats_;
+  const Timestamp start_of_call_;
+
+  // Note that `task_safety_` needs to be at a greater scope than the task queue
+  // owned by `transport_send_` since calls might arrive on the network thread
+  // while Call is being deleted and the task queue is being torn down.
+  const ScopedTaskSafety task_safety_;
+
+  // Caches transport_send_.get(), to avoid racing with destructor.
+  // Note that this is declared before transport_send_ to ensure that it is not
+  // invalidated until no more tasks can be running on the transport_send_ task
+  // queue.
+  // For more details on the background of this member variable, see:
+  // https://webrtc-review.googlesource.com/c/src/+/63023/9/call/call.cc
+  // https://bugs.chromium.org/p/chromium/issues/detail?id=992640
+  RtpTransportControllerSendInterface* const transport_send_ptr_
+      RTC_GUARDED_BY(send_transport_sequence_checker_);
+  // Declared last since it will issue callbacks from a task queue. Declaring it
+  // last ensures that it is destroyed first and any running tasks are finished.
+  const std::unique_ptr<RtpTransportControllerSendInterface> transport_send_;
+
+  bool is_started_ RTC_GUARDED_BY(worker_thread_) = false;
+
+  // Sequence checker for outgoing network traffic. Could be the network thread.
+  // Could also be a pacer owned thread or TQ such as the TaskQueuePacedSender.
+  RTC_NO_UNIQUE_ADDRESS SequenceChecker sent_packet_sequence_checker_;
+  absl::optional<rtc::SentPacket> last_sent_packet_
+      RTC_GUARDED_BY(sent_packet_sequence_checker_);
+};
+}  // namespace internal
+
+/* Mozilla: Avoid this since it could use GetRealTimeClock().
+Call* Call::Create(const Call::Config& config) {
+  Clock* clock = Clock::GetRealTimeClock();
+  return Create(config, clock,
+                RtpTransportControllerSendFactory().Create(
+                    config.ExtractTransportConfig(), clock));
+}
+ */
+
+Call* Call::Create(const Call::Config& config,
+                   Clock* clock,
+                   std::unique_ptr<RtpTransportControllerSendInterface>
+                       transportControllerSend) {
+  RTC_DCHECK(config.task_queue_factory);
+  return new internal::Call(clock, config, std::move(transportControllerSend),
+                            config.task_queue_factory);
+}
+
+// This method here to avoid subclasses has to implement this method.
+// Call perf test will use Internal::Call::CreateVideoSendStream() to inject
+// FecController.
+VideoSendStream* Call::CreateVideoSendStream(
+    VideoSendStream::Config config,
+    VideoEncoderConfig encoder_config,
+    std::unique_ptr<FecController> fec_controller) {
+  return nullptr;
+}
+
+namespace internal {
+
+Call::ReceiveStats::ReceiveStats(Clock* clock)
+    : received_bytes_per_second_counter_(clock, nullptr, false),
+      received_audio_bytes_per_second_counter_(clock, nullptr, false),
+      received_video_bytes_per_second_counter_(clock, nullptr, false),
+      received_rtcp_bytes_per_second_counter_(clock, nullptr, false) {
+  sequence_checker_.Detach();
+}
+
+void Call::ReceiveStats::AddReceivedRtcpBytes(int bytes) {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  if (received_bytes_per_second_counter_.HasSample()) {
+    // First RTP packet has been received.
+    received_bytes_per_second_counter_.Add(static_cast<int>(bytes));
+    received_rtcp_bytes_per_second_counter_.Add(static_cast<int>(bytes));
+  }
+}
+
+void Call::ReceiveStats::AddReceivedAudioBytes(int bytes,
+                                               webrtc::Timestamp arrival_time) {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  received_bytes_per_second_counter_.Add(bytes);
+  received_audio_bytes_per_second_counter_.Add(bytes);
+  if (!first_received_rtp_audio_timestamp_)
+    first_received_rtp_audio_timestamp_ = arrival_time;
+  last_received_rtp_audio_timestamp_ = arrival_time;
+}
+
+void Call::ReceiveStats::AddReceivedVideoBytes(int bytes,
+                                               webrtc::Timestamp arrival_time) {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  received_bytes_per_second_counter_.Add(bytes);
+  received_video_bytes_per_second_counter_.Add(bytes);
+  if (!first_received_rtp_video_timestamp_)
+    first_received_rtp_video_timestamp_ = arrival_time;
+  last_received_rtp_video_timestamp_ = arrival_time;
+}
+
+Call::ReceiveStats::~ReceiveStats() {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  if (first_received_rtp_audio_timestamp_) {
+    RTC_HISTOGRAM_COUNTS_100000(
+        "WebRTC.Call.TimeReceivingAudioRtpPacketsInSeconds",
+        (*last_received_rtp_audio_timestamp_ -
+         *first_received_rtp_audio_timestamp_)
+            .seconds());
+  }
+  if (first_received_rtp_video_timestamp_) {
+    RTC_HISTOGRAM_COUNTS_100000(
+        "WebRTC.Call.TimeReceivingVideoRtpPacketsInSeconds",
+        (*last_received_rtp_video_timestamp_ -
+         *first_received_rtp_video_timestamp_)
+            .seconds());
+  }
+  const int kMinRequiredPeriodicSamples = 5;
+  AggregatedStats video_bytes_per_sec =
+      received_video_bytes_per_second_counter_.GetStats();
+  if (video_bytes_per_sec.num_samples > kMinRequiredPeriodicSamples) {
+    RTC_HISTOGRAM_COUNTS_100000("WebRTC.Call.VideoBitrateReceivedInKbps",
+                                video_bytes_per_sec.average * 8 / 1000);
+    RTC_LOG(LS_INFO) << "WebRTC.Call.VideoBitrateReceivedInBps, "
+                     << video_bytes_per_sec.ToStringWithMultiplier(8);
+  }
+  AggregatedStats audio_bytes_per_sec =
+      received_audio_bytes_per_second_counter_.GetStats();
+  if (audio_bytes_per_sec.num_samples > kMinRequiredPeriodicSamples) {
+    RTC_HISTOGRAM_COUNTS_100000("WebRTC.Call.AudioBitrateReceivedInKbps",
+                                audio_bytes_per_sec.average * 8 / 1000);
+    RTC_LOG(LS_INFO) << "WebRTC.Call.AudioBitrateReceivedInBps, "
+                     << audio_bytes_per_sec.ToStringWithMultiplier(8);
+  }
+  AggregatedStats rtcp_bytes_per_sec =
+      received_rtcp_bytes_per_second_counter_.GetStats();
+  if (rtcp_bytes_per_sec.num_samples > kMinRequiredPeriodicSamples) {
+    RTC_HISTOGRAM_COUNTS_100000("WebRTC.Call.RtcpBitrateReceivedInBps",
+                                rtcp_bytes_per_sec.average * 8);
+    RTC_LOG(LS_INFO) << "WebRTC.Call.RtcpBitrateReceivedInBps, "
+                     << rtcp_bytes_per_sec.ToStringWithMultiplier(8);
+  }
+  AggregatedStats recv_bytes_per_sec =
+      received_bytes_per_second_counter_.GetStats();
+  if (recv_bytes_per_sec.num_samples > kMinRequiredPeriodicSamples) {
+    RTC_HISTOGRAM_COUNTS_100000("WebRTC.Call.BitrateReceivedInKbps",
+                                recv_bytes_per_sec.average * 8 / 1000);
+    RTC_LOG(LS_INFO) << "WebRTC.Call.BitrateReceivedInBps, "
+                     << recv_bytes_per_sec.ToStringWithMultiplier(8);
+  }
+}
+
+Call::SendStats::SendStats(Clock* clock)
+    : clock_(clock),
+      estimated_send_bitrate_kbps_counter_(clock, nullptr, true),
+      pacer_bitrate_kbps_counter_(clock, nullptr, true) {
+  destructor_sequence_checker_.Detach();
+  sequence_checker_.Detach();
+}
+
+Call::SendStats::~SendStats() {
+  RTC_DCHECK_RUN_ON(&destructor_sequence_checker_);
+  if (!first_sent_packet_time_)
+    return;
+
+  TimeDelta elapsed = clock_->CurrentTime() - *first_sent_packet_time_;
+  if (elapsed.seconds() < metrics::kMinRunTimeInSeconds)
+    return;
+
+  const int kMinRequiredPeriodicSamples = 5;
+  AggregatedStats send_bitrate_stats =
+      estimated_send_bitrate_kbps_counter_.ProcessAndGetStats();
+  if (send_bitrate_stats.num_samples > kMinRequiredPeriodicSamples) {
+    RTC_HISTOGRAM_COUNTS_100000("WebRTC.Call.EstimatedSendBitrateInKbps",
+                                send_bitrate_stats.average);
+    RTC_LOG(LS_INFO) << "WebRTC.Call.EstimatedSendBitrateInKbps, "
+                     << send_bitrate_stats.ToString();
+  }
+  AggregatedStats pacer_bitrate_stats =
+      pacer_bitrate_kbps_counter_.ProcessAndGetStats();
+  if (pacer_bitrate_stats.num_samples > kMinRequiredPeriodicSamples) {
+    RTC_HISTOGRAM_COUNTS_100000("WebRTC.Call.PacerBitrateInKbps",
+                                pacer_bitrate_stats.average);
+    RTC_LOG(LS_INFO) << "WebRTC.Call.PacerBitrateInKbps, "
+                     << pacer_bitrate_stats.ToString();
+  }
+}
+
+void Call::SendStats::SetFirstPacketTime(
+    absl::optional<Timestamp> first_sent_packet_time) {
+  RTC_DCHECK_RUN_ON(&destructor_sequence_checker_);
+  first_sent_packet_time_ = first_sent_packet_time;
+}
+
+void Call::SendStats::PauseSendAndPacerBitrateCounters() {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  estimated_send_bitrate_kbps_counter_.ProcessAndPause();
+  pacer_bitrate_kbps_counter_.ProcessAndPause();
+}
+
+void Call::SendStats::AddTargetBitrateSample(uint32_t target_bitrate_bps) {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  estimated_send_bitrate_kbps_counter_.Add(target_bitrate_bps / 1000);
+  // Pacer bitrate may be higher than bitrate estimate if enforcing min
+  // bitrate.
+  uint32_t pacer_bitrate_bps =
+      std::max(target_bitrate_bps, min_allocated_send_bitrate_bps_);
+  pacer_bitrate_kbps_counter_.Add(pacer_bitrate_bps / 1000);
+}
+
+void Call::SendStats::SetMinAllocatableRate(BitrateAllocationLimits limits) {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  min_allocated_send_bitrate_bps_ = limits.min_allocatable_rate.bps();
+}
+
+Call::Call(Clock* clock,
+           const Call::Config& config,
+           std::unique_ptr<RtpTransportControllerSendInterface> transport_send,
+           TaskQueueFactory* task_queue_factory)
+    : clock_(clock),
+      task_queue_factory_(task_queue_factory),
+      worker_thread_(GetCurrentTaskQueueOrThread()),
+      // If `network_task_queue_` was set to nullptr, network related calls
+      // must be made on `worker_thread_` (i.e. they're one and the same).
+      network_thread_(config.network_task_queue_ ? config.network_task_queue_
+                                                 : worker_thread_),
+      decode_sync_(config.metronome
+                       ? std::make_unique<DecodeSynchronizer>(clock_,
+                                                              config.metronome,
+                                                              worker_thread_)
+                       : nullptr),
+      num_cpu_cores_(CpuInfo::DetectNumberOfCores()),
+      call_stats_(new CallStats(clock_, worker_thread_)),
+      bitrate_allocator_(new BitrateAllocator(this)),
+      config_(config),
+      trials_(*config.trials),
+      audio_network_state_(kNetworkDown),
+      video_network_state_(kNetworkDown),
+      aggregate_network_up_(false),
+      event_log_(config.event_log),
+      receive_stats_(clock_),
+      send_stats_(clock_),
+      receive_side_cc_(clock,
+                       absl::bind_front(&PacketRouter::SendCombinedRtcpPacket,
+                                        transport_send->packet_router()),
+                       absl::bind_front(&PacketRouter::SendRemb,
+                                        transport_send->packet_router()),
+                       /*network_state_estimator=*/nullptr),
+      receive_time_calculator_(
+          ReceiveTimeCalculator::CreateFromFieldTrial(*config.trials)),
+      video_send_delay_stats_(new SendDelayStats(clock_)),
+      start_of_call_(clock_->CurrentTime()),
+      transport_send_ptr_(transport_send.get()),
+      transport_send_(std::move(transport_send)) {
+  RTC_DCHECK(config.event_log != nullptr);
+  RTC_DCHECK(config.trials != nullptr);
+  RTC_DCHECK(network_thread_);
+  RTC_DCHECK(worker_thread_->IsCurrent());
+
+  receive_11993_checker_.Detach();
+  send_transport_sequence_checker_.Detach();
+  sent_packet_sequence_checker_.Detach();
+
+  // Do not remove this call; it is here to convince the compiler that the
+  // WebRTC source timestamp string needs to be in the final binary.
+  LoadWebRTCVersionInRegister();
+
+  call_stats_->RegisterStatsObserver(&receive_side_cc_);
+
+  ReceiveSideCongestionController* receive_side_cc = &receive_side_cc_;
+  receive_side_cc_periodic_task_ = RepeatingTaskHandle::Start(
+      worker_thread_,
+      [receive_side_cc] { return receive_side_cc->MaybeProcess(); },
+      TaskQueueBase::DelayPrecision::kLow, clock_);
+}
+
+Call::~Call() {
+  RTC_DCHECK_RUN_ON(worker_thread_);
+
+  RTC_CHECK(audio_send_ssrcs_.empty());
+  RTC_CHECK(video_send_ssrcs_.empty());
+  RTC_CHECK(video_send_streams_.empty());
+  RTC_CHECK(audio_receive_streams_.empty());
+  RTC_CHECK(video_receive_streams_.empty());
+
+  receive_side_cc_periodic_task_.Stop();
+  call_stats_->DeregisterStatsObserver(&receive_side_cc_);
+  send_stats_.SetFirstPacketTime(transport_send_->GetFirstPacketTime());
+
+  RTC_HISTOGRAM_COUNTS_100000(
+      "WebRTC.Call.LifetimeInSeconds",
+      (clock_->CurrentTime() - start_of_call_).seconds());
+}
+
+void Call::EnsureStarted() {
+  if (is_started_) {
+    return;
+  }
+  is_started_ = true;
+
+  call_stats_->EnsureStarted();
+
+  // This call seems to kick off a number of things, so probably better left
+  // off being kicked off on request rather than in the ctor.
+  transport_send_->RegisterTargetTransferRateObserver(this);
+
+  transport_send_->EnsureStarted();
+}
+
+void Call::SetClientBitratePreferences(const BitrateSettings& preferences) {
+  RTC_DCHECK_RUN_ON(worker_thread_);
+  GetTransportControllerSend()->SetClientBitratePreferences(preferences);
+}
+
+PacketReceiver* Call::Receiver() {
+  return this;
+}
+
+webrtc::AudioSendStream* Call::CreateAudioSendStream(
+    const webrtc::AudioSendStream::Config& config) {
+  TRACE_EVENT0("webrtc", "Call::CreateAudioSendStream");
+  RTC_DCHECK_RUN_ON(worker_thread_);
+
+  EnsureStarted();
+
+  // Stream config is logged in AudioSendStream::ConfigureStream, as it may
+  // change during the stream's lifetime.
+  absl::optional<RtpState> suspended_rtp_state;
+  {
+    const auto& iter = suspended_audio_send_ssrcs_.find(config.rtp.ssrc);
+    if (iter != suspended_audio_send_ssrcs_.end()) {
+      suspended_rtp_state.emplace(iter->second);
+    }
+  }
+
+  AudioSendStream* send_stream = new AudioSendStream(
+      clock_, config, config_.audio_state, task_queue_factory_,
+      transport_send_.get(), bitrate_allocator_.get(), event_log_,
+      call_stats_->AsRtcpRttStats(), suspended_rtp_state, trials());
+  RTC_DCHECK(audio_send_ssrcs_.find(config.rtp.ssrc) ==
+             audio_send_ssrcs_.end());
+  audio_send_ssrcs_[config.rtp.ssrc] = send_stream;
+
+  // TODO(bugs.webrtc.org/11993): call AssociateSendStream and
+  // UpdateAggregateNetworkState asynchronously on the network thread.
+  for (AudioReceiveStreamImpl* stream : audio_receive_streams_) {
+    if (stream->local_ssrc() == config.rtp.ssrc) {
+      stream->AssociateSendStream(send_stream);
+    }
+  }
+
+  UpdateAggregateNetworkState();
+
+  return send_stream;
+}
+
+void Call::DestroyAudioSendStream(webrtc::AudioSendStream* send_stream) {
+  TRACE_EVENT0("webrtc", "Call::DestroyAudioSendStream");
+  RTC_DCHECK_RUN_ON(worker_thread_);
+  RTC_DCHECK(send_stream != nullptr);
+
+  send_stream->Stop();
+
+  const uint32_t ssrc = send_stream->GetConfig().rtp.ssrc;
+  webrtc::internal::AudioSendStream* audio_send_stream =
+      static_cast<webrtc::internal::AudioSendStream*>(send_stream);
+  suspended_audio_send_ssrcs_[ssrc] = audio_send_stream->GetRtpState();
+
+  size_t num_deleted = audio_send_ssrcs_.erase(ssrc);
+  RTC_DCHECK_EQ(1, num_deleted);
+
+  // TODO(bugs.webrtc.org/11993): call AssociateSendStream and
+  // UpdateAggregateNetworkState asynchronously on the network thread.
+  for (AudioReceiveStreamImpl* stream : audio_receive_streams_) {
+    if (stream->local_ssrc() == ssrc) {
+      stream->AssociateSendStream(nullptr);
+    }
+  }
+
+  UpdateAggregateNetworkState();
+
+  delete send_stream;
+}
+
+webrtc::AudioReceiveStreamInterface* Call::CreateAudioReceiveStream(
+    const webrtc::AudioReceiveStreamInterface::Config& config) {
+  TRACE_EVENT0("webrtc", "Call::CreateAudioReceiveStream");
+  RTC_DCHECK_RUN_ON(worker_thread_);
+  EnsureStarted();
+  event_log_->Log(std::make_unique<RtcEventAudioReceiveStreamConfig>(
+      CreateRtcLogStreamConfig(config)));
+
+  AudioReceiveStreamImpl* receive_stream = new AudioReceiveStreamImpl(
+      clock_, transport_send_->packet_router(), config_.neteq_factory, config,
+      config_.audio_state, event_log_);
+  audio_receive_streams_.insert(receive_stream);
+
+  // TODO(bugs.webrtc.org/11993): Make the registration on the network thread
+  // (asynchronously). The registration and `audio_receiver_controller_` need
+  // to live on the network thread.
+  receive_stream->RegisterWithTransport(&audio_receiver_controller_);
+
+  // TODO(bugs.webrtc.org/11993): Update the below on the network thread.
+  // We could possibly set up the audio_receiver_controller_ association up
+  // as part of the async setup.
+  RegisterReceiveStream(config.rtp.remote_ssrc, receive_stream);
+
+  ConfigureSync(config.sync_group);
+
+  auto it = audio_send_ssrcs_.find(config.rtp.local_ssrc);
+  if (it != audio_send_ssrcs_.end()) {
+    receive_stream->AssociateSendStream(it->second);
+  }
+
+  UpdateAggregateNetworkState();
+  return receive_stream;
+}
+
+void Call::DestroyAudioReceiveStream(
+    webrtc::AudioReceiveStreamInterface* receive_stream) {
+  TRACE_EVENT0("webrtc", "Call::DestroyAudioReceiveStream");
+  RTC_DCHECK_RUN_ON(worker_thread_);
+  RTC_DCHECK(receive_stream != nullptr);
+  webrtc::AudioReceiveStreamImpl* audio_receive_stream =
+      static_cast<webrtc::AudioReceiveStreamImpl*>(receive_stream);
+
+  // TODO(bugs.webrtc.org/11993): Access the map, rtp config, call ConfigureSync
+  // and UpdateAggregateNetworkState on the network thread. The call to
+  // `UnregisterFromTransport` should also happen on the network thread.
+  audio_receive_stream->UnregisterFromTransport();
+
+  uint32_t ssrc = audio_receive_stream->remote_ssrc();
+  receive_side_cc_.RemoveStream(ssrc);
+
+  audio_receive_streams_.erase(audio_receive_stream);
+
+  // After calling erase(), call ConfigureSync. This will clear associated
+  // video streams or associate them with a different audio stream if one exists
+  // for this sync_group.
+  ConfigureSync(audio_receive_stream->sync_group());
+
+  UnregisterReceiveStream(ssrc);
+
+  UpdateAggregateNetworkState();
+  // TODO(bugs.webrtc.org/11993): Consider if deleting `audio_receive_stream`
+  // on the network thread would be better or if we'd need to tear down the
+  // state in two phases.
+  delete audio_receive_stream;
+}
+
+// This method can be used for Call tests with external fec controller factory.
+webrtc::VideoSendStream* Call::CreateVideoSendStream(
+    webrtc::VideoSendStream::Config config,
+    VideoEncoderConfig encoder_config,
+    std::unique_ptr<FecController> fec_controller) {
+  TRACE_EVENT0("webrtc", "Call::CreateVideoSendStream");
+  RTC_DCHECK_RUN_ON(worker_thread_);
+
+  EnsureStarted();
+
+  video_send_delay_stats_->AddSsrcs(config);
+  for (size_t ssrc_index = 0; ssrc_index < config.rtp.ssrcs.size();
+       ++ssrc_index) {
+    event_log_->Log(std::make_unique<RtcEventVideoSendStreamConfig>(
+        CreateRtcLogStreamConfig(config, ssrc_index)));
+  }
+
+  // TODO(mflodman): Base the start bitrate on a current bandwidth estimate, if
+  // the call has already started.
+  // Copy ssrcs from `config` since `config` is moved.
+  std::vector<uint32_t> ssrcs = config.rtp.ssrcs;
+
+  VideoSendStream* send_stream = new VideoSendStream(
+      clock_, num_cpu_cores_, task_queue_factory_, network_thread_,
+      call_stats_->AsRtcpRttStats(), transport_send_.get(),
+      bitrate_allocator_.get(), video_send_delay_stats_.get(), event_log_,
+      std::move(config), std::move(encoder_config), suspended_video_send_ssrcs_,
+      suspended_video_payload_states_, std::move(fec_controller),
+      *config_.trials);
+
+  for (uint32_t ssrc : ssrcs) {
+    RTC_DCHECK(video_send_ssrcs_.find(ssrc) == video_send_ssrcs_.end());
+    video_send_ssrcs_[ssrc] = send_stream;
+  }
+  video_send_streams_.insert(send_stream);
+  video_send_streams_empty_.store(false, std::memory_order_relaxed);
+
+  // Forward resources that were previously added to the call to the new stream.
+  for (const auto& resource_forwarder : adaptation_resource_forwarders_) {
+    resource_forwarder->OnCreateVideoSendStream(send_stream);
+  }
+
+  UpdateAggregateNetworkState();
+
+  return send_stream;
+}
+
+webrtc::VideoSendStream* Call::CreateVideoSendStream(
+    webrtc::VideoSendStream::Config config,
+    VideoEncoderConfig encoder_config) {
+  RTC_DCHECK_RUN_ON(worker_thread_);
+  if (config_.fec_controller_factory) {
+    RTC_LOG(LS_INFO) << "External FEC Controller will be used.";
+  }
+  std::unique_ptr<FecController> fec_controller =
+      config_.fec_controller_factory
+          ? config_.fec_controller_factory->CreateFecController()
+          : std::make_unique<FecControllerDefault>(clock_);
+  return CreateVideoSendStream(std::move(config), std::move(encoder_config),
+                               std::move(fec_controller));
+}
+
+void Call::DestroyVideoSendStream(webrtc::VideoSendStream* send_stream) {
+  TRACE_EVENT0("webrtc", "Call::DestroyVideoSendStream");
+  RTC_DCHECK(send_stream != nullptr);
+  RTC_DCHECK_RUN_ON(worker_thread_);
+
+  VideoSendStream* send_stream_impl =
+      static_cast<VideoSendStream*>(send_stream);
+
+  auto it = video_send_ssrcs_.begin();
+  while (it != video_send_ssrcs_.end()) {
+    if (it->second == static_cast<VideoSendStream*>(send_stream)) {
+      send_stream_impl = it->second;
+      video_send_ssrcs_.erase(it++);
+    } else {
+      ++it;
+    }
+  }
+
+  // Stop forwarding resources to the stream being destroyed.
+  for (const auto& resource_forwarder : adaptation_resource_forwarders_) {
+    resource_forwarder->OnDestroyVideoSendStream(send_stream_impl);
+  }
+  video_send_streams_.erase(send_stream_impl);
+  if (video_send_streams_.empty())
+    video_send_streams_empty_.store(true, std::memory_order_relaxed);
+
+  VideoSendStream::RtpStateMap rtp_states;
+  VideoSendStream::RtpPayloadStateMap rtp_payload_states;
+  send_stream_impl->StopPermanentlyAndGetRtpStates(&rtp_states,
+                                                   &rtp_payload_states);
+  for (const auto& kv : rtp_states) {
+    suspended_video_send_ssrcs_[kv.first] = kv.second;
+  }
+  for (const auto& kv : rtp_payload_states) {
+    suspended_video_payload_states_[kv.first] = kv.second;
+  }
+
+  UpdateAggregateNetworkState();
+  // TODO(tommi): consider deleting on the same thread as runs
+  // StopPermanentlyAndGetRtpStates.
+  delete send_stream_impl;
+}
+
+webrtc::VideoReceiveStreamInterface* Call::CreateVideoReceiveStream(
+    webrtc::VideoReceiveStreamInterface::Config configuration) {
+  TRACE_EVENT0("webrtc", "Call::CreateVideoReceiveStream");
+  RTC_DCHECK_RUN_ON(worker_thread_);
+
+  receive_side_cc_.SetSendPeriodicFeedback(
+      SendPeriodicFeedback(configuration.rtp.extensions));
+
+  EnsureStarted();
+
+  event_log_->Log(std::make_unique<RtcEventVideoReceiveStreamConfig>(
+      CreateRtcLogStreamConfig(configuration)));
+
+  // TODO(bugs.webrtc.org/11993): Move the registration between `receive_stream`
+  // and `video_receiver_controller_` out of VideoReceiveStream2 construction
+  // and set it up asynchronously on the network thread (the registration and
+  // `video_receiver_controller_` need to live on the network thread).
+  // TODO(crbug.com/1381982): Re-enable decode synchronizer once the Chromium
+  // API has adapted to the new Metronome interface.
+  VideoReceiveStream2* receive_stream = new VideoReceiveStream2(
+      task_queue_factory_, this, num_cpu_cores_,
+      transport_send_->packet_router(), std::move(configuration),
+      call_stats_.get(), clock_, std::make_unique<VCMTiming>(clock_, trials()),
+      &nack_periodic_processor_, decode_sync_.get(), event_log_);
+  // TODO(bugs.webrtc.org/11993): Set this up asynchronously on the network
+  // thread.
+  receive_stream->RegisterWithTransport(&video_receiver_controller_);
+
+  if (receive_stream->rtx_ssrc()) {
+    // We record identical config for the rtx stream as for the main
+    // stream. Since the transport_send_cc negotiation is per payload
+    // type, we may get an incorrect value for the rtx stream, but
+    // that is unlikely to matter in practice.
+    RegisterReceiveStream(receive_stream->rtx_ssrc(), receive_stream);
+  }
+  RegisterReceiveStream(receive_stream->remote_ssrc(), receive_stream);
+  video_receive_streams_.insert(receive_stream);
+
+  ConfigureSync(receive_stream->sync_group());
+
+  receive_stream->SignalNetworkState(video_network_state_);
+  UpdateAggregateNetworkState();
+  return receive_stream;
+}
+
+void Call::DestroyVideoReceiveStream(
+    webrtc::VideoReceiveStreamInterface* receive_stream) {
+  TRACE_EVENT0("webrtc", "Call::DestroyVideoReceiveStream");
+  RTC_DCHECK_RUN_ON(worker_thread_);
+  RTC_DCHECK(receive_stream != nullptr);
+  VideoReceiveStream2* receive_stream_impl =
+      static_cast<VideoReceiveStream2*>(receive_stream);
+  // TODO(bugs.webrtc.org/11993): Unregister on the network thread.
+  receive_stream_impl->UnregisterFromTransport();
+
+  // Remove all ssrcs pointing to a receive stream. As RTX retransmits on a
+  // separate SSRC there can be either one or two.
+  UnregisterReceiveStream(receive_stream_impl->remote_ssrc());
+
+  if (receive_stream_impl->rtx_ssrc()) {
+    UnregisterReceiveStream(receive_stream_impl->rtx_ssrc());
+  }
+  video_receive_streams_.erase(receive_stream_impl);
+  ConfigureSync(receive_stream_impl->sync_group());
+
+  receive_side_cc_.RemoveStream(receive_stream_impl->remote_ssrc());
+
+  UpdateAggregateNetworkState();
+  delete receive_stream_impl;
+}
+
+FlexfecReceiveStream* Call::CreateFlexfecReceiveStream(
+    const FlexfecReceiveStream::Config config) {
+  TRACE_EVENT0("webrtc", "Call::CreateFlexfecReceiveStream");
+  RTC_DCHECK_RUN_ON(worker_thread_);
+
+  // Unlike the video and audio receive streams, FlexfecReceiveStream implements
+  // RtpPacketSinkInterface itself, and hence its constructor passes its `this`
+  // pointer to video_receiver_controller_->CreateStream(). Calling the
+  // constructor while on the worker thread ensures that we don't call
+  // OnRtpPacket until the constructor is finished and the object is
+  // in a valid state, since OnRtpPacket runs on the same thread.
+  FlexfecReceiveStreamImpl* receive_stream = new FlexfecReceiveStreamImpl(
+      clock_, std::move(config), &video_receiver_controller_,
+      call_stats_->AsRtcpRttStats());
+
+  // TODO(bugs.webrtc.org/11993): Set this up asynchronously on the network
+  // thread.
+  receive_stream->RegisterWithTransport(&video_receiver_controller_);
+  RegisterReceiveStream(receive_stream->remote_ssrc(), receive_stream);
+
+  // TODO(brandtr): Store config in RtcEventLog here.
+
+  return receive_stream;
+}
+
+void Call::DestroyFlexfecReceiveStream(FlexfecReceiveStream* receive_stream) {
+  TRACE_EVENT0("webrtc", "Call::DestroyFlexfecReceiveStream");
+  RTC_DCHECK_RUN_ON(worker_thread_);
+
+  FlexfecReceiveStreamImpl* receive_stream_impl =
+      static_cast<FlexfecReceiveStreamImpl*>(receive_stream);
+  // TODO(bugs.webrtc.org/11993): Unregister on the network thread.
+  receive_stream_impl->UnregisterFromTransport();
+
+  auto ssrc = receive_stream_impl->remote_ssrc();
+  UnregisterReceiveStream(ssrc);
+
+  // Remove all SSRCs pointing to the FlexfecReceiveStreamImpl to be
+  // destroyed.
+  receive_side_cc_.RemoveStream(ssrc);
+
+  delete receive_stream_impl;
+}
+
+void Call::AddAdaptationResource(rtc::scoped_refptr<Resource> resource) {
+  RTC_DCHECK_RUN_ON(worker_thread_);
+  adaptation_resource_forwarders_.push_back(
+      std::make_unique<ResourceVideoSendStreamForwarder>(resource));
+  const auto& resource_forwarder = adaptation_resource_forwarders_.back();
+  for (VideoSendStream* send_stream : video_send_streams_) {
+    resource_forwarder->OnCreateVideoSendStream(send_stream);
+  }
+}
+
+RtpTransportControllerSendInterface* Call::GetTransportControllerSend() {
+  return transport_send_.get();
+}
+
+Call::Stats Call::GetStats() const {
+  RTC_DCHECK_RUN_ON(worker_thread_);
+
+  Stats stats;
+  // TODO(srte): It is unclear if we only want to report queues if network is
+  // available.
+  stats.pacer_delay_ms =
+      aggregate_network_up_ ? transport_send_->GetPacerQueuingDelayMs() : 0;
+
+  stats.rtt_ms = call_stats_->LastProcessedRtt();
+
+  // Fetch available send/receive bitrates.
+  stats.recv_bandwidth_bps = receive_side_cc_.LatestReceiveSideEstimate().bps();
+  stats.send_bandwidth_bps =
+      last_bandwidth_bps_.load(std::memory_order_relaxed);
+  stats.max_padding_bitrate_bps =
+      configured_max_padding_bitrate_bps_.load(std::memory_order_relaxed);
+
+  return stats;
+}
+
+const FieldTrialsView& Call::trials() const {
+  return trials_;
+}
+
+TaskQueueBase* Call::network_thread() const {
+  return network_thread_;
+}
+
+TaskQueueBase* Call::worker_thread() const {
+  return worker_thread_;
+}
+
+void Call::SignalChannelNetworkState(MediaType media, NetworkState state) {
+  RTC_DCHECK_RUN_ON(network_thread_);
+  RTC_DCHECK(media == MediaType::AUDIO || media == MediaType::VIDEO);
+
+  auto closure = [this, media, state]() {
+    // TODO(bugs.webrtc.org/11993): Move this over to the network thread.
+    RTC_DCHECK_RUN_ON(worker_thread_);
+    if (media == MediaType::AUDIO) {
+      audio_network_state_ = state;
+    } else {
+      RTC_DCHECK_EQ(media, MediaType::VIDEO);
+      video_network_state_ = state;
+    }
+
+    // TODO(tommi): Is it necessary to always do this, including if there
+    // was no change in state?
+    UpdateAggregateNetworkState();
+
+    // TODO(tommi): Is it right to do this if media == AUDIO?
+    for (VideoReceiveStream2* video_receive_stream : video_receive_streams_) {
+      video_receive_stream->SignalNetworkState(video_network_state_);
+    }
+  };
+
+  if (network_thread_ == worker_thread_) {
+    closure();
+  } else {
+    // TODO(bugs.webrtc.org/11993): Remove workaround when we no longer need to
+    // post to the worker thread.
+    worker_thread_->PostTask(SafeTask(task_safety_.flag(), std::move(closure)));
+  }
+}
+
+void Call::OnAudioTransportOverheadChanged(int transport_overhead_per_packet) {
+  RTC_DCHECK_RUN_ON(network_thread_);
+  worker_thread_->PostTask(
+      SafeTask(task_safety_.flag(), [this, transport_overhead_per_packet]() {
+        // TODO(bugs.webrtc.org/11993): Move this over to the network thread.
+        RTC_DCHECK_RUN_ON(worker_thread_);
+        for (auto& kv : audio_send_ssrcs_) {
+          kv.second->SetTransportOverhead(transport_overhead_per_packet);
+        }
+      }));
+}
+
+void Call::UpdateAggregateNetworkState() {
+  // TODO(bugs.webrtc.org/11993): Move this over to the network thread.
+  // RTC_DCHECK_RUN_ON(network_thread_);
+
+  RTC_DCHECK_RUN_ON(worker_thread_);
+
+  bool have_audio =
+      !audio_send_ssrcs_.empty() || !audio_receive_streams_.empty();
+  bool have_video =
+      !video_send_ssrcs_.empty() || !video_receive_streams_.empty();
+
+  bool aggregate_network_up =
+      ((have_video && video_network_state_ == kNetworkUp) ||
+       (have_audio && audio_network_state_ == kNetworkUp));
+
+  if (aggregate_network_up != aggregate_network_up_) {
+    RTC_LOG(LS_INFO)
+        << "UpdateAggregateNetworkState: aggregate_state change to "
+        << (aggregate_network_up ? "up" : "down");
+  } else {
+    RTC_LOG(LS_VERBOSE)
+        << "UpdateAggregateNetworkState: aggregate_state remains at "
+        << (aggregate_network_up ? "up" : "down");
+  }
+  aggregate_network_up_ = aggregate_network_up;
+
+  transport_send_->OnNetworkAvailability(aggregate_network_up);
+}
+
+void Call::OnLocalSsrcUpdated(webrtc::AudioReceiveStreamInterface& stream,
+                              uint32_t local_ssrc) {
+  RTC_DCHECK_RUN_ON(worker_thread_);
+  webrtc::AudioReceiveStreamImpl& receive_stream =
+      static_cast<webrtc::AudioReceiveStreamImpl&>(stream);
+
+  receive_stream.SetLocalSsrc(local_ssrc);
+  auto it = audio_send_ssrcs_.find(local_ssrc);
+  receive_stream.AssociateSendStream(it != audio_send_ssrcs_.end() ? it->second
+                                                                   : nullptr);
+}
+
+void Call::OnLocalSsrcUpdated(VideoReceiveStreamInterface& stream,
+                              uint32_t local_ssrc) {
+  RTC_DCHECK_RUN_ON(worker_thread_);
+  static_cast<VideoReceiveStream2&>(stream).SetLocalSsrc(local_ssrc);
+}
+
+void Call::OnLocalSsrcUpdated(FlexfecReceiveStream& stream,
+                              uint32_t local_ssrc) {
+  RTC_DCHECK_RUN_ON(worker_thread_);
+  static_cast<FlexfecReceiveStreamImpl&>(stream).SetLocalSsrc(local_ssrc);
+}
+
+void Call::OnUpdateSyncGroup(webrtc::AudioReceiveStreamInterface& stream,
+                             absl::string_view sync_group) {
+  RTC_DCHECK_RUN_ON(worker_thread_);
+  webrtc::AudioReceiveStreamImpl& receive_stream =
+      static_cast<webrtc::AudioReceiveStreamImpl&>(stream);
+  receive_stream.SetSyncGroup(sync_group);
+  ConfigureSync(sync_group);
+}
+
+void Call::OnSentPacket(const rtc::SentPacket& sent_packet) {
+  RTC_DCHECK_RUN_ON(&sent_packet_sequence_checker_);
+  // When bundling is in effect, multiple senders may be sharing the same
+  // transport. It means every |sent_packet| will be multiply notified from
+  // different channels, WebRtcVoiceMediaChannel or WebRtcVideoChannel. Record
+  // |last_sent_packet_| to deduplicate redundant notifications to downstream.
+  // (https://crbug.com/webrtc/13437): Pass all packets without a |packet_id| to
+  // downstream.
+  if (last_sent_packet_.has_value() && last_sent_packet_->packet_id != -1 &&
+      last_sent_packet_->packet_id == sent_packet.packet_id &&
+      last_sent_packet_->send_time_ms == sent_packet.send_time_ms) {
+    return;
+  }
+  last_sent_packet_ = sent_packet;
+
+  // In production and with most tests, this method will be called on the
+  // network thread. However some test classes such as DirectTransport don't
+  // incorporate a network thread. This means that tests for RtpSenderEgress
+  // and ModuleRtpRtcpImpl2 that use DirectTransport, will call this method
+  // on a ProcessThread. This is alright as is since we forward the call to
+  // implementations that either just do a PostTask or use locking.
+  video_send_delay_stats_->OnSentPacket(sent_packet.packet_id,
+                                        clock_->TimeInMilliseconds());
+  transport_send_->OnSentPacket(sent_packet);
+}
+
+void Call::OnStartRateUpdate(DataRate start_rate) {
+  RTC_DCHECK_RUN_ON(&send_transport_sequence_checker_);
+  bitrate_allocator_->UpdateStartRate(start_rate.bps<uint32_t>());
+}
+
+void Call::OnTargetTransferRate(TargetTransferRate msg) {
+  RTC_DCHECK_RUN_ON(&send_transport_sequence_checker_);
+
+  uint32_t target_bitrate_bps = msg.target_rate.bps();
+  // For controlling the rate of feedback messages.
+  receive_side_cc_.OnBitrateChanged(target_bitrate_bps);
+  bitrate_allocator_->OnNetworkEstimateChanged(msg);
+
+  last_bandwidth_bps_.store(target_bitrate_bps, std::memory_order_relaxed);
+
+  // Ignore updates if bitrate is zero (the aggregate network state is
+  // down) or if we're not sending video.
+  // Using `video_send_streams_empty_` is racy but as the caller can't
+  // reasonably expect synchronize with changes in `video_send_streams_` (being
+  // on `send_transport_sequence_checker`), we can avoid a PostTask this way.
+  if (target_bitrate_bps == 0 ||
+      video_send_streams_empty_.load(std::memory_order_relaxed)) {
+    send_stats_.PauseSendAndPacerBitrateCounters();
+  } else {
+    send_stats_.AddTargetBitrateSample(target_bitrate_bps);
+  }
+}
+
+void Call::OnAllocationLimitsChanged(BitrateAllocationLimits limits) {
+  RTC_DCHECK_RUN_ON(&send_transport_sequence_checker_);
+
+  transport_send_ptr_->SetAllocatedSendBitrateLimits(limits);
+  send_stats_.SetMinAllocatableRate(limits);
+  configured_max_padding_bitrate_bps_.store(limits.max_padding_rate.bps(),
+                                            std::memory_order_relaxed);
+}
+
+AudioReceiveStreamImpl* Call::FindAudioStreamForSyncGroup(
+    absl::string_view sync_group) {
+  RTC_DCHECK_RUN_ON(worker_thread_);
+  RTC_DCHECK_RUN_ON(&receive_11993_checker_);
+  if (!sync_group.empty()) {
+    for (AudioReceiveStreamImpl* stream : audio_receive_streams_) {
+      if (stream->sync_group() == sync_group)
+        return stream;
+    }
+  }
+
+  return nullptr;
+}
+
+void Call::ConfigureSync(absl::string_view sync_group) {
+  // TODO(bugs.webrtc.org/11993): Expect to be called on the network thread.
+  RTC_DCHECK_RUN_ON(worker_thread_);
+  // `audio_stream` may be nullptr when clearing the audio stream for a group.
+  AudioReceiveStreamImpl* audio_stream =
+      FindAudioStreamForSyncGroup(sync_group);
+
+  size_t num_synced_streams = 0;
+  for (VideoReceiveStream2* video_stream : video_receive_streams_) {
+    if (video_stream->sync_group() != sync_group)
+      continue;
+    ++num_synced_streams;
+    // TODO(bugs.webrtc.org/4762): Support synchronizing more than one A/V pair.
+    // Attempting to sync more than one audio/video pair within the same sync
+    // group is not supported in the current implementation.
+    // Only sync the first A/V pair within this sync group.
+    if (num_synced_streams == 1) {
+      // sync_audio_stream may be null and that's ok.
+      video_stream->SetSync(audio_stream);
+    } else {
+      video_stream->SetSync(nullptr);
+    }
+  }
+}
+
+void Call::DeliverRtcpPacket(rtc::CopyOnWriteBuffer packet) {
+  RTC_DCHECK_RUN_ON(worker_thread_);
+  RTC_DCHECK(IsRtcpPacket(packet));
+  TRACE_EVENT0("webrtc", "Call::DeliverRtcp");
+
+  receive_stats_.AddReceivedRtcpBytes(static_cast<int>(packet.size()));
+  bool rtcp_delivered = false;
+  for (VideoReceiveStream2* stream : video_receive_streams_) {
+    if (stream->DeliverRtcp(packet.cdata(), packet.size()))
+      rtcp_delivered = true;
+  }
+
+  for (AudioReceiveStreamImpl* stream : audio_receive_streams_) {
+    stream->DeliverRtcp(packet.cdata(), packet.size());
+    rtcp_delivered = true;
+  }
+
+  for (VideoSendStream* stream : video_send_streams_) {
+    stream->DeliverRtcp(packet.cdata(), packet.size());
+    rtcp_delivered = true;
+  }
+
+  for (auto& kv : audio_send_ssrcs_) {
+    kv.second->DeliverRtcp(packet.cdata(), packet.size());
+    rtcp_delivered = true;
+  }
+
+  if (rtcp_delivered) {
+    event_log_->Log(std::make_unique<RtcEventRtcpPacketIncoming>(packet));
+  }
+}
+
+void Call::DeliverRtpPacket(
+    MediaType media_type,
+    RtpPacketReceived packet,
+    OnUndemuxablePacketHandler undemuxable_packet_handler) {
+  RTC_DCHECK_RUN_ON(worker_thread_);
+  RTC_DCHECK(packet.arrival_time().IsFinite());
+
+  if (receive_time_calculator_) {
+    int64_t packet_time_us = packet.arrival_time().us();
+    // Repair packet_time_us for clock resets by comparing a new read of
+    // the same clock (TimeUTCMicros) to a monotonic clock reading.
+    packet_time_us = receive_time_calculator_->ReconcileReceiveTimes(
+        packet_time_us, rtc::TimeUTCMicros(), clock_->TimeInMicroseconds());
+    packet.set_arrival_time(Timestamp::Micros(packet_time_us));
+  }
+
+  // We might get RTP keep-alive packets in accordance with RFC6263 section 4.6.
+  // These are empty (zero length payload) RTP packets with an unsignaled
+  // payload type.
+  const bool is_keep_alive_packet = packet.payload_size() == 0;
+  RTC_DCHECK(media_type == MediaType::AUDIO || media_type == MediaType::VIDEO ||
+             is_keep_alive_packet);
+  NotifyBweOfReceivedPacket(packet, media_type);
+
+  if (media_type != MediaType::AUDIO && media_type != MediaType::VIDEO) {
+    RTC_DCHECK(is_keep_alive_packet);
+    return;
+  }
+
+  RtpStreamReceiverController& receiver_controller =
+      media_type == MediaType::AUDIO ? audio_receiver_controller_
+                                     : video_receiver_controller_;
+
+  if (!receiver_controller.OnRtpPacket(packet)) {
+    // Demuxing failed.  Allow the caller to create a
+    // receive stream in order to handle unsignalled SSRCs and try again.
+    // Note that we dont want to call NotifyBweOfReceivedPacket twice per
+    // packet.
+    if (!undemuxable_packet_handler(packet)) {
+      return;
+    }
+    if (!receiver_controller.OnRtpPacket(packet)) {
+      RTC_LOG(LS_INFO) << "Failed to demux packet " << packet.Ssrc();
+      return;
+    }
+  }
+  event_log_->Log(std::make_unique<RtcEventRtpPacketIncoming>(packet));
+
+  // RateCounters expect input parameter as int, save it as int,
+  // instead of converting each time it is passed to RateCounter::Add below.
+  int length = static_cast<int>(packet.size());
+  if (media_type == MediaType::AUDIO) {
+    receive_stats_.AddReceivedAudioBytes(length, packet.arrival_time());
+  }
+  if (media_type == MediaType::VIDEO) {
+    receive_stats_.AddReceivedVideoBytes(length, packet.arrival_time());
+  }
+}
+
+void Call::NotifyBweOfReceivedPacket(const RtpPacketReceived& packet,
+                                     MediaType media_type) {
+  RTC_DCHECK_RUN_ON(worker_thread_);
+  RTPHeader header;
+  packet.GetHeader(&header);
+
+  ReceivedPacket packet_msg;
+  packet_msg.size = DataSize::Bytes(packet.payload_size());
+  packet_msg.receive_time = packet.arrival_time();
+  if (header.extension.hasAbsoluteSendTime) {
+    packet_msg.send_time = header.extension.GetAbsoluteSendTimestamp();
+  }
+  transport_send_->OnReceivedPacket(packet_msg);
+
+  // For audio, we only support send side BWE.
+  if (media_type == MediaType::VIDEO ||
+      header.extension.hasTransportSequenceNumber) {
+    receive_side_cc_.OnReceivedPacket(
+        packet.arrival_time().ms(),
+        packet.payload_size() + packet.padding_size(), header);
+  }
+}
+
+bool Call::RegisterReceiveStream(uint32_t ssrc,
+                                 ReceiveStreamInterface* stream) {
+  RTC_DCHECK_RUN_ON(&receive_11993_checker_);
+  RTC_DCHECK(stream);
+  auto inserted = receive_rtp_config_.emplace(ssrc, stream);
+  if (!inserted.second) {
+    RTC_DLOG(LS_WARNING) << "ssrc already registered: " << ssrc;
+  }
+  return inserted.second;
+}
+
+bool Call::UnregisterReceiveStream(uint32_t ssrc) {
+  RTC_DCHECK_RUN_ON(&receive_11993_checker_);
+  size_t erased = receive_rtp_config_.erase(ssrc);
+  if (!erased) {
+    RTC_DLOG(LS_WARNING) << "ssrc wasn't registered: " << ssrc;
+  }
+  return erased != 0u;
+}
+
+}  // namespace internal
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/call.h b/third_party/libwebrtc/call/call.h
new file mode 100644
index 0000000000..42daa95a6c
--- /dev/null
+++ b/third_party/libwebrtc/call/call.h
@@ -0,0 +1,147 @@
+/*
+ *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+#ifndef CALL_CALL_H_
+#define CALL_CALL_H_
+
+#include <algorithm>
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "absl/strings/string_view.h"
+#include "api/adaptation/resource.h"
+#include "api/media_types.h"
+#include "api/task_queue/task_queue_base.h"
+#include "call/audio_receive_stream.h"
+#include "call/audio_send_stream.h"
+#include "call/call_basic_stats.h"
+#include "call/call_config.h"
+#include "call/flexfec_receive_stream.h"
+#include "call/packet_receiver.h"
+#include "call/rtp_transport_controller_send_interface.h"
+#include "call/video_receive_stream.h"
+#include "call/video_send_stream.h"
+#include "rtc_base/copy_on_write_buffer.h"
+#include "rtc_base/network/sent_packet.h"
+#include "rtc_base/network_route.h"
+
+namespace webrtc {
+
+// A Call represents a two-way connection carrying zero or more outgoing
+// and incoming media streams, transported over one or more RTP transports.
+
+// A Call instance can contain several send and/or receive streams. All streams
+// are assumed to have the same remote endpoint and will share bitrate estimates
+// etc.
+
+// When using the PeerConnection API, there is an one to one relationship
+// between the PeerConnection and the Call.
+
+class Call {
+ public:
+  using Config = CallConfig;
+  using Stats = CallBasicStats;
+
+  static Call* Create(const Call::Config& config);
+  static Call* Create(const Call::Config& config,
+                      Clock* clock,
+                      std::unique_ptr<RtpTransportControllerSendInterface>
+                          transportControllerSend);
+
+  virtual AudioSendStream* CreateAudioSendStream(
+      const AudioSendStream::Config& config) = 0;
+
+  virtual void DestroyAudioSendStream(AudioSendStream* send_stream) = 0;
+
+  virtual AudioReceiveStreamInterface* CreateAudioReceiveStream(
+      const AudioReceiveStreamInterface::Config& config) = 0;
+  virtual void DestroyAudioReceiveStream(
+      AudioReceiveStreamInterface* receive_stream) = 0;
+
+  virtual VideoSendStream* CreateVideoSendStream(
+      VideoSendStream::Config config,
+      VideoEncoderConfig encoder_config) = 0;
+  virtual VideoSendStream* CreateVideoSendStream(
+      VideoSendStream::Config config,
+      VideoEncoderConfig encoder_config,
+      std::unique_ptr<FecController> fec_controller);
+  virtual void DestroyVideoSendStream(VideoSendStream* send_stream) = 0;
+
+  virtual VideoReceiveStreamInterface* CreateVideoReceiveStream(
+      VideoReceiveStreamInterface::Config configuration) = 0;
+  virtual void DestroyVideoReceiveStream(
+      VideoReceiveStreamInterface* receive_stream) = 0;
+
+  // In order for a created VideoReceiveStreamInterface to be aware that it is
+  // protected by a FlexfecReceiveStream, the latter should be created before
+  // the former.
+  virtual FlexfecReceiveStream* CreateFlexfecReceiveStream(
+      const FlexfecReceiveStream::Config config) = 0;
+  virtual void DestroyFlexfecReceiveStream(
+      FlexfecReceiveStream* receive_stream) = 0;
+
+  // When a resource is overused, the Call will try to reduce the load on the
+  // sysem, for example by reducing the resolution or frame rate of encoded
+  // streams.
+  virtual void AddAdaptationResource(rtc::scoped_refptr<Resource> resource) = 0;
+
+  // All received RTP and RTCP packets for the call should be inserted to this
+  // PacketReceiver. The PacketReceiver pointer is valid as long as the
+  // Call instance exists.
+  virtual PacketReceiver* Receiver() = 0;
+
+  // This is used to access the transport controller send instance owned by
+  // Call. The send transport controller is currently owned by Call for legacy
+  // reasons. (for instance  variants of call tests are built on this assumtion)
+  // TODO(srte): Move ownership of transport controller send out of Call and
+  // remove this method interface.
+  virtual RtpTransportControllerSendInterface* GetTransportControllerSend() = 0;
+
+  // Returns the call statistics, such as estimated send and receive bandwidth,
+  // pacing delay, etc.
+  virtual Stats GetStats() const = 0;
+
+  // TODO(skvlad): When the unbundled case with multiple streams for the same
+  // media type going over different networks is supported, track the state
+  // for each stream separately. Right now it's global per media type.
+  virtual void SignalChannelNetworkState(MediaType media,
+                                         NetworkState state) = 0;
+
+  virtual void OnAudioTransportOverheadChanged(
+      int transport_overhead_per_packet) = 0;
+
+  // Called when a receive stream's local ssrc has changed and association with
+  // send streams needs to be updated.
+  virtual void OnLocalSsrcUpdated(AudioReceiveStreamInterface& stream,
+                                  uint32_t local_ssrc) = 0;
+  virtual void OnLocalSsrcUpdated(VideoReceiveStreamInterface& stream,
+                                  uint32_t local_ssrc) = 0;
+  virtual void OnLocalSsrcUpdated(FlexfecReceiveStream& stream,
+                                  uint32_t local_ssrc) = 0;
+
+  virtual void OnUpdateSyncGroup(AudioReceiveStreamInterface& stream,
+                                 absl::string_view sync_group) = 0;
+
+  virtual void OnSentPacket(const rtc::SentPacket& sent_packet) = 0;
+
+  virtual void SetClientBitratePreferences(
+      const BitrateSettings& preferences) = 0;
+
+  virtual const FieldTrialsView& trials() const = 0;
+
+  virtual TaskQueueBase* network_thread() const = 0;
+  virtual TaskQueueBase* worker_thread() const = 0;
+
+  virtual ~Call() {}
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_CALL_H_
diff --git a/third_party/libwebrtc/call/call_basic_stats.cc b/third_party/libwebrtc/call/call_basic_stats.cc
new file mode 100644
index 0000000000..74333a663b
--- /dev/null
+++ b/third_party/libwebrtc/call/call_basic_stats.cc
@@ -0,0 +1,20 @@
+#include "call/call_basic_stats.h"
+
+#include "rtc_base/strings/string_builder.h"
+
+namespace webrtc {
+
+std::string CallBasicStats::ToString(int64_t time_ms) const {
+  char buf[1024];
+  rtc::SimpleStringBuilder ss(buf);
+  ss << "Call stats: " << time_ms << ", {";
+  ss << "send_bw_bps: " << send_bandwidth_bps << ", ";
+  ss << "recv_bw_bps: " << recv_bandwidth_bps << ", ";
+  ss << "max_pad_bps: " << max_padding_bitrate_bps << ", ";
+  ss << "pacer_delay_ms: " << pacer_delay_ms << ", ";
+  ss << "rtt_ms: " << rtt_ms;
+  ss << '}';
+  return ss.str();
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/call_basic_stats.h b/third_party/libwebrtc/call/call_basic_stats.h
new file mode 100644
index 0000000000..98febe9405
--- /dev/null
+++ b/third_party/libwebrtc/call/call_basic_stats.h
@@ -0,0 +1,21 @@
+#ifndef CALL_CALL_BASIC_STATS_H_
+#define CALL_CALL_BASIC_STATS_H_
+
+#include <string>
+
+namespace webrtc {
+
+// named to avoid conflicts with video/call_stats.h
+struct CallBasicStats {
+  std::string ToString(int64_t time_ms) const;
+
+  int send_bandwidth_bps = 0;       // Estimated available send bandwidth.
+  int max_padding_bitrate_bps = 0;  // Cumulative configured max padding.
+  int recv_bandwidth_bps = 0;       // Estimated available receive bandwidth.
+  int64_t pacer_delay_ms = 0;
+  int64_t rtt_ms = -1;
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_CALL_BASIC_STATS_H_
diff --git a/third_party/libwebrtc/call/call_config.cc b/third_party/libwebrtc/call/call_config.cc
new file mode 100644
index 0000000000..93f6b1aec4
--- /dev/null
+++ b/third_party/libwebrtc/call/call_config.cc
@@ -0,0 +1,41 @@
+/*
+ *  Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/call_config.h"
+
+#include "rtc_base/checks.h"
+
+namespace webrtc {
+
+CallConfig::CallConfig(RtcEventLog* event_log,
+                       TaskQueueBase* network_task_queue /* = nullptr*/)
+    : event_log(event_log), network_task_queue_(network_task_queue) {
+  RTC_DCHECK(event_log);
+}
+
+CallConfig::CallConfig(const CallConfig& config) = default;
+
+RtpTransportConfig CallConfig::ExtractTransportConfig() const {
+  RtpTransportConfig transportConfig;
+  transportConfig.bitrate_config = bitrate_config;
+  transportConfig.event_log = event_log;
+  transportConfig.network_controller_factory = network_controller_factory;
+  transportConfig.network_state_predictor_factory =
+      network_state_predictor_factory;
+  transportConfig.task_queue_factory = task_queue_factory;
+  transportConfig.trials = trials;
+  transportConfig.pacer_burst_interval = pacer_burst_interval;
+
+  return transportConfig;
+}
+
+CallConfig::~CallConfig() = default;
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/call_config.h b/third_party/libwebrtc/call/call_config.h
new file mode 100644
index 0000000000..6df4ab7ed4
--- /dev/null
+++ b/third_party/libwebrtc/call/call_config.h
@@ -0,0 +1,88 @@
+/*
+ *  Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+#ifndef CALL_CALL_CONFIG_H_
+#define CALL_CALL_CONFIG_H_
+
+#include "api/fec_controller.h"
+#include "api/field_trials_view.h"
+#include "api/metronome/metronome.h"
+#include "api/neteq/neteq_factory.h"
+#include "api/network_state_predictor.h"
+#include "api/rtc_error.h"
+#include "api/task_queue/task_queue_factory.h"
+#include "api/transport/bitrate_settings.h"
+#include "api/transport/network_control.h"
+#include "call/audio_state.h"
+#include "call/rtp_transport_config.h"
+#include "call/rtp_transport_controller_send_factory_interface.h"
+
+namespace webrtc {
+
+class AudioProcessing;
+class RtcEventLog;
+
+struct CallConfig {
+  // If `network_task_queue` is set to nullptr, Call will assume that network
+  // related callbacks will be made on the same TQ as the Call instance was
+  // constructed on.
+  explicit CallConfig(RtcEventLog* event_log,
+                      TaskQueueBase* network_task_queue = nullptr);
+  CallConfig(const CallConfig&);
+  RtpTransportConfig ExtractTransportConfig() const;
+  ~CallConfig();
+
+  // Bitrate config used until valid bitrate estimates are calculated. Also
+  // used to cap total bitrate used. This comes from the remote connection.
+  BitrateConstraints bitrate_config;
+
+  // AudioState which is possibly shared between multiple calls.
+  rtc::scoped_refptr<AudioState> audio_state;
+
+  // Audio Processing Module to be used in this call.
+  AudioProcessing* audio_processing = nullptr;
+
+  // RtcEventLog to use for this call. Required.
+  // Use webrtc::RtcEventLog::CreateNull() for a null implementation.
+  RtcEventLog* const event_log = nullptr;
+
+  // FecController to use for this call.
+  FecControllerFactoryInterface* fec_controller_factory = nullptr;
+
+  // Task Queue Factory to be used in this call. Required.
+  TaskQueueFactory* task_queue_factory = nullptr;
+
+  // NetworkStatePredictor to use for this call.
+  NetworkStatePredictorFactoryInterface* network_state_predictor_factory =
+      nullptr;
+
+  // Network controller factory to use for this call.
+  NetworkControllerFactoryInterface* network_controller_factory = nullptr;
+
+  // NetEq factory to use for this call.
+  NetEqFactory* neteq_factory = nullptr;
+
+  // Key-value mapping of internal configurations to apply,
+  // e.g. field trials.
+  const FieldTrialsView* trials = nullptr;
+
+  TaskQueueBase* const network_task_queue_ = nullptr;
+  // RtpTransportControllerSend to use for this call.
+  RtpTransportControllerSendFactoryInterface*
+      rtp_transport_controller_send_factory = nullptr;
+
+  Metronome* metronome = nullptr;
+
+  // The burst interval of the pacer, see TaskQueuePacedSender constructor.
+  absl::optional<TimeDelta> pacer_burst_interval;
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_CALL_CONFIG_H_
diff --git a/third_party/libwebrtc/call/call_factory.cc b/third_party/libwebrtc/call/call_factory.cc
new file mode 100644
index 0000000000..253f8cd7de
--- /dev/null
+++ b/third_party/libwebrtc/call/call_factory.cc
@@ -0,0 +1,120 @@
+/*
+ *  Copyright 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/call_factory.h"
+
+#include <stdio.h>
+
+#include <memory>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "absl/memory/memory.h"
+#include "absl/types/optional.h"
+#include "api/test/simulated_network.h"
+#include "api/units/time_delta.h"
+#include "call/call.h"
+#include "call/degraded_call.h"
+#include "call/rtp_transport_config.h"
+#include "rtc_base/checks.h"
+#include "rtc_base/experiments/field_trial_list.h"
+#include "rtc_base/experiments/field_trial_parser.h"
+
+namespace webrtc {
+namespace {
+using TimeScopedNetworkConfig = DegradedCall::TimeScopedNetworkConfig;
+
+std::vector<TimeScopedNetworkConfig> GetNetworkConfigs(
+    const FieldTrialsView& trials,
+    bool send) {
+  FieldTrialStructList<TimeScopedNetworkConfig> trials_list(
+      {FieldTrialStructMember("queue_length_packets",
+                              [](TimeScopedNetworkConfig* p) {
+                                // FieldTrialParser does not natively support
+                                // size_t type, so use this ugly cast as
+                                // workaround.
+                                return reinterpret_cast<unsigned*>(
+                                    &p->queue_length_packets);
+                              }),
+       FieldTrialStructMember(
+           "queue_delay_ms",
+           [](TimeScopedNetworkConfig* p) { return &p->queue_delay_ms; }),
+       FieldTrialStructMember("delay_standard_deviation_ms",
+                              [](TimeScopedNetworkConfig* p) {
+                                return &p->delay_standard_deviation_ms;
+                              }),
+       FieldTrialStructMember(
+           "link_capacity_kbps",
+           [](TimeScopedNetworkConfig* p) { return &p->link_capacity_kbps; }),
+       FieldTrialStructMember(
+           "loss_percent",
+           [](TimeScopedNetworkConfig* p) { return &p->loss_percent; }),
+       FieldTrialStructMember(
+           "allow_reordering",
+           [](TimeScopedNetworkConfig* p) { return &p->allow_reordering; }),
+       FieldTrialStructMember("avg_burst_loss_length",
+                              [](TimeScopedNetworkConfig* p) {
+                                return &p->avg_burst_loss_length;
+                              }),
+       FieldTrialStructMember(
+           "packet_overhead",
+           [](TimeScopedNetworkConfig* p) { return &p->packet_overhead; }),
+       FieldTrialStructMember(
+           "duration",
+           [](TimeScopedNetworkConfig* p) { return &p->duration; })},
+      {});
+  ParseFieldTrial({&trials_list},
+                  trials.Lookup(send ? "WebRTC-FakeNetworkSendConfig"
+                                     : "WebRTC-FakeNetworkReceiveConfig"));
+  return trials_list.Get();
+}
+
+}  // namespace
+
+CallFactory::CallFactory() {
+  call_thread_.Detach();
+}
+
+Call* CallFactory::CreateCall(const Call::Config& config) {
+  RTC_DCHECK_RUN_ON(&call_thread_);
+  RTC_DCHECK(config.trials);
+
+  std::vector<DegradedCall::TimeScopedNetworkConfig> send_degradation_configs =
+      GetNetworkConfigs(*config.trials, /*send=*/true);
+  std::vector<DegradedCall::TimeScopedNetworkConfig>
+      receive_degradation_configs =
+          GetNetworkConfigs(*config.trials, /*send=*/false);
+
+  RtpTransportConfig transportConfig = config.ExtractTransportConfig();
+
+  RTC_CHECK(false);
+  return nullptr;
+  /* Mozilla: Avoid this since it could use GetRealTimeClock().
+  Call* call =
+      Call::Create(config, Clock::GetRealTimeClock(),
+                   config.rtp_transport_controller_send_factory->Create(
+                       transportConfig, Clock::GetRealTimeClock()));
+
+  if (!send_degradation_configs.empty() ||
+      !receive_degradation_configs.empty()) {
+    return new DegradedCall(absl::WrapUnique(call), send_degradation_configs,
+                            receive_degradation_configs);
+  }
+
+  return call;
+   */
+}
+
+std::unique_ptr<CallFactoryInterface> CreateCallFactory() {
+  return std::unique_ptr<CallFactoryInterface>(new CallFactory());
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/call_factory.h b/third_party/libwebrtc/call/call_factory.h
new file mode 100644
index 0000000000..9feed7bbb6
--- /dev/null
+++ b/third_party/libwebrtc/call/call_factory.h
@@ -0,0 +1,36 @@
+/*
+ *  Copyright 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_CALL_FACTORY_H_
+#define CALL_CALL_FACTORY_H_
+
+#include "api/call/call_factory_interface.h"
+#include "api/sequence_checker.h"
+#include "call/call.h"
+#include "call/call_config.h"
+#include "rtc_base/system/no_unique_address.h"
+
+namespace webrtc {
+
+class CallFactory : public CallFactoryInterface {
+ public:
+  CallFactory();
+
+ private:
+  ~CallFactory() override {}
+
+  Call* CreateCall(const CallConfig& config) override;
+
+  RTC_NO_UNIQUE_ADDRESS SequenceChecker call_thread_;
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_CALL_FACTORY_H_
diff --git a/third_party/libwebrtc/call/call_gn/moz.build b/third_party/libwebrtc/call/call_gn/moz.build
new file mode 100644
index 0000000000..1f51906494
--- /dev/null
+++ b/third_party/libwebrtc/call/call_gn/moz.build
@@ -0,0 +1,235 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+  ### This moz.build was AUTOMATICALLY GENERATED from a GN config,  ###
+  ### DO NOT edit it by hand.                                       ###
+
+COMPILE_FLAGS["OS_INCLUDES"] = []
+AllowCompilerWarnings()
+
+DEFINES["ABSL_ALLOCATOR_NOTHROW"] = "1"
+DEFINES["RTC_DAV1D_IN_INTERNAL_DECODER_FACTORY"] = True
+DEFINES["RTC_ENABLE_VP9"] = True
+DEFINES["WEBRTC_ENABLE_PROTOBUF"] = "0"
+DEFINES["WEBRTC_LIBRARY_IMPL"] = True
+DEFINES["WEBRTC_MOZILLA_BUILD"] = True
+DEFINES["WEBRTC_NON_STATIC_TRACE_EVENT_HANDLERS"] = "0"
+DEFINES["WEBRTC_STRICT_FIELD_TRIALS"] = "0"
+
+FINAL_LIBRARY = "webrtc"
+
+
+LOCAL_INCLUDES += [
+    "!/ipc/ipdl/_ipdlheaders",
+    "!/third_party/libwebrtc/gen",
+    "/ipc/chromium/src",
+    "/third_party/libwebrtc/",
+    "/third_party/libwebrtc/third_party/abseil-cpp/",
+    "/tools/profiler/public"
+]
+
+UNIFIED_SOURCES += [
+    "/third_party/libwebrtc/call/call.cc",
+    "/third_party/libwebrtc/call/flexfec_receive_stream_impl.cc",
+    "/third_party/libwebrtc/call/receive_time_calculator.cc"
+]
+
+if not CONFIG["MOZ_DEBUG"]:
+
+    DEFINES["DYNAMIC_ANNOTATIONS_ENABLED"] = "0"
+    DEFINES["NDEBUG"] = True
+    DEFINES["NVALGRIND"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1":
+
+    DEFINES["DYNAMIC_ANNOTATIONS_ENABLED"] = "1"
+
+if CONFIG["OS_TARGET"] == "Android":
+
+    DEFINES["ANDROID"] = True
+    DEFINES["ANDROID_NDK_VERSION_ROLL"] = "r22_1"
+    DEFINES["HAVE_SYS_UIO_H"] = True
+    DEFINES["WEBRTC_ANDROID"] = True
+    DEFINES["WEBRTC_ANDROID_OPENSLES"] = True
+    DEFINES["WEBRTC_LINUX"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_GNU_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+    OS_LIBS += [
+        "GLESv2",
+        "log"
+    ]
+
+if CONFIG["OS_TARGET"] == "Darwin":
+
+    DEFINES["WEBRTC_MAC"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_LIBCPP_HAS_NO_ALIGNED_ALLOCATION"] = True
+    DEFINES["__ASSERT_MACROS_DEFINE_VERSIONS_WITHOUT_UNDERSCORES"] = "0"
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+if CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["USE_AURA"] = "1"
+    DEFINES["USE_GLIB"] = "1"
+    DEFINES["USE_NSS_CERTS"] = "1"
+    DEFINES["USE_OZONE"] = "1"
+    DEFINES["USE_UDEV"] = True
+    DEFINES["WEBRTC_LINUX"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_FILE_OFFSET_BITS"] = "64"
+    DEFINES["_LARGEFILE64_SOURCE"] = True
+    DEFINES["_LARGEFILE_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+    OS_LIBS += [
+        "rt"
+    ]
+
+if CONFIG["OS_TARGET"] == "OpenBSD":
+
+    DEFINES["USE_GLIB"] = "1"
+    DEFINES["USE_OZONE"] = "1"
+    DEFINES["USE_X11"] = "1"
+    DEFINES["WEBRTC_BSD"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_FILE_OFFSET_BITS"] = "64"
+    DEFINES["_LARGEFILE64_SOURCE"] = True
+    DEFINES["_LARGEFILE_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+if CONFIG["OS_TARGET"] == "WINNT":
+
+    DEFINES["CERT_CHAIN_PARA_HAS_EXTRA_FIELDS"] = True
+    DEFINES["NOMINMAX"] = True
+    DEFINES["NTDDI_VERSION"] = "0x0A000000"
+    DEFINES["PSAPI_VERSION"] = "2"
+    DEFINES["UNICODE"] = True
+    DEFINES["USE_AURA"] = "1"
+    DEFINES["WEBRTC_WIN"] = True
+    DEFINES["WIN32"] = True
+    DEFINES["WIN32_LEAN_AND_MEAN"] = True
+    DEFINES["WINAPI_FAMILY"] = "WINAPI_FAMILY_DESKTOP_APP"
+    DEFINES["WINVER"] = "0x0A00"
+    DEFINES["_ATL_NO_OPENGL"] = True
+    DEFINES["_CRT_RAND_S"] = True
+    DEFINES["_CRT_SECURE_NO_DEPRECATE"] = True
+    DEFINES["_ENABLE_EXTENDED_ALIGNED_STORAGE"] = True
+    DEFINES["_HAS_EXCEPTIONS"] = "0"
+    DEFINES["_HAS_NODISCARD"] = True
+    DEFINES["_SCL_SECURE_NO_DEPRECATE"] = True
+    DEFINES["_SECURE_ATL"] = True
+    DEFINES["_UNICODE"] = True
+    DEFINES["_WIN32_WINNT"] = "0x0A00"
+    DEFINES["_WINDOWS"] = True
+    DEFINES["__STD_C"] = True
+
+    OS_LIBS += [
+        "crypt32",
+        "iphlpapi",
+        "secur32",
+        "winmm"
+    ]
+
+if CONFIG["CPU_ARCH"] == "aarch64":
+
+    DEFINES["WEBRTC_ARCH_ARM64"] = True
+    DEFINES["WEBRTC_HAS_NEON"] = True
+
+if CONFIG["CPU_ARCH"] == "arm":
+
+    CXXFLAGS += [
+        "-mfpu=neon"
+    ]
+
+    DEFINES["WEBRTC_ARCH_ARM"] = True
+    DEFINES["WEBRTC_ARCH_ARM_V7"] = True
+    DEFINES["WEBRTC_HAS_NEON"] = True
+
+if CONFIG["CPU_ARCH"] == "mips32":
+
+    DEFINES["MIPS32_LE"] = True
+    DEFINES["MIPS_FPU_LE"] = True
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "mips64":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86":
+
+    DEFINES["WEBRTC_ENABLE_AVX2"] = True
+
+if CONFIG["CPU_ARCH"] == "x86_64":
+
+    DEFINES["WEBRTC_ENABLE_AVX2"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Android":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Darwin":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "OpenBSD":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "WINNT":
+
+    DEFINES["_HAS_ITERATOR_DEBUGGING"] = "0"
+
+if CONFIG["MOZ_X11"] == "1" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["USE_X11"] = "1"
+
+if CONFIG["CPU_ARCH"] == "arm" and CONFIG["OS_TARGET"] == "Android":
+
+    OS_LIBS += [
+        "android_support",
+        "unwind"
+    ]
+
+if CONFIG["CPU_ARCH"] == "x86" and CONFIG["OS_TARGET"] == "Android":
+
+    CXXFLAGS += [
+        "-msse2"
+    ]
+
+    OS_LIBS += [
+        "android_support"
+    ]
+
+if CONFIG["CPU_ARCH"] == "aarch64" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "arm" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86" and CONFIG["OS_TARGET"] == "Linux":
+
+    CXXFLAGS += [
+        "-msse2"
+    ]
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86_64" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+Library("call_gn")
diff --git a/third_party/libwebrtc/call/call_interfaces_gn/moz.build b/third_party/libwebrtc/call/call_interfaces_gn/moz.build
new file mode 100644
index 0000000000..9782bf65f4
--- /dev/null
+++ b/third_party/libwebrtc/call/call_interfaces_gn/moz.build
@@ -0,0 +1,238 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+  ### This moz.build was AUTOMATICALLY GENERATED from a GN config,  ###
+  ### DO NOT edit it by hand.                                       ###
+
+COMPILE_FLAGS["OS_INCLUDES"] = []
+AllowCompilerWarnings()
+
+DEFINES["ABSL_ALLOCATOR_NOTHROW"] = "1"
+DEFINES["RTC_DAV1D_IN_INTERNAL_DECODER_FACTORY"] = True
+DEFINES["RTC_ENABLE_VP9"] = True
+DEFINES["WEBRTC_ENABLE_PROTOBUF"] = "0"
+DEFINES["WEBRTC_LIBRARY_IMPL"] = True
+DEFINES["WEBRTC_MOZILLA_BUILD"] = True
+DEFINES["WEBRTC_NON_STATIC_TRACE_EVENT_HANDLERS"] = "0"
+DEFINES["WEBRTC_STRICT_FIELD_TRIALS"] = "0"
+
+FINAL_LIBRARY = "webrtc"
+
+
+LOCAL_INCLUDES += [
+    "!/ipc/ipdl/_ipdlheaders",
+    "!/third_party/libwebrtc/gen",
+    "/ipc/chromium/src",
+    "/third_party/libwebrtc/",
+    "/third_party/libwebrtc/third_party/abseil-cpp/",
+    "/tools/profiler/public"
+]
+
+UNIFIED_SOURCES += [
+    "/third_party/libwebrtc/call/audio_receive_stream.cc",
+    "/third_party/libwebrtc/call/audio_send_stream.cc",
+    "/third_party/libwebrtc/call/audio_state.cc",
+    "/third_party/libwebrtc/call/call_basic_stats.cc",
+    "/third_party/libwebrtc/call/call_config.cc",
+    "/third_party/libwebrtc/call/flexfec_receive_stream.cc",
+    "/third_party/libwebrtc/call/syncable.cc"
+]
+
+if not CONFIG["MOZ_DEBUG"]:
+
+    DEFINES["DYNAMIC_ANNOTATIONS_ENABLED"] = "0"
+    DEFINES["NDEBUG"] = True
+    DEFINES["NVALGRIND"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1":
+
+    DEFINES["DYNAMIC_ANNOTATIONS_ENABLED"] = "1"
+
+if CONFIG["OS_TARGET"] == "Android":
+
+    DEFINES["ANDROID"] = True
+    DEFINES["ANDROID_NDK_VERSION_ROLL"] = "r22_1"
+    DEFINES["HAVE_SYS_UIO_H"] = True
+    DEFINES["WEBRTC_ANDROID"] = True
+    DEFINES["WEBRTC_ANDROID_OPENSLES"] = True
+    DEFINES["WEBRTC_LINUX"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_GNU_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+    OS_LIBS += [
+        "log"
+    ]
+
+if CONFIG["OS_TARGET"] == "Darwin":
+
+    DEFINES["WEBRTC_MAC"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_LIBCPP_HAS_NO_ALIGNED_ALLOCATION"] = True
+    DEFINES["__ASSERT_MACROS_DEFINE_VERSIONS_WITHOUT_UNDERSCORES"] = "0"
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+if CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["USE_AURA"] = "1"
+    DEFINES["USE_GLIB"] = "1"
+    DEFINES["USE_NSS_CERTS"] = "1"
+    DEFINES["USE_OZONE"] = "1"
+    DEFINES["USE_UDEV"] = True
+    DEFINES["WEBRTC_LINUX"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_FILE_OFFSET_BITS"] = "64"
+    DEFINES["_LARGEFILE64_SOURCE"] = True
+    DEFINES["_LARGEFILE_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+    OS_LIBS += [
+        "rt"
+    ]
+
+if CONFIG["OS_TARGET"] == "OpenBSD":
+
+    DEFINES["USE_GLIB"] = "1"
+    DEFINES["USE_OZONE"] = "1"
+    DEFINES["USE_X11"] = "1"
+    DEFINES["WEBRTC_BSD"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_FILE_OFFSET_BITS"] = "64"
+    DEFINES["_LARGEFILE64_SOURCE"] = True
+    DEFINES["_LARGEFILE_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+if CONFIG["OS_TARGET"] == "WINNT":
+
+    DEFINES["CERT_CHAIN_PARA_HAS_EXTRA_FIELDS"] = True
+    DEFINES["NOMINMAX"] = True
+    DEFINES["NTDDI_VERSION"] = "0x0A000000"
+    DEFINES["PSAPI_VERSION"] = "2"
+    DEFINES["UNICODE"] = True
+    DEFINES["USE_AURA"] = "1"
+    DEFINES["WEBRTC_WIN"] = True
+    DEFINES["WIN32"] = True
+    DEFINES["WIN32_LEAN_AND_MEAN"] = True
+    DEFINES["WINAPI_FAMILY"] = "WINAPI_FAMILY_DESKTOP_APP"
+    DEFINES["WINVER"] = "0x0A00"
+    DEFINES["_ATL_NO_OPENGL"] = True
+    DEFINES["_CRT_RAND_S"] = True
+    DEFINES["_CRT_SECURE_NO_DEPRECATE"] = True
+    DEFINES["_ENABLE_EXTENDED_ALIGNED_STORAGE"] = True
+    DEFINES["_HAS_EXCEPTIONS"] = "0"
+    DEFINES["_HAS_NODISCARD"] = True
+    DEFINES["_SCL_SECURE_NO_DEPRECATE"] = True
+    DEFINES["_SECURE_ATL"] = True
+    DEFINES["_UNICODE"] = True
+    DEFINES["_WIN32_WINNT"] = "0x0A00"
+    DEFINES["_WINDOWS"] = True
+    DEFINES["__STD_C"] = True
+
+    OS_LIBS += [
+        "crypt32",
+        "iphlpapi",
+        "secur32",
+        "winmm"
+    ]
+
+if CONFIG["CPU_ARCH"] == "aarch64":
+
+    DEFINES["WEBRTC_ARCH_ARM64"] = True
+    DEFINES["WEBRTC_HAS_NEON"] = True
+
+if CONFIG["CPU_ARCH"] == "arm":
+
+    CXXFLAGS += [
+        "-mfpu=neon"
+    ]
+
+    DEFINES["WEBRTC_ARCH_ARM"] = True
+    DEFINES["WEBRTC_ARCH_ARM_V7"] = True
+    DEFINES["WEBRTC_HAS_NEON"] = True
+
+if CONFIG["CPU_ARCH"] == "mips32":
+
+    DEFINES["MIPS32_LE"] = True
+    DEFINES["MIPS_FPU_LE"] = True
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "mips64":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86":
+
+    DEFINES["WEBRTC_ENABLE_AVX2"] = True
+
+if CONFIG["CPU_ARCH"] == "x86_64":
+
+    DEFINES["WEBRTC_ENABLE_AVX2"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Android":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Darwin":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "OpenBSD":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "WINNT":
+
+    DEFINES["_HAS_ITERATOR_DEBUGGING"] = "0"
+
+if CONFIG["MOZ_X11"] == "1" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["USE_X11"] = "1"
+
+if CONFIG["CPU_ARCH"] == "arm" and CONFIG["OS_TARGET"] == "Android":
+
+    OS_LIBS += [
+        "android_support",
+        "unwind"
+    ]
+
+if CONFIG["CPU_ARCH"] == "x86" and CONFIG["OS_TARGET"] == "Android":
+
+    CXXFLAGS += [
+        "-msse2"
+    ]
+
+    OS_LIBS += [
+        "android_support"
+    ]
+
+if CONFIG["CPU_ARCH"] == "aarch64" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "arm" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86" and CONFIG["OS_TARGET"] == "Linux":
+
+    CXXFLAGS += [
+        "-msse2"
+    ]
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86_64" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+Library("call_interfaces_gn")
diff --git a/third_party/libwebrtc/call/call_perf_tests.cc b/third_party/libwebrtc/call/call_perf_tests.cc
new file mode 100644
index 0000000000..a50f5ee605
--- /dev/null
+++ b/third_party/libwebrtc/call/call_perf_tests.cc
@@ -0,0 +1,1202 @@
+/*
+ *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include <algorithm>
+#include <limits>
+#include <memory>
+#include <string>
+
+#include "absl/strings/string_view.h"
+#include "api/audio_codecs/builtin_audio_encoder_factory.h"
+#include "api/numerics/samples_stats_counter.h"
+#include "api/rtc_event_log/rtc_event_log.h"
+#include "api/task_queue/pending_task_safety_flag.h"
+#include "api/task_queue/task_queue_base.h"
+#include "api/test/metrics/global_metrics_logger_and_exporter.h"
+#include "api/test/metrics/metric.h"
+#include "api/test/simulated_network.h"
+#include "api/video/builtin_video_bitrate_allocator_factory.h"
+#include "api/video/video_bitrate_allocation.h"
+#include "api/video_codecs/video_encoder.h"
+#include "call/call.h"
+#include "call/fake_network_pipe.h"
+#include "call/simulated_network.h"
+#include "media/engine/internal_encoder_factory.h"
+#include "media/engine/simulcast_encoder_adapter.h"
+#include "modules/audio_coding/include/audio_coding_module.h"
+#include "modules/audio_device/include/test_audio_device.h"
+#include "modules/audio_mixer/audio_mixer_impl.h"
+#include "modules/rtp_rtcp/source/rtp_packet.h"
+#include "rtc_base/checks.h"
+#include "rtc_base/synchronization/mutex.h"
+#include "rtc_base/task_queue_for_test.h"
+#include "rtc_base/thread.h"
+#include "rtc_base/thread_annotations.h"
+#include "system_wrappers/include/metrics.h"
+#include "test/call_test.h"
+#include "test/direct_transport.h"
+#include "test/drifting_clock.h"
+#include "test/encoder_settings.h"
+#include "test/fake_encoder.h"
+#include "test/field_trial.h"
+#include "test/frame_generator_capturer.h"
+#include "test/gtest.h"
+#include "test/null_transport.h"
+#include "test/rtp_rtcp_observer.h"
+#include "test/testsupport/file_utils.h"
+#include "test/video_encoder_proxy_factory.h"
+#include "video/config/video_encoder_config.h"
+#include "video/transport_adapter.h"
+
+using webrtc::test::DriftingClock;
+
+namespace webrtc {
+namespace {
+
+using ::webrtc::test::GetGlobalMetricsLogger;
+using ::webrtc::test::ImprovementDirection;
+using ::webrtc::test::Unit;
+
+enum : int {  // The first valid value is 1.
+  kTransportSequenceNumberExtensionId = 1,
+};
+
+}  // namespace
+
+class CallPerfTest : public test::CallTest {
+ public:
+  CallPerfTest() {
+    RegisterRtpExtension(RtpExtension(RtpExtension::kTransportSequenceNumberUri,
+                                      kTransportSequenceNumberExtensionId));
+  }
+
+ protected:
+  enum class FecMode { kOn, kOff };
+  enum class CreateOrder { kAudioFirst, kVideoFirst };
+  void TestAudioVideoSync(FecMode fec,
+                          CreateOrder create_first,
+                          float video_ntp_speed,
+                          float video_rtp_speed,
+                          float audio_rtp_speed,
+                          absl::string_view test_label);
+
+  void TestMinTransmitBitrate(bool pad_to_min_bitrate);
+
+  void TestCaptureNtpTime(const BuiltInNetworkBehaviorConfig& net_config,
+                          int threshold_ms,
+                          int start_time_ms,
+                          int run_time_ms);
+  void TestMinAudioVideoBitrate(int test_bitrate_from,
+                                int test_bitrate_to,
+                                int test_bitrate_step,
+                                int min_bwe,
+                                int start_bwe,
+                                int max_bwe);
+  void TestEncodeFramerate(VideoEncoderFactory* encoder_factory,
+                           absl::string_view payload_name,
+                           const std::vector<int>& max_framerates);
+};
+
+class VideoRtcpAndSyncObserver : public test::RtpRtcpObserver,
+                                 public rtc::VideoSinkInterface<VideoFrame> {
+  static const int kInSyncThresholdMs = 50;
+  static const int kStartupTimeMs = 2000;
+  static const int kMinRunTimeMs = 30000;
+
+ public:
+  explicit VideoRtcpAndSyncObserver(TaskQueueBase* task_queue,
+                                    Clock* clock,
+                                    absl::string_view test_label)
+      : test::RtpRtcpObserver(CallPerfTest::kLongTimeout),
+        clock_(clock),
+        test_label_(test_label),
+        creation_time_ms_(clock_->TimeInMilliseconds()),
+        task_queue_(task_queue) {}
+
+  void OnFrame(const VideoFrame& video_frame) override {
+    task_queue_->PostTask([this]() { CheckStats(); });
+  }
+
+  void CheckStats() {
+    if (!receive_stream_)
+      return;
+
+    VideoReceiveStreamInterface::Stats stats = receive_stream_->GetStats();
+    if (stats.sync_offset_ms == std::numeric_limits<int>::max())
+      return;
+
+    int64_t now_ms = clock_->TimeInMilliseconds();
+    int64_t time_since_creation = now_ms - creation_time_ms_;
+    // During the first couple of seconds audio and video can falsely be
+    // estimated as being synchronized. We don't want to trigger on those.
+    if (time_since_creation < kStartupTimeMs)
+      return;
+    if (std::abs(stats.sync_offset_ms) < kInSyncThresholdMs) {
+      if (first_time_in_sync_ == -1) {
+        first_time_in_sync_ = now_ms;
+        GetGlobalMetricsLogger()->LogSingleValueMetric(
+            "sync_convergence_time" + test_label_, "synchronization",
+            time_since_creation, Unit::kMilliseconds,
+            ImprovementDirection::kSmallerIsBetter);
+      }
+      if (time_since_creation > kMinRunTimeMs)
+        observation_complete_.Set();
+    }
+    if (first_time_in_sync_ != -1)
+      sync_offset_ms_list_.AddSample(stats.sync_offset_ms);
+  }
+
+  void set_receive_stream(VideoReceiveStreamInterface* receive_stream) {
+    RTC_DCHECK_EQ(task_queue_, TaskQueueBase::Current());
+    // Note that receive_stream may be nullptr.
+    receive_stream_ = receive_stream;
+  }
+
+  void PrintResults() {
+    GetGlobalMetricsLogger()->LogMetric(
+        "stream_offset" + test_label_, "synchronization", sync_offset_ms_list_,
+        Unit::kMilliseconds, ImprovementDirection::kNeitherIsBetter);
+  }
+
+ private:
+  Clock* const clock_;
+  const std::string test_label_;
+  const int64_t creation_time_ms_;
+  int64_t first_time_in_sync_ = -1;
+  VideoReceiveStreamInterface* receive_stream_ = nullptr;
+  SamplesStatsCounter sync_offset_ms_list_;
+  TaskQueueBase* const task_queue_;
+};
+
+void CallPerfTest::TestAudioVideoSync(FecMode fec,
+                                      CreateOrder create_first,
+                                      float video_ntp_speed,
+                                      float video_rtp_speed,
+                                      float audio_rtp_speed,
+                                      absl::string_view test_label) {
+  const char* kSyncGroup = "av_sync";
+  const uint32_t kAudioSendSsrc = 1234;
+  const uint32_t kAudioRecvSsrc = 5678;
+
+  BuiltInNetworkBehaviorConfig audio_net_config;
+  audio_net_config.queue_delay_ms = 500;
+  audio_net_config.loss_percent = 5;
+
+  auto observer = std::make_unique<VideoRtcpAndSyncObserver>(
+      task_queue(), Clock::GetRealTimeClock(), test_label);
+
+  std::map<uint8_t, MediaType> audio_pt_map;
+  std::map<uint8_t, MediaType> video_pt_map;
+
+  std::unique_ptr<test::PacketTransport> audio_send_transport;
+  std::unique_ptr<test::PacketTransport> video_send_transport;
+  std::unique_ptr<test::PacketTransport> receive_transport;
+
+  AudioSendStream* audio_send_stream;
+  AudioReceiveStreamInterface* audio_receive_stream;
+  std::unique_ptr<DriftingClock> drifting_clock;
+
+  SendTask(task_queue(), [&]() {
+    metrics::Reset();
+    rtc::scoped_refptr<TestAudioDeviceModule> fake_audio_device =
+        TestAudioDeviceModule::Create(
+            task_queue_factory_.get(),
+            TestAudioDeviceModule::CreatePulsedNoiseCapturer(256, 48000),
+            TestAudioDeviceModule::CreateDiscardRenderer(48000),
+            audio_rtp_speed);
+    EXPECT_EQ(0, fake_audio_device->Init());
+
+    AudioState::Config send_audio_state_config;
+    send_audio_state_config.audio_mixer = AudioMixerImpl::Create();
+    send_audio_state_config.audio_processing =
+        AudioProcessingBuilder().Create();
+    send_audio_state_config.audio_device_module = fake_audio_device;
+    Call::Config sender_config(send_event_log_.get());
+
+    auto audio_state = AudioState::Create(send_audio_state_config);
+    fake_audio_device->RegisterAudioCallback(audio_state->audio_transport());
+    sender_config.audio_state = audio_state;
+    Call::Config receiver_config(recv_event_log_.get());
+    receiver_config.audio_state = audio_state;
+    CreateCalls(sender_config, receiver_config);
+
+    std::copy_if(std::begin(payload_type_map_), std::end(payload_type_map_),
+                 std::inserter(audio_pt_map, audio_pt_map.end()),
+                 [](const std::pair<const uint8_t, MediaType>& pair) {
+                   return pair.second == MediaType::AUDIO;
+                 });
+    std::copy_if(std::begin(payload_type_map_), std::end(payload_type_map_),
+                 std::inserter(video_pt_map, video_pt_map.end()),
+                 [](const std::pair<const uint8_t, MediaType>& pair) {
+                   return pair.second == MediaType::VIDEO;
+                 });
+
+    audio_send_transport = std::make_unique<test::PacketTransport>(
+        task_queue(), sender_call_.get(), observer.get(),
+        test::PacketTransport::kSender, audio_pt_map,
+        std::make_unique<FakeNetworkPipe>(
+            Clock::GetRealTimeClock(),
+            std::make_unique<SimulatedNetwork>(audio_net_config)),
+        GetRegisteredExtensions(), GetRegisteredExtensions());
+    audio_send_transport->SetReceiver(receiver_call_->Receiver());
+
+    video_send_transport = std::make_unique<test::PacketTransport>(
+        task_queue(), sender_call_.get(), observer.get(),
+        test::PacketTransport::kSender, video_pt_map,
+        std::make_unique<FakeNetworkPipe>(
+            Clock::GetRealTimeClock(),
+            std::make_unique<SimulatedNetwork>(BuiltInNetworkBehaviorConfig())),
+        GetRegisteredExtensions(), GetRegisteredExtensions());
+    video_send_transport->SetReceiver(receiver_call_->Receiver());
+
+    receive_transport = std::make_unique<test::PacketTransport>(
+        task_queue(), receiver_call_.get(), observer.get(),
+        test::PacketTransport::kReceiver, payload_type_map_,
+        std::make_unique<FakeNetworkPipe>(
+            Clock::GetRealTimeClock(),
+            std::make_unique<SimulatedNetwork>(BuiltInNetworkBehaviorConfig())),
+        GetRegisteredExtensions(), GetRegisteredExtensions());
+    receive_transport->SetReceiver(sender_call_->Receiver());
+
+    CreateSendConfig(1, 0, 0, video_send_transport.get());
+    CreateMatchingReceiveConfigs(receive_transport.get());
+
+    AudioSendStream::Config audio_send_config(audio_send_transport.get());
+    audio_send_config.rtp.ssrc = kAudioSendSsrc;
+    // TODO(bugs.webrtc.org/14683): Let the tests fail with invalid config.
+    audio_send_config.send_codec_spec = AudioSendStream::Config::SendCodecSpec(
+        kAudioSendPayloadType, {"OPUS", 48000, 2});
+    audio_send_config.min_bitrate_bps = 6000;
+    audio_send_config.max_bitrate_bps = 510000;
+    audio_send_config.encoder_factory = CreateBuiltinAudioEncoderFactory();
+    audio_send_stream = sender_call_->CreateAudioSendStream(audio_send_config);
+
+    GetVideoSendConfig()->rtp.nack.rtp_history_ms = kNackRtpHistoryMs;
+    if (fec == FecMode::kOn) {
+      GetVideoSendConfig()->rtp.ulpfec.red_payload_type = kRedPayloadType;
+      GetVideoSendConfig()->rtp.ulpfec.ulpfec_payload_type = kUlpfecPayloadType;
+      video_receive_configs_[0].rtp.red_payload_type = kRedPayloadType;
+      video_receive_configs_[0].rtp.ulpfec_payload_type = kUlpfecPayloadType;
+    }
+    video_receive_configs_[0].rtp.nack.rtp_history_ms = 1000;
+    video_receive_configs_[0].renderer = observer.get();
+    video_receive_configs_[0].sync_group = kSyncGroup;
+
+    AudioReceiveStreamInterface::Config audio_recv_config;
+    audio_recv_config.rtp.remote_ssrc = kAudioSendSsrc;
+    audio_recv_config.rtp.local_ssrc = kAudioRecvSsrc;
+    audio_recv_config.rtcp_send_transport = receive_transport.get();
+    audio_recv_config.sync_group = kSyncGroup;
+    audio_recv_config.decoder_factory = audio_decoder_factory_;
+    audio_recv_config.decoder_map = {
+        {kAudioSendPayloadType, {"OPUS", 48000, 2}}};
+
+    if (create_first == CreateOrder::kAudioFirst) {
+      audio_receive_stream =
+          receiver_call_->CreateAudioReceiveStream(audio_recv_config);
+      CreateVideoStreams();
+    } else {
+      CreateVideoStreams();
+      audio_receive_stream =
+          receiver_call_->CreateAudioReceiveStream(audio_recv_config);
+    }
+    EXPECT_EQ(1u, video_receive_streams_.size());
+    observer->set_receive_stream(video_receive_streams_[0]);
+    drifting_clock = std::make_unique<DriftingClock>(clock_, video_ntp_speed);
+    CreateFrameGeneratorCapturerWithDrift(drifting_clock.get(), video_rtp_speed,
+                                          kDefaultFramerate, kDefaultWidth,
+                                          kDefaultHeight);
+
+    Start();
+
+    audio_send_stream->Start();
+    audio_receive_stream->Start();
+  });
+
+  EXPECT_TRUE(observer->Wait())
+      << "Timed out while waiting for audio and video to be synchronized.";
+
+  SendTask(task_queue(), [&]() {
+    // Clear the pointer to the receive stream since it will now be deleted.
+    observer->set_receive_stream(nullptr);
+
+    audio_send_stream->Stop();
+    audio_receive_stream->Stop();
+
+    Stop();
+
+    DestroyStreams();
+
+    sender_call_->DestroyAudioSendStream(audio_send_stream);
+    receiver_call_->DestroyAudioReceiveStream(audio_receive_stream);
+
+    DestroyCalls();
+    // Call may post periodic rtcp packet to the transport on the process
+    // thread, thus transport should be destroyed after the call objects.
+    // Though transports keep pointers to the call objects, transports handle
+    // packets on the task_queue() and thus wouldn't create a race while current
+    // destruction happens in the same task as destruction of the call objects.
+    video_send_transport.reset();
+    audio_send_transport.reset();
+    receive_transport.reset();
+  });
+
+  observer->PrintResults();
+
+  // In quick test synchronization may not be achieved in time.
+  if (!field_trial::IsEnabled("WebRTC-QuickPerfTest")) {
+// TODO(bugs.webrtc.org/10417): Reenable this for iOS
+#if !defined(WEBRTC_IOS)
+    EXPECT_METRIC_EQ(1, metrics::NumSamples("WebRTC.Video.AVSyncOffsetInMs"));
+#endif
+  }
+
+  task_queue()->PostTask(
+      [to_delete = observer.release()]() { delete to_delete; });
+}
+
+TEST_F(CallPerfTest, Synchronization_PlaysOutAudioAndVideoWithoutClockDrift) {
+  TestAudioVideoSync(FecMode::kOff, CreateOrder::kAudioFirst,
+                     DriftingClock::kNoDrift, DriftingClock::kNoDrift,
+                     DriftingClock::kNoDrift, "_video_no_drift");
+}
+
+TEST_F(CallPerfTest, Synchronization_PlaysOutAudioAndVideoWithVideoNtpDrift) {
+  TestAudioVideoSync(FecMode::kOff, CreateOrder::kAudioFirst,
+                     DriftingClock::PercentsFaster(10.0f),
+                     DriftingClock::kNoDrift, DriftingClock::kNoDrift,
+                     "_video_ntp_drift");
+}
+
+TEST_F(CallPerfTest,
+       Synchronization_PlaysOutAudioAndVideoWithAudioFasterThanVideoDrift) {
+  TestAudioVideoSync(FecMode::kOff, CreateOrder::kAudioFirst,
+                     DriftingClock::kNoDrift,
+                     DriftingClock::PercentsSlower(30.0f),
+                     DriftingClock::PercentsFaster(30.0f), "_audio_faster");
+}
+
+TEST_F(CallPerfTest,
+       Synchronization_PlaysOutAudioAndVideoWithVideoFasterThanAudioDrift) {
+  TestAudioVideoSync(FecMode::kOn, CreateOrder::kVideoFirst,
+                     DriftingClock::kNoDrift,
+                     DriftingClock::PercentsFaster(30.0f),
+                     DriftingClock::PercentsSlower(30.0f), "_video_faster");
+}
+
+void CallPerfTest::TestCaptureNtpTime(
+    const BuiltInNetworkBehaviorConfig& net_config,
+    int threshold_ms,
+    int start_time_ms,
+    int run_time_ms) {
+  class CaptureNtpTimeObserver : public test::EndToEndTest,
+                                 public rtc::VideoSinkInterface<VideoFrame> {
+   public:
+    CaptureNtpTimeObserver(const BuiltInNetworkBehaviorConfig& net_config,
+                           int threshold_ms,
+                           int start_time_ms,
+                           int run_time_ms)
+        : EndToEndTest(kLongTimeout),
+          net_config_(net_config),
+          clock_(Clock::GetRealTimeClock()),
+          threshold_ms_(threshold_ms),
+          start_time_ms_(start_time_ms),
+          run_time_ms_(run_time_ms),
+          creation_time_ms_(clock_->TimeInMilliseconds()),
+          capturer_(nullptr),
+          rtp_start_timestamp_set_(false),
+          rtp_start_timestamp_(0) {}
+
+   private:
+    BuiltInNetworkBehaviorConfig GetSendTransportConfig() const override {
+      return net_config_;
+    }
+
+    BuiltInNetworkBehaviorConfig GetReceiveTransportConfig() const override {
+      return net_config_;
+    }
+
+    void OnFrame(const VideoFrame& video_frame) override {
+      MutexLock lock(&mutex_);
+      if (video_frame.ntp_time_ms() <= 0) {
+        // Haven't got enough RTCP SR in order to calculate the capture ntp
+        // time.
+        return;
+      }
+
+      int64_t now_ms = clock_->TimeInMilliseconds();
+      int64_t time_since_creation = now_ms - creation_time_ms_;
+      if (time_since_creation < start_time_ms_) {
+        // Wait for `start_time_ms_` before start measuring.
+        return;
+      }
+
+      if (time_since_creation > run_time_ms_) {
+        observation_complete_.Set();
+      }
+
+      FrameCaptureTimeList::iterator iter =
+          capture_time_list_.find(video_frame.timestamp());
+      EXPECT_TRUE(iter != capture_time_list_.end());
+
+      // The real capture time has been wrapped to uint32_t before converted
+      // to rtp timestamp in the sender side. So here we convert the estimated
+      // capture time to a uint32_t 90k timestamp also for comparing.
+      uint32_t estimated_capture_timestamp =
+          90 * static_cast<uint32_t>(video_frame.ntp_time_ms());
+      uint32_t real_capture_timestamp = iter->second;
+      int time_offset_ms = real_capture_timestamp - estimated_capture_timestamp;
+      time_offset_ms = time_offset_ms / 90;
+      time_offset_ms_list_.AddSample(time_offset_ms);
+
+      EXPECT_TRUE(std::abs(time_offset_ms) < threshold_ms_);
+    }
+
+    Action OnSendRtp(const uint8_t* packet, size_t length) override {
+      MutexLock lock(&mutex_);
+      RtpPacket rtp_packet;
+      EXPECT_TRUE(rtp_packet.Parse(packet, length));
+
+      if (!rtp_start_timestamp_set_) {
+        // Calculate the rtp timestamp offset in order to calculate the real
+        // capture time.
+        uint32_t first_capture_timestamp =
+            90 * static_cast<uint32_t>(capturer_->first_frame_capture_time());
+        rtp_start_timestamp_ = rtp_packet.Timestamp() - first_capture_timestamp;
+        rtp_start_timestamp_set_ = true;
+      }
+
+      uint32_t capture_timestamp =
+          rtp_packet.Timestamp() - rtp_start_timestamp_;
+      capture_time_list_.insert(
+          capture_time_list_.end(),
+          std::make_pair(rtp_packet.Timestamp(), capture_timestamp));
+      return SEND_PACKET;
+    }
+
+    void OnFrameGeneratorCapturerCreated(
+        test::FrameGeneratorCapturer* frame_generator_capturer) override {
+      capturer_ = frame_generator_capturer;
+    }
+
+    void ModifyVideoConfigs(
+        VideoSendStream::Config* send_config,
+        std::vector<VideoReceiveStreamInterface::Config>* receive_configs,
+        VideoEncoderConfig* encoder_config) override {
+      (*receive_configs)[0].renderer = this;
+      // Enable the receiver side rtt calculation.
+      (*receive_configs)[0].rtp.rtcp_xr.receiver_reference_time_report = true;
+    }
+
+    void PerformTest() override {
+      EXPECT_TRUE(Wait()) << "Timed out while waiting for estimated capture "
+                             "NTP time to be within bounds.";
+      GetGlobalMetricsLogger()->LogMetric(
+          "capture_ntp_time", "real - estimated", time_offset_ms_list_,
+          Unit::kMilliseconds, ImprovementDirection::kNeitherIsBetter);
+    }
+
+    Mutex mutex_;
+    const BuiltInNetworkBehaviorConfig net_config_;
+    Clock* const clock_;
+    const int threshold_ms_;
+    const int start_time_ms_;
+    const int run_time_ms_;
+    const int64_t creation_time_ms_;
+    test::FrameGeneratorCapturer* capturer_;
+    bool rtp_start_timestamp_set_;
+    uint32_t rtp_start_timestamp_;
+    typedef std::map<uint32_t, uint32_t> FrameCaptureTimeList;
+    FrameCaptureTimeList capture_time_list_ RTC_GUARDED_BY(&mutex_);
+    SamplesStatsCounter time_offset_ms_list_;
+  } test(net_config, threshold_ms, start_time_ms, run_time_ms);
+
+  RunBaseTest(&test);
+}
+
+// Flaky tests, disabled on Mac and Windows due to webrtc:8291.
+#if !(defined(WEBRTC_MAC) || defined(WEBRTC_WIN))
+TEST_F(CallPerfTest, Real_Estimated_CaptureNtpTimeWithNetworkDelay) {
+  BuiltInNetworkBehaviorConfig net_config;
+  net_config.queue_delay_ms = 100;
+  // TODO(wu): lower the threshold as the calculation/estimation becomes more
+  // accurate.
+  const int kThresholdMs = 100;
+  const int kStartTimeMs = 10000;
+  const int kRunTimeMs = 20000;
+  TestCaptureNtpTime(net_config, kThresholdMs, kStartTimeMs, kRunTimeMs);
+}
+
+TEST_F(CallPerfTest, Real_Estimated_CaptureNtpTimeWithNetworkJitter) {
+  BuiltInNetworkBehaviorConfig net_config;
+  net_config.queue_delay_ms = 100;
+  net_config.delay_standard_deviation_ms = 10;
+  // TODO(wu): lower the threshold as the calculation/estimation becomes more
+  // accurate.
+  const int kThresholdMs = 100;
+  const int kStartTimeMs = 10000;
+  const int kRunTimeMs = 20000;
+  TestCaptureNtpTime(net_config, kThresholdMs, kStartTimeMs, kRunTimeMs);
+}
+#endif
+
+TEST_F(CallPerfTest, ReceivesCpuOveruseAndUnderuse) {
+  // Minimal normal usage at the start, then 30s overuse to allow filter to
+  // settle, and then 80s underuse to allow plenty of time for rampup again.
+  test::ScopedFieldTrials fake_overuse_settings(
+      "WebRTC-ForceSimulatedOveruseIntervalMs/1-30000-80000/");
+
+  class LoadObserver : public test::SendTest,
+                       public test::FrameGeneratorCapturer::SinkWantsObserver {
+   public:
+    LoadObserver() : SendTest(kLongTimeout), test_phase_(TestPhase::kInit) {}
+
+    void OnFrameGeneratorCapturerCreated(
+        test::FrameGeneratorCapturer* frame_generator_capturer) override {
+      frame_generator_capturer->SetSinkWantsObserver(this);
+      // Set a high initial resolution to be sure that we can scale down.
+      frame_generator_capturer->ChangeResolution(1920, 1080);
+    }
+
+    // OnSinkWantsChanged is called when FrameGeneratorCapturer::AddOrUpdateSink
+    // is called.
+    // TODO(sprang): Add integration test for maintain-framerate mode?
+    void OnSinkWantsChanged(rtc::VideoSinkInterface<VideoFrame>* sink,
+                            const rtc::VideoSinkWants& wants) override {
+      // The sink wants can change either because an adaptation happened (i.e.
+      // the pixels or frame rate changed) or for other reasons, such as encoded
+      // resolutions being communicated (happens whenever we capture a new frame
+      // size). In this test, we only care about adaptations.
+      bool did_adapt =
+          last_wants_.max_pixel_count != wants.max_pixel_count ||
+          last_wants_.target_pixel_count != wants.target_pixel_count ||
+          last_wants_.max_framerate_fps != wants.max_framerate_fps;
+      last_wants_ = wants;
+      if (!did_adapt) {
+        return;
+      }
+      // At kStart expect CPU overuse. Then expect CPU underuse when the encoder
+      // delay has been decreased.
+      switch (test_phase_) {
+        case TestPhase::kInit:
+          // Max framerate should be set initially.
+          if (wants.max_framerate_fps != std::numeric_limits<int>::max() &&
+              wants.max_pixel_count == std::numeric_limits<int>::max()) {
+            test_phase_ = TestPhase::kStart;
+          } else {
+            ADD_FAILURE() << "Got unexpected adaptation request, max res = "
+                          << wants.max_pixel_count << ", target res = "
+                          << wants.target_pixel_count.value_or(-1)
+                          << ", max fps = " << wants.max_framerate_fps;
+          }
+          break;
+        case TestPhase::kStart:
+          if (wants.max_pixel_count < std::numeric_limits<int>::max()) {
+            // On adapting down, VideoStreamEncoder::VideoSourceProxy will set
+            // only the max pixel count, leaving the target unset.
+            test_phase_ = TestPhase::kAdaptedDown;
+          } else {
+            ADD_FAILURE() << "Got unexpected adaptation request, max res = "
+                          << wants.max_pixel_count << ", target res = "
+                          << wants.target_pixel_count.value_or(-1)
+                          << ", max fps = " << wants.max_framerate_fps;
+          }
+          break;
+        case TestPhase::kAdaptedDown:
+          // On adapting up, the adaptation counter will again be at zero, and
+          // so all constraints will be reset.
+          if (wants.max_pixel_count == std::numeric_limits<int>::max() &&
+              !wants.target_pixel_count) {
+            test_phase_ = TestPhase::kAdaptedUp;
+            observation_complete_.Set();
+          } else {
+            ADD_FAILURE() << "Got unexpected adaptation request, max res = "
+                          << wants.max_pixel_count << ", target res = "
+                          << wants.target_pixel_count.value_or(-1)
+                          << ", max fps = " << wants.max_framerate_fps;
+          }
+          break;
+        case TestPhase::kAdaptedUp:
+          ADD_FAILURE() << "Got unexpected adaptation request, max res = "
+                        << wants.max_pixel_count << ", target res = "
+                        << wants.target_pixel_count.value_or(-1)
+                        << ", max fps = " << wants.max_framerate_fps;
+      }
+    }
+
+    void ModifyVideoConfigs(
+        VideoSendStream::Config* send_config,
+        std::vector<VideoReceiveStreamInterface::Config>* receive_configs,
+        VideoEncoderConfig* encoder_config) override {}
+
+    void PerformTest() override {
+      EXPECT_TRUE(Wait()) << "Timed out before receiving an overuse callback.";
+    }
+
+    enum class TestPhase {
+      kInit,
+      kStart,
+      kAdaptedDown,
+      kAdaptedUp
+    } test_phase_;
+
+   private:
+    rtc::VideoSinkWants last_wants_;
+  } test;
+
+  RunBaseTest(&test);
+}
+
+void CallPerfTest::TestMinTransmitBitrate(bool pad_to_min_bitrate) {
+  static const int kMaxEncodeBitrateKbps = 30;
+  static const int kMinTransmitBitrateBps = 150000;
+  static const int kMinAcceptableTransmitBitrate = 130;
+  static const int kMaxAcceptableTransmitBitrate = 170;
+  static const int kNumBitrateObservationsInRange = 100;
+  static const int kAcceptableBitrateErrorMargin = 15;  // +- 7
+  class BitrateObserver : public test::EndToEndTest {
+   public:
+    explicit BitrateObserver(bool using_min_transmit_bitrate,
+                             TaskQueueBase* task_queue)
+        : EndToEndTest(kLongTimeout),
+          send_stream_(nullptr),
+          converged_(false),
+          pad_to_min_bitrate_(using_min_transmit_bitrate),
+          min_acceptable_bitrate_(using_min_transmit_bitrate
+                                      ? kMinAcceptableTransmitBitrate
+                                      : (kMaxEncodeBitrateKbps -
+                                         kAcceptableBitrateErrorMargin / 2)),
+          max_acceptable_bitrate_(using_min_transmit_bitrate
+                                      ? kMaxAcceptableTransmitBitrate
+                                      : (kMaxEncodeBitrateKbps +
+                                         kAcceptableBitrateErrorMargin / 2)),
+          num_bitrate_observations_in_range_(0),
+          task_queue_(task_queue),
+          task_safety_flag_(PendingTaskSafetyFlag::CreateDetached()) {}
+
+   private:
+    // TODO(holmer): Run this with a timer instead of once per packet.
+    Action OnSendRtp(const uint8_t* packet, size_t length) override {
+      task_queue_->PostTask(SafeTask(task_safety_flag_, [this]() {
+        VideoSendStream::Stats stats = send_stream_->GetStats();
+
+        if (!stats.substreams.empty()) {
+          RTC_DCHECK_EQ(1, stats.substreams.size());
+          int bitrate_kbps =
+              stats.substreams.begin()->second.total_bitrate_bps / 1000;
+          if (bitrate_kbps > min_acceptable_bitrate_ &&
+              bitrate_kbps < max_acceptable_bitrate_) {
+            converged_ = true;
+            ++num_bitrate_observations_in_range_;
+            if (num_bitrate_observations_in_range_ ==
+                kNumBitrateObservationsInRange)
+              observation_complete_.Set();
+          }
+          if (converged_)
+            bitrate_kbps_list_.AddSample(bitrate_kbps);
+        }
+      }));
+      return SEND_PACKET;
+    }
+
+    void OnVideoStreamsCreated(VideoSendStream* send_stream,
+                               const std::vector<VideoReceiveStreamInterface*>&
+                                   receive_streams) override {
+      send_stream_ = send_stream;
+    }
+
+    void OnStreamsStopped() override { task_safety_flag_->SetNotAlive(); }
+
+    void ModifyVideoConfigs(
+        VideoSendStream::Config* send_config,
+        std::vector<VideoReceiveStreamInterface::Config>* receive_configs,
+        VideoEncoderConfig* encoder_config) override {
+      if (pad_to_min_bitrate_) {
+        encoder_config->min_transmit_bitrate_bps = kMinTransmitBitrateBps;
+      } else {
+        RTC_DCHECK_EQ(0, encoder_config->min_transmit_bitrate_bps);
+      }
+    }
+
+    void PerformTest() override {
+      EXPECT_TRUE(Wait()) << "Timeout while waiting for send-bitrate stats.";
+      GetGlobalMetricsLogger()->LogMetric(
+          std::string("bitrate_stats_") +
+              (pad_to_min_bitrate_ ? "min_transmit_bitrate"
+                                   : "without_min_transmit_bitrate"),
+          "bitrate_kbps", bitrate_kbps_list_, Unit::kUnitless,
+          ImprovementDirection::kNeitherIsBetter);
+    }
+
+    VideoSendStream* send_stream_;
+    bool converged_;
+    const bool pad_to_min_bitrate_;
+    const int min_acceptable_bitrate_;
+    const int max_acceptable_bitrate_;
+    int num_bitrate_observations_in_range_;
+    SamplesStatsCounter bitrate_kbps_list_;
+    TaskQueueBase* task_queue_;
+    rtc::scoped_refptr<PendingTaskSafetyFlag> task_safety_flag_;
+  } test(pad_to_min_bitrate, task_queue());
+
+  fake_encoder_max_bitrate_ = kMaxEncodeBitrateKbps;
+  RunBaseTest(&test);
+}
+
+TEST_F(CallPerfTest, Bitrate_Kbps_PadsToMinTransmitBitrate) {
+  TestMinTransmitBitrate(true);
+}
+
+TEST_F(CallPerfTest, Bitrate_Kbps_NoPadWithoutMinTransmitBitrate) {
+  TestMinTransmitBitrate(false);
+}
+
+// TODO(bugs.webrtc.org/8878)
+#if defined(WEBRTC_MAC)
+#define MAYBE_KeepsHighBitrateWhenReconfiguringSender \
+  DISABLED_KeepsHighBitrateWhenReconfiguringSender
+#else
+#define MAYBE_KeepsHighBitrateWhenReconfiguringSender \
+  KeepsHighBitrateWhenReconfiguringSender
+#endif
+TEST_F(CallPerfTest, MAYBE_KeepsHighBitrateWhenReconfiguringSender) {
+  static const uint32_t kInitialBitrateKbps = 400;
+  static const uint32_t kInitialBitrateOverheadKpbs = 6;
+  static const uint32_t kReconfigureThresholdKbps = 600;
+
+  class VideoStreamFactory
+      : public VideoEncoderConfig::VideoStreamFactoryInterface {
+   public:
+    VideoStreamFactory() {}
+
+   private:
+    std::vector<VideoStream> CreateEncoderStreams(
+        int frame_width,
+        int frame_height,
+        const webrtc::VideoEncoderConfig& encoder_config) override {
+      std::vector<VideoStream> streams =
+          test::CreateVideoStreams(frame_width, frame_height, encoder_config);
+      streams[0].min_bitrate_bps = 50000;
+      streams[0].target_bitrate_bps = streams[0].max_bitrate_bps = 2000000;
+      return streams;
+    }
+  };
+
+  class BitrateObserver : public test::EndToEndTest, public test::FakeEncoder {
+   public:
+    explicit BitrateObserver(TaskQueueBase* task_queue)
+        : EndToEndTest(kDefaultTimeout),
+          FakeEncoder(Clock::GetRealTimeClock()),
+          encoder_inits_(0),
+          last_set_bitrate_kbps_(0),
+          send_stream_(nullptr),
+          frame_generator_(nullptr),
+          encoder_factory_(this),
+          bitrate_allocator_factory_(
+              CreateBuiltinVideoBitrateAllocatorFactory()),
+          task_queue_(task_queue) {}
+
+    int32_t InitEncode(const VideoCodec* config,
+                       const VideoEncoder::Settings& settings) override {
+      ++encoder_inits_;
+      if (encoder_inits_ == 1) {
+        // First time initialization. Frame size is known.
+        // `expected_bitrate` is affected by bandwidth estimation before the
+        // first frame arrives to the encoder.
+        uint32_t expected_bitrate =
+            last_set_bitrate_kbps_ > 0
+                ? last_set_bitrate_kbps_
+                : kInitialBitrateKbps - kInitialBitrateOverheadKpbs;
+        EXPECT_EQ(expected_bitrate, config->startBitrate)
+            << "Encoder not initialized at expected bitrate.";
+        EXPECT_EQ(kDefaultWidth, config->width);
+        EXPECT_EQ(kDefaultHeight, config->height);
+      } else if (encoder_inits_ == 2) {
+        EXPECT_EQ(2 * kDefaultWidth, config->width);
+        EXPECT_EQ(2 * kDefaultHeight, config->height);
+        EXPECT_GE(last_set_bitrate_kbps_, kReconfigureThresholdKbps);
+        EXPECT_GT(config->startBitrate, kReconfigureThresholdKbps)
+            << "Encoder reconfigured with bitrate too far away from last set.";
+        observation_complete_.Set();
+      }
+      return FakeEncoder::InitEncode(config, settings);
+    }
+
+    void SetRates(const RateControlParameters& parameters) override {
+      last_set_bitrate_kbps_ = parameters.bitrate.get_sum_kbps();
+      if (encoder_inits_ == 1 &&
+          parameters.bitrate.get_sum_kbps() > kReconfigureThresholdKbps) {
+        time_to_reconfigure_.Set();
+      }
+      FakeEncoder::SetRates(parameters);
+    }
+
+    void ModifySenderBitrateConfig(
+        BitrateConstraints* bitrate_config) override {
+      bitrate_config->start_bitrate_bps = kInitialBitrateKbps * 1000;
+    }
+
+    void ModifyVideoConfigs(
+        VideoSendStream::Config* send_config,
+        std::vector<VideoReceiveStreamInterface::Config>* receive_configs,
+        VideoEncoderConfig* encoder_config) override {
+      send_config->encoder_settings.encoder_factory = &encoder_factory_;
+      send_config->encoder_settings.bitrate_allocator_factory =
+          bitrate_allocator_factory_.get();
+      encoder_config->max_bitrate_bps = 2 * kReconfigureThresholdKbps * 1000;
+      encoder_config->video_stream_factory =
+          rtc::make_ref_counted<VideoStreamFactory>();
+
+      encoder_config_ = encoder_config->Copy();
+    }
+
+    void OnVideoStreamsCreated(VideoSendStream* send_stream,
+                               const std::vector<VideoReceiveStreamInterface*>&
+                                   receive_streams) override {
+      send_stream_ = send_stream;
+    }
+
+    void OnFrameGeneratorCapturerCreated(
+        test::FrameGeneratorCapturer* frame_generator_capturer) override {
+      frame_generator_ = frame_generator_capturer;
+    }
+
+    void PerformTest() override {
+      ASSERT_TRUE(time_to_reconfigure_.Wait(kDefaultTimeout))
+          << "Timed out before receiving an initial high bitrate.";
+      frame_generator_->ChangeResolution(kDefaultWidth * 2, kDefaultHeight * 2);
+      SendTask(task_queue_, [&]() {
+        send_stream_->ReconfigureVideoEncoder(encoder_config_.Copy());
+      });
+      EXPECT_TRUE(Wait())
+          << "Timed out while waiting for a couple of high bitrate estimates "
+             "after reconfiguring the send stream.";
+    }
+
+   private:
+    rtc::Event time_to_reconfigure_;
+    int encoder_inits_;
+    uint32_t last_set_bitrate_kbps_;
+    VideoSendStream* send_stream_;
+    test::FrameGeneratorCapturer* frame_generator_;
+    test::VideoEncoderProxyFactory encoder_factory_;
+    std::unique_ptr<VideoBitrateAllocatorFactory> bitrate_allocator_factory_;
+    VideoEncoderConfig encoder_config_;
+    TaskQueueBase* task_queue_;
+  } test(task_queue());
+
+  RunBaseTest(&test);
+}
+
+// Discovers the minimal supported audio+video bitrate. The test bitrate is
+// considered supported if Rtt does not go above 400ms with the network
+// contrained to the test bitrate.
+//
+// |test_bitrate_from test_bitrate_to| bitrate constraint range
+// `test_bitrate_step` bitrate constraint update step during the test
+// |min_bwe max_bwe| BWE range
+// `start_bwe` initial BWE
+void CallPerfTest::TestMinAudioVideoBitrate(int test_bitrate_from,
+                                            int test_bitrate_to,
+                                            int test_bitrate_step,
+                                            int min_bwe,
+                                            int start_bwe,
+                                            int max_bwe) {
+  static const std::string kAudioTrackId = "audio_track_0";
+  static constexpr int kOpusBitrateFbBps = 32000;
+  static constexpr int kBitrateStabilizationMs = 10000;
+  static constexpr int kBitrateMeasurements = 10;
+  static constexpr int kBitrateMeasurementMs = 1000;
+  static constexpr int kShortDelayMs = 10;
+  static constexpr int kMinGoodRttMs = 400;
+
+  class MinVideoAndAudioBitrateTester : public test::EndToEndTest {
+   public:
+    MinVideoAndAudioBitrateTester(int test_bitrate_from,
+                                  int test_bitrate_to,
+                                  int test_bitrate_step,
+                                  int min_bwe,
+                                  int start_bwe,
+                                  int max_bwe,
+                                  TaskQueueBase* task_queue)
+        : EndToEndTest(),
+          test_bitrate_from_(test_bitrate_from),
+          test_bitrate_to_(test_bitrate_to),
+          test_bitrate_step_(test_bitrate_step),
+          min_bwe_(min_bwe),
+          start_bwe_(start_bwe),
+          max_bwe_(max_bwe),
+          task_queue_(task_queue) {}
+
+   protected:
+    BuiltInNetworkBehaviorConfig GetFakeNetworkPipeConfig() const {
+      BuiltInNetworkBehaviorConfig pipe_config;
+      pipe_config.link_capacity_kbps = test_bitrate_from_;
+      return pipe_config;
+    }
+
+    BuiltInNetworkBehaviorConfig GetSendTransportConfig() const override {
+      return GetFakeNetworkPipeConfig();
+    }
+    BuiltInNetworkBehaviorConfig GetReceiveTransportConfig() const override {
+      return GetFakeNetworkPipeConfig();
+    }
+
+    void OnTransportCreated(
+        test::PacketTransport* to_receiver,
+        SimulatedNetworkInterface* sender_network,
+        test::PacketTransport* to_sender,
+        SimulatedNetworkInterface* receiver_network) override {
+      send_simulated_network_ = sender_network;
+      receive_simulated_network_ = receiver_network;
+    }
+
+    void PerformTest() override {
+      // Quick test mode, just to exercise all the code paths without actually
+      // caring about performance measurements.
+      const bool quick_perf_test =
+          field_trial::IsEnabled("WebRTC-QuickPerfTest");
+      int last_passed_test_bitrate = -1;
+      for (int test_bitrate = test_bitrate_from_;
+           test_bitrate_from_ < test_bitrate_to_
+               ? test_bitrate <= test_bitrate_to_
+               : test_bitrate >= test_bitrate_to_;
+           test_bitrate += test_bitrate_step_) {
+        BuiltInNetworkBehaviorConfig pipe_config;
+        pipe_config.link_capacity_kbps = test_bitrate;
+        send_simulated_network_->SetConfig(pipe_config);
+        receive_simulated_network_->SetConfig(pipe_config);
+
+        rtc::Thread::SleepMs(quick_perf_test ? kShortDelayMs
+                                             : kBitrateStabilizationMs);
+
+        int64_t avg_rtt = 0;
+        for (int i = 0; i < kBitrateMeasurements; i++) {
+          Call::Stats call_stats;
+          SendTask(task_queue_, [this, &call_stats]() {
+            call_stats = sender_call_->GetStats();
+          });
+          avg_rtt += call_stats.rtt_ms;
+          rtc::Thread::SleepMs(quick_perf_test ? kShortDelayMs
+                                               : kBitrateMeasurementMs);
+        }
+        avg_rtt = avg_rtt / kBitrateMeasurements;
+        if (avg_rtt > kMinGoodRttMs) {
+          break;
+        } else {
+          last_passed_test_bitrate = test_bitrate;
+        }
+      }
+      EXPECT_GT(last_passed_test_bitrate, -1)
+          << "Minimum supported bitrate out of the test scope";
+      GetGlobalMetricsLogger()->LogSingleValueMetric(
+          "min_test_bitrate_", "min_bitrate", last_passed_test_bitrate,
+          Unit::kUnitless, ImprovementDirection::kNeitherIsBetter);
+    }
+
+    void OnCallsCreated(Call* sender_call, Call* receiver_call) override {
+      sender_call_ = sender_call;
+      BitrateConstraints bitrate_config;
+      bitrate_config.min_bitrate_bps = min_bwe_;
+      bitrate_config.start_bitrate_bps = start_bwe_;
+      bitrate_config.max_bitrate_bps = max_bwe_;
+      sender_call->GetTransportControllerSend()->SetSdpBitrateParameters(
+          bitrate_config);
+    }
+
+    size_t GetNumVideoStreams() const override { return 1; }
+
+    size_t GetNumAudioStreams() const override { return 1; }
+
+    void ModifyAudioConfigs(AudioSendStream::Config* send_config,
+                            std::vector<AudioReceiveStreamInterface::Config>*
+                                receive_configs) override {
+      send_config->send_codec_spec->target_bitrate_bps =
+          absl::optional<int>(kOpusBitrateFbBps);
+    }
+
+   private:
+    const int test_bitrate_from_;
+    const int test_bitrate_to_;
+    const int test_bitrate_step_;
+    const int min_bwe_;
+    const int start_bwe_;
+    const int max_bwe_;
+    SimulatedNetworkInterface* send_simulated_network_;
+    SimulatedNetworkInterface* receive_simulated_network_;
+    Call* sender_call_;
+    TaskQueueBase* const task_queue_;
+  } test(test_bitrate_from, test_bitrate_to, test_bitrate_step, min_bwe,
+         start_bwe, max_bwe, task_queue());
+
+  RunBaseTest(&test);
+}
+
+// TODO(bugs.webrtc.org/8878)
+#if defined(WEBRTC_MAC)
+#define MAYBE_Min_Bitrate_VideoAndAudio DISABLED_Min_Bitrate_VideoAndAudio
+#else
+#define MAYBE_Min_Bitrate_VideoAndAudio Min_Bitrate_VideoAndAudio
+#endif
+TEST_F(CallPerfTest, MAYBE_Min_Bitrate_VideoAndAudio) {
+  TestMinAudioVideoBitrate(110, 40, -10, 10000, 70000, 200000);
+}
+
+void CallPerfTest::TestEncodeFramerate(VideoEncoderFactory* encoder_factory,
+                                       absl::string_view payload_name,
+                                       const std::vector<int>& max_framerates) {
+  static constexpr double kAllowedFpsDiff = 1.5;
+  static constexpr TimeDelta kMinGetStatsInterval = TimeDelta::Millis(400);
+  static constexpr TimeDelta kMinRunTime = TimeDelta::Seconds(15);
+  static constexpr DataRate kMaxBitrate = DataRate::KilobitsPerSec(1000);
+
+  class FramerateObserver
+      : public test::EndToEndTest,
+        public test::FrameGeneratorCapturer::SinkWantsObserver {
+   public:
+    FramerateObserver(VideoEncoderFactory* encoder_factory,
+                      absl::string_view payload_name,
+                      const std::vector<int>& max_framerates,
+                      TaskQueueBase* task_queue)
+        : EndToEndTest(kDefaultTimeout),
+          clock_(Clock::GetRealTimeClock()),
+          encoder_factory_(encoder_factory),
+          payload_name_(payload_name),
+          max_framerates_(max_framerates),
+          task_queue_(task_queue),
+          start_time_(clock_->CurrentTime()),
+          last_getstats_time_(start_time_),
+          send_stream_(nullptr) {}
+
+    void OnFrameGeneratorCapturerCreated(
+        test::FrameGeneratorCapturer* frame_generator_capturer) override {
+      frame_generator_capturer->ChangeResolution(640, 360);
+    }
+
+    void OnSinkWantsChanged(rtc::VideoSinkInterface<VideoFrame>* sink,
+                            const rtc::VideoSinkWants& wants) override {}
+
+    void ModifySenderBitrateConfig(
+        BitrateConstraints* bitrate_config) override {
+      bitrate_config->start_bitrate_bps = kMaxBitrate.bps() / 2;
+    }
+
+    void OnVideoStreamsCreated(VideoSendStream* send_stream,
+                               const std::vector<VideoReceiveStreamInterface*>&
+                                   receive_streams) override {
+      send_stream_ = send_stream;
+    }
+
+    size_t GetNumVideoStreams() const override {
+      return max_framerates_.size();
+    }
+
+    void ModifyVideoConfigs(
+        VideoSendStream::Config* send_config,
+        std::vector<VideoReceiveStreamInterface::Config>* receive_configs,
+        VideoEncoderConfig* encoder_config) override {
+      send_config->encoder_settings.encoder_factory = encoder_factory_;
+      send_config->rtp.payload_name = payload_name_;
+      send_config->rtp.payload_type = test::CallTest::kVideoSendPayloadType;
+      encoder_config->video_format.name = payload_name_;
+      encoder_config->codec_type = PayloadStringToCodecType(payload_name_);
+      encoder_config->max_bitrate_bps = kMaxBitrate.bps();
+      for (size_t i = 0; i < max_framerates_.size(); ++i) {
+        encoder_config->simulcast_layers[i].max_framerate = max_framerates_[i];
+        configured_framerates_[send_config->rtp.ssrcs[i]] = max_framerates_[i];
+      }
+    }
+
+    void PerformTest() override {
+      EXPECT_TRUE(Wait()) << "Timeout while waiting for framerate stats.";
+    }
+
+    void VerifyStats() const {
+      const bool quick_perf_test =
+          field_trial::IsEnabled("WebRTC-QuickPerfTest");
+      double input_fps = 0.0;
+      for (const auto& configured_framerate : configured_framerates_) {
+        input_fps = std::max(configured_framerate.second, input_fps);
+      }
+      for (const auto& encode_frame_rate_list : encode_frame_rate_lists_) {
+        const SamplesStatsCounter& values = encode_frame_rate_list.second;
+        GetGlobalMetricsLogger()->LogMetric(
+            "substream_fps", "encode_frame_rate", values, Unit::kUnitless,
+            ImprovementDirection::kNeitherIsBetter);
+        if (values.IsEmpty()) {
+          continue;
+        }
+        double average_fps = values.GetAverage();
+        uint32_t ssrc = encode_frame_rate_list.first;
+        double expected_fps = configured_framerates_.find(ssrc)->second;
+        if (quick_perf_test && expected_fps != input_fps)
+          EXPECT_NEAR(expected_fps, average_fps, kAllowedFpsDiff);
+      }
+    }
+
+    Action OnSendRtp(const uint8_t* packet, size_t length) override {
+      const Timestamp now = clock_->CurrentTime();
+      if (now - last_getstats_time_ > kMinGetStatsInterval) {
+        last_getstats_time_ = now;
+        task_queue_->PostTask([this, now]() {
+          VideoSendStream::Stats stats = send_stream_->GetStats();
+          for (const auto& stat : stats.substreams) {
+            encode_frame_rate_lists_[stat.first].AddSample(
+                stat.second.encode_frame_rate);
+          }
+          if (now - start_time_ > kMinRunTime) {
+            VerifyStats();
+            observation_complete_.Set();
+          }
+        });
+      }
+      return SEND_PACKET;
+    }
+
+    Clock* const clock_;
+    VideoEncoderFactory* const encoder_factory_;
+    const std::string payload_name_;
+    const std::vector<int> max_framerates_;
+    TaskQueueBase* const task_queue_;
+    const Timestamp start_time_;
+    Timestamp last_getstats_time_;
+    VideoSendStream* send_stream_;
+    std::map<uint32_t, SamplesStatsCounter> encode_frame_rate_lists_;
+    std::map<uint32_t, double> configured_framerates_;
+  } test(encoder_factory, payload_name, max_framerates, task_queue());
+
+  RunBaseTest(&test);
+}
+
+TEST_F(CallPerfTest, TestEncodeFramerateVp8Simulcast) {
+  InternalEncoderFactory internal_encoder_factory;
+  test::FunctionVideoEncoderFactory encoder_factory(
+      [&internal_encoder_factory]() {
+        return std::make_unique<SimulcastEncoderAdapter>(
+            &internal_encoder_factory, SdpVideoFormat("VP8"));
+      });
+
+  TestEncodeFramerate(&encoder_factory, "VP8",
+                      /*max_framerates=*/{20, 30});
+}
+
+TEST_F(CallPerfTest, TestEncodeFramerateVp8SimulcastLowerInputFps) {
+  InternalEncoderFactory internal_encoder_factory;
+  test::FunctionVideoEncoderFactory encoder_factory(
+      [&internal_encoder_factory]() {
+        return std::make_unique<SimulcastEncoderAdapter>(
+            &internal_encoder_factory, SdpVideoFormat("VP8"));
+      });
+
+  TestEncodeFramerate(&encoder_factory, "VP8",
+                      /*max_framerates=*/{14, 20});
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/call_unittest.cc b/third_party/libwebrtc/call/call_unittest.cc
new file mode 100644
index 0000000000..5db3f5902b
--- /dev/null
+++ b/third_party/libwebrtc/call/call_unittest.cc
@@ -0,0 +1,478 @@
+/*
+ *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/call.h"
+
+#include <list>
+#include <map>
+#include <memory>
+#include <utility>
+
+#include "absl/memory/memory.h"
+#include "absl/strings/string_view.h"
+#include "api/audio_codecs/builtin_audio_decoder_factory.h"
+#include "api/rtc_event_log/rtc_event_log.h"
+#include "api/task_queue/default_task_queue_factory.h"
+#include "api/test/mock_audio_mixer.h"
+#include "api/test/video/function_video_encoder_factory.h"
+#include "api/transport/field_trial_based_config.h"
+#include "api/video/builtin_video_bitrate_allocator_factory.h"
+#include "audio/audio_receive_stream.h"
+#include "audio/audio_send_stream.h"
+#include "call/adaptation/test/fake_resource.h"
+#include "call/adaptation/test/mock_resource_listener.h"
+#include "call/audio_state.h"
+#include "modules/audio_device/include/mock_audio_device.h"
+#include "modules/audio_processing/include/mock_audio_processing.h"
+#include "modules/rtp_rtcp/source/rtp_rtcp_interface.h"
+#include "test/fake_encoder.h"
+#include "test/gtest.h"
+#include "test/mock_audio_decoder_factory.h"
+#include "test/mock_transport.h"
+#include "test/run_loop.h"
+
+namespace {
+
+using ::testing::_;
+using ::testing::Contains;
+using ::testing::NiceMock;
+using ::testing::StrictMock;
+
+struct CallHelper {
+  explicit CallHelper(bool use_null_audio_processing) {
+    task_queue_factory_ = webrtc::CreateDefaultTaskQueueFactory();
+    webrtc::AudioState::Config audio_state_config;
+    audio_state_config.audio_mixer =
+        rtc::make_ref_counted<webrtc::test::MockAudioMixer>();
+    audio_state_config.audio_processing =
+        use_null_audio_processing
+            ? nullptr
+            : rtc::make_ref_counted<
+                  NiceMock<webrtc::test::MockAudioProcessing>>();
+    audio_state_config.audio_device_module =
+        rtc::make_ref_counted<webrtc::test::MockAudioDeviceModule>();
+    webrtc::Call::Config config(&event_log_);
+    config.audio_state = webrtc::AudioState::Create(audio_state_config);
+    config.task_queue_factory = task_queue_factory_.get();
+    config.trials = &field_trials_;
+    call_.reset(webrtc::Call::Create(config));
+  }
+
+  webrtc::Call* operator->() { return call_.get(); }
+
+ private:
+  webrtc::test::RunLoop loop_;
+  webrtc::RtcEventLogNull event_log_;
+  webrtc::FieldTrialBasedConfig field_trials_;
+  std::unique_ptr<webrtc::TaskQueueFactory> task_queue_factory_;
+  std::unique_ptr<webrtc::Call> call_;
+};
+}  // namespace
+
+namespace webrtc {
+
+namespace {
+
+rtc::scoped_refptr<Resource> FindResourceWhoseNameContains(
+    const std::vector<rtc::scoped_refptr<Resource>>& resources,
+    absl::string_view name_contains) {
+  for (const auto& resource : resources) {
+    if (resource->Name().find(std::string(name_contains)) != std::string::npos)
+      return resource;
+  }
+  return nullptr;
+}
+
+}  // namespace
+
+TEST(CallTest, ConstructDestruct) {
+  for (bool use_null_audio_processing : {false, true}) {
+    CallHelper call(use_null_audio_processing);
+  }
+}
+
+TEST(CallTest, CreateDestroy_AudioSendStream) {
+  for (bool use_null_audio_processing : {false, true}) {
+    CallHelper call(use_null_audio_processing);
+    MockTransport send_transport;
+    AudioSendStream::Config config(&send_transport);
+    config.rtp.ssrc = 42;
+    AudioSendStream* stream = call->CreateAudioSendStream(config);
+    EXPECT_NE(stream, nullptr);
+    call->DestroyAudioSendStream(stream);
+  }
+}
+
+TEST(CallTest, CreateDestroy_AudioReceiveStream) {
+  for (bool use_null_audio_processing : {false, true}) {
+    CallHelper call(use_null_audio_processing);
+    AudioReceiveStreamInterface::Config config;
+    MockTransport rtcp_send_transport;
+    config.rtp.remote_ssrc = 42;
+    config.rtcp_send_transport = &rtcp_send_transport;
+    config.decoder_factory =
+        rtc::make_ref_counted<webrtc::MockAudioDecoderFactory>();
+    AudioReceiveStreamInterface* stream =
+        call->CreateAudioReceiveStream(config);
+    EXPECT_NE(stream, nullptr);
+    call->DestroyAudioReceiveStream(stream);
+  }
+}
+
+TEST(CallTest, CreateDestroy_AudioSendStreams) {
+  for (bool use_null_audio_processing : {false, true}) {
+    CallHelper call(use_null_audio_processing);
+    MockTransport send_transport;
+    AudioSendStream::Config config(&send_transport);
+    std::list<AudioSendStream*> streams;
+    for (int i = 0; i < 2; ++i) {
+      for (uint32_t ssrc = 0; ssrc < 1234567; ssrc += 34567) {
+        config.rtp.ssrc = ssrc;
+        AudioSendStream* stream = call->CreateAudioSendStream(config);
+        EXPECT_NE(stream, nullptr);
+        if (ssrc & 1) {
+          streams.push_back(stream);
+        } else {
+          streams.push_front(stream);
+        }
+      }
+      for (auto s : streams) {
+        call->DestroyAudioSendStream(s);
+      }
+      streams.clear();
+    }
+  }
+}
+
+TEST(CallTest, CreateDestroy_AudioReceiveStreams) {
+  for (bool use_null_audio_processing : {false, true}) {
+    CallHelper call(use_null_audio_processing);
+    AudioReceiveStreamInterface::Config config;
+    MockTransport rtcp_send_transport;
+    config.rtcp_send_transport = &rtcp_send_transport;
+    config.decoder_factory =
+        rtc::make_ref_counted<webrtc::MockAudioDecoderFactory>();
+    std::list<AudioReceiveStreamInterface*> streams;
+    for (int i = 0; i < 2; ++i) {
+      for (uint32_t ssrc = 0; ssrc < 1234567; ssrc += 34567) {
+        config.rtp.remote_ssrc = ssrc;
+        AudioReceiveStreamInterface* stream =
+            call->CreateAudioReceiveStream(config);
+        EXPECT_NE(stream, nullptr);
+        if (ssrc & 1) {
+          streams.push_back(stream);
+        } else {
+          streams.push_front(stream);
+        }
+      }
+      for (auto s : streams) {
+        call->DestroyAudioReceiveStream(s);
+      }
+      streams.clear();
+    }
+  }
+}
+
+TEST(CallTest, CreateDestroy_AssociateAudioSendReceiveStreams_RecvFirst) {
+  for (bool use_null_audio_processing : {false, true}) {
+    CallHelper call(use_null_audio_processing);
+    AudioReceiveStreamInterface::Config recv_config;
+    MockTransport rtcp_send_transport;
+    recv_config.rtp.remote_ssrc = 42;
+    recv_config.rtp.local_ssrc = 777;
+    recv_config.rtcp_send_transport = &rtcp_send_transport;
+    recv_config.decoder_factory =
+        rtc::make_ref_counted<webrtc::MockAudioDecoderFactory>();
+    AudioReceiveStreamInterface* recv_stream =
+        call->CreateAudioReceiveStream(recv_config);
+    EXPECT_NE(recv_stream, nullptr);
+
+    MockTransport send_transport;
+    AudioSendStream::Config send_config(&send_transport);
+    send_config.rtp.ssrc = 777;
+    AudioSendStream* send_stream = call->CreateAudioSendStream(send_config);
+    EXPECT_NE(send_stream, nullptr);
+
+    AudioReceiveStreamImpl* internal_recv_stream =
+        static_cast<AudioReceiveStreamImpl*>(recv_stream);
+    EXPECT_EQ(send_stream,
+              internal_recv_stream->GetAssociatedSendStreamForTesting());
+
+    call->DestroyAudioSendStream(send_stream);
+    EXPECT_EQ(nullptr,
+              internal_recv_stream->GetAssociatedSendStreamForTesting());
+
+    call->DestroyAudioReceiveStream(recv_stream);
+  }
+}
+
+TEST(CallTest, CreateDestroy_AssociateAudioSendReceiveStreams_SendFirst) {
+  for (bool use_null_audio_processing : {false, true}) {
+    CallHelper call(use_null_audio_processing);
+    MockTransport send_transport;
+    AudioSendStream::Config send_config(&send_transport);
+    send_config.rtp.ssrc = 777;
+    AudioSendStream* send_stream = call->CreateAudioSendStream(send_config);
+    EXPECT_NE(send_stream, nullptr);
+
+    AudioReceiveStreamInterface::Config recv_config;
+    MockTransport rtcp_send_transport;
+    recv_config.rtp.remote_ssrc = 42;
+    recv_config.rtp.local_ssrc = 777;
+    recv_config.rtcp_send_transport = &rtcp_send_transport;
+    recv_config.decoder_factory =
+        rtc::make_ref_counted<webrtc::MockAudioDecoderFactory>();
+    AudioReceiveStreamInterface* recv_stream =
+        call->CreateAudioReceiveStream(recv_config);
+    EXPECT_NE(recv_stream, nullptr);
+
+    AudioReceiveStreamImpl* internal_recv_stream =
+        static_cast<AudioReceiveStreamImpl*>(recv_stream);
+    EXPECT_EQ(send_stream,
+              internal_recv_stream->GetAssociatedSendStreamForTesting());
+
+    call->DestroyAudioReceiveStream(recv_stream);
+
+    call->DestroyAudioSendStream(send_stream);
+  }
+}
+
+TEST(CallTest, CreateDestroy_FlexfecReceiveStream) {
+  for (bool use_null_audio_processing : {false, true}) {
+    CallHelper call(use_null_audio_processing);
+    MockTransport rtcp_send_transport;
+    FlexfecReceiveStream::Config config(&rtcp_send_transport);
+    config.payload_type = 118;
+    config.rtp.remote_ssrc = 38837212;
+    config.protected_media_ssrcs = {27273};
+
+    FlexfecReceiveStream* stream = call->CreateFlexfecReceiveStream(config);
+    EXPECT_NE(stream, nullptr);
+    call->DestroyFlexfecReceiveStream(stream);
+  }
+}
+
+TEST(CallTest, CreateDestroy_FlexfecReceiveStreams) {
+  for (bool use_null_audio_processing : {false, true}) {
+    CallHelper call(use_null_audio_processing);
+    MockTransport rtcp_send_transport;
+    FlexfecReceiveStream::Config config(&rtcp_send_transport);
+    config.payload_type = 118;
+    std::list<FlexfecReceiveStream*> streams;
+
+    for (int i = 0; i < 2; ++i) {
+      for (uint32_t ssrc = 0; ssrc < 1234567; ssrc += 34567) {
+        config.rtp.remote_ssrc = ssrc;
+        config.protected_media_ssrcs = {ssrc + 1};
+        FlexfecReceiveStream* stream = call->CreateFlexfecReceiveStream(config);
+        EXPECT_NE(stream, nullptr);
+        if (ssrc & 1) {
+          streams.push_back(stream);
+        } else {
+          streams.push_front(stream);
+        }
+      }
+      for (auto s : streams) {
+        call->DestroyFlexfecReceiveStream(s);
+      }
+      streams.clear();
+    }
+  }
+}
+
+TEST(CallTest, MultipleFlexfecReceiveStreamsProtectingSingleVideoStream) {
+  for (bool use_null_audio_processing : {false, true}) {
+    CallHelper call(use_null_audio_processing);
+    MockTransport rtcp_send_transport;
+    FlexfecReceiveStream::Config config(&rtcp_send_transport);
+    config.payload_type = 118;
+    config.protected_media_ssrcs = {1324234};
+    FlexfecReceiveStream* stream;
+    std::list<FlexfecReceiveStream*> streams;
+
+    config.rtp.remote_ssrc = 838383;
+    stream = call->CreateFlexfecReceiveStream(config);
+    EXPECT_NE(stream, nullptr);
+    streams.push_back(stream);
+
+    config.rtp.remote_ssrc = 424993;
+    stream = call->CreateFlexfecReceiveStream(config);
+    EXPECT_NE(stream, nullptr);
+    streams.push_back(stream);
+
+    config.rtp.remote_ssrc = 99383;
+    stream = call->CreateFlexfecReceiveStream(config);
+    EXPECT_NE(stream, nullptr);
+    streams.push_back(stream);
+
+    config.rtp.remote_ssrc = 5548;
+    stream = call->CreateFlexfecReceiveStream(config);
+    EXPECT_NE(stream, nullptr);
+    streams.push_back(stream);
+
+    for (auto s : streams) {
+      call->DestroyFlexfecReceiveStream(s);
+    }
+  }
+}
+
+TEST(CallTest, RecreatingAudioStreamWithSameSsrcReusesRtpState) {
+  constexpr uint32_t kSSRC = 12345;
+  for (bool use_null_audio_processing : {false, true}) {
+    CallHelper call(use_null_audio_processing);
+
+    auto create_stream_and_get_rtp_state = [&](uint32_t ssrc) {
+      MockTransport send_transport;
+      AudioSendStream::Config config(&send_transport);
+      config.rtp.ssrc = ssrc;
+      AudioSendStream* stream = call->CreateAudioSendStream(config);
+      const RtpState rtp_state =
+          static_cast<internal::AudioSendStream*>(stream)->GetRtpState();
+      call->DestroyAudioSendStream(stream);
+      return rtp_state;
+    };
+
+    const RtpState rtp_state1 = create_stream_and_get_rtp_state(kSSRC);
+    const RtpState rtp_state2 = create_stream_and_get_rtp_state(kSSRC);
+
+    EXPECT_EQ(rtp_state1.sequence_number, rtp_state2.sequence_number);
+    EXPECT_EQ(rtp_state1.start_timestamp, rtp_state2.start_timestamp);
+    EXPECT_EQ(rtp_state1.timestamp, rtp_state2.timestamp);
+    EXPECT_EQ(rtp_state1.capture_time_ms, rtp_state2.capture_time_ms);
+    EXPECT_EQ(rtp_state1.last_timestamp_time_ms,
+              rtp_state2.last_timestamp_time_ms);
+  }
+}
+
+TEST(CallTest, AddAdaptationResourceAfterCreatingVideoSendStream) {
+  CallHelper call(true);
+  // Create a VideoSendStream.
+  test::FunctionVideoEncoderFactory fake_encoder_factory([]() {
+    return std::make_unique<test::FakeEncoder>(Clock::GetRealTimeClock());
+  });
+  auto bitrate_allocator_factory = CreateBuiltinVideoBitrateAllocatorFactory();
+  MockTransport send_transport;
+  VideoSendStream::Config config(&send_transport);
+  config.rtp.payload_type = 110;
+  config.rtp.ssrcs = {42};
+  config.encoder_settings.encoder_factory = &fake_encoder_factory;
+  config.encoder_settings.bitrate_allocator_factory =
+      bitrate_allocator_factory.get();
+  VideoEncoderConfig encoder_config;
+  encoder_config.max_bitrate_bps = 1337;
+  VideoSendStream* stream1 =
+      call->CreateVideoSendStream(config.Copy(), encoder_config.Copy());
+  EXPECT_NE(stream1, nullptr);
+  config.rtp.ssrcs = {43};
+  VideoSendStream* stream2 =
+      call->CreateVideoSendStream(config.Copy(), encoder_config.Copy());
+  EXPECT_NE(stream2, nullptr);
+  // Add a fake resource.
+  auto fake_resource = FakeResource::Create("FakeResource");
+  call->AddAdaptationResource(fake_resource);
+  // An adapter resource mirroring the `fake_resource` should now be present on
+  // both streams.
+  auto injected_resource1 = FindResourceWhoseNameContains(
+      stream1->GetAdaptationResources(), fake_resource->Name());
+  EXPECT_TRUE(injected_resource1);
+  auto injected_resource2 = FindResourceWhoseNameContains(
+      stream2->GetAdaptationResources(), fake_resource->Name());
+  EXPECT_TRUE(injected_resource2);
+  // Overwrite the real resource listeners with mock ones to verify the signal
+  // gets through.
+  injected_resource1->SetResourceListener(nullptr);
+  StrictMock<MockResourceListener> resource_listener1;
+  EXPECT_CALL(resource_listener1, OnResourceUsageStateMeasured(_, _))
+      .Times(1)
+      .WillOnce([injected_resource1](rtc::scoped_refptr<Resource> resource,
+                                     ResourceUsageState usage_state) {
+        EXPECT_EQ(injected_resource1, resource);
+        EXPECT_EQ(ResourceUsageState::kOveruse, usage_state);
+      });
+  injected_resource1->SetResourceListener(&resource_listener1);
+  injected_resource2->SetResourceListener(nullptr);
+  StrictMock<MockResourceListener> resource_listener2;
+  EXPECT_CALL(resource_listener2, OnResourceUsageStateMeasured(_, _))
+      .Times(1)
+      .WillOnce([injected_resource2](rtc::scoped_refptr<Resource> resource,
+                                     ResourceUsageState usage_state) {
+        EXPECT_EQ(injected_resource2, resource);
+        EXPECT_EQ(ResourceUsageState::kOveruse, usage_state);
+      });
+  injected_resource2->SetResourceListener(&resource_listener2);
+  // The kOveruse signal should get to our resource listeners.
+  fake_resource->SetUsageState(ResourceUsageState::kOveruse);
+  call->DestroyVideoSendStream(stream1);
+  call->DestroyVideoSendStream(stream2);
+}
+
+TEST(CallTest, AddAdaptationResourceBeforeCreatingVideoSendStream) {
+  CallHelper call(true);
+  // Add a fake resource.
+  auto fake_resource = FakeResource::Create("FakeResource");
+  call->AddAdaptationResource(fake_resource);
+  // Create a VideoSendStream.
+  test::FunctionVideoEncoderFactory fake_encoder_factory([]() {
+    return std::make_unique<test::FakeEncoder>(Clock::GetRealTimeClock());
+  });
+  auto bitrate_allocator_factory = CreateBuiltinVideoBitrateAllocatorFactory();
+  MockTransport send_transport;
+  VideoSendStream::Config config(&send_transport);
+  config.rtp.payload_type = 110;
+  config.rtp.ssrcs = {42};
+  config.encoder_settings.encoder_factory = &fake_encoder_factory;
+  config.encoder_settings.bitrate_allocator_factory =
+      bitrate_allocator_factory.get();
+  VideoEncoderConfig encoder_config;
+  encoder_config.max_bitrate_bps = 1337;
+  VideoSendStream* stream1 =
+      call->CreateVideoSendStream(config.Copy(), encoder_config.Copy());
+  EXPECT_NE(stream1, nullptr);
+  config.rtp.ssrcs = {43};
+  VideoSendStream* stream2 =
+      call->CreateVideoSendStream(config.Copy(), encoder_config.Copy());
+  EXPECT_NE(stream2, nullptr);
+  // An adapter resource mirroring the `fake_resource` should be present on both
+  // streams.
+  auto injected_resource1 = FindResourceWhoseNameContains(
+      stream1->GetAdaptationResources(), fake_resource->Name());
+  EXPECT_TRUE(injected_resource1);
+  auto injected_resource2 = FindResourceWhoseNameContains(
+      stream2->GetAdaptationResources(), fake_resource->Name());
+  EXPECT_TRUE(injected_resource2);
+  // Overwrite the real resource listeners with mock ones to verify the signal
+  // gets through.
+  injected_resource1->SetResourceListener(nullptr);
+  StrictMock<MockResourceListener> resource_listener1;
+  EXPECT_CALL(resource_listener1, OnResourceUsageStateMeasured(_, _))
+      .Times(1)
+      .WillOnce([injected_resource1](rtc::scoped_refptr<Resource> resource,
+                                     ResourceUsageState usage_state) {
+        EXPECT_EQ(injected_resource1, resource);
+        EXPECT_EQ(ResourceUsageState::kUnderuse, usage_state);
+      });
+  injected_resource1->SetResourceListener(&resource_listener1);
+  injected_resource2->SetResourceListener(nullptr);
+  StrictMock<MockResourceListener> resource_listener2;
+  EXPECT_CALL(resource_listener2, OnResourceUsageStateMeasured(_, _))
+      .Times(1)
+      .WillOnce([injected_resource2](rtc::scoped_refptr<Resource> resource,
+                                     ResourceUsageState usage_state) {
+        EXPECT_EQ(injected_resource2, resource);
+        EXPECT_EQ(ResourceUsageState::kUnderuse, usage_state);
+      });
+  injected_resource2->SetResourceListener(&resource_listener2);
+  // The kUnderuse signal should get to our resource listeners.
+  fake_resource->SetUsageState(ResourceUsageState::kUnderuse);
+  call->DestroyVideoSendStream(stream1);
+  call->DestroyVideoSendStream(stream2);
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/degraded_call.cc b/third_party/libwebrtc/call/degraded_call.cc
new file mode 100644
index 0000000000..99c32296c3
--- /dev/null
+++ b/third_party/libwebrtc/call/degraded_call.cc
@@ -0,0 +1,388 @@
+/*
+ *  Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/degraded_call.h"
+
+#include <memory>
+#include <utility>
+
+#include "absl/strings/string_view.h"
+#include "api/sequence_checker.h"
+#include "modules/rtp_rtcp/source/rtp_util.h"
+#include "rtc_base/event.h"
+
+namespace webrtc {
+
+DegradedCall::FakeNetworkPipeOnTaskQueue::FakeNetworkPipeOnTaskQueue(
+    TaskQueueBase* task_queue,
+    rtc::scoped_refptr<PendingTaskSafetyFlag> call_alive,
+    Clock* clock,
+    std::unique_ptr<NetworkBehaviorInterface> network_behavior)
+    : clock_(clock),
+      task_queue_(task_queue),
+      call_alive_(std::move(call_alive)),
+      pipe_(clock, std::move(network_behavior)) {}
+
+void DegradedCall::FakeNetworkPipeOnTaskQueue::SendRtp(
+    const uint8_t* packet,
+    size_t length,
+    const PacketOptions& options,
+    Transport* transport) {
+  pipe_.SendRtp(packet, length, options, transport);
+  Process();
+}
+
+void DegradedCall::FakeNetworkPipeOnTaskQueue::SendRtcp(const uint8_t* packet,
+                                                        size_t length,
+                                                        Transport* transport) {
+  pipe_.SendRtcp(packet, length, transport);
+  Process();
+}
+
+void DegradedCall::FakeNetworkPipeOnTaskQueue::AddActiveTransport(
+    Transport* transport) {
+  pipe_.AddActiveTransport(transport);
+}
+
+void DegradedCall::FakeNetworkPipeOnTaskQueue::RemoveActiveTransport(
+    Transport* transport) {
+  pipe_.RemoveActiveTransport(transport);
+}
+
+bool DegradedCall::FakeNetworkPipeOnTaskQueue::Process() {
+  pipe_.Process();
+  auto time_to_next = pipe_.TimeUntilNextProcess();
+  if (!time_to_next) {
+    // Packet was probably sent immediately.
+    return false;
+  }
+
+  task_queue_->PostTask(SafeTask(call_alive_, [this, time_to_next] {
+    RTC_DCHECK_RUN_ON(task_queue_);
+    int64_t next_process_time = *time_to_next + clock_->TimeInMilliseconds();
+    if (!next_process_ms_ || next_process_time < *next_process_ms_) {
+      next_process_ms_ = next_process_time;
+      task_queue_->PostDelayedHighPrecisionTask(
+          SafeTask(call_alive_,
+                   [this] {
+                     RTC_DCHECK_RUN_ON(task_queue_);
+                     if (!Process()) {
+                       next_process_ms_.reset();
+                     }
+                   }),
+          TimeDelta::Millis(*time_to_next));
+    }
+  }));
+
+  return true;
+}
+
+DegradedCall::FakeNetworkPipeTransportAdapter::FakeNetworkPipeTransportAdapter(
+    FakeNetworkPipeOnTaskQueue* fake_network,
+    Call* call,
+    Clock* clock,
+    Transport* real_transport)
+    : network_pipe_(fake_network),
+      call_(call),
+      clock_(clock),
+      real_transport_(real_transport) {
+  network_pipe_->AddActiveTransport(real_transport);
+}
+
+DegradedCall::FakeNetworkPipeTransportAdapter::
+    ~FakeNetworkPipeTransportAdapter() {
+  network_pipe_->RemoveActiveTransport(real_transport_);
+}
+
+bool DegradedCall::FakeNetworkPipeTransportAdapter::SendRtp(
+    const uint8_t* packet,
+    size_t length,
+    const PacketOptions& options) {
+  // A call here comes from the RTP stack (probably pacer). We intercept it and
+  // put it in the fake network pipe instead, but report to Call that is has
+  // been sent, so that the bandwidth estimator sees the delay we add.
+  network_pipe_->SendRtp(packet, length, options, real_transport_);
+  if (options.packet_id != -1) {
+    rtc::SentPacket sent_packet;
+    sent_packet.packet_id = options.packet_id;
+    sent_packet.send_time_ms = clock_->TimeInMilliseconds();
+    sent_packet.info.included_in_feedback = options.included_in_feedback;
+    sent_packet.info.included_in_allocation = options.included_in_allocation;
+    sent_packet.info.packet_size_bytes = length;
+    sent_packet.info.packet_type = rtc::PacketType::kData;
+    call_->OnSentPacket(sent_packet);
+  }
+  return true;
+}
+
+bool DegradedCall::FakeNetworkPipeTransportAdapter::SendRtcp(
+    const uint8_t* packet,
+    size_t length) {
+  network_pipe_->SendRtcp(packet, length, real_transport_);
+  return true;
+}
+
+/* Mozilla: Avoid this since it could use GetRealTimeClock().
+DegradedCall::DegradedCall(
+    std::unique_ptr<Call> call,
+    const std::vector<TimeScopedNetworkConfig>& send_configs,
+    const std::vector<TimeScopedNetworkConfig>& receive_configs)
+    : clock_(Clock::GetRealTimeClock()),
+      call_(std::move(call)),
+      call_alive_(PendingTaskSafetyFlag::CreateDetached()),
+      send_config_index_(0),
+      send_configs_(send_configs),
+      send_simulated_network_(nullptr),
+      receive_config_index_(0),
+      receive_configs_(receive_configs) {
+  if (!receive_configs_.empty()) {
+    auto network = std::make_unique<SimulatedNetwork>(receive_configs_[0]);
+    receive_simulated_network_ = network.get();
+    receive_pipe_ =
+        std::make_unique<webrtc::FakeNetworkPipe>(clock_, std::move(network));
+    receive_pipe_->SetReceiver(call_->Receiver());
+    if (receive_configs_.size() > 1) {
+      call_->network_thread()->PostDelayedTask(
+          SafeTask(call_alive_, [this] { UpdateReceiveNetworkConfig(); }),
+          receive_configs_[0].duration);
+    }
+  }
+  if (!send_configs_.empty()) {
+    auto network = std::make_unique<SimulatedNetwork>(send_configs_[0]);
+    send_simulated_network_ = network.get();
+    send_pipe_ = std::make_unique<FakeNetworkPipeOnTaskQueue>(
+        call_->network_thread(), call_alive_, clock_, std::move(network));
+    if (send_configs_.size() > 1) {
+      call_->network_thread()->PostDelayedTask(
+          SafeTask(call_alive_, [this] { UpdateSendNetworkConfig(); }),
+          send_configs_[0].duration);
+    }
+  }
+}
+*/
+
+DegradedCall::~DegradedCall() {
+  RTC_DCHECK_RUN_ON(call_->worker_thread());
+  // Thread synchronization is required to call `SetNotAlive`.
+  // Otherwise, when the `DegradedCall` object is destroyed but
+  // `SetNotAlive` has not yet been called,
+  // another Closure guarded by `call_alive_` may be called.
+  rtc::Event event;
+  call_->network_thread()->PostTask(
+      [flag = std::move(call_alive_), &event]() mutable {
+        flag->SetNotAlive();
+        event.Set();
+      });
+  event.Wait(rtc::Event::kForever);
+}
+
+AudioSendStream* DegradedCall::CreateAudioSendStream(
+    const AudioSendStream::Config& config) {
+  if (!send_configs_.empty()) {
+    auto transport_adapter = std::make_unique<FakeNetworkPipeTransportAdapter>(
+        send_pipe_.get(), call_.get(), clock_, config.send_transport);
+    AudioSendStream::Config degrade_config = config;
+    degrade_config.send_transport = transport_adapter.get();
+    AudioSendStream* send_stream = call_->CreateAudioSendStream(degrade_config);
+    if (send_stream) {
+      audio_send_transport_adapters_[send_stream] =
+          std::move(transport_adapter);
+    }
+    return send_stream;
+  }
+  return call_->CreateAudioSendStream(config);
+}
+
+void DegradedCall::DestroyAudioSendStream(AudioSendStream* send_stream) {
+  call_->DestroyAudioSendStream(send_stream);
+  audio_send_transport_adapters_.erase(send_stream);
+}
+
+AudioReceiveStreamInterface* DegradedCall::CreateAudioReceiveStream(
+    const AudioReceiveStreamInterface::Config& config) {
+  return call_->CreateAudioReceiveStream(config);
+}
+
+void DegradedCall::DestroyAudioReceiveStream(
+    AudioReceiveStreamInterface* receive_stream) {
+  call_->DestroyAudioReceiveStream(receive_stream);
+}
+
+VideoSendStream* DegradedCall::CreateVideoSendStream(
+    VideoSendStream::Config config,
+    VideoEncoderConfig encoder_config) {
+  std::unique_ptr<FakeNetworkPipeTransportAdapter> transport_adapter;
+  if (!send_configs_.empty()) {
+    transport_adapter = std::make_unique<FakeNetworkPipeTransportAdapter>(
+        send_pipe_.get(), call_.get(), clock_, config.send_transport);
+    config.send_transport = transport_adapter.get();
+  }
+  VideoSendStream* send_stream = call_->CreateVideoSendStream(
+      std::move(config), std::move(encoder_config));
+  if (send_stream && transport_adapter) {
+    video_send_transport_adapters_[send_stream] = std::move(transport_adapter);
+  }
+  return send_stream;
+}
+
+VideoSendStream* DegradedCall::CreateVideoSendStream(
+    VideoSendStream::Config config,
+    VideoEncoderConfig encoder_config,
+    std::unique_ptr<FecController> fec_controller) {
+  std::unique_ptr<FakeNetworkPipeTransportAdapter> transport_adapter;
+  if (!send_configs_.empty()) {
+    transport_adapter = std::make_unique<FakeNetworkPipeTransportAdapter>(
+        send_pipe_.get(), call_.get(), clock_, config.send_transport);
+    config.send_transport = transport_adapter.get();
+  }
+  VideoSendStream* send_stream = call_->CreateVideoSendStream(
+      std::move(config), std::move(encoder_config), std::move(fec_controller));
+  if (send_stream && transport_adapter) {
+    video_send_transport_adapters_[send_stream] = std::move(transport_adapter);
+  }
+  return send_stream;
+}
+
+void DegradedCall::DestroyVideoSendStream(VideoSendStream* send_stream) {
+  call_->DestroyVideoSendStream(send_stream);
+  video_send_transport_adapters_.erase(send_stream);
+}
+
+VideoReceiveStreamInterface* DegradedCall::CreateVideoReceiveStream(
+    VideoReceiveStreamInterface::Config configuration) {
+  return call_->CreateVideoReceiveStream(std::move(configuration));
+}
+
+void DegradedCall::DestroyVideoReceiveStream(
+    VideoReceiveStreamInterface* receive_stream) {
+  call_->DestroyVideoReceiveStream(receive_stream);
+}
+
+FlexfecReceiveStream* DegradedCall::CreateFlexfecReceiveStream(
+    const FlexfecReceiveStream::Config config) {
+  return call_->CreateFlexfecReceiveStream(std::move(config));
+}
+
+void DegradedCall::DestroyFlexfecReceiveStream(
+    FlexfecReceiveStream* receive_stream) {
+  call_->DestroyFlexfecReceiveStream(receive_stream);
+}
+
+void DegradedCall::AddAdaptationResource(
+    rtc::scoped_refptr<Resource> resource) {
+  call_->AddAdaptationResource(std::move(resource));
+}
+
+PacketReceiver* DegradedCall::Receiver() {
+  if (!receive_configs_.empty()) {
+    return this;
+  }
+  return call_->Receiver();
+}
+
+RtpTransportControllerSendInterface*
+DegradedCall::GetTransportControllerSend() {
+  return call_->GetTransportControllerSend();
+}
+
+Call::Stats DegradedCall::GetStats() const {
+  return call_->GetStats();
+}
+
+const FieldTrialsView& DegradedCall::trials() const {
+  return call_->trials();
+}
+
+TaskQueueBase* DegradedCall::network_thread() const {
+  return call_->network_thread();
+}
+
+TaskQueueBase* DegradedCall::worker_thread() const {
+  return call_->worker_thread();
+}
+
+void DegradedCall::SignalChannelNetworkState(MediaType media,
+                                             NetworkState state) {
+  call_->SignalChannelNetworkState(media, state);
+}
+
+void DegradedCall::OnAudioTransportOverheadChanged(
+    int transport_overhead_per_packet) {
+  call_->OnAudioTransportOverheadChanged(transport_overhead_per_packet);
+}
+
+void DegradedCall::OnLocalSsrcUpdated(AudioReceiveStreamInterface& stream,
+                                      uint32_t local_ssrc) {
+  call_->OnLocalSsrcUpdated(stream, local_ssrc);
+}
+
+void DegradedCall::OnLocalSsrcUpdated(VideoReceiveStreamInterface& stream,
+                                      uint32_t local_ssrc) {
+  call_->OnLocalSsrcUpdated(stream, local_ssrc);
+}
+
+void DegradedCall::OnLocalSsrcUpdated(FlexfecReceiveStream& stream,
+                                      uint32_t local_ssrc) {
+  call_->OnLocalSsrcUpdated(stream, local_ssrc);
+}
+
+void DegradedCall::OnUpdateSyncGroup(AudioReceiveStreamInterface& stream,
+                                     absl::string_view sync_group) {
+  call_->OnUpdateSyncGroup(stream, sync_group);
+}
+
+void DegradedCall::OnSentPacket(const rtc::SentPacket& sent_packet) {
+  if (!send_configs_.empty()) {
+    // If we have a degraded send-transport, we have already notified call
+    // about the supposed network send time. Discard the actual network send
+    // time in order to properly fool the BWE.
+    return;
+  }
+  call_->OnSentPacket(sent_packet);
+}
+
+void DegradedCall::DeliverRtpPacket(
+    MediaType media_type,
+    RtpPacketReceived packet,
+    OnUndemuxablePacketHandler undemuxable_packet_handler) {
+  RTC_DCHECK_RUN_ON(&received_packet_sequence_checker_);
+  receive_pipe_->DeliverRtpPacket(media_type, std::move(packet),
+                                  std::move(undemuxable_packet_handler));
+  receive_pipe_->Process();
+}
+
+void DegradedCall::DeliverRtcpPacket(rtc::CopyOnWriteBuffer packet) {
+  RTC_DCHECK_RUN_ON(&received_packet_sequence_checker_);
+  receive_pipe_->DeliverRtcpPacket(std::move(packet));
+  receive_pipe_->Process();
+}
+
+void DegradedCall::SetClientBitratePreferences(
+    const webrtc::BitrateSettings& preferences) {
+  call_->SetClientBitratePreferences(preferences);
+}
+
+void DegradedCall::UpdateSendNetworkConfig() {
+  send_config_index_ = (send_config_index_ + 1) % send_configs_.size();
+  send_simulated_network_->SetConfig(send_configs_[send_config_index_]);
+  call_->network_thread()->PostDelayedTask(
+      SafeTask(call_alive_, [this] { UpdateSendNetworkConfig(); }),
+      send_configs_[send_config_index_].duration);
+}
+
+void DegradedCall::UpdateReceiveNetworkConfig() {
+  receive_config_index_ = (receive_config_index_ + 1) % receive_configs_.size();
+  receive_simulated_network_->SetConfig(
+      receive_configs_[receive_config_index_]);
+  call_->network_thread()->PostDelayedTask(
+      SafeTask(call_alive_, [this] { UpdateReceiveNetworkConfig(); }),
+      receive_configs_[receive_config_index_].duration);
+}
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/degraded_call.h b/third_party/libwebrtc/call/degraded_call.h
new file mode 100644
index 0000000000..98e7891d6a
--- /dev/null
+++ b/third_party/libwebrtc/call/degraded_call.h
@@ -0,0 +1,204 @@
+/*
+ *  Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_DEGRADED_CALL_H_
+#define CALL_DEGRADED_CALL_H_
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include <map>
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "absl/strings/string_view.h"
+#include "absl/types/optional.h"
+#include "api/call/transport.h"
+#include "api/fec_controller.h"
+#include "api/media_types.h"
+#include "api/rtp_headers.h"
+#include "api/task_queue/pending_task_safety_flag.h"
+#include "api/test/simulated_network.h"
+#include "call/audio_receive_stream.h"
+#include "call/audio_send_stream.h"
+#include "call/call.h"
+#include "call/fake_network_pipe.h"
+#include "call/flexfec_receive_stream.h"
+#include "call/packet_receiver.h"
+#include "call/rtp_transport_controller_send_interface.h"
+#include "call/simulated_network.h"
+#include "call/video_receive_stream.h"
+#include "call/video_send_stream.h"
+#include "rtc_base/copy_on_write_buffer.h"
+#include "rtc_base/network/sent_packet.h"
+#include "rtc_base/task_queue.h"
+#include "system_wrappers/include/clock.h"
+#include "video/config/video_encoder_config.h"
+
+namespace webrtc {
+class DegradedCall : public Call, private PacketReceiver {
+ public:
+  struct TimeScopedNetworkConfig : public BuiltInNetworkBehaviorConfig {
+    TimeDelta duration = TimeDelta::PlusInfinity();
+  };
+
+  explicit DegradedCall(
+      std::unique_ptr<Call> call,
+      const std::vector<TimeScopedNetworkConfig>& send_configs,
+      const std::vector<TimeScopedNetworkConfig>& receive_configs);
+  ~DegradedCall() override;
+
+  // Implements Call.
+  AudioSendStream* CreateAudioSendStream(
+      const AudioSendStream::Config& config) override;
+  void DestroyAudioSendStream(AudioSendStream* send_stream) override;
+
+  AudioReceiveStreamInterface* CreateAudioReceiveStream(
+      const AudioReceiveStreamInterface::Config& config) override;
+  void DestroyAudioReceiveStream(
+      AudioReceiveStreamInterface* receive_stream) override;
+
+  VideoSendStream* CreateVideoSendStream(
+      VideoSendStream::Config config,
+      VideoEncoderConfig encoder_config) override;
+  VideoSendStream* CreateVideoSendStream(
+      VideoSendStream::Config config,
+      VideoEncoderConfig encoder_config,
+      std::unique_ptr<FecController> fec_controller) override;
+  void DestroyVideoSendStream(VideoSendStream* send_stream) override;
+
+  VideoReceiveStreamInterface* CreateVideoReceiveStream(
+      VideoReceiveStreamInterface::Config configuration) override;
+  void DestroyVideoReceiveStream(
+      VideoReceiveStreamInterface* receive_stream) override;
+
+  FlexfecReceiveStream* CreateFlexfecReceiveStream(
+      const FlexfecReceiveStream::Config config) override;
+  void DestroyFlexfecReceiveStream(
+      FlexfecReceiveStream* receive_stream) override;
+
+  void AddAdaptationResource(rtc::scoped_refptr<Resource> resource) override;
+
+  PacketReceiver* Receiver() override;
+
+  RtpTransportControllerSendInterface* GetTransportControllerSend() override;
+
+  Stats GetStats() const override;
+
+  const FieldTrialsView& trials() const override;
+
+  TaskQueueBase* network_thread() const override;
+  TaskQueueBase* worker_thread() const override;
+
+  void SignalChannelNetworkState(MediaType media, NetworkState state) override;
+  void OnAudioTransportOverheadChanged(
+      int transport_overhead_per_packet) override;
+  void OnLocalSsrcUpdated(AudioReceiveStreamInterface& stream,
+                          uint32_t local_ssrc) override;
+  void OnLocalSsrcUpdated(VideoReceiveStreamInterface& stream,
+                          uint32_t local_ssrc) override;
+  void OnLocalSsrcUpdated(FlexfecReceiveStream& stream,
+                          uint32_t local_ssrc) override;
+  void OnUpdateSyncGroup(AudioReceiveStreamInterface& stream,
+                         absl::string_view sync_group) override;
+  void OnSentPacket(const rtc::SentPacket& sent_packet) override;
+
+ protected:
+  // Implements PacketReceiver.
+  void DeliverRtpPacket(
+      MediaType media_type,
+      RtpPacketReceived packet,
+      OnUndemuxablePacketHandler undemuxable_packet_handler) override;
+  void DeliverRtcpPacket(rtc::CopyOnWriteBuffer packet) override;
+
+ private:
+  class FakeNetworkPipeOnTaskQueue {
+   public:
+    FakeNetworkPipeOnTaskQueue(
+        TaskQueueBase* task_queue,
+        rtc::scoped_refptr<PendingTaskSafetyFlag> call_alive,
+        Clock* clock,
+        std::unique_ptr<NetworkBehaviorInterface> network_behavior);
+
+    void SendRtp(const uint8_t* packet,
+                 size_t length,
+                 const PacketOptions& options,
+                 Transport* transport);
+    void SendRtcp(const uint8_t* packet, size_t length, Transport* transport);
+
+    void AddActiveTransport(Transport* transport);
+    void RemoveActiveTransport(Transport* transport);
+
+   private:
+    // Try to process packets on the fake network queue.
+    // Returns true if call resulted in a delayed process, false if queue empty.
+    bool Process();
+
+    Clock* const clock_;
+    TaskQueueBase* const task_queue_;
+    rtc::scoped_refptr<PendingTaskSafetyFlag> call_alive_;
+    FakeNetworkPipe pipe_;
+    absl::optional<int64_t> next_process_ms_ RTC_GUARDED_BY(&task_queue_);
+  };
+
+  // For audio/video send stream, a TransportAdapter instance is used to
+  // intercept packets to be sent, and put them into a common FakeNetworkPipe
+  // in such as way that they will eventually (unless dropped) be forwarded to
+  // the correct Transport for that stream.
+  class FakeNetworkPipeTransportAdapter : public Transport {
+   public:
+    FakeNetworkPipeTransportAdapter(FakeNetworkPipeOnTaskQueue* fake_network,
+                                    Call* call,
+                                    Clock* clock,
+                                    Transport* real_transport);
+    ~FakeNetworkPipeTransportAdapter();
+
+    bool SendRtp(const uint8_t* packet,
+                 size_t length,
+                 const PacketOptions& options) override;
+    bool SendRtcp(const uint8_t* packet, size_t length) override;
+
+   private:
+    FakeNetworkPipeOnTaskQueue* const network_pipe_;
+    Call* const call_;
+    Clock* const clock_;
+    Transport* const real_transport_;
+  };
+
+  void SetClientBitratePreferences(
+      const webrtc::BitrateSettings& preferences) override;
+  void UpdateSendNetworkConfig();
+  void UpdateReceiveNetworkConfig();
+
+  Clock* const clock_;
+  const std::unique_ptr<Call> call_;
+  // For cancelling tasks on the network thread when DegradedCall is destroyed
+  rtc::scoped_refptr<PendingTaskSafetyFlag> call_alive_;
+  size_t send_config_index_;
+  const std::vector<TimeScopedNetworkConfig> send_configs_;
+  SimulatedNetwork* send_simulated_network_;
+  std::unique_ptr<FakeNetworkPipeOnTaskQueue> send_pipe_;
+  std::map<AudioSendStream*, std::unique_ptr<FakeNetworkPipeTransportAdapter>>
+      audio_send_transport_adapters_;
+  std::map<VideoSendStream*, std::unique_ptr<FakeNetworkPipeTransportAdapter>>
+      video_send_transport_adapters_;
+
+  size_t receive_config_index_;
+  const std::vector<TimeScopedNetworkConfig> receive_configs_;
+  SimulatedNetwork* receive_simulated_network_;
+  SequenceChecker received_packet_sequence_checker_;
+  std::unique_ptr<FakeNetworkPipe> receive_pipe_
+      RTC_GUARDED_BY(received_packet_sequence_checker_);
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_DEGRADED_CALL_H_
diff --git a/third_party/libwebrtc/call/fake_network_pipe.cc b/third_party/libwebrtc/call/fake_network_pipe.cc
new file mode 100644
index 0000000000..8879927a5b
--- /dev/null
+++ b/third_party/libwebrtc/call/fake_network_pipe.cc
@@ -0,0 +1,421 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/fake_network_pipe.h"
+
+#include <string.h>
+
+#include <algorithm>
+#include <queue>
+#include <utility>
+#include <vector>
+
+#include "api/media_types.h"
+#include "api/units/timestamp.h"
+#include "modules/rtp_rtcp/source/rtp_packet_received.h"
+#include "rtc_base/checks.h"
+#include "rtc_base/logging.h"
+#include "system_wrappers/include/clock.h"
+
+namespace webrtc {
+
+namespace {
+constexpr int64_t kLogIntervalMs = 5000;
+}  // namespace
+
+NetworkPacket::NetworkPacket(rtc::CopyOnWriteBuffer packet,
+                             int64_t send_time,
+                             int64_t arrival_time,
+                             absl::optional<PacketOptions> packet_options,
+                             bool is_rtcp,
+                             MediaType media_type,
+                             absl::optional<int64_t> packet_time_us,
+                             Transport* transport)
+    : packet_(std::move(packet)),
+      send_time_(send_time),
+      arrival_time_(arrival_time),
+      packet_options_(packet_options),
+      is_rtcp_(is_rtcp),
+      media_type_(media_type),
+      packet_time_us_(packet_time_us),
+      transport_(transport) {}
+
+NetworkPacket::NetworkPacket(RtpPacketReceived packet_received,
+                             MediaType media_type,
+                             int64_t send_time,
+                             int64_t arrival_time)
+    : packet_(packet_received.Buffer()),
+      send_time_(send_time),
+      arrival_time_(arrival_time),
+      is_rtcp_(false),
+      media_type_(media_type),
+      packet_time_us_(packet_received.arrival_time().us()),
+      packet_received_(std::move(packet_received)),
+      transport_(nullptr) {}
+
+NetworkPacket::NetworkPacket(NetworkPacket&& o)
+    : packet_(std::move(o.packet_)),
+      send_time_(o.send_time_),
+      arrival_time_(o.arrival_time_),
+      packet_options_(o.packet_options_),
+      is_rtcp_(o.is_rtcp_),
+      media_type_(o.media_type_),
+      packet_time_us_(o.packet_time_us_),
+      packet_received_(std::move(o.packet_received_)),
+      transport_(o.transport_) {}
+
+NetworkPacket::~NetworkPacket() = default;
+
+NetworkPacket& NetworkPacket::operator=(NetworkPacket&& o) {
+  packet_ = std::move(o.packet_);
+  send_time_ = o.send_time_;
+  arrival_time_ = o.arrival_time_;
+  packet_options_ = o.packet_options_;
+  is_rtcp_ = o.is_rtcp_;
+  media_type_ = o.media_type_;
+  packet_time_us_ = o.packet_time_us_;
+  packet_received_ = o.packet_received_;
+  transport_ = o.transport_;
+
+  return *this;
+}
+
+FakeNetworkPipe::FakeNetworkPipe(
+    Clock* clock,
+    std::unique_ptr<NetworkBehaviorInterface> network_behavior)
+    : FakeNetworkPipe(clock, std::move(network_behavior), nullptr, 1) {}
+
+FakeNetworkPipe::FakeNetworkPipe(
+    Clock* clock,
+    std::unique_ptr<NetworkBehaviorInterface> network_behavior,
+    PacketReceiver* receiver)
+    : FakeNetworkPipe(clock, std::move(network_behavior), receiver, 1) {}
+
+FakeNetworkPipe::FakeNetworkPipe(
+    Clock* clock,
+    std::unique_ptr<NetworkBehaviorInterface> network_behavior,
+    PacketReceiver* receiver,
+    uint64_t seed)
+    : clock_(clock),
+      network_behavior_(std::move(network_behavior)),
+      receiver_(receiver),
+      global_transport_(nullptr),
+      clock_offset_ms_(0),
+      dropped_packets_(0),
+      sent_packets_(0),
+      total_packet_delay_us_(0),
+      last_log_time_us_(clock_->TimeInMicroseconds()) {}
+
+FakeNetworkPipe::FakeNetworkPipe(
+    Clock* clock,
+    std::unique_ptr<NetworkBehaviorInterface> network_behavior,
+    Transport* transport)
+    : clock_(clock),
+      network_behavior_(std::move(network_behavior)),
+      receiver_(nullptr),
+      global_transport_(transport),
+      clock_offset_ms_(0),
+      dropped_packets_(0),
+      sent_packets_(0),
+      total_packet_delay_us_(0),
+      last_log_time_us_(clock_->TimeInMicroseconds()) {
+  RTC_DCHECK(global_transport_);
+  AddActiveTransport(global_transport_);
+}
+
+FakeNetworkPipe::~FakeNetworkPipe() {
+  if (global_transport_) {
+    RemoveActiveTransport(global_transport_);
+  }
+  RTC_DCHECK(active_transports_.empty());
+}
+
+void FakeNetworkPipe::SetReceiver(PacketReceiver* receiver) {
+  MutexLock lock(&config_lock_);
+  receiver_ = receiver;
+}
+
+void FakeNetworkPipe::AddActiveTransport(Transport* transport) {
+  MutexLock lock(&config_lock_);
+  active_transports_[transport]++;
+}
+
+void FakeNetworkPipe::RemoveActiveTransport(Transport* transport) {
+  MutexLock lock(&config_lock_);
+  auto it = active_transports_.find(transport);
+  RTC_CHECK(it != active_transports_.end());
+  if (--(it->second) == 0) {
+    active_transports_.erase(it);
+  }
+}
+
+bool FakeNetworkPipe::SendRtp(const uint8_t* packet,
+                              size_t length,
+                              const PacketOptions& options) {
+  RTC_DCHECK(global_transport_);
+  EnqueuePacket(rtc::CopyOnWriteBuffer(packet, length), options, false,
+                global_transport_);
+  return true;
+}
+
+bool FakeNetworkPipe::SendRtcp(const uint8_t* packet, size_t length) {
+  RTC_DCHECK(global_transport_);
+  EnqueuePacket(rtc::CopyOnWriteBuffer(packet, length), absl::nullopt, true,
+                global_transport_);
+  return true;
+}
+
+bool FakeNetworkPipe::SendRtp(const uint8_t* packet,
+                              size_t length,
+                              const PacketOptions& options,
+                              Transport* transport) {
+  RTC_DCHECK(transport);
+  EnqueuePacket(rtc::CopyOnWriteBuffer(packet, length), options, false,
+                transport);
+  return true;
+}
+
+bool FakeNetworkPipe::SendRtcp(const uint8_t* packet,
+                               size_t length,
+                               Transport* transport) {
+  RTC_DCHECK(transport);
+  EnqueuePacket(rtc::CopyOnWriteBuffer(packet, length), absl::nullopt, true,
+                transport);
+  return true;
+}
+
+void FakeNetworkPipe::DeliverRtpPacket(
+    MediaType media_type,
+    RtpPacketReceived packet,
+    OnUndemuxablePacketHandler undemuxable_packet_handler) {
+  MutexLock lock(&process_lock_);
+  int64_t time_now_us = clock_->TimeInMicroseconds();
+  EnqueuePacket(
+      NetworkPacket(std::move(packet), media_type, time_now_us, time_now_us));
+}
+
+void FakeNetworkPipe::DeliverRtcpPacket(rtc::CopyOnWriteBuffer packet) {
+  EnqueuePacket(std::move(packet), absl::nullopt, true, MediaType::ANY,
+                absl::nullopt);
+}
+
+void FakeNetworkPipe::SetClockOffset(int64_t offset_ms) {
+  MutexLock lock(&config_lock_);
+  clock_offset_ms_ = offset_ms;
+}
+
+FakeNetworkPipe::StoredPacket::StoredPacket(NetworkPacket&& packet)
+    : packet(std::move(packet)) {}
+
+bool FakeNetworkPipe::EnqueuePacket(rtc::CopyOnWriteBuffer packet,
+                                    absl::optional<PacketOptions> options,
+                                    bool is_rtcp,
+                                    MediaType media_type,
+                                    absl::optional<int64_t> packet_time_us) {
+  MutexLock lock(&process_lock_);
+  int64_t time_now_us = clock_->TimeInMicroseconds();
+  return EnqueuePacket(NetworkPacket(std::move(packet), time_now_us,
+                                     time_now_us, options, is_rtcp, media_type,
+                                     packet_time_us, nullptr));
+}
+
+bool FakeNetworkPipe::EnqueuePacket(rtc::CopyOnWriteBuffer packet,
+                                    absl::optional<PacketOptions> options,
+                                    bool is_rtcp,
+                                    Transport* transport) {
+  MutexLock lock(&process_lock_);
+  int64_t time_now_us = clock_->TimeInMicroseconds();
+  return EnqueuePacket(NetworkPacket(std::move(packet), time_now_us,
+                                     time_now_us, options, is_rtcp,
+                                     MediaType::ANY, absl::nullopt, transport));
+}
+
+bool FakeNetworkPipe::EnqueuePacket(NetworkPacket&& net_packet) {
+  int64_t send_time_us = net_packet.send_time();
+  size_t packet_size = net_packet.data_length();
+
+  packets_in_flight_.emplace_back(StoredPacket(std::move(net_packet)));
+  int64_t packet_id = reinterpret_cast<uint64_t>(&packets_in_flight_.back());
+  bool sent = network_behavior_->EnqueuePacket(
+      PacketInFlightInfo(packet_size, send_time_us, packet_id));
+
+  if (!sent) {
+    packets_in_flight_.pop_back();
+    ++dropped_packets_;
+  }
+  return sent;
+}
+
+float FakeNetworkPipe::PercentageLoss() {
+  MutexLock lock(&process_lock_);
+  if (sent_packets_ == 0)
+    return 0;
+
+  return static_cast<float>(dropped_packets_) /
+         (sent_packets_ + dropped_packets_);
+}
+
+int FakeNetworkPipe::AverageDelay() {
+  MutexLock lock(&process_lock_);
+  if (sent_packets_ == 0)
+    return 0;
+
+  return static_cast<int>(total_packet_delay_us_ /
+                          (1000 * static_cast<int64_t>(sent_packets_)));
+}
+
+size_t FakeNetworkPipe::DroppedPackets() {
+  MutexLock lock(&process_lock_);
+  return dropped_packets_;
+}
+
+size_t FakeNetworkPipe::SentPackets() {
+  MutexLock lock(&process_lock_);
+  return sent_packets_;
+}
+
+void FakeNetworkPipe::Process() {
+  int64_t time_now_us;
+  std::queue<NetworkPacket> packets_to_deliver;
+  {
+    MutexLock lock(&process_lock_);
+    time_now_us = clock_->TimeInMicroseconds();
+    if (time_now_us - last_log_time_us_ > kLogIntervalMs * 1000) {
+      int64_t queueing_delay_us = 0;
+      if (!packets_in_flight_.empty())
+        queueing_delay_us =
+            time_now_us - packets_in_flight_.front().packet.send_time();
+
+      RTC_LOG(LS_INFO) << "Network queue: " << queueing_delay_us / 1000
+                       << " ms.";
+      last_log_time_us_ = time_now_us;
+    }
+
+    std::vector<PacketDeliveryInfo> delivery_infos =
+        network_behavior_->DequeueDeliverablePackets(time_now_us);
+    for (auto& delivery_info : delivery_infos) {
+      // In the common case where no reordering happens, find will return early
+      // as the first packet will be a match.
+      auto packet_it =
+          std::find_if(packets_in_flight_.begin(), packets_in_flight_.end(),
+                       [&delivery_info](StoredPacket& packet_ref) {
+                         return reinterpret_cast<uint64_t>(&packet_ref) ==
+                                delivery_info.packet_id;
+                       });
+      // Check that the packet is in the deque of packets in flight.
+      RTC_CHECK(packet_it != packets_in_flight_.end());
+      // Check that the packet is not already removed.
+      RTC_DCHECK(!packet_it->removed);
+
+      NetworkPacket packet = std::move(packet_it->packet);
+      packet_it->removed = true;
+
+      // Cleanup of removed packets at the beginning of the deque.
+      while (!packets_in_flight_.empty() &&
+             packets_in_flight_.front().removed) {
+        packets_in_flight_.pop_front();
+      }
+
+      if (delivery_info.receive_time_us != PacketDeliveryInfo::kNotReceived) {
+        int64_t added_delay_us =
+            delivery_info.receive_time_us - packet.send_time();
+        packet.IncrementArrivalTime(added_delay_us);
+        packets_to_deliver.emplace(std::move(packet));
+        // `time_now_us` might be later than when the packet should have
+        // arrived, due to NetworkProcess being called too late. For stats, use
+        // the time it should have been on the link.
+        total_packet_delay_us_ += added_delay_us;
+        ++sent_packets_;
+      } else {
+        ++dropped_packets_;
+      }
+    }
+  }
+
+  MutexLock lock(&config_lock_);
+  while (!packets_to_deliver.empty()) {
+    NetworkPacket packet = std::move(packets_to_deliver.front());
+    packets_to_deliver.pop();
+    DeliverNetworkPacket(&packet);
+  }
+}
+
+void FakeNetworkPipe::DeliverNetworkPacket(NetworkPacket* packet) {
+  Transport* transport = packet->transport();
+  if (transport) {
+    RTC_DCHECK(!receiver_);
+    if (active_transports_.find(transport) == active_transports_.end()) {
+      // Transport has been destroyed, ignore this packet.
+      return;
+    }
+    if (packet->is_rtcp()) {
+      transport->SendRtcp(packet->data(), packet->data_length());
+    } else {
+      transport->SendRtp(packet->data(), packet->data_length(),
+                         packet->packet_options());
+    }
+  } else if (receiver_) {
+    int64_t packet_time_us = packet->packet_time_us().value_or(-1);
+    if (packet_time_us != -1) {
+      int64_t queue_time_us = packet->arrival_time() - packet->send_time();
+      RTC_CHECK(queue_time_us >= 0);
+      packet_time_us += queue_time_us;
+      packet_time_us += (clock_offset_ms_ * 1000);
+    }
+    if (packet->is_rtcp()) {
+      receiver_->DeliverRtcpPacket(std::move(*packet->raw_packet()));
+    } else if (packet->packet_received()) {
+      packet->packet_received()->set_arrival_time(
+          Timestamp::Micros(packet_time_us));
+      receiver_->DeliverRtpPacket(
+          packet->media_type(), *packet->packet_received(),
+          [](const RtpPacketReceived& packet) {
+            RTC_LOG(LS_WARNING)
+                << "Unexpected failed demuxing packet in FakeNetworkPipe, "
+                   "Ssrc: "
+                << packet.Ssrc() << " seq : " << packet.SequenceNumber();
+            return false;
+          });
+    }
+  }
+}
+
+absl::optional<int64_t> FakeNetworkPipe::TimeUntilNextProcess() {
+  MutexLock lock(&process_lock_);
+  absl::optional<int64_t> delivery_us = network_behavior_->NextDeliveryTimeUs();
+  if (delivery_us) {
+    int64_t delay_us = *delivery_us - clock_->TimeInMicroseconds();
+    return std::max<int64_t>((delay_us + 500) / 1000, 0);
+  }
+  return absl::nullopt;
+}
+
+bool FakeNetworkPipe::HasReceiver() const {
+  MutexLock lock(&config_lock_);
+  return receiver_ != nullptr;
+}
+
+void FakeNetworkPipe::DeliverPacketWithLock(NetworkPacket* packet) {
+  MutexLock lock(&config_lock_);
+  DeliverNetworkPacket(packet);
+}
+
+void FakeNetworkPipe::ResetStats() {
+  MutexLock lock(&process_lock_);
+  dropped_packets_ = 0;
+  sent_packets_ = 0;
+  total_packet_delay_us_ = 0;
+}
+
+int64_t FakeNetworkPipe::GetTimeInMicroseconds() const {
+  return clock_->TimeInMicroseconds();
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/fake_network_pipe.h b/third_party/libwebrtc/call/fake_network_pipe.h
new file mode 100644
index 0000000000..ba4c89e382
--- /dev/null
+++ b/third_party/libwebrtc/call/fake_network_pipe.h
@@ -0,0 +1,246 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_FAKE_NETWORK_PIPE_H_
+#define CALL_FAKE_NETWORK_PIPE_H_
+
+#include <deque>
+#include <map>
+#include <memory>
+#include <queue>
+#include <set>
+#include <string>
+#include <vector>
+
+#include "api/call/transport.h"
+#include "api/test/simulated_network.h"
+#include "call/simulated_packet_receiver.h"
+#include "modules/rtp_rtcp/source/rtp_packet_received.h"
+#include "rtc_base/synchronization/mutex.h"
+#include "rtc_base/thread_annotations.h"
+
+namespace webrtc {
+
+class Clock;
+class PacketReceiver;
+enum class MediaType;
+
+class NetworkPacket {
+ public:
+  NetworkPacket(rtc::CopyOnWriteBuffer packet,
+                int64_t send_time,
+                int64_t arrival_time,
+                absl::optional<PacketOptions> packet_options,
+                bool is_rtcp,
+                MediaType media_type,
+                absl::optional<int64_t> packet_time_us,
+                Transport* transport);
+
+  NetworkPacket(RtpPacketReceived packet,
+                MediaType media_type,
+                int64_t send_time,
+                int64_t arrival_time);
+
+  // Disallow copy constructor and copy assignment (no deep copies of `data_`).
+  NetworkPacket(const NetworkPacket&) = delete;
+  ~NetworkPacket();
+  NetworkPacket& operator=(const NetworkPacket&) = delete;
+  // Allow move constructor/assignment, so that we can use in stl containers.
+  NetworkPacket(NetworkPacket&&);
+  NetworkPacket& operator=(NetworkPacket&&);
+
+  const uint8_t* data() const { return packet_.data(); }
+  size_t data_length() const { return packet_.size(); }
+  rtc::CopyOnWriteBuffer* raw_packet() { return &packet_; }
+  int64_t send_time() const { return send_time_; }
+  int64_t arrival_time() const { return arrival_time_; }
+  void IncrementArrivalTime(int64_t extra_delay) {
+    arrival_time_ += extra_delay;
+  }
+  PacketOptions packet_options() const {
+    return packet_options_.value_or(PacketOptions());
+  }
+  bool is_rtcp() const { return is_rtcp_; }
+  MediaType media_type() const { return media_type_; }
+  absl::optional<int64_t> packet_time_us() const { return packet_time_us_; }
+  RtpPacketReceived* packet_received() {
+    return packet_received_ ? &packet_received_.value() : nullptr;
+  }
+  absl::optional<RtpPacketReceived> packet_received() const {
+    return packet_received_;
+  }
+  Transport* transport() const { return transport_; }
+
+ private:
+  rtc::CopyOnWriteBuffer packet_;
+  // The time the packet was sent out on the network.
+  int64_t send_time_;
+  // The time the packet should arrive at the receiver.
+  int64_t arrival_time_;
+  // If using a Transport for outgoing degradation, populate with
+  // PacketOptions (transport-wide sequence number) for RTP.
+  absl::optional<PacketOptions> packet_options_;
+  bool is_rtcp_;
+  // If using a PacketReceiver for incoming degradation, populate with
+  // appropriate MediaType and packet time. This type/timing will be kept and
+  // forwarded. The packet time might be altered to reflect time spent in fake
+  // network pipe.
+  MediaType media_type_;
+  absl::optional<int64_t> packet_time_us_;
+  absl::optional<RtpPacketReceived> packet_received_;
+  Transport* transport_;
+};
+
+// Class faking a network link, internally is uses an implementation of a
+// SimulatedNetworkInterface to simulate network behavior.
+class FakeNetworkPipe : public SimulatedPacketReceiverInterface {
+ public:
+  // Will keep `network_behavior` alive while pipe is alive itself.
+  FakeNetworkPipe(Clock* clock,
+                  std::unique_ptr<NetworkBehaviorInterface> network_behavior);
+  FakeNetworkPipe(Clock* clock,
+                  std::unique_ptr<NetworkBehaviorInterface> network_behavior,
+                  PacketReceiver* receiver);
+  FakeNetworkPipe(Clock* clock,
+                  std::unique_ptr<NetworkBehaviorInterface> network_behavior,
+                  PacketReceiver* receiver,
+                  uint64_t seed);
+
+  // Use this constructor if you plan to insert packets using SendRt[c?]p().
+  FakeNetworkPipe(Clock* clock,
+                  std::unique_ptr<NetworkBehaviorInterface> network_behavior,
+                  Transport* transport);
+
+  ~FakeNetworkPipe() override;
+
+  FakeNetworkPipe(const FakeNetworkPipe&) = delete;
+  FakeNetworkPipe& operator=(const FakeNetworkPipe&) = delete;
+
+  void SetClockOffset(int64_t offset_ms);
+
+  // Must not be called in parallel with DeliverPacket or Process.
+  void SetReceiver(PacketReceiver* receiver) override;
+
+  // Adds/subtracts references to Transport instances. If a Transport is
+  // destroyed we cannot use to forward a potential delayed packet, these
+  // methods are used to maintain a map of which instances are live.
+  void AddActiveTransport(Transport* transport);
+  void RemoveActiveTransport(Transport* transport);
+
+  // Implements Transport interface. When/if packets are delivered, they will
+  // be passed to the transport instance given in SetReceiverTransport(). These
+  // methods should only be called if a Transport instance was provided in the
+  // constructor.
+  bool SendRtp(const uint8_t* packet,
+               size_t length,
+               const PacketOptions& options);
+  bool SendRtcp(const uint8_t* packet, size_t length);
+
+  // Methods for use with Transport interface. When/if packets are delivered,
+  // they will be passed to the instance specified by the `transport` parameter.
+  // Note that that instance must be in the map of active transports.
+  bool SendRtp(const uint8_t* packet,
+               size_t length,
+               const PacketOptions& options,
+               Transport* transport);
+  bool SendRtcp(const uint8_t* packet, size_t length, Transport* transport);
+
+  // Implements the PacketReceiver interface. When/if packets are delivered,
+  // they will be passed directly to the receiver instance given in
+  // SetReceiver(). The receive time will be increased by the amount of time the
+  // packet spent in the fake network pipe.
+  void DeliverRtpPacket(
+      MediaType media_type,
+      RtpPacketReceived packet,
+      OnUndemuxablePacketHandler undemuxable_packet_handler) override;
+  void DeliverRtcpPacket(rtc::CopyOnWriteBuffer packet) override;
+
+  // Processes the network queues and trigger PacketReceiver::IncomingPacket for
+  // packets ready to be delivered.
+  void Process() override;
+  absl::optional<int64_t> TimeUntilNextProcess() override;
+
+  // Get statistics.
+  float PercentageLoss();
+  int AverageDelay() override;
+  size_t DroppedPackets();
+  size_t SentPackets();
+  void ResetStats();
+
+ protected:
+  void DeliverPacketWithLock(NetworkPacket* packet);
+  int64_t GetTimeInMicroseconds() const;
+  bool ShouldProcess(int64_t time_now_us) const;
+  void SetTimeToNextProcess(int64_t skip_us);
+
+ private:
+  struct StoredPacket {
+    NetworkPacket packet;
+    bool removed = false;
+    explicit StoredPacket(NetworkPacket&& packet);
+    StoredPacket(StoredPacket&&) = default;
+    StoredPacket(const StoredPacket&) = delete;
+    StoredPacket& operator=(const StoredPacket&) = delete;
+    StoredPacket() = delete;
+  };
+
+  // Returns true if enqueued, or false if packet was dropped. Use this method
+  // when enqueueing packets that should be received by PacketReceiver instance.
+  bool EnqueuePacket(rtc::CopyOnWriteBuffer packet,
+                     absl::optional<PacketOptions> options,
+                     bool is_rtcp,
+                     MediaType media_type,
+                     absl::optional<int64_t> packet_time_us);
+
+  // Returns true if enqueued, or false if packet was dropped. Use this method
+  // when enqueueing packets that should be received by Transport instance.
+  bool EnqueuePacket(rtc::CopyOnWriteBuffer packet,
+                     absl::optional<PacketOptions> options,
+                     bool is_rtcp,
+                     Transport* transport);
+
+  bool EnqueuePacket(NetworkPacket&& net_packet)
+      RTC_EXCLUSIVE_LOCKS_REQUIRED(process_lock_);
+
+  void DeliverNetworkPacket(NetworkPacket* packet)
+      RTC_EXCLUSIVE_LOCKS_REQUIRED(config_lock_);
+  bool HasReceiver() const;
+
+  Clock* const clock_;
+  // `config_lock` guards the mostly constant things like the callbacks.
+  mutable Mutex config_lock_;
+  const std::unique_ptr<NetworkBehaviorInterface> network_behavior_;
+  PacketReceiver* receiver_ RTC_GUARDED_BY(config_lock_);
+  Transport* const global_transport_;
+
+  // `process_lock` guards the data structures involved in delay and loss
+  // processes, such as the packet queues.
+  Mutex process_lock_;
+  // Packets  are added at the back of the deque, this makes the deque ordered
+  // by increasing send time. The common case when removing packets from the
+  // deque is removing early packets, which will be close to the front of the
+  // deque. This makes finding the packets in the deque efficient in the common
+  // case.
+  std::deque<StoredPacket> packets_in_flight_ RTC_GUARDED_BY(process_lock_);
+
+  int64_t clock_offset_ms_ RTC_GUARDED_BY(config_lock_);
+
+  // Statistics.
+  size_t dropped_packets_ RTC_GUARDED_BY(process_lock_);
+  size_t sent_packets_ RTC_GUARDED_BY(process_lock_);
+  int64_t total_packet_delay_us_ RTC_GUARDED_BY(process_lock_);
+  int64_t last_log_time_us_;
+
+  std::map<Transport*, size_t> active_transports_ RTC_GUARDED_BY(config_lock_);
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_FAKE_NETWORK_PIPE_H_
diff --git a/third_party/libwebrtc/call/fake_network_pipe_unittest.cc b/third_party/libwebrtc/call/fake_network_pipe_unittest.cc
new file mode 100644
index 0000000000..31f97fc85c
--- /dev/null
+++ b/third_party/libwebrtc/call/fake_network_pipe_unittest.cc
@@ -0,0 +1,509 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/fake_network_pipe.h"
+
+#include <memory>
+#include <utility>
+
+#include "api/units/time_delta.h"
+#include "api/units/timestamp.h"
+#include "call/simulated_network.h"
+#include "modules/rtp_rtcp/include/rtp_header_extension_map.h"
+#include "modules/rtp_rtcp/source/rtp_header_extensions.h"
+#include "modules/rtp_rtcp/source/rtp_packet_received.h"
+#include "rtc_base/checks.h"
+#include "system_wrappers/include/clock.h"
+#include "test/gmock.h"
+#include "test/gtest.h"
+
+using ::testing::_;
+using ::testing::Property;
+using ::testing::WithArg;
+
+namespace webrtc {
+class MockReceiver : public PacketReceiver {
+ public:
+  MOCK_METHOD(void,
+              DeliverRtcpPacket,
+              (rtc::CopyOnWriteBuffer packet),
+              (override));
+  MOCK_METHOD(void,
+              DeliverRtpPacket,
+              (MediaType media_type,
+               RtpPacketReceived packet,
+               OnUndemuxablePacketHandler undemuxable_packet_handler),
+              (override));
+  virtual ~MockReceiver() = default;
+};
+
+class ReorderTestReceiver : public MockReceiver {
+ public:
+  void DeliverRtpPacket(
+      MediaType media_type,
+      RtpPacketReceived packet,
+      OnUndemuxablePacketHandler undemuxable_packet_handler) override {
+    RTC_DCHECK_GE(packet.size(), sizeof(int));
+    delivered_sequence_numbers_.push_back(packet.SequenceNumber());
+  }
+  std::vector<int> delivered_sequence_numbers_;
+};
+
+class FakeNetworkPipeTest : public ::testing::Test {
+ public:
+  FakeNetworkPipeTest() : fake_clock_(12345) {}
+
+ protected:
+  void SendPackets(FakeNetworkPipe* pipe, int number_packets, int packet_size) {
+    RTC_DCHECK_GE(packet_size, sizeof(int));
+    for (int i = 0; i < number_packets; ++i) {
+      RtpPacketReceived packet;
+      constexpr size_t kFixedHeaderSize = 12;
+      packet.AllocatePayload(packet_size - kFixedHeaderSize);
+      packet.SetSequenceNumber(i);
+      packet.set_arrival_time(fake_clock_.CurrentTime());
+      RTC_DCHECK_EQ(packet.Buffer().size(), packet_size);
+      pipe->DeliverRtpPacket(MediaType::ANY, std::move(packet),
+                             [](const RtpPacketReceived&) { return false; });
+    }
+  }
+
+  int PacketTimeMs(int capacity_kbps, int packet_size) const {
+    return 8 * packet_size / capacity_kbps;
+  }
+
+  SimulatedClock fake_clock_;
+};
+
+// Test the capacity link and verify we get as many packets as we expect.
+TEST_F(FakeNetworkPipeTest, CapacityTest) {
+  BuiltInNetworkBehaviorConfig config;
+  config.queue_length_packets = 20;
+  config.link_capacity_kbps = 80;
+  MockReceiver receiver;
+  auto simulated_network = std::make_unique<SimulatedNetwork>(config);
+  std::unique_ptr<FakeNetworkPipe> pipe(new FakeNetworkPipe(
+      &fake_clock_, std::move(simulated_network), &receiver));
+
+  // Add 10 packets of 1000 bytes, = 80 kb, and verify it takes one second to
+  // get through the pipe.
+  const int kNumPackets = 10;
+  const int kPacketSize = 1000;
+  SendPackets(pipe.get(), kNumPackets, kPacketSize);
+
+  // Time to get one packet through the link.
+  const int kPacketTimeMs =
+      PacketTimeMs(config.link_capacity_kbps, kPacketSize);
+
+  // Time haven't increased yet, so we souldn't get any packets.
+  EXPECT_CALL(receiver, DeliverRtpPacket).Times(0);
+  pipe->Process();
+
+  // Advance enough time to release one packet.
+  fake_clock_.AdvanceTimeMilliseconds(kPacketTimeMs);
+  EXPECT_CALL(receiver, DeliverRtpPacket).Times(1);
+  pipe->Process();
+
+  // Release all but one packet
+  fake_clock_.AdvanceTimeMilliseconds(9 * kPacketTimeMs - 1);
+  EXPECT_CALL(receiver, DeliverRtpPacket).Times(8);
+  pipe->Process();
+
+  // And the last one.
+  fake_clock_.AdvanceTimeMilliseconds(1);
+  EXPECT_CALL(receiver, DeliverRtpPacket).Times(1);
+  pipe->Process();
+}
+
+// Test the extra network delay.
+TEST_F(FakeNetworkPipeTest, ExtraDelayTest) {
+  BuiltInNetworkBehaviorConfig config;
+  config.queue_length_packets = 20;
+  config.queue_delay_ms = 100;
+  config.link_capacity_kbps = 80;
+  MockReceiver receiver;
+  auto simulated_network = std::make_unique<SimulatedNetwork>(config);
+  std::unique_ptr<FakeNetworkPipe> pipe(new FakeNetworkPipe(
+      &fake_clock_, std::move(simulated_network), &receiver));
+
+  const int kNumPackets = 2;
+  const int kPacketSize = 1000;
+  SendPackets(pipe.get(), kNumPackets, kPacketSize);
+
+  // Time to get one packet through the link.
+  const int kPacketTimeMs =
+      PacketTimeMs(config.link_capacity_kbps, kPacketSize);
+
+  // Increase more than kPacketTimeMs, but not more than the extra delay.
+  fake_clock_.AdvanceTimeMilliseconds(kPacketTimeMs);
+  EXPECT_CALL(receiver, DeliverRtpPacket).Times(0);
+  pipe->Process();
+
+  // Advance the network delay to get the first packet.
+  fake_clock_.AdvanceTimeMilliseconds(config.queue_delay_ms);
+  EXPECT_CALL(receiver, DeliverRtpPacket).Times(1);
+  pipe->Process();
+
+  // Advance one more kPacketTimeMs to get the last packet.
+  fake_clock_.AdvanceTimeMilliseconds(kPacketTimeMs);
+  EXPECT_CALL(receiver, DeliverRtpPacket).Times(1);
+  pipe->Process();
+}
+
+// Test the number of buffers and packets are dropped when sending too many
+// packets too quickly.
+TEST_F(FakeNetworkPipeTest, QueueLengthTest) {
+  BuiltInNetworkBehaviorConfig config;
+  config.queue_length_packets = 2;
+  config.link_capacity_kbps = 80;
+  MockReceiver receiver;
+  auto simulated_network = std::make_unique<SimulatedNetwork>(config);
+  std::unique_ptr<FakeNetworkPipe> pipe(new FakeNetworkPipe(
+      &fake_clock_, std::move(simulated_network), &receiver));
+
+  const int kPacketSize = 1000;
+  const int kPacketTimeMs =
+      PacketTimeMs(config.link_capacity_kbps, kPacketSize);
+
+  // Send three packets and verify only 2 are delivered.
+  SendPackets(pipe.get(), 3, kPacketSize);
+
+  // Increase time enough to deliver all three packets, verify only two are
+  // delivered.
+  fake_clock_.AdvanceTimeMilliseconds(3 * kPacketTimeMs);
+  EXPECT_CALL(receiver, DeliverRtpPacket).Times(2);
+  pipe->Process();
+}
+
+// Test we get statistics as expected.
+TEST_F(FakeNetworkPipeTest, StatisticsTest) {
+  BuiltInNetworkBehaviorConfig config;
+  config.queue_length_packets = 2;
+  config.queue_delay_ms = 20;
+  config.link_capacity_kbps = 80;
+  MockReceiver receiver;
+  auto simulated_network = std::make_unique<SimulatedNetwork>(config);
+  std::unique_ptr<FakeNetworkPipe> pipe(new FakeNetworkPipe(
+      &fake_clock_, std::move(simulated_network), &receiver));
+
+  const int kPacketSize = 1000;
+  const int kPacketTimeMs =
+      PacketTimeMs(config.link_capacity_kbps, kPacketSize);
+
+  // Send three packets and verify only 2 are delivered.
+  SendPackets(pipe.get(), 3, kPacketSize);
+  fake_clock_.AdvanceTimeMilliseconds(3 * kPacketTimeMs +
+                                      config.queue_delay_ms);
+
+  EXPECT_CALL(receiver, DeliverRtpPacket).Times(2);
+  pipe->Process();
+
+  // Packet 1: kPacketTimeMs + config.queue_delay_ms,
+  // packet 2: 2 * kPacketTimeMs + config.queue_delay_ms => 170 ms average.
+  EXPECT_EQ(pipe->AverageDelay(), 170);
+  EXPECT_EQ(pipe->SentPackets(), 2u);
+  EXPECT_EQ(pipe->DroppedPackets(), 1u);
+  EXPECT_EQ(pipe->PercentageLoss(), 1 / 3.f);
+}
+
+// Change the link capacity half-way through the test and verify that the
+// delivery times change accordingly.
+TEST_F(FakeNetworkPipeTest, ChangingCapacityWithEmptyPipeTest) {
+  BuiltInNetworkBehaviorConfig config;
+  config.queue_length_packets = 20;
+  config.link_capacity_kbps = 80;
+  MockReceiver receiver;
+  std::unique_ptr<SimulatedNetwork> network(new SimulatedNetwork(config));
+  SimulatedNetwork* simulated_network = network.get();
+  std::unique_ptr<FakeNetworkPipe> pipe(
+      new FakeNetworkPipe(&fake_clock_, std::move(network), &receiver));
+
+  // Add 10 packets of 1000 bytes, = 80 kb, and verify it takes one second to
+  // get through the pipe.
+  const int kNumPackets = 10;
+  const int kPacketSize = 1000;
+  SendPackets(pipe.get(), kNumPackets, kPacketSize);
+
+  // Time to get one packet through the link.
+  int packet_time_ms = PacketTimeMs(config.link_capacity_kbps, kPacketSize);
+
+  // Time hasn't increased yet, so we souldn't get any packets.
+  EXPECT_CALL(receiver, DeliverRtpPacket).Times(0);
+  pipe->Process();
+
+  // Advance time in steps to release one packet at a time.
+  for (int i = 0; i < kNumPackets; ++i) {
+    fake_clock_.AdvanceTimeMilliseconds(packet_time_ms);
+    EXPECT_CALL(receiver, DeliverRtpPacket).Times(1);
+    pipe->Process();
+  }
+
+  // Change the capacity.
+  config.link_capacity_kbps /= 2;  // Reduce to 50%.
+  simulated_network->SetConfig(config);
+
+  // Add another 10 packets of 1000 bytes, = 80 kb, and verify it takes two
+  // seconds to get them through the pipe.
+  SendPackets(pipe.get(), kNumPackets, kPacketSize);
+
+  // Time to get one packet through the link.
+  packet_time_ms = PacketTimeMs(config.link_capacity_kbps, kPacketSize);
+
+  // Time hasn't increased yet, so we souldn't get any packets.
+  EXPECT_CALL(receiver, DeliverRtpPacket).Times(0);
+  pipe->Process();
+
+  // Advance time in steps to release one packet at a time.
+  for (int i = 0; i < kNumPackets; ++i) {
+    fake_clock_.AdvanceTimeMilliseconds(packet_time_ms);
+    EXPECT_CALL(receiver, DeliverRtpPacket).Times(1);
+    pipe->Process();
+  }
+
+  // Check that all the packets were sent.
+  EXPECT_EQ(static_cast<size_t>(2 * kNumPackets), pipe->SentPackets());
+  EXPECT_FALSE(pipe->TimeUntilNextProcess().has_value());
+  fake_clock_.AdvanceTimeMilliseconds(1000);
+  EXPECT_CALL(receiver, DeliverRtpPacket).Times(0);
+  pipe->Process();
+}
+
+// Change the link capacity half-way through the test and verify that the
+// delivery times change accordingly.
+TEST_F(FakeNetworkPipeTest, ChangingCapacityWithPacketsInPipeTest) {
+  BuiltInNetworkBehaviorConfig config;
+  config.queue_length_packets = 20;
+  config.link_capacity_kbps = 80;
+  MockReceiver receiver;
+  std::unique_ptr<SimulatedNetwork> network(new SimulatedNetwork(config));
+  SimulatedNetwork* simulated_network = network.get();
+  std::unique_ptr<FakeNetworkPipe> pipe(
+      new FakeNetworkPipe(&fake_clock_, std::move(network), &receiver));
+
+  // Add 20 packets of 1000 bytes, = 160 kb.
+  const int kNumPackets = 20;
+  const int kPacketSize = 1000;
+  SendPackets(pipe.get(), kNumPackets, kPacketSize);
+
+  // Time hasn't increased yet, so we souldn't get any packets.
+  EXPECT_CALL(receiver, DeliverRtpPacket).Times(0);
+  pipe->Process();
+
+  // Advance time in steps to release half of the packets one at a time.
+  int step_ms = PacketTimeMs(config.link_capacity_kbps, kPacketSize);
+  for (int i = 0; i < kNumPackets / 2; ++i) {
+    fake_clock_.AdvanceTimeMilliseconds(step_ms);
+    EXPECT_CALL(receiver, DeliverRtpPacket).Times(1);
+    pipe->Process();
+  }
+
+  // Change the capacity.
+  config.link_capacity_kbps *= 2;  // Double the capacity.
+  simulated_network->SetConfig(config);
+
+  // Advance time in steps to release remaining packets one at a time.
+  step_ms = PacketTimeMs(config.link_capacity_kbps, kPacketSize);
+  for (int i = 0; i < kNumPackets / 2; ++i) {
+    fake_clock_.AdvanceTimeMilliseconds(step_ms);
+    EXPECT_CALL(receiver, DeliverRtpPacket).Times(1);
+    pipe->Process();
+  }
+
+  // Check that all the packets were sent.
+  EXPECT_EQ(static_cast<size_t>(kNumPackets), pipe->SentPackets());
+  EXPECT_FALSE(pipe->TimeUntilNextProcess().has_value());
+  fake_clock_.AdvanceTimeMilliseconds(1000);
+  EXPECT_CALL(receiver, DeliverRtpPacket).Times(0);
+  pipe->Process();
+}
+
+// At first disallow reordering and then allow reordering.
+TEST_F(FakeNetworkPipeTest, DisallowReorderingThenAllowReordering) {
+  BuiltInNetworkBehaviorConfig config;
+  config.queue_length_packets = 1000;
+  config.link_capacity_kbps = 800;
+  config.queue_delay_ms = 100;
+  config.delay_standard_deviation_ms = 10;
+  ReorderTestReceiver receiver;
+  std::unique_ptr<SimulatedNetwork> network(new SimulatedNetwork(config));
+  SimulatedNetwork* simulated_network = network.get();
+  std::unique_ptr<FakeNetworkPipe> pipe(
+      new FakeNetworkPipe(&fake_clock_, std::move(network), &receiver));
+
+  const uint32_t kNumPackets = 100;
+  const int kPacketSize = 10;
+  SendPackets(pipe.get(), kNumPackets, kPacketSize);
+  fake_clock_.AdvanceTimeMilliseconds(1000);
+  pipe->Process();
+
+  // Confirm that all packets have been delivered in order.
+  EXPECT_EQ(kNumPackets, receiver.delivered_sequence_numbers_.size());
+  int last_seq_num = -1;
+  for (int seq_num : receiver.delivered_sequence_numbers_) {
+    EXPECT_GT(seq_num, last_seq_num);
+    last_seq_num = seq_num;
+  }
+
+  config.allow_reordering = true;
+  simulated_network->SetConfig(config);
+  SendPackets(pipe.get(), kNumPackets, kPacketSize);
+  fake_clock_.AdvanceTimeMilliseconds(1000);
+  receiver.delivered_sequence_numbers_.clear();
+  pipe->Process();
+
+  // Confirm that all packets have been delivered
+  // and that reordering has occured.
+  EXPECT_EQ(kNumPackets, receiver.delivered_sequence_numbers_.size());
+  bool reordering_has_occured = false;
+  last_seq_num = -1;
+  for (int seq_num : receiver.delivered_sequence_numbers_) {
+    if (last_seq_num > seq_num) {
+      reordering_has_occured = true;
+      break;
+    }
+    last_seq_num = seq_num;
+  }
+  EXPECT_TRUE(reordering_has_occured);
+}
+
+TEST_F(FakeNetworkPipeTest, BurstLoss) {
+  const int kLossPercent = 5;
+  const int kAvgBurstLength = 3;
+  const int kNumPackets = 10000;
+  const int kPacketSize = 10;
+
+  BuiltInNetworkBehaviorConfig config;
+  config.queue_length_packets = kNumPackets;
+  config.loss_percent = kLossPercent;
+  config.avg_burst_loss_length = kAvgBurstLength;
+  ReorderTestReceiver receiver;
+  auto simulated_network = std::make_unique<SimulatedNetwork>(config);
+  std::unique_ptr<FakeNetworkPipe> pipe(new FakeNetworkPipe(
+      &fake_clock_, std::move(simulated_network), &receiver));
+
+  SendPackets(pipe.get(), kNumPackets, kPacketSize);
+  fake_clock_.AdvanceTimeMilliseconds(1000);
+  pipe->Process();
+
+  // Check that the average loss is `kLossPercent` percent.
+  int lost_packets = kNumPackets - receiver.delivered_sequence_numbers_.size();
+  double loss_fraction = lost_packets / static_cast<double>(kNumPackets);
+
+  EXPECT_NEAR(kLossPercent / 100.0, loss_fraction, 0.05);
+
+  // Find the number of bursts that has occurred.
+  size_t received_packets = receiver.delivered_sequence_numbers_.size();
+  int num_bursts = 0;
+  for (size_t i = 0; i < received_packets - 1; ++i) {
+    int diff = receiver.delivered_sequence_numbers_[i + 1] -
+               receiver.delivered_sequence_numbers_[i];
+    if (diff > 1)
+      ++num_bursts;
+  }
+
+  double average_burst_length = static_cast<double>(lost_packets) / num_bursts;
+
+  EXPECT_NEAR(kAvgBurstLength, average_burst_length, 0.3);
+}
+
+TEST_F(FakeNetworkPipeTest, SetReceiver) {
+  BuiltInNetworkBehaviorConfig config;
+  config.link_capacity_kbps = 800;
+  MockReceiver receiver;
+  auto simulated_network = std::make_unique<SimulatedNetwork>(config);
+  std::unique_ptr<FakeNetworkPipe> pipe(new FakeNetworkPipe(
+      &fake_clock_, std::move(simulated_network), &receiver));
+
+  const int kPacketSize = 1000;
+  const int kPacketTimeMs =
+      PacketTimeMs(config.link_capacity_kbps, kPacketSize);
+  SendPackets(pipe.get(), 1, kPacketSize);
+  fake_clock_.AdvanceTimeMilliseconds(kPacketTimeMs);
+  EXPECT_CALL(receiver, DeliverRtpPacket).Times(1);
+  pipe->Process();
+
+  MockReceiver new_receiver;
+  pipe->SetReceiver(&new_receiver);
+
+  SendPackets(pipe.get(), 1, kPacketSize);
+  fake_clock_.AdvanceTimeMilliseconds(kPacketTimeMs);
+  EXPECT_CALL(receiver, DeliverRtpPacket).Times(0);
+  EXPECT_CALL(new_receiver, DeliverRtpPacket).Times(1);
+  pipe->Process();
+}
+
+TEST_F(FakeNetworkPipeTest, DeliverRtpPacketSetsCorrectArrivalTime) {
+  BuiltInNetworkBehaviorConfig config;
+  config.queue_delay_ms = 100;
+  MockReceiver receiver;
+  auto simulated_network = std::make_unique<SimulatedNetwork>(config);
+  std::unique_ptr<FakeNetworkPipe> pipe(new FakeNetworkPipe(
+      &fake_clock_, std::move(simulated_network), &receiver));
+
+  Timestamp send_time = fake_clock_.CurrentTime();
+  RtpPacketReceived packet(nullptr, send_time);
+  packet.SetExtension<TransportSequenceNumber>(123);
+  pipe->DeliverRtpPacket(MediaType::VIDEO, std::move(packet),
+                         [](const RtpPacketReceived&) { return false; });
+
+  // Advance the network delay to get the first packet.
+  fake_clock_.AdvanceTimeMilliseconds(config.queue_delay_ms);
+  EXPECT_CALL(receiver, DeliverRtpPacket(MediaType::VIDEO, _, _))
+      .WillOnce(WithArg<1>([&](RtpPacketReceived packet) {
+        EXPECT_EQ(packet.arrival_time(),
+                  send_time + TimeDelta::Millis(config.queue_delay_ms));
+      }));
+  pipe->Process();
+}
+
+TEST_F(FakeNetworkPipeTest, DeliverRtpPacketPropagatesExtensions) {
+  BuiltInNetworkBehaviorConfig config;
+  config.queue_delay_ms = 100;
+  MockReceiver receiver;
+  auto simulated_network = std::make_unique<SimulatedNetwork>(config);
+  std::unique_ptr<FakeNetworkPipe> pipe(new FakeNetworkPipe(
+      &fake_clock_, std::move(simulated_network), &receiver));
+  RtpHeaderExtensionMap extension_map;
+  extension_map.Register<TransportSequenceNumber>(/*id=*/7);
+
+  RtpPacketReceived packet(&extension_map, fake_clock_.CurrentTime());
+  packet.SetExtension<TransportSequenceNumber>(123);
+  pipe->DeliverRtpPacket(MediaType::VIDEO, std::move(packet),
+                         [](const RtpPacketReceived&) { return false; });
+
+  // Advance the network delay to get the first packet.
+  fake_clock_.AdvanceTimeMilliseconds(config.queue_delay_ms);
+  EXPECT_CALL(receiver, DeliverRtpPacket(MediaType::VIDEO, _, _))
+      .WillOnce(WithArg<1>([](RtpPacketReceived packet) {
+        EXPECT_EQ(packet.GetExtension<TransportSequenceNumber>(), 123);
+      }));
+  pipe->Process();
+}
+
+TEST_F(FakeNetworkPipeTest, DeliverRtcpPacket) {
+  BuiltInNetworkBehaviorConfig config;
+  config.queue_delay_ms = 100;
+  MockReceiver receiver;
+  auto simulated_network = std::make_unique<SimulatedNetwork>(config);
+  std::unique_ptr<FakeNetworkPipe> pipe(new FakeNetworkPipe(
+      &fake_clock_, std::move(simulated_network), &receiver));
+
+  rtc::CopyOnWriteBuffer buffer(100);
+  memset(buffer.MutableData(), 0, 100);
+  pipe->DeliverRtcpPacket(std::move(buffer));
+
+  // Advance the network delay to get the first packet.
+  fake_clock_.AdvanceTimeMilliseconds(config.queue_delay_ms);
+  EXPECT_CALL(receiver,
+              DeliverRtcpPacket(Property(&rtc::CopyOnWriteBuffer::size, 100)));
+  pipe->Process();
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/flexfec_receive_stream.cc b/third_party/libwebrtc/call/flexfec_receive_stream.cc
new file mode 100644
index 0000000000..ab6dde37b4
--- /dev/null
+++ b/third_party/libwebrtc/call/flexfec_receive_stream.cc
@@ -0,0 +1,26 @@
+/*
+ *  Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/flexfec_receive_stream.h"
+
+#include "rtc_base/checks.h"
+
+namespace webrtc {
+
+FlexfecReceiveStream::Config::Config(Transport* rtcp_send_transport)
+    : rtcp_send_transport(rtcp_send_transport) {
+  RTC_DCHECK(rtcp_send_transport);
+}
+
+FlexfecReceiveStream::Config::Config(const Config& config) = default;
+
+FlexfecReceiveStream::Config::~Config() = default;
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/flexfec_receive_stream.h b/third_party/libwebrtc/call/flexfec_receive_stream.h
new file mode 100644
index 0000000000..4f6fe44afa
--- /dev/null
+++ b/third_party/libwebrtc/call/flexfec_receive_stream.h
@@ -0,0 +1,76 @@
+/*
+ *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_FLEXFEC_RECEIVE_STREAM_H_
+#define CALL_FLEXFEC_RECEIVE_STREAM_H_
+
+#include <stdint.h>
+
+#include <string>
+#include <vector>
+
+#include "api/call/transport.h"
+#include "api/rtp_headers.h"
+#include "api/rtp_parameters.h"
+#include "call/receive_stream.h"
+#include "call/rtp_packet_sink_interface.h"
+
+namespace webrtc {
+
+class FlexfecReceiveStream : public RtpPacketSinkInterface,
+                             public ReceiveStreamInterface {
+ public:
+  ~FlexfecReceiveStream() override = default;
+
+  struct Config {
+    explicit Config(Transport* rtcp_send_transport);
+    Config(const Config&);
+    ~Config();
+
+    std::string ToString() const;
+
+    // Returns true if all RTP information is available in order to
+    // enable receiving FlexFEC.
+    bool IsCompleteAndEnabled() const;
+
+    // Payload type for FlexFEC.
+    int payload_type = -1;
+
+    ReceiveStreamRtpConfig rtp;
+
+    // Vector containing a single element, corresponding to the SSRC of the
+    // media stream being protected by this FlexFEC stream. The vector MUST have
+    // size 1.
+    //
+    // TODO(brandtr): Update comment above when we support multistream
+    // protection.
+    std::vector<uint32_t> protected_media_ssrcs;
+
+    // What RTCP mode to use in the reports.
+    RtcpMode rtcp_mode = RtcpMode::kCompound;
+
+    // Transport for outgoing RTCP packets.
+    Transport* rtcp_send_transport = nullptr;
+  };
+
+  // TODO(tommi): FlexfecReceiveStream inherits from ReceiveStreamInterface,
+  // not VideoReceiveStreamInterface where there's also a SetRtcpMode method.
+  // Perhaps this should be in ReceiveStreamInterface and apply to audio streams
+  // as well (although there's no logic that would use it at present).
+  virtual void SetRtcpMode(RtcpMode mode) = 0;
+
+  // Called to change the payload type after initialization.
+  virtual void SetPayloadType(int payload_type) = 0;
+  virtual int payload_type() const = 0;
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_FLEXFEC_RECEIVE_STREAM_H_
diff --git a/third_party/libwebrtc/call/flexfec_receive_stream_impl.cc b/third_party/libwebrtc/call/flexfec_receive_stream_impl.cc
new file mode 100644
index 0000000000..23cfec4633
--- /dev/null
+++ b/third_party/libwebrtc/call/flexfec_receive_stream_impl.cc
@@ -0,0 +1,220 @@
+/*
+ *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/flexfec_receive_stream_impl.h"
+
+#include <stddef.h>
+
+#include <cstdint>
+#include <string>
+#include <utility>
+
+#include "api/array_view.h"
+#include "api/call/transport.h"
+#include "api/rtp_parameters.h"
+#include "call/rtp_stream_receiver_controller_interface.h"
+#include "modules/rtp_rtcp/include/flexfec_receiver.h"
+#include "modules/rtp_rtcp/include/receive_statistics.h"
+#include "modules/rtp_rtcp/source/rtp_packet_received.h"
+#include "rtc_base/checks.h"
+#include "rtc_base/logging.h"
+#include "rtc_base/strings/string_builder.h"
+#include "system_wrappers/include/clock.h"
+
+namespace webrtc {
+
+std::string FlexfecReceiveStream::Config::ToString() const {
+  char buf[1024];
+  rtc::SimpleStringBuilder ss(buf);
+  ss << "{payload_type: " << payload_type;
+  ss << ", remote_ssrc: " << rtp.remote_ssrc;
+  ss << ", local_ssrc: " << rtp.local_ssrc;
+  ss << ", protected_media_ssrcs: [";
+  size_t i = 0;
+  for (; i + 1 < protected_media_ssrcs.size(); ++i)
+    ss << protected_media_ssrcs[i] << ", ";
+  if (!protected_media_ssrcs.empty())
+    ss << protected_media_ssrcs[i];
+  ss << ", rtp.extensions: [";
+  i = 0;
+  for (; i + 1 < rtp.extensions.size(); ++i)
+    ss << rtp.extensions[i].ToString() << ", ";
+  if (!rtp.extensions.empty())
+    ss << rtp.extensions[i].ToString();
+  ss << "]}";
+  return ss.str();
+}
+
+bool FlexfecReceiveStream::Config::IsCompleteAndEnabled() const {
+  // Check if FlexFEC is enabled.
+  if (payload_type < 0)
+    return false;
+  // Do we have the necessary SSRC information?
+  if (rtp.remote_ssrc == 0)
+    return false;
+  // TODO(brandtr): Update this check when we support multistream protection.
+  if (protected_media_ssrcs.size() != 1u)
+    return false;
+  return true;
+}
+
+namespace {
+
+// TODO(brandtr): Update this function when we support multistream protection.
+std::unique_ptr<FlexfecReceiver> MaybeCreateFlexfecReceiver(
+    Clock* clock,
+    const FlexfecReceiveStream::Config& config,
+    RecoveredPacketReceiver* recovered_packet_receiver) {
+  if (config.payload_type < 0) {
+    RTC_LOG(LS_WARNING)
+        << "Invalid FlexFEC payload type given. "
+           "This FlexfecReceiveStream will therefore be useless.";
+    return nullptr;
+  }
+  RTC_DCHECK_GE(config.payload_type, 0);
+  RTC_DCHECK_LE(config.payload_type, 127);
+  if (config.rtp.remote_ssrc == 0) {
+    RTC_LOG(LS_WARNING)
+        << "Invalid FlexFEC SSRC given. "
+           "This FlexfecReceiveStream will therefore be useless.";
+    return nullptr;
+  }
+  if (config.protected_media_ssrcs.empty()) {
+    RTC_LOG(LS_WARNING)
+        << "No protected media SSRC supplied. "
+           "This FlexfecReceiveStream will therefore be useless.";
+    return nullptr;
+  }
+
+  if (config.protected_media_ssrcs.size() > 1) {
+    RTC_LOG(LS_WARNING)
+        << "The supplied FlexfecConfig contained multiple protected "
+           "media streams, but our implementation currently only "
+           "supports protecting a single media stream. "
+           "To avoid confusion, disabling FlexFEC completely.";
+    return nullptr;
+  }
+  RTC_DCHECK_EQ(1U, config.protected_media_ssrcs.size());
+  return std::unique_ptr<FlexfecReceiver>(new FlexfecReceiver(
+      clock, config.rtp.remote_ssrc, config.protected_media_ssrcs[0],
+      recovered_packet_receiver));
+}
+
+std::unique_ptr<ModuleRtpRtcpImpl2> CreateRtpRtcpModule(
+    Clock* clock,
+    ReceiveStatistics* receive_statistics,
+    const FlexfecReceiveStreamImpl::Config& config,
+    RtcpRttStats* rtt_stats) {
+  RtpRtcpInterface::Configuration configuration;
+  configuration.audio = false;
+  configuration.receiver_only = true;
+  configuration.clock = clock;
+  configuration.receive_statistics = receive_statistics;
+  configuration.outgoing_transport = config.rtcp_send_transport;
+  configuration.rtt_stats = rtt_stats;
+  configuration.local_media_ssrc = config.rtp.local_ssrc;
+  return ModuleRtpRtcpImpl2::Create(configuration);
+}
+
+}  // namespace
+
+FlexfecReceiveStreamImpl::FlexfecReceiveStreamImpl(
+    Clock* clock,
+    Config config,
+    RecoveredPacketReceiver* recovered_packet_receiver,
+    RtcpRttStats* rtt_stats)
+    : extension_map_(std::move(config.rtp.extensions)),
+      remote_ssrc_(config.rtp.remote_ssrc),
+      payload_type_(config.payload_type),
+      receiver_(
+          MaybeCreateFlexfecReceiver(clock, config, recovered_packet_receiver)),
+      rtp_receive_statistics_(ReceiveStatistics::Create(clock)),
+      rtp_rtcp_(CreateRtpRtcpModule(clock,
+                                    rtp_receive_statistics_.get(),
+                                    config,
+                                    rtt_stats)) {
+  RTC_LOG(LS_INFO) << "FlexfecReceiveStreamImpl: " << config.ToString();
+  RTC_DCHECK_GE(payload_type_, -1);
+
+  packet_sequence_checker_.Detach();
+
+  // RTCP reporting.
+  rtp_rtcp_->SetRTCPStatus(config.rtcp_mode);
+}
+
+FlexfecReceiveStreamImpl::~FlexfecReceiveStreamImpl() {
+  RTC_DLOG(LS_INFO) << "~FlexfecReceiveStreamImpl: ssrc: " << remote_ssrc_;
+}
+
+void FlexfecReceiveStreamImpl::RegisterWithTransport(
+    RtpStreamReceiverControllerInterface* receiver_controller) {
+  RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
+  RTC_DCHECK(!rtp_stream_receiver_);
+
+  if (!receiver_)
+    return;
+
+  // TODO(nisse): OnRtpPacket in this class delegates all real work to
+  // `receiver_`. So maybe we don't need to implement RtpPacketSinkInterface
+  // here at all, we'd then delete the OnRtpPacket method and instead register
+  // `receiver_` as the RtpPacketSinkInterface for this stream.
+  rtp_stream_receiver_ =
+      receiver_controller->CreateReceiver(remote_ssrc(), this);
+}
+
+void FlexfecReceiveStreamImpl::UnregisterFromTransport() {
+  RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
+  rtp_stream_receiver_.reset();
+}
+
+void FlexfecReceiveStreamImpl::OnRtpPacket(const RtpPacketReceived& packet) {
+  RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
+  if (!receiver_)
+    return;
+
+  receiver_->OnRtpPacket(packet);
+
+  // Do not report media packets in the RTCP RRs generated by `rtp_rtcp_`.
+  if (packet.Ssrc() == remote_ssrc()) {
+    rtp_receive_statistics_->OnRtpPacket(packet);
+  }
+}
+
+void FlexfecReceiveStreamImpl::SetPayloadType(int payload_type) {
+  RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
+  RTC_DCHECK_GE(payload_type, -1);
+  payload_type_ = payload_type;
+}
+
+int FlexfecReceiveStreamImpl::payload_type() const {
+  RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
+  return payload_type_;
+}
+
+void FlexfecReceiveStreamImpl::SetRtpExtensions(
+    std::vector<RtpExtension> extensions) {
+  RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
+  extension_map_.Reset(extensions);
+}
+
+RtpHeaderExtensionMap FlexfecReceiveStreamImpl::GetRtpExtensionMap() const {
+  RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
+  return extension_map_;
+}
+
+void FlexfecReceiveStreamImpl::SetLocalSsrc(uint32_t local_ssrc) {
+  RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
+  if (local_ssrc == rtp_rtcp_->local_media_ssrc())
+    return;
+
+  rtp_rtcp_->SetLocalSsrc(local_ssrc);
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/flexfec_receive_stream_impl.h b/third_party/libwebrtc/call/flexfec_receive_stream_impl.h
new file mode 100644
index 0000000000..60cc9fe34d
--- /dev/null
+++ b/third_party/libwebrtc/call/flexfec_receive_stream_impl.h
@@ -0,0 +1,101 @@
+/*
+ *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_FLEXFEC_RECEIVE_STREAM_IMPL_H_
+#define CALL_FLEXFEC_RECEIVE_STREAM_IMPL_H_
+
+#include <memory>
+#include <vector>
+
+#include "call/flexfec_receive_stream.h"
+#include "call/rtp_packet_sink_interface.h"
+#include "modules/rtp_rtcp/source/rtp_rtcp_impl2.h"
+#include "rtc_base/system/no_unique_address.h"
+#include "system_wrappers/include/clock.h"
+
+namespace webrtc {
+
+class FlexfecReceiver;
+class ReceiveStatistics;
+class RecoveredPacketReceiver;
+class RtcpRttStats;
+class RtpPacketReceived;
+class RtpRtcp;
+class RtpStreamReceiverControllerInterface;
+class RtpStreamReceiverInterface;
+
+class FlexfecReceiveStreamImpl : public FlexfecReceiveStream {
+ public:
+  FlexfecReceiveStreamImpl(Clock* clock,
+                           Config config,
+                           RecoveredPacketReceiver* recovered_packet_receiver,
+                           RtcpRttStats* rtt_stats);
+  // Destruction happens on the worker thread. Prior to destruction the caller
+  // must ensure that a registration with the transport has been cleared. See
+  // `RegisterWithTransport` for details.
+  // TODO(tommi): As a further improvement to this, performing the full
+  // destruction on the network thread could be made the default.
+  ~FlexfecReceiveStreamImpl() override;
+
+  // Called on the network thread to register/unregister with the network
+  // transport.
+  void RegisterWithTransport(
+      RtpStreamReceiverControllerInterface* receiver_controller);
+  // If registration has previously been done (via `RegisterWithTransport`) then
+  // `UnregisterFromTransport` must be called prior to destruction, on the
+  // network thread.
+  void UnregisterFromTransport();
+
+  // RtpPacketSinkInterface.
+  void OnRtpPacket(const RtpPacketReceived& packet) override;
+
+  void SetPayloadType(int payload_type) override;
+  int payload_type() const override;
+
+  // ReceiveStreamInterface impl.
+  void SetRtpExtensions(std::vector<RtpExtension> extensions) override;
+  RtpHeaderExtensionMap GetRtpExtensionMap() const override;
+
+  // Updates the `rtp_video_stream_receiver_`'s `local_ssrc` when the default
+  // sender has been created, changed or removed.
+  void SetLocalSsrc(uint32_t local_ssrc);
+
+  uint32_t remote_ssrc() const { return remote_ssrc_; }
+
+  void SetRtcpMode(RtcpMode mode) override {
+    RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
+    rtp_rtcp_->SetRTCPStatus(mode);
+  }
+
+ private:
+  RTC_NO_UNIQUE_ADDRESS SequenceChecker packet_sequence_checker_;
+
+  RtpHeaderExtensionMap extension_map_;
+
+  const uint32_t remote_ssrc_;
+
+  // `payload_type_` is initially set to -1, indicating that FlexFec is
+  // disabled.
+  int payload_type_ RTC_GUARDED_BY(packet_sequence_checker_) = -1;
+
+  // Erasure code interfacing.
+  const std::unique_ptr<FlexfecReceiver> receiver_;
+
+  // RTCP reporting.
+  const std::unique_ptr<ReceiveStatistics> rtp_receive_statistics_;
+  const std::unique_ptr<ModuleRtpRtcpImpl2> rtp_rtcp_;
+
+  std::unique_ptr<RtpStreamReceiverInterface> rtp_stream_receiver_
+      RTC_GUARDED_BY(packet_sequence_checker_);
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_FLEXFEC_RECEIVE_STREAM_IMPL_H_
diff --git a/third_party/libwebrtc/call/flexfec_receive_stream_unittest.cc b/third_party/libwebrtc/call/flexfec_receive_stream_unittest.cc
new file mode 100644
index 0000000000..0c16521240
--- /dev/null
+++ b/third_party/libwebrtc/call/flexfec_receive_stream_unittest.cc
@@ -0,0 +1,157 @@
+/*
+ *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/flexfec_receive_stream.h"
+
+#include <cstdint>
+#include <memory>
+#include <vector>
+
+#include "api/array_view.h"
+#include "api/call/transport.h"
+#include "api/rtp_headers.h"
+#include "api/rtp_parameters.h"
+#include "call/flexfec_receive_stream_impl.h"
+#include "call/rtp_stream_receiver_controller.h"
+#include "modules/rtp_rtcp/include/rtp_rtcp_defines.h"
+#include "modules/rtp_rtcp/mocks/mock_recovered_packet_receiver.h"
+#include "modules/rtp_rtcp/mocks/mock_rtcp_rtt_stats.h"
+#include "modules/rtp_rtcp/source/byte_io.h"
+#include "modules/rtp_rtcp/source/rtp_header_extensions.h"
+#include "modules/rtp_rtcp/source/rtp_packet_received.h"
+#include "rtc_base/thread.h"
+#include "test/gmock.h"
+#include "test/gtest.h"
+#include "test/mock_transport.h"
+
+namespace webrtc {
+
+namespace {
+
+using ::testing::_;
+using ::testing::Eq;
+using ::testing::Property;
+
+constexpr uint8_t kFlexfecPlType = 118;
+constexpr uint8_t kFlexfecSsrc[] = {0x00, 0x00, 0x00, 0x01};
+constexpr uint8_t kMediaSsrc[] = {0x00, 0x00, 0x00, 0x02};
+
+FlexfecReceiveStream::Config CreateDefaultConfig(
+    Transport* rtcp_send_transport) {
+  FlexfecReceiveStream::Config config(rtcp_send_transport);
+  config.payload_type = kFlexfecPlType;
+  config.rtp.remote_ssrc = ByteReader<uint32_t>::ReadBigEndian(kFlexfecSsrc);
+  config.protected_media_ssrcs = {
+      ByteReader<uint32_t>::ReadBigEndian(kMediaSsrc)};
+  EXPECT_TRUE(config.IsCompleteAndEnabled());
+  return config;
+}
+
+RtpPacketReceived ParsePacket(rtc::ArrayView<const uint8_t> packet) {
+  RtpPacketReceived parsed_packet(nullptr);
+  EXPECT_TRUE(parsed_packet.Parse(packet));
+  return parsed_packet;
+}
+
+}  // namespace
+
+TEST(FlexfecReceiveStreamConfigTest, IsCompleteAndEnabled) {
+  MockTransport rtcp_send_transport;
+  FlexfecReceiveStream::Config config(&rtcp_send_transport);
+
+  config.rtp.local_ssrc = 18374743;
+  config.rtcp_mode = RtcpMode::kCompound;
+  config.rtp.extensions.emplace_back(TransportSequenceNumber::Uri(), 7);
+  EXPECT_FALSE(config.IsCompleteAndEnabled());
+
+  config.payload_type = 123;
+  EXPECT_FALSE(config.IsCompleteAndEnabled());
+
+  config.rtp.remote_ssrc = 238423838;
+  EXPECT_FALSE(config.IsCompleteAndEnabled());
+
+  config.protected_media_ssrcs.push_back(138989393);
+  EXPECT_TRUE(config.IsCompleteAndEnabled());
+
+  config.protected_media_ssrcs.push_back(33423423);
+  EXPECT_FALSE(config.IsCompleteAndEnabled());
+}
+
+class FlexfecReceiveStreamTest : public ::testing::Test {
+ protected:
+  FlexfecReceiveStreamTest()
+      : config_(CreateDefaultConfig(&rtcp_send_transport_)) {
+    receive_stream_ = std::make_unique<FlexfecReceiveStreamImpl>(
+        Clock::GetRealTimeClock(), config_, &recovered_packet_receiver_,
+        &rtt_stats_);
+    receive_stream_->RegisterWithTransport(&rtp_stream_receiver_controller_);
+  }
+
+  ~FlexfecReceiveStreamTest() {
+    receive_stream_->UnregisterFromTransport();
+  }
+
+  rtc::AutoThread main_thread_;
+  MockTransport rtcp_send_transport_;
+  FlexfecReceiveStream::Config config_;
+  MockRecoveredPacketReceiver recovered_packet_receiver_;
+  MockRtcpRttStats rtt_stats_;
+  RtpStreamReceiverController rtp_stream_receiver_controller_;
+  std::unique_ptr<FlexfecReceiveStreamImpl> receive_stream_;
+};
+
+TEST_F(FlexfecReceiveStreamTest, ConstructDestruct) {}
+
+// Create a FlexFEC packet that protects a single media packet and ensure
+// that the callback is called. Correctness of recovery is checked in the
+// FlexfecReceiver unit tests.
+TEST_F(FlexfecReceiveStreamTest, RecoversPacket) {
+  constexpr uint8_t kFlexfecSeqNum[] = {0x00, 0x01};
+  constexpr uint8_t kFlexfecTs[] = {0x00, 0x11, 0x22, 0x33};
+  constexpr uint8_t kMediaPlType = 107;
+  constexpr uint8_t kMediaSeqNum[] = {0x00, 0x02};
+  constexpr uint8_t kMediaTs[] = {0xaa, 0xbb, 0xcc, 0xdd};
+
+  // This packet mask protects a single media packet, i.e., the FlexFEC payload
+  // is a copy of that media packet. When inserted in the FlexFEC pipeline,
+  // it will thus trivially recover the lost media packet.
+  constexpr uint8_t kKBit0 = 1 << 7;
+  constexpr uint8_t kFlexfecPktMask[] = {kKBit0 | 0x00, 0x01};
+  constexpr uint8_t kPayloadLength[] = {0x00, 0x04};
+  constexpr uint8_t kSsrcCount = 1;
+  constexpr uint8_t kReservedBits = 0x00;
+  constexpr uint8_t kPayloadBits = 0x00;
+  // clang-format off
+  constexpr uint8_t kFlexfecPacket[] = {
+      // RTP header.
+      0x80,            kFlexfecPlType,  kFlexfecSeqNum[0],  kFlexfecSeqNum[1],
+      kFlexfecTs[0],   kFlexfecTs[1],   kFlexfecTs[2],      kFlexfecTs[3],
+      kFlexfecSsrc[0], kFlexfecSsrc[1], kFlexfecSsrc[2],    kFlexfecSsrc[3],
+      // FlexFEC header.
+      0x00,            kMediaPlType,    kPayloadLength[0],  kPayloadLength[1],
+      kMediaTs[0],     kMediaTs[1],     kMediaTs[2],        kMediaTs[3],
+      kSsrcCount,      kReservedBits,   kReservedBits,      kReservedBits,
+      kMediaSsrc[0],   kMediaSsrc[1],   kMediaSsrc[2],      kMediaSsrc[3],
+      kMediaSeqNum[0], kMediaSeqNum[1], kFlexfecPktMask[0], kFlexfecPktMask[1],
+      // FEC payload.
+      kPayloadBits,    kPayloadBits,    kPayloadBits,       kPayloadBits};
+  // clang-format on
+
+  EXPECT_CALL(recovered_packet_receiver_,
+              OnRecoveredPacket(Property(&RtpPacketReceived::payload_size,
+                                         Eq(kPayloadLength[1]))));
+
+  receive_stream_->OnRtpPacket(ParsePacket(kFlexfecPacket));
+
+  // Tear-down
+  receive_stream_->UnregisterFromTransport();
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/packet_receiver.h b/third_party/libwebrtc/call/packet_receiver.h
new file mode 100644
index 0000000000..c7f55ac46c
--- /dev/null
+++ b/third_party/libwebrtc/call/packet_receiver.h
@@ -0,0 +1,43 @@
+/*
+ *  Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+#ifndef CALL_PACKET_RECEIVER_H_
+#define CALL_PACKET_RECEIVER_H_
+
+#include "absl/functional/any_invocable.h"
+#include "api/media_types.h"
+#include "modules/rtp_rtcp/source/rtp_packet_received.h"
+#include "rtc_base/checks.h"
+#include "rtc_base/copy_on_write_buffer.h"
+
+namespace webrtc {
+
+class PacketReceiver {
+ public:
+  // Demux RTCP packets. Must be called on the worker thread.
+  virtual void DeliverRtcpPacket(rtc::CopyOnWriteBuffer packet) = 0;
+
+  // Invoked once when a packet packet is received that can not be demuxed.
+  // If the method returns true, a new attempt is made to demux the packet.
+  using OnUndemuxablePacketHandler =
+      absl::AnyInvocable<bool(const RtpPacketReceived& parsed_packet)>;
+
+  // Demux RTP packets. Must be called on the worker thread.
+  virtual void DeliverRtpPacket(
+      MediaType media_type,
+      RtpPacketReceived packet,
+      OnUndemuxablePacketHandler undemuxable_packet_handler) = 0;
+
+ protected:
+  virtual ~PacketReceiver() {}
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_PACKET_RECEIVER_H_
diff --git a/third_party/libwebrtc/call/rampup_tests.cc b/third_party/libwebrtc/call/rampup_tests.cc
new file mode 100644
index 0000000000..3c89670a9f
--- /dev/null
+++ b/third_party/libwebrtc/call/rampup_tests.cc
@@ -0,0 +1,704 @@
+/*
+ *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/rampup_tests.h"
+
+#include <memory>
+
+#include "absl/flags/flag.h"
+#include "absl/strings/string_view.h"
+#include "api/rtc_event_log/rtc_event_log_factory.h"
+#include "api/rtc_event_log_output_file.h"
+#include "api/task_queue/default_task_queue_factory.h"
+#include "api/task_queue/task_queue_base.h"
+#include "api/task_queue/task_queue_factory.h"
+#include "api/test/metrics/global_metrics_logger_and_exporter.h"
+#include "api/test/metrics/metric.h"
+#include "call/fake_network_pipe.h"
+#include "rtc_base/checks.h"
+#include "rtc_base/logging.h"
+#include "rtc_base/platform_thread.h"
+#include "rtc_base/string_encode.h"
+#include "rtc_base/task_queue_for_test.h"
+#include "rtc_base/time_utils.h"
+#include "test/encoder_settings.h"
+#include "test/gtest.h"
+
+ABSL_FLAG(std::string,
+          ramp_dump_name,
+          "",
+          "Filename for dumped received RTP stream.");
+
+namespace webrtc {
+namespace {
+
+using ::webrtc::test::GetGlobalMetricsLogger;
+using ::webrtc::test::ImprovementDirection;
+using ::webrtc::test::Unit;
+
+constexpr TimeDelta kPollInterval = TimeDelta::Millis(20);
+static const int kExpectedHighVideoBitrateBps = 80000;
+static const int kExpectedHighAudioBitrateBps = 30000;
+static const int kLowBandwidthLimitBps = 20000;
+// Set target detected bitrate to slightly larger than the target bitrate to
+// avoid flakiness.
+static const int kLowBitrateMarginBps = 2000;
+
+std::vector<uint32_t> GenerateSsrcs(size_t num_streams, uint32_t ssrc_offset) {
+  std::vector<uint32_t> ssrcs;
+  for (size_t i = 0; i != num_streams; ++i)
+    ssrcs.push_back(static_cast<uint32_t>(ssrc_offset + i));
+  return ssrcs;
+}
+
+}  // namespace
+
+RampUpTester::RampUpTester(size_t num_video_streams,
+                           size_t num_audio_streams,
+                           size_t num_flexfec_streams,
+                           unsigned int start_bitrate_bps,
+                           int64_t min_run_time_ms,
+                           bool rtx,
+                           bool red,
+                           bool report_perf_stats,
+                           TaskQueueBase* task_queue)
+    : EndToEndTest(test::CallTest::kLongTimeout),
+      clock_(Clock::GetRealTimeClock()),
+      num_video_streams_(num_video_streams),
+      num_audio_streams_(num_audio_streams),
+      num_flexfec_streams_(num_flexfec_streams),
+      rtx_(rtx),
+      red_(red),
+      report_perf_stats_(report_perf_stats),
+      sender_call_(nullptr),
+      send_stream_(nullptr),
+      send_transport_(nullptr),
+      send_simulated_network_(nullptr),
+      start_bitrate_bps_(start_bitrate_bps),
+      min_run_time_ms_(min_run_time_ms),
+      expected_bitrate_bps_(0),
+      test_start_ms_(-1),
+      ramp_up_finished_ms_(-1),
+      video_ssrcs_(GenerateSsrcs(num_video_streams_, 100)),
+      video_rtx_ssrcs_(GenerateSsrcs(num_video_streams_, 200)),
+      audio_ssrcs_(GenerateSsrcs(num_audio_streams_, 300)),
+      task_queue_(task_queue) {
+  if (red_)
+    EXPECT_EQ(0u, num_flexfec_streams_);
+  EXPECT_LE(num_audio_streams_, 1u);
+}
+
+RampUpTester::~RampUpTester() = default;
+
+void RampUpTester::ModifySenderBitrateConfig(
+    BitrateConstraints* bitrate_config) {
+  if (start_bitrate_bps_ != 0) {
+    bitrate_config->start_bitrate_bps = start_bitrate_bps_;
+  }
+  bitrate_config->min_bitrate_bps = 10000;
+}
+
+void RampUpTester::OnVideoStreamsCreated(
+    VideoSendStream* send_stream,
+    const std::vector<VideoReceiveStreamInterface*>& receive_streams) {
+  send_stream_ = send_stream;
+}
+
+BuiltInNetworkBehaviorConfig RampUpTester::GetSendTransportConfig() const {
+  return forward_transport_config_;
+}
+
+size_t RampUpTester::GetNumVideoStreams() const {
+  return num_video_streams_;
+}
+
+size_t RampUpTester::GetNumAudioStreams() const {
+  return num_audio_streams_;
+}
+
+size_t RampUpTester::GetNumFlexfecStreams() const {
+  return num_flexfec_streams_;
+}
+
+class RampUpTester::VideoStreamFactory
+    : public VideoEncoderConfig::VideoStreamFactoryInterface {
+ public:
+  VideoStreamFactory() {}
+
+ private:
+  std::vector<VideoStream> CreateEncoderStreams(
+      int frame_width,
+      int frame_height,
+      const VideoEncoderConfig& encoder_config) override {
+    std::vector<VideoStream> streams =
+        test::CreateVideoStreams(frame_width, frame_height, encoder_config);
+    if (encoder_config.number_of_streams == 1) {
+      streams[0].target_bitrate_bps = streams[0].max_bitrate_bps = 2000000;
+    }
+    return streams;
+  }
+};
+
+void RampUpTester::ModifyVideoConfigs(
+    VideoSendStream::Config* send_config,
+    std::vector<VideoReceiveStreamInterface::Config>* receive_configs,
+    VideoEncoderConfig* encoder_config) {
+  send_config->suspend_below_min_bitrate = true;
+  encoder_config->number_of_streams = num_video_streams_;
+  encoder_config->max_bitrate_bps = 2000000;
+  encoder_config->video_stream_factory =
+      rtc::make_ref_counted<RampUpTester::VideoStreamFactory>();
+  if (num_video_streams_ == 1) {
+    // For single stream rampup until 1mbps
+    expected_bitrate_bps_ = kSingleStreamTargetBps;
+  } else {
+    // To ensure simulcast rate allocation.
+    send_config->rtp.payload_name = "VP8";
+    encoder_config->codec_type = kVideoCodecVP8;
+    std::vector<VideoStream> streams = test::CreateVideoStreams(
+        test::CallTest::kDefaultWidth, test::CallTest::kDefaultHeight,
+        *encoder_config);
+    // For multi stream rampup until all streams are being sent. That means
+    // enough bitrate to send all the target streams plus the min bitrate of
+    // the last one.
+    expected_bitrate_bps_ = streams.back().min_bitrate_bps;
+    for (size_t i = 0; i < streams.size() - 1; ++i) {
+      expected_bitrate_bps_ += streams[i].target_bitrate_bps;
+    }
+  }
+
+  send_config->rtp.nack.rtp_history_ms = test::CallTest::kNackRtpHistoryMs;
+  send_config->rtp.ssrcs = video_ssrcs_;
+  if (rtx_) {
+    send_config->rtp.rtx.payload_type = test::CallTest::kSendRtxPayloadType;
+    send_config->rtp.rtx.ssrcs = video_rtx_ssrcs_;
+  }
+  if (red_) {
+    send_config->rtp.ulpfec.ulpfec_payload_type =
+        test::CallTest::kUlpfecPayloadType;
+    send_config->rtp.ulpfec.red_payload_type = test::CallTest::kRedPayloadType;
+    if (rtx_) {
+      send_config->rtp.ulpfec.red_rtx_payload_type =
+          test::CallTest::kRtxRedPayloadType;
+    }
+  }
+
+  size_t i = 0;
+  for (VideoReceiveStreamInterface::Config& recv_config : *receive_configs) {
+    recv_config.decoders.reserve(1);
+    recv_config.decoders[0].payload_type = send_config->rtp.payload_type;
+    recv_config.decoders[0].video_format =
+        SdpVideoFormat(send_config->rtp.payload_name);
+
+    recv_config.rtp.remote_ssrc = video_ssrcs_[i];
+    recv_config.rtp.nack.rtp_history_ms = send_config->rtp.nack.rtp_history_ms;
+
+    if (red_) {
+      recv_config.rtp.red_payload_type =
+          send_config->rtp.ulpfec.red_payload_type;
+      recv_config.rtp.ulpfec_payload_type =
+          send_config->rtp.ulpfec.ulpfec_payload_type;
+      if (rtx_) {
+        recv_config.rtp.rtx_associated_payload_types
+            [send_config->rtp.ulpfec.red_rtx_payload_type] =
+            send_config->rtp.ulpfec.red_payload_type;
+      }
+    }
+
+    if (rtx_) {
+      recv_config.rtp.rtx_ssrc = video_rtx_ssrcs_[i];
+      recv_config.rtp
+          .rtx_associated_payload_types[send_config->rtp.rtx.payload_type] =
+          send_config->rtp.payload_type;
+    }
+    ++i;
+  }
+
+  RTC_DCHECK_LE(num_flexfec_streams_, 1);
+  if (num_flexfec_streams_ == 1) {
+    send_config->rtp.flexfec.payload_type = test::CallTest::kFlexfecPayloadType;
+    send_config->rtp.flexfec.ssrc = test::CallTest::kFlexfecSendSsrc;
+    send_config->rtp.flexfec.protected_media_ssrcs = {video_ssrcs_[0]};
+  }
+}
+
+void RampUpTester::ModifyAudioConfigs(
+    AudioSendStream::Config* send_config,
+    std::vector<AudioReceiveStreamInterface::Config>* receive_configs) {
+  if (num_audio_streams_ == 0)
+    return;
+
+  send_config->rtp.ssrc = audio_ssrcs_[0];
+  send_config->min_bitrate_bps = 6000;
+  send_config->max_bitrate_bps = 60000;
+
+  for (AudioReceiveStreamInterface::Config& recv_config : *receive_configs) {
+    recv_config.rtp.remote_ssrc = send_config->rtp.ssrc;
+  }
+}
+
+void RampUpTester::ModifyFlexfecConfigs(
+    std::vector<FlexfecReceiveStream::Config>* receive_configs) {
+  if (num_flexfec_streams_ == 0)
+    return;
+  RTC_DCHECK_EQ(1, num_flexfec_streams_);
+  (*receive_configs)[0].payload_type = test::CallTest::kFlexfecPayloadType;
+  (*receive_configs)[0].rtp.remote_ssrc = test::CallTest::kFlexfecSendSsrc;
+  (*receive_configs)[0].protected_media_ssrcs = {video_ssrcs_[0]};
+  (*receive_configs)[0].rtp.local_ssrc = video_ssrcs_[0];
+}
+
+void RampUpTester::OnCallsCreated(Call* sender_call, Call* receiver_call) {
+  RTC_DCHECK(sender_call);
+  sender_call_ = sender_call;
+  pending_task_ = RepeatingTaskHandle::Start(task_queue_, [this] {
+    PollStats();
+    return kPollInterval;
+  });
+}
+
+void RampUpTester::OnTransportCreated(
+    test::PacketTransport* to_receiver,
+    SimulatedNetworkInterface* sender_network,
+    test::PacketTransport* to_sender,
+    SimulatedNetworkInterface* receiver_network) {
+  RTC_DCHECK_RUN_ON(task_queue_);
+
+  send_transport_ = to_receiver;
+  send_simulated_network_ = sender_network;
+}
+
+void RampUpTester::PollStats() {
+  RTC_DCHECK_RUN_ON(task_queue_);
+
+  Call::Stats stats = sender_call_->GetStats();
+  EXPECT_GE(expected_bitrate_bps_, 0);
+
+  if (stats.send_bandwidth_bps >= expected_bitrate_bps_ &&
+      (min_run_time_ms_ == -1 ||
+       clock_->TimeInMilliseconds() - test_start_ms_ >= min_run_time_ms_)) {
+    ramp_up_finished_ms_ = clock_->TimeInMilliseconds();
+    observation_complete_.Set();
+    pending_task_.Stop();
+  }
+}
+
+void RampUpTester::ReportResult(
+    absl::string_view measurement,
+    size_t value,
+    Unit unit,
+    ImprovementDirection improvement_direction) const {
+  GetGlobalMetricsLogger()->LogSingleValueMetric(
+      measurement,
+      ::testing::UnitTest::GetInstance()->current_test_info()->name(), value,
+      unit, improvement_direction);
+}
+
+void RampUpTester::AccumulateStats(const VideoSendStream::StreamStats& stream,
+                                   size_t* total_packets_sent,
+                                   size_t* total_sent,
+                                   size_t* padding_sent,
+                                   size_t* media_sent) const {
+  *total_packets_sent += stream.rtp_stats.transmitted.packets +
+                         stream.rtp_stats.retransmitted.packets +
+                         stream.rtp_stats.fec.packets;
+  *total_sent += stream.rtp_stats.transmitted.TotalBytes() +
+                 stream.rtp_stats.retransmitted.TotalBytes() +
+                 stream.rtp_stats.fec.TotalBytes();
+  *padding_sent += stream.rtp_stats.transmitted.padding_bytes +
+                   stream.rtp_stats.retransmitted.padding_bytes +
+                   stream.rtp_stats.fec.padding_bytes;
+  *media_sent += stream.rtp_stats.MediaPayloadBytes();
+}
+
+void RampUpTester::TriggerTestDone() {
+  RTC_DCHECK_GE(test_start_ms_, 0);
+
+  // Stop polling stats.
+  // Corner case for field_trials=WebRTC-QuickPerfTest/Enabled/
+  SendTask(task_queue_, [this] { pending_task_.Stop(); });
+
+  // TODO(holmer): Add audio send stats here too when those APIs are available.
+  if (!send_stream_)
+    return;
+
+  VideoSendStream::Stats send_stats;
+  SendTask(task_queue_, [&] { send_stats = send_stream_->GetStats(); });
+
+  send_stream_ = nullptr;  // To avoid dereferencing a bad pointer.
+
+  size_t total_packets_sent = 0;
+  size_t total_sent = 0;
+  size_t padding_sent = 0;
+  size_t media_sent = 0;
+  for (uint32_t ssrc : video_ssrcs_) {
+    AccumulateStats(send_stats.substreams[ssrc], &total_packets_sent,
+                    &total_sent, &padding_sent, &media_sent);
+  }
+
+  size_t rtx_total_packets_sent = 0;
+  size_t rtx_total_sent = 0;
+  size_t rtx_padding_sent = 0;
+  size_t rtx_media_sent = 0;
+  for (uint32_t rtx_ssrc : video_rtx_ssrcs_) {
+    AccumulateStats(send_stats.substreams[rtx_ssrc], &rtx_total_packets_sent,
+                    &rtx_total_sent, &rtx_padding_sent, &rtx_media_sent);
+  }
+
+  if (report_perf_stats_) {
+    ReportResult("ramp-up-media-sent", media_sent, Unit::kBytes,
+                 ImprovementDirection::kBiggerIsBetter);
+    ReportResult("ramp-up-padding-sent", padding_sent, Unit::kBytes,
+                 ImprovementDirection::kSmallerIsBetter);
+    ReportResult("ramp-up-rtx-media-sent", rtx_media_sent, Unit::kBytes,
+                 ImprovementDirection::kBiggerIsBetter);
+    ReportResult("ramp-up-rtx-padding-sent", rtx_padding_sent, Unit::kBytes,
+                 ImprovementDirection::kSmallerIsBetter);
+    if (ramp_up_finished_ms_ >= 0) {
+      ReportResult("ramp-up-time", ramp_up_finished_ms_ - test_start_ms_,
+                   Unit::kMilliseconds, ImprovementDirection::kSmallerIsBetter);
+    }
+    ReportResult("ramp-up-average-network-latency",
+                 send_transport_->GetAverageDelayMs(), Unit::kMilliseconds,
+                 ImprovementDirection::kSmallerIsBetter);
+  }
+}
+
+void RampUpTester::PerformTest() {
+  test_start_ms_ = clock_->TimeInMilliseconds();
+  EXPECT_TRUE(Wait()) << "Timed out while waiting for ramp-up to complete.";
+  TriggerTestDone();
+}
+
+RampUpDownUpTester::RampUpDownUpTester(size_t num_video_streams,
+                                       size_t num_audio_streams,
+                                       size_t num_flexfec_streams,
+                                       unsigned int start_bitrate_bps,
+                                       bool rtx,
+                                       bool red,
+                                       const std::vector<int>& loss_rates,
+                                       bool report_perf_stats,
+                                       TaskQueueBase* task_queue)
+    : RampUpTester(num_video_streams,
+                   num_audio_streams,
+                   num_flexfec_streams,
+                   start_bitrate_bps,
+                   0,
+                   rtx,
+                   red,
+                   report_perf_stats,
+                   task_queue),
+      link_rates_({4 * GetExpectedHighBitrate() / (3 * 1000),
+                   kLowBandwidthLimitBps / 1000,
+                   4 * GetExpectedHighBitrate() / (3 * 1000), 0}),
+      test_state_(kFirstRampup),
+      next_state_(kTransitionToNextState),
+      state_start_ms_(clock_->TimeInMilliseconds()),
+      interval_start_ms_(clock_->TimeInMilliseconds()),
+      sent_bytes_(0),
+      loss_rates_(loss_rates) {
+  forward_transport_config_.link_capacity_kbps = link_rates_[test_state_];
+  forward_transport_config_.queue_delay_ms = 100;
+  forward_transport_config_.loss_percent = loss_rates_[test_state_];
+}
+
+RampUpDownUpTester::~RampUpDownUpTester() {}
+
+void RampUpDownUpTester::PollStats() {
+  if (test_state_ == kTestEnd) {
+    pending_task_.Stop();
+  }
+
+  int transmit_bitrate_bps = 0;
+  bool suspended = false;
+  if (num_video_streams_ > 0 && send_stream_) {
+    webrtc::VideoSendStream::Stats stats = send_stream_->GetStats();
+    for (const auto& it : stats.substreams) {
+      transmit_bitrate_bps += it.second.total_bitrate_bps;
+    }
+    suspended = stats.suspended;
+  }
+  if (num_audio_streams_ > 0 && sender_call_) {
+    // An audio send stream doesn't have bitrate stats, so the call send BW is
+    // currently used instead.
+    transmit_bitrate_bps = sender_call_->GetStats().send_bandwidth_bps;
+  }
+
+  EvolveTestState(transmit_bitrate_bps, suspended);
+}
+
+void RampUpDownUpTester::ModifyReceiverBitrateConfig(
+    BitrateConstraints* bitrate_config) {
+  bitrate_config->min_bitrate_bps = 10000;
+}
+
+std::string RampUpDownUpTester::GetModifierString() const {
+  std::string str("_");
+  if (num_video_streams_ > 0) {
+    str += rtc::ToString(num_video_streams_);
+    str += "stream";
+    str += (num_video_streams_ > 1 ? "s" : "");
+    str += "_";
+  }
+  if (num_audio_streams_ > 0) {
+    str += rtc::ToString(num_audio_streams_);
+    str += "stream";
+    str += (num_audio_streams_ > 1 ? "s" : "");
+    str += "_";
+  }
+  str += (rtx_ ? "" : "no");
+  str += "rtx_";
+  str += (red_ ? "" : "no");
+  str += "red";
+  return str;
+}
+
+int RampUpDownUpTester::GetExpectedHighBitrate() const {
+  int expected_bitrate_bps = 0;
+  if (num_audio_streams_ > 0)
+    expected_bitrate_bps += kExpectedHighAudioBitrateBps;
+  if (num_video_streams_ > 0)
+    expected_bitrate_bps += kExpectedHighVideoBitrateBps;
+  return expected_bitrate_bps;
+}
+
+size_t RampUpDownUpTester::GetFecBytes() const {
+  size_t flex_fec_bytes = 0;
+  if (num_flexfec_streams_ > 0) {
+    webrtc::VideoSendStream::Stats stats = send_stream_->GetStats();
+    for (const auto& kv : stats.substreams)
+      flex_fec_bytes += kv.second.rtp_stats.fec.TotalBytes();
+  }
+  return flex_fec_bytes;
+}
+
+bool RampUpDownUpTester::ExpectingFec() const {
+  return num_flexfec_streams_ > 0 && forward_transport_config_.loss_percent > 0;
+}
+
+void RampUpDownUpTester::EvolveTestState(int bitrate_bps, bool suspended) {
+  int64_t now = clock_->TimeInMilliseconds();
+  switch (test_state_) {
+    case kFirstRampup:
+      EXPECT_FALSE(suspended);
+      if (bitrate_bps >= GetExpectedHighBitrate()) {
+        if (report_perf_stats_) {
+          GetGlobalMetricsLogger()->LogSingleValueMetric(
+              "ramp_up_down_up" + GetModifierString(), "first_rampup",
+              now - state_start_ms_, Unit::kMilliseconds,
+              ImprovementDirection::kSmallerIsBetter);
+        }
+        // Apply loss during the transition between states if FEC is enabled.
+        forward_transport_config_.loss_percent = loss_rates_[test_state_];
+        test_state_ = kTransitionToNextState;
+        next_state_ = kLowRate;
+      }
+      break;
+    case kLowRate: {
+      // Audio streams are never suspended.
+      bool check_suspend_state = num_video_streams_ > 0;
+      if (bitrate_bps < kLowBandwidthLimitBps + kLowBitrateMarginBps &&
+          suspended == check_suspend_state) {
+        if (report_perf_stats_) {
+          GetGlobalMetricsLogger()->LogSingleValueMetric(
+              "ramp_up_down_up" + GetModifierString(), "rampdown",
+              now - state_start_ms_, Unit::kMilliseconds,
+              ImprovementDirection::kSmallerIsBetter);
+        }
+        // Apply loss during the transition between states if FEC is enabled.
+        forward_transport_config_.loss_percent = loss_rates_[test_state_];
+        test_state_ = kTransitionToNextState;
+        next_state_ = kSecondRampup;
+      }
+      break;
+    }
+    case kSecondRampup:
+      if (bitrate_bps >= GetExpectedHighBitrate() && !suspended) {
+        if (report_perf_stats_) {
+          GetGlobalMetricsLogger()->LogSingleValueMetric(
+              "ramp_up_down_up" + GetModifierString(), "second_rampup",
+              now - state_start_ms_, Unit::kMilliseconds,
+              ImprovementDirection::kSmallerIsBetter);
+          ReportResult("ramp-up-down-up-average-network-latency",
+                       send_transport_->GetAverageDelayMs(),
+                       Unit::kMilliseconds,
+                       ImprovementDirection::kSmallerIsBetter);
+        }
+        // Apply loss during the transition between states if FEC is enabled.
+        forward_transport_config_.loss_percent = loss_rates_[test_state_];
+        test_state_ = kTransitionToNextState;
+        next_state_ = kTestEnd;
+      }
+      break;
+    case kTestEnd:
+      observation_complete_.Set();
+      break;
+    case kTransitionToNextState:
+      if (!ExpectingFec() || GetFecBytes() > 0) {
+        test_state_ = next_state_;
+        forward_transport_config_.link_capacity_kbps = link_rates_[test_state_];
+        // No loss while ramping up and down as it may affect the BWE
+        // negatively, making the test flaky.
+        forward_transport_config_.loss_percent = 0;
+        state_start_ms_ = now;
+        interval_start_ms_ = now;
+        sent_bytes_ = 0;
+        send_simulated_network_->SetConfig(forward_transport_config_);
+      }
+      break;
+  }
+}
+
+class RampUpTest : public test::CallTest {
+ public:
+  RampUpTest()
+      : task_queue_factory_(CreateDefaultTaskQueueFactory()),
+        rtc_event_log_factory_(task_queue_factory_.get()) {
+    std::string dump_name(absl::GetFlag(FLAGS_ramp_dump_name));
+    if (!dump_name.empty()) {
+      send_event_log_ = rtc_event_log_factory_.CreateRtcEventLog(
+          RtcEventLog::EncodingType::Legacy);
+      recv_event_log_ = rtc_event_log_factory_.CreateRtcEventLog(
+          RtcEventLog::EncodingType::Legacy);
+      bool event_log_started =
+          send_event_log_->StartLogging(
+              std::make_unique<RtcEventLogOutputFile>(
+                  dump_name + ".send.rtc.dat", RtcEventLog::kUnlimitedOutput),
+              RtcEventLog::kImmediateOutput) &&
+          recv_event_log_->StartLogging(
+              std::make_unique<RtcEventLogOutputFile>(
+                  dump_name + ".recv.rtc.dat", RtcEventLog::kUnlimitedOutput),
+              RtcEventLog::kImmediateOutput);
+      RTC_DCHECK(event_log_started);
+    }
+  }
+
+ private:
+  const std::unique_ptr<TaskQueueFactory> task_queue_factory_;
+  RtcEventLogFactory rtc_event_log_factory_;
+};
+
+static const uint32_t kStartBitrateBps = 60000;
+
+TEST_F(RampUpTest, UpDownUpAbsSendTimeSimulcastRedRtx) {
+  std::vector<int> loss_rates = {0, 0, 0, 0};
+  RegisterRtpExtension(
+      RtpExtension(RtpExtension::kAbsSendTimeUri, kAbsSendTimeExtensionId));
+  RampUpDownUpTester test(3, 0, 0, kStartBitrateBps, true, true, loss_rates,
+                          true, task_queue());
+  RunBaseTest(&test);
+}
+
+// TODO(bugs.webrtc.org/8878)
+#if defined(WEBRTC_MAC)
+#define MAYBE_UpDownUpTransportSequenceNumberRtx \
+  DISABLED_UpDownUpTransportSequenceNumberRtx
+#else
+#define MAYBE_UpDownUpTransportSequenceNumberRtx \
+  UpDownUpTransportSequenceNumberRtx
+#endif
+TEST_F(RampUpTest, MAYBE_UpDownUpTransportSequenceNumberRtx) {
+  std::vector<int> loss_rates = {0, 0, 0, 0};
+  RegisterRtpExtension(RtpExtension(RtpExtension::kTransportSequenceNumberUri,
+                                    kTransportSequenceNumberExtensionId));
+  RampUpDownUpTester test(3, 0, 0, kStartBitrateBps, true, false, loss_rates,
+                          true, task_queue());
+  RunBaseTest(&test);
+}
+
+// TODO(holmer): Tests which don't report perf stats should be moved to a
+// different executable since they per definition are not perf tests.
+// This test is disabled because it crashes on Linux, and is flaky on other
+// platforms. See: crbug.com/webrtc/7919
+TEST_F(RampUpTest, DISABLED_UpDownUpTransportSequenceNumberPacketLoss) {
+  std::vector<int> loss_rates = {20, 0, 0, 0};
+  RegisterRtpExtension(RtpExtension(RtpExtension::kTransportSequenceNumberUri,
+                                    kTransportSequenceNumberExtensionId));
+  RampUpDownUpTester test(1, 0, 1, kStartBitrateBps, true, false, loss_rates,
+                          false, task_queue());
+  RunBaseTest(&test);
+}
+
+// TODO(bugs.webrtc.org/8878)
+#if defined(WEBRTC_MAC)
+#define MAYBE_UpDownUpAudioVideoTransportSequenceNumberRtx \
+  DISABLED_UpDownUpAudioVideoTransportSequenceNumberRtx
+#else
+#define MAYBE_UpDownUpAudioVideoTransportSequenceNumberRtx \
+  UpDownUpAudioVideoTransportSequenceNumberRtx
+#endif
+TEST_F(RampUpTest, MAYBE_UpDownUpAudioVideoTransportSequenceNumberRtx) {
+  std::vector<int> loss_rates = {0, 0, 0, 0};
+  RegisterRtpExtension(RtpExtension(RtpExtension::kTransportSequenceNumberUri,
+                                    kTransportSequenceNumberExtensionId));
+  RampUpDownUpTester test(3, 1, 0, kStartBitrateBps, true, false, loss_rates,
+                          false, task_queue());
+  RunBaseTest(&test);
+}
+
+TEST_F(RampUpTest, UpDownUpAudioTransportSequenceNumberRtx) {
+  std::vector<int> loss_rates = {0, 0, 0, 0};
+  RegisterRtpExtension(RtpExtension(RtpExtension::kTransportSequenceNumberUri,
+                                    kTransportSequenceNumberExtensionId));
+  RampUpDownUpTester test(0, 1, 0, kStartBitrateBps, true, false, loss_rates,
+                          false, task_queue());
+  RunBaseTest(&test);
+}
+
+TEST_F(RampUpTest, TOffsetSimulcastRedRtx) {
+  RegisterRtpExtension(RtpExtension(RtpExtension::kTimestampOffsetUri,
+                                    kTransmissionTimeOffsetExtensionId));
+  RampUpTester test(3, 0, 0, 0, 0, true, true, true, task_queue());
+  RunBaseTest(&test);
+}
+
+TEST_F(RampUpTest, AbsSendTime) {
+  RegisterRtpExtension(
+      RtpExtension(RtpExtension::kAbsSendTimeUri, kAbsSendTimeExtensionId));
+  RampUpTester test(1, 0, 0, 0, 0, false, false, false, task_queue());
+  RunBaseTest(&test);
+}
+
+TEST_F(RampUpTest, AbsSendTimeSimulcastRedRtx) {
+  RegisterRtpExtension(
+      RtpExtension(RtpExtension::kAbsSendTimeUri, kAbsSendTimeExtensionId));
+  RampUpTester test(3, 0, 0, 0, 0, true, true, true, task_queue());
+  RunBaseTest(&test);
+}
+
+TEST_F(RampUpTest, TransportSequenceNumber) {
+  RegisterRtpExtension(RtpExtension(RtpExtension::kTransportSequenceNumberUri,
+                                    kTransportSequenceNumberExtensionId));
+  RampUpTester test(1, 0, 0, 0, 0, false, false, false, task_queue());
+  RunBaseTest(&test);
+}
+
+TEST_F(RampUpTest, TransportSequenceNumberSimulcast) {
+  RegisterRtpExtension(RtpExtension(RtpExtension::kTransportSequenceNumberUri,
+                                    kTransportSequenceNumberExtensionId));
+  RampUpTester test(3, 0, 0, 0, 0, false, false, false, task_queue());
+  RunBaseTest(&test);
+}
+
+TEST_F(RampUpTest, TransportSequenceNumberSimulcastRedRtx) {
+  RegisterRtpExtension(RtpExtension(RtpExtension::kTransportSequenceNumberUri,
+                                    kTransportSequenceNumberExtensionId));
+  RampUpTester test(3, 0, 0, 0, 0, true, true, true, task_queue());
+  RunBaseTest(&test);
+}
+
+TEST_F(RampUpTest, AudioTransportSequenceNumber) {
+  RegisterRtpExtension(RtpExtension(RtpExtension::kTransportSequenceNumberUri,
+                                    kTransportSequenceNumberExtensionId));
+  RampUpTester test(0, 1, 0, 300000, 10000, false, false, false, task_queue());
+  RunBaseTest(&test);
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/rampup_tests.h b/third_party/libwebrtc/call/rampup_tests.h
new file mode 100644
index 0000000000..ba9989d25c
--- /dev/null
+++ b/third_party/libwebrtc/call/rampup_tests.h
@@ -0,0 +1,170 @@
+/*
+ *  Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_RAMPUP_TESTS_H_
+#define CALL_RAMPUP_TESTS_H_
+
+#include <map>
+#include <memory>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "absl/strings/string_view.h"
+#include "api/rtc_event_log/rtc_event_log.h"
+#include "api/task_queue/task_queue_base.h"
+#include "api/test/metrics/metric.h"
+#include "api/test/simulated_network.h"
+#include "call/call.h"
+#include "call/simulated_network.h"
+#include "rtc_base/event.h"
+#include "rtc_base/task_utils/repeating_task.h"
+#include "test/call_test.h"
+
+namespace webrtc {
+
+static const int kTransmissionTimeOffsetExtensionId = 6;
+static const int kAbsSendTimeExtensionId = 7;
+static const int kTransportSequenceNumberExtensionId = 8;
+static const unsigned int kSingleStreamTargetBps = 1000000;
+
+class Clock;
+
+class RampUpTester : public test::EndToEndTest {
+ public:
+  RampUpTester(size_t num_video_streams,
+               size_t num_audio_streams,
+               size_t num_flexfec_streams,
+               unsigned int start_bitrate_bps,
+               int64_t min_run_time_ms,
+               bool rtx,
+               bool red,
+               bool report_perf_stats,
+               TaskQueueBase* task_queue);
+  ~RampUpTester() override;
+
+  size_t GetNumVideoStreams() const override;
+  size_t GetNumAudioStreams() const override;
+  size_t GetNumFlexfecStreams() const override;
+
+  void PerformTest() override;
+
+ protected:
+  virtual void PollStats();
+
+  void AccumulateStats(const VideoSendStream::StreamStats& stream,
+                       size_t* total_packets_sent,
+                       size_t* total_sent,
+                       size_t* padding_sent,
+                       size_t* media_sent) const;
+
+  void ReportResult(absl::string_view measurement,
+                    size_t value,
+                    test::Unit unit,
+                    test::ImprovementDirection improvement_direction) const;
+  void TriggerTestDone();
+
+  Clock* const clock_;
+  BuiltInNetworkBehaviorConfig forward_transport_config_;
+  const size_t num_video_streams_;
+  const size_t num_audio_streams_;
+  const size_t num_flexfec_streams_;
+  const bool rtx_;
+  const bool red_;
+  const bool report_perf_stats_;
+  Call* sender_call_;
+  VideoSendStream* send_stream_;
+  test::PacketTransport* send_transport_;
+  SimulatedNetworkInterface* send_simulated_network_;
+
+ private:
+  typedef std::map<uint32_t, uint32_t> SsrcMap;
+  class VideoStreamFactory;
+
+  void ModifySenderBitrateConfig(BitrateConstraints* bitrate_config) override;
+  void OnVideoStreamsCreated(VideoSendStream* send_stream,
+                             const std::vector<VideoReceiveStreamInterface*>&
+                                 receive_streams) override;
+  BuiltInNetworkBehaviorConfig GetSendTransportConfig() const override;
+  void ModifyVideoConfigs(
+      VideoSendStream::Config* send_config,
+      std::vector<VideoReceiveStreamInterface::Config>* receive_configs,
+      VideoEncoderConfig* encoder_config) override;
+  void ModifyAudioConfigs(AudioSendStream::Config* send_config,
+                          std::vector<AudioReceiveStreamInterface::Config>*
+                              receive_configs) override;
+  void ModifyFlexfecConfigs(
+      std::vector<FlexfecReceiveStream::Config>* receive_configs) override;
+  void OnCallsCreated(Call* sender_call, Call* receiver_call) override;
+  void OnTransportCreated(test::PacketTransport* to_receiver,
+                          SimulatedNetworkInterface* sender_network,
+                          test::PacketTransport* to_sender,
+                          SimulatedNetworkInterface* receiver_network) override;
+
+  const int start_bitrate_bps_;
+  const int64_t min_run_time_ms_;
+  int expected_bitrate_bps_;
+  int64_t test_start_ms_;
+  int64_t ramp_up_finished_ms_;
+
+  std::vector<uint32_t> video_ssrcs_;
+  std::vector<uint32_t> video_rtx_ssrcs_;
+  std::vector<uint32_t> audio_ssrcs_;
+
+ protected:
+  TaskQueueBase* const task_queue_;
+  RepeatingTaskHandle pending_task_;
+};
+
+class RampUpDownUpTester : public RampUpTester {
+ public:
+  RampUpDownUpTester(size_t num_video_streams,
+                     size_t num_audio_streams,
+                     size_t num_flexfec_streams,
+                     unsigned int start_bitrate_bps,
+                     bool rtx,
+                     bool red,
+                     const std::vector<int>& loss_rates,
+                     bool report_perf_stats,
+                     TaskQueueBase* task_queue);
+  ~RampUpDownUpTester() override;
+
+ protected:
+  void PollStats() override;
+
+ private:
+  enum TestStates {
+    kFirstRampup = 0,
+    kLowRate,
+    kSecondRampup,
+    kTestEnd,
+    kTransitionToNextState,
+  };
+
+  void ModifyReceiverBitrateConfig(BitrateConstraints* bitrate_config) override;
+
+  std::string GetModifierString() const;
+  int GetExpectedHighBitrate() const;
+  int GetHighLinkCapacity() const;
+  size_t GetFecBytes() const;
+  bool ExpectingFec() const;
+  void EvolveTestState(int bitrate_bps, bool suspended);
+
+  const std::vector<int> link_rates_;
+  TestStates test_state_;
+  TestStates next_state_;
+  int64_t state_start_ms_;
+  int64_t interval_start_ms_;
+  int sent_bytes_;
+  std::vector<int> loss_rates_;
+};
+
+}  // namespace webrtc
+#endif  // CALL_RAMPUP_TESTS_H_
diff --git a/third_party/libwebrtc/call/receive_stream.h b/third_party/libwebrtc/call/receive_stream.h
new file mode 100644
index 0000000000..eb954ab6ff
--- /dev/null
+++ b/third_party/libwebrtc/call/receive_stream.h
@@ -0,0 +1,83 @@
+/*
+ *  Copyright (c) 2021 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_RECEIVE_STREAM_H_
+#define CALL_RECEIVE_STREAM_H_
+
+#include <vector>
+
+#include "api/crypto/frame_decryptor_interface.h"
+#include "api/frame_transformer_interface.h"
+#include "api/media_types.h"
+#include "api/scoped_refptr.h"
+#include "api/transport/rtp/rtp_source.h"
+#include "modules/rtp_rtcp/include/rtp_header_extension_map.h"
+
+namespace webrtc {
+
+// Common base interface for MediaReceiveStreamInterface based classes and
+// FlexfecReceiveStream.
+class ReceiveStreamInterface {
+ public:
+  // Receive-stream specific RTP settings.
+  // TODO(tommi): This struct isn't needed at this level anymore. Move it closer
+  // to where it's used.
+  struct ReceiveStreamRtpConfig {
+    // Synchronization source (stream identifier) to be received.
+    // This member will not change mid-stream and can be assumed to be const
+    // post initialization.
+    uint32_t remote_ssrc = 0;
+
+    // Sender SSRC used for sending RTCP (such as receiver reports).
+    // This value may change mid-stream and must be done on the same thread
+    // that the value is read on (i.e. packet delivery).
+    uint32_t local_ssrc = 0;
+
+    // RTP header extensions used for the received stream.
+    // This value may change mid-stream and must be done on the same thread
+    // that the value is read on (i.e. packet delivery).
+    std::vector<RtpExtension> extensions;
+  };
+
+  // Set/change the rtp header extensions. Must be called on the packet
+  // delivery thread.
+  virtual void SetRtpExtensions(std::vector<RtpExtension> extensions) = 0;
+  virtual RtpHeaderExtensionMap GetRtpExtensionMap() const = 0;
+
+ protected:
+  virtual ~ReceiveStreamInterface() {}
+};
+
+// Either an audio or video receive stream.
+class MediaReceiveStreamInterface : public ReceiveStreamInterface {
+ public:
+  // Starts stream activity.
+  // When a stream is active, it can receive, process and deliver packets.
+  virtual void Start() = 0;
+
+  // Stops stream activity. Must be called to match with a previous call to
+  // `Start()`. When a stream has been stopped, it won't receive, decode,
+  // process or deliver packets to downstream objects such as callback pointers
+  // set in the config struct.
+  virtual void Stop() = 0;
+
+  virtual void SetDepacketizerToDecoderFrameTransformer(
+      rtc::scoped_refptr<webrtc::FrameTransformerInterface>
+          frame_transformer) = 0;
+
+  virtual void SetFrameDecryptor(
+      rtc::scoped_refptr<webrtc::FrameDecryptorInterface> frame_decryptor) = 0;
+
+  virtual std::vector<RtpSource> GetSources() const = 0;
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_RECEIVE_STREAM_H_
diff --git a/third_party/libwebrtc/call/receive_stream_interface_gn/moz.build b/third_party/libwebrtc/call/receive_stream_interface_gn/moz.build
new file mode 100644
index 0000000000..7be3350326
--- /dev/null
+++ b/third_party/libwebrtc/call/receive_stream_interface_gn/moz.build
@@ -0,0 +1,216 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+  ### This moz.build was AUTOMATICALLY GENERATED from a GN config,  ###
+  ### DO NOT edit it by hand.                                       ###
+
+COMPILE_FLAGS["OS_INCLUDES"] = []
+AllowCompilerWarnings()
+
+DEFINES["ABSL_ALLOCATOR_NOTHROW"] = "1"
+DEFINES["RTC_DAV1D_IN_INTERNAL_DECODER_FACTORY"] = True
+DEFINES["RTC_ENABLE_VP9"] = True
+DEFINES["WEBRTC_ENABLE_PROTOBUF"] = "0"
+DEFINES["WEBRTC_LIBRARY_IMPL"] = True
+DEFINES["WEBRTC_MOZILLA_BUILD"] = True
+DEFINES["WEBRTC_NON_STATIC_TRACE_EVENT_HANDLERS"] = "0"
+DEFINES["WEBRTC_STRICT_FIELD_TRIALS"] = "0"
+
+FINAL_LIBRARY = "webrtc"
+
+
+LOCAL_INCLUDES += [
+    "!/ipc/ipdl/_ipdlheaders",
+    "!/third_party/libwebrtc/gen",
+    "/ipc/chromium/src",
+    "/third_party/libwebrtc/",
+    "/third_party/libwebrtc/third_party/abseil-cpp/",
+    "/tools/profiler/public"
+]
+
+if not CONFIG["MOZ_DEBUG"]:
+
+    DEFINES["DYNAMIC_ANNOTATIONS_ENABLED"] = "0"
+    DEFINES["NDEBUG"] = True
+    DEFINES["NVALGRIND"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1":
+
+    DEFINES["DYNAMIC_ANNOTATIONS_ENABLED"] = "1"
+
+if CONFIG["OS_TARGET"] == "Android":
+
+    DEFINES["ANDROID"] = True
+    DEFINES["ANDROID_NDK_VERSION_ROLL"] = "r22_1"
+    DEFINES["HAVE_SYS_UIO_H"] = True
+    DEFINES["WEBRTC_ANDROID"] = True
+    DEFINES["WEBRTC_ANDROID_OPENSLES"] = True
+    DEFINES["WEBRTC_LINUX"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_GNU_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+    OS_LIBS += [
+        "log"
+    ]
+
+if CONFIG["OS_TARGET"] == "Darwin":
+
+    DEFINES["WEBRTC_MAC"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_LIBCPP_HAS_NO_ALIGNED_ALLOCATION"] = True
+    DEFINES["__ASSERT_MACROS_DEFINE_VERSIONS_WITHOUT_UNDERSCORES"] = "0"
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+if CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["USE_AURA"] = "1"
+    DEFINES["USE_GLIB"] = "1"
+    DEFINES["USE_NSS_CERTS"] = "1"
+    DEFINES["USE_OZONE"] = "1"
+    DEFINES["USE_UDEV"] = True
+    DEFINES["WEBRTC_LINUX"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_FILE_OFFSET_BITS"] = "64"
+    DEFINES["_LARGEFILE64_SOURCE"] = True
+    DEFINES["_LARGEFILE_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+    OS_LIBS += [
+        "rt"
+    ]
+
+if CONFIG["OS_TARGET"] == "OpenBSD":
+
+    DEFINES["USE_GLIB"] = "1"
+    DEFINES["USE_OZONE"] = "1"
+    DEFINES["USE_X11"] = "1"
+    DEFINES["WEBRTC_BSD"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_FILE_OFFSET_BITS"] = "64"
+    DEFINES["_LARGEFILE64_SOURCE"] = True
+    DEFINES["_LARGEFILE_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+if CONFIG["OS_TARGET"] == "WINNT":
+
+    DEFINES["CERT_CHAIN_PARA_HAS_EXTRA_FIELDS"] = True
+    DEFINES["NOMINMAX"] = True
+    DEFINES["NTDDI_VERSION"] = "0x0A000000"
+    DEFINES["PSAPI_VERSION"] = "2"
+    DEFINES["UNICODE"] = True
+    DEFINES["USE_AURA"] = "1"
+    DEFINES["WEBRTC_WIN"] = True
+    DEFINES["WIN32"] = True
+    DEFINES["WIN32_LEAN_AND_MEAN"] = True
+    DEFINES["WINAPI_FAMILY"] = "WINAPI_FAMILY_DESKTOP_APP"
+    DEFINES["WINVER"] = "0x0A00"
+    DEFINES["_ATL_NO_OPENGL"] = True
+    DEFINES["_CRT_RAND_S"] = True
+    DEFINES["_CRT_SECURE_NO_DEPRECATE"] = True
+    DEFINES["_ENABLE_EXTENDED_ALIGNED_STORAGE"] = True
+    DEFINES["_HAS_EXCEPTIONS"] = "0"
+    DEFINES["_HAS_NODISCARD"] = True
+    DEFINES["_SCL_SECURE_NO_DEPRECATE"] = True
+    DEFINES["_SECURE_ATL"] = True
+    DEFINES["_UNICODE"] = True
+    DEFINES["_WIN32_WINNT"] = "0x0A00"
+    DEFINES["_WINDOWS"] = True
+    DEFINES["__STD_C"] = True
+
+    OS_LIBS += [
+        "crypt32",
+        "iphlpapi",
+        "secur32",
+        "winmm"
+    ]
+
+if CONFIG["CPU_ARCH"] == "aarch64":
+
+    DEFINES["WEBRTC_ARCH_ARM64"] = True
+    DEFINES["WEBRTC_HAS_NEON"] = True
+
+if CONFIG["CPU_ARCH"] == "arm":
+
+    DEFINES["WEBRTC_ARCH_ARM"] = True
+    DEFINES["WEBRTC_ARCH_ARM_V7"] = True
+    DEFINES["WEBRTC_HAS_NEON"] = True
+
+if CONFIG["CPU_ARCH"] == "mips32":
+
+    DEFINES["MIPS32_LE"] = True
+    DEFINES["MIPS_FPU_LE"] = True
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "mips64":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86":
+
+    DEFINES["WEBRTC_ENABLE_AVX2"] = True
+
+if CONFIG["CPU_ARCH"] == "x86_64":
+
+    DEFINES["WEBRTC_ENABLE_AVX2"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Android":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Darwin":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "OpenBSD":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "WINNT":
+
+    DEFINES["_HAS_ITERATOR_DEBUGGING"] = "0"
+
+if CONFIG["MOZ_X11"] == "1" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["USE_X11"] = "1"
+
+if CONFIG["CPU_ARCH"] == "arm" and CONFIG["OS_TARGET"] == "Android":
+
+    OS_LIBS += [
+        "android_support",
+        "unwind"
+    ]
+
+if CONFIG["CPU_ARCH"] == "x86" and CONFIG["OS_TARGET"] == "Android":
+
+    OS_LIBS += [
+        "android_support"
+    ]
+
+if CONFIG["CPU_ARCH"] == "aarch64" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "arm" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86_64" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+Library("receive_stream_interface_gn")
diff --git a/third_party/libwebrtc/call/receive_time_calculator.cc b/third_party/libwebrtc/call/receive_time_calculator.cc
new file mode 100644
index 0000000000..417168b15d
--- /dev/null
+++ b/third_party/libwebrtc/call/receive_time_calculator.cc
@@ -0,0 +1,120 @@
+/*
+ *  Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/receive_time_calculator.h"
+
+#include <memory>
+#include <string>
+#include <type_traits>
+
+#include "rtc_base/experiments/field_trial_parser.h"
+#include "rtc_base/numerics/safe_minmax.h"
+
+namespace webrtc {
+namespace {
+
+const char kBweReceiveTimeCorrection[] = "WebRTC-Bwe-ReceiveTimeFix";
+}  // namespace
+
+ReceiveTimeCalculatorConfig::ReceiveTimeCalculatorConfig(
+    const FieldTrialsView& field_trials)
+    : max_packet_time_repair("maxrep", TimeDelta::Millis(2000)),
+      stall_threshold("stall", TimeDelta::Millis(5)),
+      tolerance("tol", TimeDelta::Millis(1)),
+      max_stall("maxstall", TimeDelta::Seconds(5)) {
+  std::string trial_string = field_trials.Lookup(kBweReceiveTimeCorrection);
+  ParseFieldTrial(
+      {&max_packet_time_repair, &stall_threshold, &tolerance, &max_stall},
+      trial_string);
+}
+ReceiveTimeCalculatorConfig::ReceiveTimeCalculatorConfig(
+    const ReceiveTimeCalculatorConfig&) = default;
+ReceiveTimeCalculatorConfig::~ReceiveTimeCalculatorConfig() = default;
+
+ReceiveTimeCalculator::ReceiveTimeCalculator(
+    const FieldTrialsView& field_trials)
+    : config_(field_trials) {}
+
+std::unique_ptr<ReceiveTimeCalculator>
+ReceiveTimeCalculator::CreateFromFieldTrial(
+    const FieldTrialsView& field_trials) {
+  if (!field_trials.IsEnabled(kBweReceiveTimeCorrection))
+    return nullptr;
+  return std::make_unique<ReceiveTimeCalculator>(field_trials);
+}
+
+int64_t ReceiveTimeCalculator::ReconcileReceiveTimes(int64_t packet_time_us,
+                                                     int64_t system_time_us,
+                                                     int64_t safe_time_us) {
+  int64_t stall_time_us = system_time_us - packet_time_us;
+  if (total_system_time_passed_us_ < config_.stall_threshold->us()) {
+    stall_time_us = rtc::SafeMin(stall_time_us, config_.max_stall->us());
+  }
+  int64_t corrected_time_us = safe_time_us - stall_time_us;
+
+  if (last_packet_time_us_ == -1 && stall_time_us < 0) {
+    static_clock_offset_us_ = stall_time_us;
+    corrected_time_us += static_clock_offset_us_;
+  } else if (last_packet_time_us_ > 0) {
+    // All repairs depend on variables being intialized
+    int64_t packet_time_delta_us = packet_time_us - last_packet_time_us_;
+    int64_t system_time_delta_us = system_time_us - last_system_time_us_;
+    int64_t safe_time_delta_us = safe_time_us - last_safe_time_us_;
+
+    // Repair backwards clock resets during initial stall. In this case, the
+    // reset is observed only in packet time but never in system time.
+    if (system_time_delta_us < 0)
+      total_system_time_passed_us_ += config_.stall_threshold->us();
+    else
+      total_system_time_passed_us_ += system_time_delta_us;
+    if (packet_time_delta_us < 0 &&
+        total_system_time_passed_us_ < config_.stall_threshold->us()) {
+      static_clock_offset_us_ -= packet_time_delta_us;
+    }
+    corrected_time_us += static_clock_offset_us_;
+
+    // Detect resets inbetween clock readings in socket and app.
+    bool forward_clock_reset =
+        corrected_time_us + config_.tolerance->us() < last_corrected_time_us_;
+    bool obvious_backward_clock_reset = system_time_us < packet_time_us;
+
+    // Harder case with backward clock reset during stall, the reset being
+    // smaller than the stall. Compensate throughout the stall.
+    bool small_backward_clock_reset =
+        !obvious_backward_clock_reset &&
+        safe_time_delta_us > system_time_delta_us + config_.tolerance->us();
+    bool stall_start =
+        packet_time_delta_us >= 0 &&
+        system_time_delta_us > packet_time_delta_us + config_.tolerance->us();
+    bool stall_is_over = safe_time_delta_us > config_.stall_threshold->us();
+    bool packet_time_caught_up =
+        packet_time_delta_us < 0 && system_time_delta_us >= 0;
+    if (stall_start && small_backward_clock_reset)
+      small_reset_during_stall_ = true;
+    else if (stall_is_over || packet_time_caught_up)
+      small_reset_during_stall_ = false;
+
+    // If resets are detected, advance time by (capped) packet time increase.
+    if (forward_clock_reset || obvious_backward_clock_reset ||
+        small_reset_during_stall_) {
+      corrected_time_us = last_corrected_time_us_ +
+                          rtc::SafeClamp(packet_time_delta_us, 0,
+                                         config_.max_packet_time_repair->us());
+    }
+  }
+
+  last_corrected_time_us_ = corrected_time_us;
+  last_packet_time_us_ = packet_time_us;
+  last_system_time_us_ = system_time_us;
+  last_safe_time_us_ = safe_time_us;
+  return corrected_time_us;
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/receive_time_calculator.h b/third_party/libwebrtc/call/receive_time_calculator.h
new file mode 100644
index 0000000000..57ba331844
--- /dev/null
+++ b/third_party/libwebrtc/call/receive_time_calculator.h
@@ -0,0 +1,63 @@
+/*
+ *  Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+#ifndef CALL_RECEIVE_TIME_CALCULATOR_H_
+#define CALL_RECEIVE_TIME_CALCULATOR_H_
+
+#include <stdint.h>
+
+#include <memory>
+
+#include "api/field_trials_view.h"
+#include "api/units/time_delta.h"
+#include "rtc_base/experiments/field_trial_parser.h"
+
+namespace webrtc {
+
+struct ReceiveTimeCalculatorConfig {
+  explicit ReceiveTimeCalculatorConfig(const FieldTrialsView& field_trials);
+  ReceiveTimeCalculatorConfig(const ReceiveTimeCalculatorConfig&);
+  ReceiveTimeCalculatorConfig& operator=(const ReceiveTimeCalculatorConfig&) =
+      default;
+  ~ReceiveTimeCalculatorConfig();
+  FieldTrialParameter<TimeDelta> max_packet_time_repair;
+  FieldTrialParameter<TimeDelta> stall_threshold;
+  FieldTrialParameter<TimeDelta> tolerance;
+  FieldTrialParameter<TimeDelta> max_stall;
+};
+
+// The receive time calculator serves the purpose of combining packet time
+// stamps with a safely incremental clock. This assumes that the packet time
+// stamps are based on lower layer timestamps that have more accurate time
+// increments since they are based on the exact receive time. They might
+// however, have large jumps due to clock resets in the system. To compensate
+// this they are combined with a safe clock source that is guaranteed to be
+// consistent, but it will not be able to measure the exact time when a packet
+// is received.
+class ReceiveTimeCalculator {
+ public:
+  static std::unique_ptr<ReceiveTimeCalculator> CreateFromFieldTrial(
+      const FieldTrialsView& field_trials);
+  explicit ReceiveTimeCalculator(const FieldTrialsView& field_trials);
+  int64_t ReconcileReceiveTimes(int64_t packet_time_us_,
+                                int64_t system_time_us_,
+                                int64_t safe_time_us_);
+
+ private:
+  int64_t last_corrected_time_us_ = -1;
+  int64_t last_packet_time_us_ = -1;
+  int64_t last_system_time_us_ = -1;
+  int64_t last_safe_time_us_ = -1;
+  int64_t total_system_time_passed_us_ = 0;
+  int64_t static_clock_offset_us_ = 0;
+  int64_t small_reset_during_stall_ = false;
+  ReceiveTimeCalculatorConfig config_;
+};
+}  // namespace webrtc
+#endif  // CALL_RECEIVE_TIME_CALCULATOR_H_
diff --git a/third_party/libwebrtc/call/receive_time_calculator_unittest.cc b/third_party/libwebrtc/call/receive_time_calculator_unittest.cc
new file mode 100644
index 0000000000..f2e3d54f0c
--- /dev/null
+++ b/third_party/libwebrtc/call/receive_time_calculator_unittest.cc
@@ -0,0 +1,249 @@
+/*
+ *  Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/receive_time_calculator.h"
+
+#include <stdlib.h>
+
+#include <algorithm>
+#include <cmath>
+#include <cstdint>
+#include <vector>
+
+#include "absl/types/optional.h"
+#include "rtc_base/random.h"
+#include "rtc_base/time_utils.h"
+#include "test/gtest.h"
+#include "test/scoped_key_value_config.h"
+
+namespace webrtc {
+namespace test {
+namespace {
+
+class EmulatedClock {
+ public:
+  explicit EmulatedClock(int seed, float drift = 0.0f)
+      : random_(seed), clock_us_(random_.Rand<uint32_t>()), drift_(drift) {}
+  virtual ~EmulatedClock() = default;
+  int64_t GetClockUs() const { return clock_us_; }
+
+ protected:
+  int64_t UpdateClock(int64_t time_us) {
+    if (!last_query_us_)
+      last_query_us_ = time_us;
+    int64_t skip_us = time_us - *last_query_us_;
+    accumulated_drift_us_ += skip_us * drift_;
+    int64_t drift_correction_us = static_cast<int64_t>(accumulated_drift_us_);
+    accumulated_drift_us_ -= drift_correction_us;
+    clock_us_ += skip_us + drift_correction_us;
+    last_query_us_ = time_us;
+    return skip_us;
+  }
+  Random random_;
+
+ private:
+  int64_t clock_us_;
+  absl::optional<int64_t> last_query_us_;
+  float drift_;
+  float accumulated_drift_us_ = 0;
+};
+
+class EmulatedMonotoneousClock : public EmulatedClock {
+ public:
+  explicit EmulatedMonotoneousClock(int seed) : EmulatedClock(seed) {}
+  ~EmulatedMonotoneousClock() = default;
+
+  int64_t Query(int64_t time_us) {
+    int64_t skip_us = UpdateClock(time_us);
+
+    // In a stall
+    if (stall_recovery_time_us_ > 0) {
+      if (GetClockUs() > stall_recovery_time_us_) {
+        stall_recovery_time_us_ = 0;
+        return GetClockUs();
+      } else {
+        return stall_recovery_time_us_;
+      }
+    }
+
+    // Check if we enter a stall
+    for (int k = 0; k < skip_us; ++k) {
+      if (random_.Rand<double>() < kChanceOfStallPerUs) {
+        int64_t stall_duration_us =
+            static_cast<int64_t>(random_.Rand<float>() * kMaxStallDurationUs);
+        stall_recovery_time_us_ = GetClockUs() + stall_duration_us;
+        return stall_recovery_time_us_;
+      }
+    }
+    return GetClockUs();
+  }
+
+  void ForceStallUs() {
+    int64_t stall_duration_us =
+        static_cast<int64_t>(random_.Rand<float>() * kMaxStallDurationUs);
+    stall_recovery_time_us_ = GetClockUs() + stall_duration_us;
+  }
+
+  bool Stalled() const { return stall_recovery_time_us_ > 0; }
+
+  int64_t GetRemainingStall(int64_t time_us) const {
+    return stall_recovery_time_us_ > 0 ? stall_recovery_time_us_ - GetClockUs()
+                                       : 0;
+  }
+
+  const int64_t kMaxStallDurationUs = rtc::kNumMicrosecsPerSec;
+
+ private:
+  const float kChanceOfStallPerUs = 5e-6f;
+  int64_t stall_recovery_time_us_ = 0;
+};
+
+class EmulatedNonMonotoneousClock : public EmulatedClock {
+ public:
+  EmulatedNonMonotoneousClock(int seed, int64_t duration_us, float drift = 0)
+      : EmulatedClock(seed, drift) {
+    Pregenerate(duration_us);
+  }
+  ~EmulatedNonMonotoneousClock() = default;
+
+  void Pregenerate(int64_t duration_us) {
+    int64_t time_since_reset_us = kMinTimeBetweenResetsUs;
+    int64_t clock_offset_us = 0;
+    for (int64_t time_us = 0; time_us < duration_us; time_us += kResolutionUs) {
+      int64_t skip_us = UpdateClock(time_us);
+      time_since_reset_us += skip_us;
+      int64_t reset_us = 0;
+      if (time_since_reset_us >= kMinTimeBetweenResetsUs) {
+        for (int k = 0; k < skip_us; ++k) {
+          if (random_.Rand<double>() < kChanceOfResetPerUs) {
+            reset_us = static_cast<int64_t>(2 * random_.Rand<float>() *
+                                            kMaxAbsResetUs) -
+                       kMaxAbsResetUs;
+            clock_offset_us += reset_us;
+            time_since_reset_us = 0;
+            break;
+          }
+        }
+      }
+      pregenerated_clock_.emplace_back(GetClockUs() + clock_offset_us);
+      resets_us_.emplace_back(reset_us);
+    }
+  }
+
+  int64_t Query(int64_t time_us) {
+    size_t ixStart =
+        (last_reset_query_time_us_ + (kResolutionUs >> 1)) / kResolutionUs + 1;
+    size_t ixEnd = (time_us + (kResolutionUs >> 1)) / kResolutionUs;
+    if (ixEnd >= pregenerated_clock_.size())
+      return -1;
+    last_reset_size_us_ = 0;
+    for (size_t ix = ixStart; ix <= ixEnd; ++ix) {
+      if (resets_us_[ix] != 0) {
+        last_reset_size_us_ = resets_us_[ix];
+      }
+    }
+    last_reset_query_time_us_ = time_us;
+    return pregenerated_clock_[ixEnd];
+  }
+
+  bool WasReset() const { return last_reset_size_us_ != 0; }
+  bool WasNegativeReset() const { return last_reset_size_us_ < 0; }
+  int64_t GetLastResetUs() const { return last_reset_size_us_; }
+
+ private:
+  const float kChanceOfResetPerUs = 1e-6f;
+  const int64_t kMaxAbsResetUs = rtc::kNumMicrosecsPerSec;
+  const int64_t kMinTimeBetweenResetsUs = 3 * rtc::kNumMicrosecsPerSec;
+  const int64_t kResolutionUs = rtc::kNumMicrosecsPerMillisec;
+  int64_t last_reset_query_time_us_ = 0;
+  int64_t last_reset_size_us_ = 0;
+  std::vector<int64_t> pregenerated_clock_;
+  std::vector<int64_t> resets_us_;
+};
+
+TEST(ClockRepair, NoClockDrift) {
+  webrtc::test::ScopedKeyValueConfig field_trials;
+  const int kSeeds = 10;
+  const int kFirstSeed = 1;
+  const int64_t kRuntimeUs = 10 * rtc::kNumMicrosecsPerSec;
+  const float kDrift = 0.0f;
+  const int64_t kMaxPacketInterarrivalUs = 50 * rtc::kNumMicrosecsPerMillisec;
+  for (int seed = kFirstSeed; seed < kSeeds + kFirstSeed; ++seed) {
+    EmulatedMonotoneousClock monotone_clock(seed);
+    EmulatedNonMonotoneousClock non_monotone_clock(
+        seed + 1, kRuntimeUs + rtc::kNumMicrosecsPerSec, kDrift);
+    ReceiveTimeCalculator reception_time_tracker(field_trials);
+    int64_t corrected_clock_0 = 0;
+    int64_t reset_during_stall_tol_us = 0;
+    bool initial_clock_stall = true;
+    int64_t accumulated_upper_bound_tolerance_us = 0;
+    int64_t accumulated_lower_bound_tolerance_us = 0;
+    Random random(1);
+    monotone_clock.ForceStallUs();
+    int64_t last_time_us = 0;
+    bool add_tolerance_on_next_packet = false;
+    int64_t monotone_noise_us = 1000;
+
+    for (int64_t time_us = 0; time_us < kRuntimeUs;
+         time_us += static_cast<int64_t>(random.Rand<float>() *
+                                         kMaxPacketInterarrivalUs)) {
+      int64_t socket_time_us = non_monotone_clock.Query(time_us);
+      int64_t monotone_us = monotone_clock.Query(time_us) +
+                            2 * random.Rand<float>() * monotone_noise_us -
+                            monotone_noise_us;
+      int64_t system_time_us = non_monotone_clock.Query(
+          time_us + monotone_clock.GetRemainingStall(time_us));
+
+      int64_t corrected_clock_us = reception_time_tracker.ReconcileReceiveTimes(
+          socket_time_us, system_time_us, monotone_us);
+      if (time_us == 0)
+        corrected_clock_0 = corrected_clock_us;
+
+      if (add_tolerance_on_next_packet)
+        accumulated_lower_bound_tolerance_us -= (time_us - last_time_us);
+
+      // Perfect repair cannot be achiveved if non-monotone clock resets during
+      // a monotone clock stall.
+      add_tolerance_on_next_packet = false;
+      if (monotone_clock.Stalled() && non_monotone_clock.WasReset()) {
+        reset_during_stall_tol_us =
+            std::max(reset_during_stall_tol_us, time_us - last_time_us);
+        if (non_monotone_clock.WasNegativeReset()) {
+          add_tolerance_on_next_packet = true;
+        }
+        if (initial_clock_stall && !non_monotone_clock.WasNegativeReset()) {
+          // Positive resets during an initial clock stall cannot be repaired
+          // and error will propagate through rest of trace.
+          accumulated_upper_bound_tolerance_us +=
+              std::abs(non_monotone_clock.GetLastResetUs());
+        }
+      } else {
+        reset_during_stall_tol_us = 0;
+        initial_clock_stall = false;
+      }
+      int64_t err = corrected_clock_us - corrected_clock_0 - time_us;
+
+      // Resets during stalls may lead to small errors temporarily.
+      int64_t lower_tol_us = accumulated_lower_bound_tolerance_us -
+                             reset_during_stall_tol_us - monotone_noise_us -
+                             2 * rtc::kNumMicrosecsPerMillisec;
+      EXPECT_GE(err, lower_tol_us);
+      int64_t upper_tol_us = accumulated_upper_bound_tolerance_us +
+                             monotone_noise_us +
+                             2 * rtc::kNumMicrosecsPerMillisec;
+      EXPECT_LE(err, upper_tol_us);
+
+      last_time_us = time_us;
+    }
+  }
+}
+}  // namespace
+}  // namespace test
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/rtp_bitrate_configurator.cc b/third_party/libwebrtc/call/rtp_bitrate_configurator.cc
new file mode 100644
index 0000000000..264dcdcb81
--- /dev/null
+++ b/third_party/libwebrtc/call/rtp_bitrate_configurator.cc
@@ -0,0 +1,135 @@
+/*
+ *  Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/rtp_bitrate_configurator.h"
+
+#include <algorithm>
+
+#include "rtc_base/checks.h"
+
+namespace {
+
+// Returns its smallest positive argument. If neither argument is positive,
+// returns an arbitrary nonpositive value.
+int MinPositive(int a, int b) {
+  if (a <= 0) {
+    return b;
+  }
+  if (b <= 0) {
+    return a;
+  }
+  return std::min(a, b);
+}
+
+}  // namespace
+
+namespace webrtc {
+RtpBitrateConfigurator::RtpBitrateConfigurator(
+    const BitrateConstraints& bitrate_config)
+    : bitrate_config_(bitrate_config), base_bitrate_config_(bitrate_config) {
+  RTC_DCHECK_GE(bitrate_config.min_bitrate_bps, 0);
+  RTC_DCHECK_GE(bitrate_config.start_bitrate_bps,
+                bitrate_config.min_bitrate_bps);
+  if (bitrate_config.max_bitrate_bps != -1) {
+    RTC_DCHECK_GE(bitrate_config.max_bitrate_bps,
+                  bitrate_config.start_bitrate_bps);
+  }
+}
+
+RtpBitrateConfigurator::~RtpBitrateConfigurator() = default;
+
+BitrateConstraints RtpBitrateConfigurator::GetConfig() const {
+  return bitrate_config_;
+}
+
+absl::optional<BitrateConstraints>
+RtpBitrateConfigurator::UpdateWithSdpParameters(
+    const BitrateConstraints& bitrate_config) {
+  RTC_DCHECK_GE(bitrate_config.min_bitrate_bps, 0);
+  RTC_DCHECK_NE(bitrate_config.start_bitrate_bps, 0);
+  if (bitrate_config.max_bitrate_bps != -1) {
+    RTC_DCHECK_GT(bitrate_config.max_bitrate_bps, 0);
+  }
+
+  absl::optional<int> new_start;
+  // Only update the "start" bitrate if it's set, and different from the old
+  // value. In practice, this value comes from the x-google-start-bitrate codec
+  // parameter in SDP, and setting the same remote description twice shouldn't
+  // restart bandwidth estimation.
+  if (bitrate_config.start_bitrate_bps != -1 &&
+      bitrate_config.start_bitrate_bps !=
+          base_bitrate_config_.start_bitrate_bps) {
+    new_start.emplace(bitrate_config.start_bitrate_bps);
+  }
+  base_bitrate_config_ = bitrate_config;
+  return UpdateConstraints(new_start);
+}
+
+absl::optional<BitrateConstraints>
+RtpBitrateConfigurator::UpdateWithClientPreferences(
+    const BitrateSettings& bitrate_mask) {
+  bitrate_config_mask_ = bitrate_mask;
+  return UpdateConstraints(bitrate_mask.start_bitrate_bps);
+}
+
+// Relay cap can change only max bitrate.
+absl::optional<BitrateConstraints> RtpBitrateConfigurator::UpdateWithRelayCap(
+    DataRate cap) {
+  if (cap.IsFinite()) {
+    RTC_DCHECK(!cap.IsZero());
+  }
+  max_bitrate_over_relay_ = cap;
+  return UpdateConstraints(absl::nullopt);
+}
+
+absl::optional<BitrateConstraints> RtpBitrateConfigurator::UpdateConstraints(
+    const absl::optional<int>& new_start) {
+  BitrateConstraints updated;
+  updated.min_bitrate_bps =
+      std::max(bitrate_config_mask_.min_bitrate_bps.value_or(0),
+               base_bitrate_config_.min_bitrate_bps);
+
+  updated.max_bitrate_bps =
+      MinPositive(bitrate_config_mask_.max_bitrate_bps.value_or(-1),
+                  base_bitrate_config_.max_bitrate_bps);
+  updated.max_bitrate_bps =
+      MinPositive(updated.max_bitrate_bps, max_bitrate_over_relay_.bps_or(-1));
+
+  // If the combined min ends up greater than the combined max, the max takes
+  // priority.
+  if (updated.max_bitrate_bps != -1 &&
+      updated.min_bitrate_bps > updated.max_bitrate_bps) {
+    updated.min_bitrate_bps = updated.max_bitrate_bps;
+  }
+
+  // If there is nothing to update (min/max unchanged, no new bandwidth
+  // estimation start value), return early.
+  if (updated.min_bitrate_bps == bitrate_config_.min_bitrate_bps &&
+      updated.max_bitrate_bps == bitrate_config_.max_bitrate_bps &&
+      !new_start) {
+    return absl::nullopt;
+  }
+
+  if (new_start) {
+    // Clamp start by min and max.
+    updated.start_bitrate_bps = MinPositive(
+        std::max(*new_start, updated.min_bitrate_bps), updated.max_bitrate_bps);
+  } else {
+    updated.start_bitrate_bps = -1;
+  }
+  BitrateConstraints config_to_return = updated;
+  if (!new_start) {
+    updated.start_bitrate_bps = bitrate_config_.start_bitrate_bps;
+  }
+  bitrate_config_ = updated;
+  return config_to_return;
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/rtp_bitrate_configurator.h b/third_party/libwebrtc/call/rtp_bitrate_configurator.h
new file mode 100644
index 0000000000..5cb779a3b3
--- /dev/null
+++ b/third_party/libwebrtc/call/rtp_bitrate_configurator.h
@@ -0,0 +1,77 @@
+/*
+ *  Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_RTP_BITRATE_CONFIGURATOR_H_
+#define CALL_RTP_BITRATE_CONFIGURATOR_H_
+
+#include "absl/types/optional.h"
+#include "api/transport/bitrate_settings.h"
+#include "api/units/data_rate.h"
+
+namespace webrtc {
+
+// RtpBitrateConfigurator calculates the bitrate configuration based on received
+// remote configuration combined with local overrides.
+class RtpBitrateConfigurator {
+ public:
+  explicit RtpBitrateConfigurator(const BitrateConstraints& bitrate_config);
+  ~RtpBitrateConfigurator();
+
+  RtpBitrateConfigurator(const RtpBitrateConfigurator&) = delete;
+  RtpBitrateConfigurator& operator=(const RtpBitrateConfigurator&) = delete;
+
+  BitrateConstraints GetConfig() const;
+
+  // The greater min and smaller max set by this and SetClientBitratePreferences
+  // will be used. The latest non-negative start value from either call will be
+  // used. Specifying a start bitrate (>0) will reset the current bitrate
+  // estimate. This is due to how the 'x-google-start-bitrate' flag is currently
+  // implemented. Passing -1 leaves the start bitrate unchanged. Behavior is not
+  // guaranteed for other negative values or 0.
+  // The optional return value is set with new configuration if it was updated.
+  absl::optional<BitrateConstraints> UpdateWithSdpParameters(
+      const BitrateConstraints& bitrate_config_);
+
+  // The greater min and smaller max set by this and SetSdpBitrateParameters
+  // will be used. The latest non-negative start value form either call will be
+  // used. Specifying a start bitrate will reset the current bitrate estimate.
+  // Assumes 0 <= min <= start <= max holds for set parameters.
+  // Update the bitrate configuration
+  // The optional return value is set with new configuration if it was updated.
+  absl::optional<BitrateConstraints> UpdateWithClientPreferences(
+      const BitrateSettings& bitrate_mask);
+
+  // Apply a cap for relayed calls.
+  absl::optional<BitrateConstraints> UpdateWithRelayCap(DataRate cap);
+
+ private:
+  // Applies update to the BitrateConstraints cached in `config_`, resetting
+  // with `new_start` if set.
+  absl::optional<BitrateConstraints> UpdateConstraints(
+      const absl::optional<int>& new_start);
+
+  // Bitrate config used until valid bitrate estimates are calculated. Also
+  // used to cap total bitrate used. This comes from the remote connection.
+  BitrateConstraints bitrate_config_;
+
+  // The config mask set by SetClientBitratePreferences.
+  // 0 <= min <= start <= max
+  BitrateSettings bitrate_config_mask_;
+
+  // The config set by SetSdpBitrateParameters.
+  // min >= 0, start != 0, max == -1 || max > 0
+  BitrateConstraints base_bitrate_config_;
+
+  // Bandwidth cap applied for relayed calls.
+  DataRate max_bitrate_over_relay_ = DataRate::PlusInfinity();
+};
+}  // namespace webrtc
+
+#endif  // CALL_RTP_BITRATE_CONFIGURATOR_H_
diff --git a/third_party/libwebrtc/call/rtp_bitrate_configurator_unittest.cc b/third_party/libwebrtc/call/rtp_bitrate_configurator_unittest.cc
new file mode 100644
index 0000000000..6449a1a0f5
--- /dev/null
+++ b/third_party/libwebrtc/call/rtp_bitrate_configurator_unittest.cc
@@ -0,0 +1,300 @@
+/*
+ *  Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+#include "call/rtp_bitrate_configurator.h"
+
+#include <memory>
+
+#include "test/gtest.h"
+
+namespace webrtc {
+using absl::nullopt;
+
+class RtpBitrateConfiguratorTest : public ::testing::Test {
+ public:
+  RtpBitrateConfiguratorTest()
+      : configurator_(new RtpBitrateConfigurator(BitrateConstraints())) {}
+  std::unique_ptr<RtpBitrateConfigurator> configurator_;
+  void UpdateConfigMatches(BitrateConstraints bitrate_config,
+                           absl::optional<int> min_bitrate_bps,
+                           absl::optional<int> start_bitrate_bps,
+                           absl::optional<int> max_bitrate_bps) {
+    absl::optional<BitrateConstraints> result =
+        configurator_->UpdateWithSdpParameters(bitrate_config);
+    EXPECT_TRUE(result.has_value());
+    if (start_bitrate_bps.has_value())
+      EXPECT_EQ(result->start_bitrate_bps, start_bitrate_bps);
+    if (min_bitrate_bps.has_value())
+      EXPECT_EQ(result->min_bitrate_bps, min_bitrate_bps);
+    if (max_bitrate_bps.has_value())
+      EXPECT_EQ(result->max_bitrate_bps, max_bitrate_bps);
+  }
+
+  void UpdateMaskMatches(BitrateSettings bitrate_mask,
+                         absl::optional<int> min_bitrate_bps,
+                         absl::optional<int> start_bitrate_bps,
+                         absl::optional<int> max_bitrate_bps) {
+    absl::optional<BitrateConstraints> result =
+        configurator_->UpdateWithClientPreferences(bitrate_mask);
+    EXPECT_TRUE(result.has_value());
+    if (start_bitrate_bps.has_value())
+      EXPECT_EQ(result->start_bitrate_bps, start_bitrate_bps);
+    if (min_bitrate_bps.has_value())
+      EXPECT_EQ(result->min_bitrate_bps, min_bitrate_bps);
+    if (max_bitrate_bps.has_value())
+      EXPECT_EQ(result->max_bitrate_bps, max_bitrate_bps);
+  }
+};
+
+TEST_F(RtpBitrateConfiguratorTest, NewConfigWithValidConfigReturnsNewConfig) {
+  BitrateConstraints bitrate_config;
+  bitrate_config.min_bitrate_bps = 1;
+  bitrate_config.start_bitrate_bps = 2;
+  bitrate_config.max_bitrate_bps = 3;
+
+  UpdateConfigMatches(bitrate_config, 1, 2, 3);
+}
+
+TEST_F(RtpBitrateConfiguratorTest, NewConfigWithDifferentMinReturnsNewConfig) {
+  BitrateConstraints bitrate_config;
+  bitrate_config.min_bitrate_bps = 10;
+  bitrate_config.start_bitrate_bps = 20;
+  bitrate_config.max_bitrate_bps = 30;
+  configurator_.reset(new RtpBitrateConfigurator(bitrate_config));
+
+  bitrate_config.min_bitrate_bps = 11;
+  UpdateConfigMatches(bitrate_config, 11, -1, 30);
+}
+
+TEST_F(RtpBitrateConfiguratorTest,
+       NewConfigWithDifferentStartReturnsNewConfig) {
+  BitrateConstraints bitrate_config;
+  bitrate_config.min_bitrate_bps = 10;
+  bitrate_config.start_bitrate_bps = 20;
+  bitrate_config.max_bitrate_bps = 30;
+  configurator_.reset(new RtpBitrateConfigurator(bitrate_config));
+
+  bitrate_config.start_bitrate_bps = 21;
+  UpdateConfigMatches(bitrate_config, 10, 21, 30);
+}
+
+TEST_F(RtpBitrateConfiguratorTest, NewConfigWithDifferentMaxReturnsNewConfig) {
+  BitrateConstraints bitrate_config;
+  bitrate_config.min_bitrate_bps = 10;
+  bitrate_config.start_bitrate_bps = 20;
+  bitrate_config.max_bitrate_bps = 30;
+  configurator_.reset(new RtpBitrateConfigurator(bitrate_config));
+
+  bitrate_config.max_bitrate_bps = 31;
+  UpdateConfigMatches(bitrate_config, 10, -1, 31);
+}
+
+TEST_F(RtpBitrateConfiguratorTest, NewConfigWithSameConfigElidesSecondCall) {
+  BitrateConstraints bitrate_config;
+  bitrate_config.min_bitrate_bps = 1;
+  bitrate_config.start_bitrate_bps = 2;
+  bitrate_config.max_bitrate_bps = 3;
+
+  UpdateConfigMatches(bitrate_config, 1, 2, 3);
+  EXPECT_FALSE(
+      configurator_->UpdateWithSdpParameters(bitrate_config).has_value());
+}
+
+TEST_F(RtpBitrateConfiguratorTest,
+       NewConfigWithSameMinMaxAndNegativeStartElidesSecondCall) {
+  BitrateConstraints bitrate_config;
+  bitrate_config.min_bitrate_bps = 1;
+  bitrate_config.start_bitrate_bps = 2;
+  bitrate_config.max_bitrate_bps = 3;
+
+  UpdateConfigMatches(bitrate_config, 1, 2, 3);
+
+  bitrate_config.start_bitrate_bps = -1;
+  EXPECT_FALSE(
+      configurator_->UpdateWithSdpParameters(bitrate_config).has_value());
+}
+
+TEST_F(RtpBitrateConfiguratorTest, BiggerMaskMinUsed) {
+  BitrateSettings mask;
+  mask.min_bitrate_bps = 1234;
+  UpdateMaskMatches(mask, *mask.min_bitrate_bps, nullopt, nullopt);
+}
+
+TEST_F(RtpBitrateConfiguratorTest, BiggerConfigMinUsed) {
+  BitrateSettings mask;
+  mask.min_bitrate_bps = 1000;
+  UpdateMaskMatches(mask, 1000, nullopt, nullopt);
+
+  BitrateConstraints config;
+  config.min_bitrate_bps = 1234;
+  UpdateConfigMatches(config, 1234, nullopt, nullopt);
+}
+
+// The last call to set start should be used.
+TEST_F(RtpBitrateConfiguratorTest, LatestStartMaskPreferred) {
+  BitrateSettings mask;
+  mask.start_bitrate_bps = 1300;
+  UpdateMaskMatches(mask, nullopt, *mask.start_bitrate_bps, nullopt);
+
+  BitrateConstraints bitrate_config;
+  bitrate_config.start_bitrate_bps = 1200;
+
+  UpdateConfigMatches(bitrate_config, nullopt, bitrate_config.start_bitrate_bps,
+                      nullopt);
+}
+
+TEST_F(RtpBitrateConfiguratorTest, SmallerMaskMaxUsed) {
+  BitrateConstraints bitrate_config;
+  bitrate_config.max_bitrate_bps = bitrate_config.start_bitrate_bps + 2000;
+  configurator_.reset(new RtpBitrateConfigurator(bitrate_config));
+
+  BitrateSettings mask;
+  mask.max_bitrate_bps = bitrate_config.start_bitrate_bps + 1000;
+
+  UpdateMaskMatches(mask, nullopt, nullopt, *mask.max_bitrate_bps);
+}
+
+TEST_F(RtpBitrateConfiguratorTest, SmallerConfigMaxUsed) {
+  BitrateConstraints bitrate_config;
+  bitrate_config.max_bitrate_bps = bitrate_config.start_bitrate_bps + 1000;
+  configurator_.reset(new RtpBitrateConfigurator(bitrate_config));
+
+  BitrateSettings mask;
+  mask.max_bitrate_bps = bitrate_config.start_bitrate_bps + 2000;
+
+  // Expect no return because nothing changes
+  EXPECT_FALSE(configurator_->UpdateWithClientPreferences(mask).has_value());
+}
+
+TEST_F(RtpBitrateConfiguratorTest, MaskStartLessThanConfigMinClamped) {
+  BitrateConstraints bitrate_config;
+  bitrate_config.min_bitrate_bps = 2000;
+  configurator_.reset(new RtpBitrateConfigurator(bitrate_config));
+
+  BitrateSettings mask;
+  mask.start_bitrate_bps = 1000;
+  UpdateMaskMatches(mask, 2000, 2000, nullopt);
+}
+
+TEST_F(RtpBitrateConfiguratorTest, MaskStartGreaterThanConfigMaxClamped) {
+  BitrateConstraints bitrate_config;
+  bitrate_config.start_bitrate_bps = 2000;
+  configurator_.reset(new RtpBitrateConfigurator(bitrate_config));
+
+  BitrateSettings mask;
+  mask.max_bitrate_bps = 1000;
+
+  UpdateMaskMatches(mask, nullopt, -1, 1000);
+}
+
+TEST_F(RtpBitrateConfiguratorTest, MaskMinGreaterThanConfigMaxClamped) {
+  BitrateConstraints bitrate_config;
+  bitrate_config.min_bitrate_bps = 2000;
+  configurator_.reset(new RtpBitrateConfigurator(bitrate_config));
+
+  BitrateSettings mask;
+  mask.max_bitrate_bps = 1000;
+
+  UpdateMaskMatches(mask, 1000, nullopt, 1000);
+}
+
+TEST_F(RtpBitrateConfiguratorTest, SettingMaskStartForcesUpdate) {
+  BitrateSettings mask;
+  mask.start_bitrate_bps = 1000;
+
+  // Config should be returned twice with the same params since
+  // start_bitrate_bps is set.
+  UpdateMaskMatches(mask, nullopt, 1000, nullopt);
+  UpdateMaskMatches(mask, nullopt, 1000, nullopt);
+}
+
+TEST_F(RtpBitrateConfiguratorTest, NewConfigWithNoChangesDoesNotCallNewConfig) {
+  BitrateConstraints config1;
+  config1.min_bitrate_bps = 0;
+  config1.start_bitrate_bps = 1000;
+  config1.max_bitrate_bps = -1;
+
+  BitrateConstraints config2;
+  config2.min_bitrate_bps = 0;
+  config2.start_bitrate_bps = -1;
+  config2.max_bitrate_bps = -1;
+
+  // The second call should not return anything because it doesn't
+  // change any values.
+  UpdateConfigMatches(config1, 0, 1000, -1);
+  EXPECT_FALSE(configurator_->UpdateWithSdpParameters(config2).has_value());
+}
+
+// If config changes the max, but not the effective max,
+// new config shouldn't be returned, to avoid unnecessary encoder
+// reconfigurations.
+TEST_F(RtpBitrateConfiguratorTest,
+       NewConfigNotReturnedWhenEffectiveMaxUnchanged) {
+  BitrateConstraints config;
+  config.min_bitrate_bps = 0;
+  config.start_bitrate_bps = -1;
+  config.max_bitrate_bps = 2000;
+  UpdateConfigMatches(config, nullopt, nullopt, 2000);
+
+  // Reduce effective max to 1000 with the mask.
+  BitrateSettings mask;
+  mask.max_bitrate_bps = 1000;
+  UpdateMaskMatches(mask, nullopt, nullopt, 1000);
+
+  // This leaves the effective max unchanged, so new config shouldn't be
+  // returned again.
+  config.max_bitrate_bps = 1000;
+  EXPECT_FALSE(configurator_->UpdateWithSdpParameters(config).has_value());
+}
+
+// When the "start bitrate" mask is removed, new config shouldn't be returned
+// again, since nothing's changing.
+TEST_F(RtpBitrateConfiguratorTest, NewConfigNotReturnedWhenStartMaskRemoved) {
+  BitrateSettings mask;
+  mask.start_bitrate_bps = 1000;
+  UpdateMaskMatches(mask, 0, 1000, -1);
+
+  mask.start_bitrate_bps.reset();
+  EXPECT_FALSE(configurator_->UpdateWithClientPreferences(mask).has_value());
+}
+
+// Test that if a new config is returned after BitrateSettings applies a
+// "start" value, the new config won't return that start value a
+// second time.
+TEST_F(RtpBitrateConfiguratorTest, NewConfigAfterBitrateConfigMaskWithStart) {
+  BitrateSettings mask;
+  mask.start_bitrate_bps = 1000;
+  UpdateMaskMatches(mask, 0, 1000, -1);
+
+  BitrateConstraints config;
+  config.min_bitrate_bps = 0;
+  config.start_bitrate_bps = -1;
+  config.max_bitrate_bps = 5000;
+  // The start value isn't changing, so new config should be returned with
+  // -1.
+  UpdateConfigMatches(config, 0, -1, 5000);
+}
+
+TEST_F(RtpBitrateConfiguratorTest,
+       NewConfigNotReturnedWhenClampedMinUnchanged) {
+  BitrateConstraints bitrate_config;
+  bitrate_config.start_bitrate_bps = 500;
+  bitrate_config.max_bitrate_bps = 1000;
+  configurator_.reset(new RtpBitrateConfigurator(bitrate_config));
+
+  // Set min to 2000; it is clamped to the max (1000).
+  BitrateSettings mask;
+  mask.min_bitrate_bps = 2000;
+  UpdateMaskMatches(mask, 1000, -1, 1000);
+
+  // Set min to 3000; the clamped value stays the same so nothing happens.
+  mask.min_bitrate_bps = 3000;
+  EXPECT_FALSE(configurator_->UpdateWithClientPreferences(mask).has_value());
+}
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/rtp_config.cc b/third_party/libwebrtc/call/rtp_config.cc
new file mode 100644
index 0000000000..5457a94696
--- /dev/null
+++ b/third_party/libwebrtc/call/rtp_config.cc
@@ -0,0 +1,203 @@
+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/rtp_config.h"
+
+#include <cstdint>
+
+#include "absl/algorithm/container.h"
+#include "api/array_view.h"
+#include "rtc_base/checks.h"
+#include "rtc_base/strings/string_builder.h"
+
+namespace webrtc {
+
+namespace {
+
+uint32_t FindAssociatedSsrc(uint32_t ssrc,
+                            const std::vector<uint32_t>& ssrcs,
+                            const std::vector<uint32_t>& associated_ssrcs) {
+  RTC_DCHECK_EQ(ssrcs.size(), associated_ssrcs.size());
+  for (size_t i = 0; i < ssrcs.size(); ++i) {
+    if (ssrcs[i] == ssrc)
+      return associated_ssrcs[i];
+  }
+  RTC_DCHECK_NOTREACHED();
+  return 0;
+}
+
+}  // namespace
+
+std::string LntfConfig::ToString() const {
+  return enabled ? "{enabled: true}" : "{enabled: false}";
+}
+
+std::string NackConfig::ToString() const {
+  char buf[1024];
+  rtc::SimpleStringBuilder ss(buf);
+  ss << "{rtp_history_ms: " << rtp_history_ms;
+  ss << '}';
+  return ss.str();
+}
+
+std::string UlpfecConfig::ToString() const {
+  char buf[1024];
+  rtc::SimpleStringBuilder ss(buf);
+  ss << "{ulpfec_payload_type: " << ulpfec_payload_type;
+  ss << ", red_payload_type: " << red_payload_type;
+  ss << ", red_rtx_payload_type: " << red_rtx_payload_type;
+  ss << '}';
+  return ss.str();
+}
+
+bool UlpfecConfig::operator==(const UlpfecConfig& other) const {
+  return ulpfec_payload_type == other.ulpfec_payload_type &&
+         red_payload_type == other.red_payload_type &&
+         red_rtx_payload_type == other.red_rtx_payload_type;
+}
+
+RtpConfig::RtpConfig() = default;
+RtpConfig::RtpConfig(const RtpConfig&) = default;
+RtpConfig::~RtpConfig() = default;
+
+RtpConfig::Flexfec::Flexfec() = default;
+RtpConfig::Flexfec::Flexfec(const Flexfec&) = default;
+RtpConfig::Flexfec::~Flexfec() = default;
+
+std::string RtpConfig::ToString() const {
+  char buf[2 * 1024];
+  rtc::SimpleStringBuilder ss(buf);
+  ss << "{ssrcs: [";
+  for (size_t i = 0; i < ssrcs.size(); ++i) {
+    ss << ssrcs[i];
+    if (i != ssrcs.size() - 1)
+      ss << ", ";
+  }
+  ss << "], rids: [";
+  for (size_t i = 0; i < rids.size(); ++i) {
+    ss << rids[i];
+    if (i != rids.size() - 1)
+      ss << ", ";
+  }
+  ss << "], mid: '" << mid << "'";
+  ss << ", rtcp_mode: "
+     << (rtcp_mode == RtcpMode::kCompound ? "RtcpMode::kCompound"
+                                          : "RtcpMode::kReducedSize");
+  ss << ", max_packet_size: " << max_packet_size;
+  ss << ", extmap-allow-mixed: " << (extmap_allow_mixed ? "true" : "false");
+  ss << ", extensions: [";
+  for (size_t i = 0; i < extensions.size(); ++i) {
+    ss << extensions[i].ToString();
+    if (i != extensions.size() - 1)
+      ss << ", ";
+  }
+  ss << ']';
+
+  ss << ", lntf: " << lntf.ToString();
+  ss << ", nack: {rtp_history_ms: " << nack.rtp_history_ms << '}';
+  ss << ", ulpfec: " << ulpfec.ToString();
+  ss << ", payload_name: " << payload_name;
+  ss << ", payload_type: " << payload_type;
+  ss << ", raw_payload: " << (raw_payload ? "true" : "false");
+
+  ss << ", flexfec: {payload_type: " << flexfec.payload_type;
+  ss << ", ssrc: " << flexfec.ssrc;
+  ss << ", protected_media_ssrcs: [";
+  for (size_t i = 0; i < flexfec.protected_media_ssrcs.size(); ++i) {
+    ss << flexfec.protected_media_ssrcs[i];
+    if (i != flexfec.protected_media_ssrcs.size() - 1)
+      ss << ", ";
+  }
+  ss << "]}";
+
+  ss << ", rtx: " << rtx.ToString();
+  ss << ", c_name: " << c_name;
+  ss << '}';
+  return ss.str();
+}
+
+RtpConfig::Rtx::Rtx() = default;
+RtpConfig::Rtx::Rtx(const Rtx&) = default;
+RtpConfig::Rtx::~Rtx() = default;
+
+std::string RtpConfig::Rtx::ToString() const {
+  char buf[1024];
+  rtc::SimpleStringBuilder ss(buf);
+  ss << "{ssrcs: [";
+  for (size_t i = 0; i < ssrcs.size(); ++i) {
+    ss << ssrcs[i];
+    if (i != ssrcs.size() - 1)
+      ss << ", ";
+  }
+  ss << ']';
+
+  ss << ", payload_type: " << payload_type;
+  ss << '}';
+  return ss.str();
+}
+
+bool RtpConfig::IsMediaSsrc(uint32_t ssrc) const {
+  return absl::c_linear_search(ssrcs, ssrc);
+}
+
+bool RtpConfig::IsRtxSsrc(uint32_t ssrc) const {
+  return absl::c_linear_search(rtx.ssrcs, ssrc);
+}
+
+bool RtpConfig::IsFlexfecSsrc(uint32_t ssrc) const {
+  return flexfec.payload_type != -1 && ssrc == flexfec.ssrc;
+}
+
+absl::optional<uint32_t> RtpConfig::GetRtxSsrcAssociatedWithMediaSsrc(
+    uint32_t media_ssrc) const {
+  RTC_DCHECK(IsMediaSsrc(media_ssrc));
+  // If we don't use RTX there is no association.
+  if (rtx.ssrcs.empty())
+    return absl::nullopt;
+  // If we use RTX there MUST be an association ssrcs[i] <-> rtx.ssrcs[i].
+  RTC_DCHECK_EQ(ssrcs.size(), rtx.ssrcs.size());
+  return FindAssociatedSsrc(media_ssrc, ssrcs, rtx.ssrcs);
+}
+
+uint32_t RtpConfig::GetMediaSsrcAssociatedWithRtxSsrc(uint32_t rtx_ssrc) const {
+  RTC_DCHECK(IsRtxSsrc(rtx_ssrc));
+  // If we use RTX there MUST be an association ssrcs[i] <-> rtx.ssrcs[i].
+  RTC_DCHECK_EQ(ssrcs.size(), rtx.ssrcs.size());
+  return FindAssociatedSsrc(rtx_ssrc, rtx.ssrcs, ssrcs);
+}
+
+uint32_t RtpConfig::GetMediaSsrcAssociatedWithFlexfecSsrc(
+    uint32_t flexfec_ssrc) const {
+  RTC_DCHECK(IsFlexfecSsrc(flexfec_ssrc));
+  // If we use FlexFEC there MUST be an associated media ssrc.
+  //
+  // TODO(brandtr/hbos): The current implementation only supports an association
+  // with a single media ssrc. If multiple ssrcs are to be supported in the
+  // future, in order not to break GetStats()'s packet and byte counters, we
+  // must be able to tell how many packets and bytes have contributed to which
+  // SSRC.
+  RTC_DCHECK_EQ(1u, flexfec.protected_media_ssrcs.size());
+  uint32_t media_ssrc = flexfec.protected_media_ssrcs[0];
+  RTC_DCHECK(IsMediaSsrc(media_ssrc));
+  return media_ssrc;
+}
+
+absl::optional<std::string> RtpConfig::GetRidForSsrc(uint32_t ssrc) const {
+  auto it = std::find(ssrcs.begin(), ssrcs.end(), ssrc);
+  if (it != ssrcs.end()) {
+    size_t ssrc_index = std::distance(ssrcs.begin(), it);
+    if (ssrc_index < rids.size()) {
+      return rids[ssrc_index];
+    }
+  }
+  return absl::nullopt;
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/rtp_config.h b/third_party/libwebrtc/call/rtp_config.h
new file mode 100644
index 0000000000..0cc9466a9f
--- /dev/null
+++ b/third_party/libwebrtc/call/rtp_config.h
@@ -0,0 +1,172 @@
+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_RTP_CONFIG_H_
+#define CALL_RTP_CONFIG_H_
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include <string>
+#include <vector>
+
+#include "absl/types/optional.h"
+#include "api/rtp_headers.h"
+#include "api/rtp_parameters.h"
+
+namespace webrtc {
+// Currently only VP8/VP9 specific.
+struct RtpPayloadState {
+  int16_t picture_id = -1;
+  uint8_t tl0_pic_idx = 0;
+  int64_t shared_frame_id = 0;
+};
+
+// Settings for LNTF (LossNotification). Still highly experimental.
+struct LntfConfig {
+  std::string ToString() const;
+
+  bool enabled{false};
+};
+
+// Settings for NACK, see RFC 4585 for details.
+struct NackConfig {
+  NackConfig() : rtp_history_ms(0) {}
+  std::string ToString() const;
+  // Send side: the time RTP packets are stored for retransmissions.
+  // Receive side: the time the receiver is prepared to wait for
+  // retransmissions.
+  // Set to '0' to disable.
+  int rtp_history_ms;
+};
+
+// Settings for ULPFEC forward error correction.
+// Set the payload types to '-1' to disable.
+struct UlpfecConfig {
+  UlpfecConfig()
+      : ulpfec_payload_type(-1),
+        red_payload_type(-1),
+        red_rtx_payload_type(-1) {}
+  std::string ToString() const;
+  bool operator==(const UlpfecConfig& other) const;
+
+  // Payload type used for ULPFEC packets.
+  int ulpfec_payload_type;
+
+  // Payload type used for RED packets.
+  int red_payload_type;
+
+  // RTX payload type for RED payload.
+  int red_rtx_payload_type;
+};
+
+static const size_t kDefaultMaxPacketSize = 1500 - 40;  // TCP over IPv4.
+struct RtpConfig {
+  RtpConfig();
+  RtpConfig(const RtpConfig&);
+  ~RtpConfig();
+  std::string ToString() const;
+
+  std::vector<uint32_t> ssrcs;
+
+  // The Rtp Stream Ids (aka RIDs) to send in the RID RTP header extension
+  // if the extension is included in the list of extensions.
+  // If rids are specified, they should correspond to the `ssrcs` vector.
+  // This means that:
+  // 1. rids.size() == 0 || rids.size() == ssrcs.size().
+  // 2. If rids is not empty, then `rids[i]` should use `ssrcs[i]`.
+  std::vector<std::string> rids;
+
+  // The value to send in the MID RTP header extension if the extension is
+  // included in the list of extensions.
+  std::string mid;
+
+  // See RtcpMode for description.
+  RtcpMode rtcp_mode = RtcpMode::kCompound;
+
+  // Max RTP packet size delivered to send transport from VideoEngine.
+  size_t max_packet_size = kDefaultMaxPacketSize;
+
+  // Corresponds to the SDP attribute extmap-allow-mixed.
+  bool extmap_allow_mixed = false;
+
+  // RTP header extensions to use for this send stream.
+  std::vector<RtpExtension> extensions;
+
+  // TODO(nisse): For now, these are fixed, but we'd like to support
+  // changing codec without recreating the VideoSendStream. Then these
+  // fields must be removed, and association between payload type and codec
+  // must move above the per-stream level. Ownership could be with
+  // RtpTransportControllerSend, with a reference from RtpVideoSender, where
+  // the latter would be responsible for mapping the codec type of encoded
+  // images to the right payload type.
+  std::string payload_name;
+  int payload_type = -1;
+  // Payload should be packetized using raw packetizer (payload header will
+  // not be added, additional meta data is expected to be present in generic
+  // frame descriptor RTP header extension).
+  bool raw_payload = false;
+
+  // See LntfConfig for description.
+  LntfConfig lntf;
+
+  // See NackConfig for description.
+  NackConfig nack;
+
+  // See UlpfecConfig for description.
+  UlpfecConfig ulpfec;
+
+  struct Flexfec {
+    Flexfec();
+    Flexfec(const Flexfec&);
+    ~Flexfec();
+    // Payload type of FlexFEC. Set to -1 to disable sending FlexFEC.
+    int payload_type = -1;
+
+    // SSRC of FlexFEC stream.
+    uint32_t ssrc = 0;
+
+    // Vector containing a single element, corresponding to the SSRC of the
+    // media stream being protected by this FlexFEC stream.
+    // The vector MUST have size 1.
+    //
+    // TODO(brandtr): Update comment above when we support
+    // multistream protection.
+    std::vector<uint32_t> protected_media_ssrcs;
+  } flexfec;
+
+  // Settings for RTP retransmission payload format, see RFC 4588 for
+  // details.
+  struct Rtx {
+    Rtx();
+    Rtx(const Rtx&);
+    ~Rtx();
+    std::string ToString() const;
+    // SSRCs to use for the RTX streams.
+    std::vector<uint32_t> ssrcs;
+
+    // Payload type to use for the RTX stream.
+    int payload_type = -1;
+  } rtx;
+
+  // RTCP CNAME, see RFC 3550.
+  std::string c_name;
+
+  bool IsMediaSsrc(uint32_t ssrc) const;
+  bool IsRtxSsrc(uint32_t ssrc) const;
+  bool IsFlexfecSsrc(uint32_t ssrc) const;
+  absl::optional<uint32_t> GetRtxSsrcAssociatedWithMediaSsrc(
+      uint32_t media_ssrc) const;
+  uint32_t GetMediaSsrcAssociatedWithRtxSsrc(uint32_t rtx_ssrc) const;
+  uint32_t GetMediaSsrcAssociatedWithFlexfecSsrc(uint32_t flexfec_ssrc) const;
+  absl::optional<std::string> GetRidForSsrc(uint32_t ssrc) const;
+};
+}  // namespace webrtc
+#endif  // CALL_RTP_CONFIG_H_
diff --git a/third_party/libwebrtc/call/rtp_demuxer.cc b/third_party/libwebrtc/call/rtp_demuxer.cc
new file mode 100644
index 0000000000..5c53f48144
--- /dev/null
+++ b/third_party/libwebrtc/call/rtp_demuxer.cc
@@ -0,0 +1,444 @@
+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/rtp_demuxer.h"
+
+#include "absl/strings/string_view.h"
+#include "call/rtp_packet_sink_interface.h"
+#include "modules/rtp_rtcp/source/rtp_header_extensions.h"
+#include "modules/rtp_rtcp/source/rtp_packet_received.h"
+#include "rtc_base/checks.h"
+#include "rtc_base/logging.h"
+#include "rtc_base/strings/string_builder.h"
+
+namespace webrtc {
+namespace {
+
+template <typename Container, typename Value>
+size_t RemoveFromMultimapByValue(Container* multimap, const Value& value) {
+  size_t count = 0;
+  for (auto it = multimap->begin(); it != multimap->end();) {
+    if (it->second == value) {
+      it = multimap->erase(it);
+      ++count;
+    } else {
+      ++it;
+    }
+  }
+  return count;
+}
+
+template <typename Map, typename Value>
+size_t RemoveFromMapByValue(Map* map, const Value& value) {
+  return EraseIf(*map, [&](const auto& elem) { return elem.second == value; });
+}
+
+// Temp fix: MID in SDP is allowed to be slightly longer than what's allowed
+// in the RTP demuxer. Truncate if needed; this won't match, but it only
+// makes sense in places that wouldn't use this for matching anyway.
+// TODO(bugs.webrtc.org/12517): remove when length 16 is policed by parser.
+std::string CheckMidLength(absl::string_view mid) {
+  std::string new_mid(mid);
+  if (new_mid.length() > BaseRtpStringExtension::kMaxValueSizeBytes) {
+    RTC_LOG(LS_WARNING) << "`mid` attribute too long. Truncating.";
+    new_mid.resize(BaseRtpStringExtension::kMaxValueSizeBytes);
+  }
+  return new_mid;
+}
+
+}  // namespace
+
+RtpDemuxerCriteria::RtpDemuxerCriteria(
+    absl::string_view mid,
+    absl::string_view rsid /*= absl::string_view()*/)
+    : mid_(CheckMidLength(mid)), rsid_(rsid) {}
+
+RtpDemuxerCriteria::RtpDemuxerCriteria() = default;
+RtpDemuxerCriteria::~RtpDemuxerCriteria() = default;
+
+bool RtpDemuxerCriteria::operator==(const RtpDemuxerCriteria& other) const {
+  return mid_ == other.mid_ && rsid_ == other.rsid_ && ssrcs_ == other.ssrcs_ &&
+         payload_types_ == other.payload_types_;
+}
+
+bool RtpDemuxerCriteria::operator!=(const RtpDemuxerCriteria& other) const {
+  return !(*this == other);
+}
+
+std::string RtpDemuxerCriteria::ToString() const {
+  rtc::StringBuilder sb;
+  sb << "{mid: " << (mid_.empty() ? "<empty>" : mid_)
+     << ", rsid: " << (rsid_.empty() ? "<empty>" : rsid_) << ", ssrcs: [";
+
+  for (auto ssrc : ssrcs_) {
+    sb << ssrc << ", ";
+  }
+
+  sb << "], payload_types = [";
+
+  for (auto pt : payload_types_) {
+    sb << pt << ", ";
+  }
+
+  sb << "]}";
+  return sb.Release();
+}
+
+// static
+std::string RtpDemuxer::DescribePacket(const RtpPacketReceived& packet) {
+  rtc::StringBuilder sb;
+  sb << "PT=" << packet.PayloadType() << " SSRC=" << packet.Ssrc();
+  std::string mid;
+  if (packet.GetExtension<RtpMid>(&mid)) {
+    sb << " MID=" << mid;
+  }
+  std::string rsid;
+  if (packet.GetExtension<RtpStreamId>(&rsid)) {
+    sb << " RSID=" << rsid;
+  }
+  std::string rrsid;
+  if (packet.GetExtension<RepairedRtpStreamId>(&rrsid)) {
+    sb << " RRSID=" << rrsid;
+  }
+  return sb.Release();
+}
+
+RtpDemuxer::RtpDemuxer(bool use_mid /* = true*/) : use_mid_(use_mid) {}
+
+RtpDemuxer::~RtpDemuxer() {
+  RTC_DCHECK(sink_by_mid_.empty());
+  RTC_DCHECK(sink_by_ssrc_.empty());
+  RTC_DCHECK(sinks_by_pt_.empty());
+  RTC_DCHECK(sink_by_mid_and_rsid_.empty());
+  RTC_DCHECK(sink_by_rsid_.empty());
+}
+
+bool RtpDemuxer::AddSink(const RtpDemuxerCriteria& criteria,
+                         RtpPacketSinkInterface* sink) {
+  RTC_DCHECK(!criteria.payload_types().empty() || !criteria.ssrcs().empty() ||
+             !criteria.mid().empty() || !criteria.rsid().empty());
+  RTC_DCHECK(criteria.mid().empty() || IsLegalMidName(criteria.mid()));
+  RTC_DCHECK(criteria.rsid().empty() || IsLegalRsidName(criteria.rsid()));
+  RTC_DCHECK(sink);
+
+  // We return false instead of DCHECKing for logical conflicts with the new
+  // criteria because new sinks are created according to user-specified SDP and
+  // we do not want to crash due to a data validation error.
+  if (CriteriaWouldConflict(criteria)) {
+    RTC_LOG(LS_ERROR) << "Unable to add sink=" << sink
+                      << " due to conflicting criteria " << criteria.ToString();
+    return false;
+  }
+
+  if (!criteria.mid().empty()) {
+    if (criteria.rsid().empty()) {
+      sink_by_mid_.emplace(criteria.mid(), sink);
+    } else {
+      sink_by_mid_and_rsid_.emplace(
+          std::make_pair(criteria.mid(), criteria.rsid()), sink);
+    }
+  } else {
+    if (!criteria.rsid().empty()) {
+      sink_by_rsid_.emplace(criteria.rsid(), sink);
+    }
+  }
+
+  for (uint32_t ssrc : criteria.ssrcs()) {
+    sink_by_ssrc_.emplace(ssrc, sink);
+  }
+
+  for (uint8_t payload_type : criteria.payload_types()) {
+    sinks_by_pt_.emplace(payload_type, sink);
+  }
+
+  RefreshKnownMids();
+
+  RTC_DLOG(LS_INFO) << "Added sink = " << sink << " for criteria "
+                    << criteria.ToString();
+
+  return true;
+}
+
+bool RtpDemuxer::CriteriaWouldConflict(
+    const RtpDemuxerCriteria& criteria) const {
+  if (!criteria.mid().empty()) {
+    if (criteria.rsid().empty()) {
+      // If the MID is in the known_mids_ set, then there is already a sink
+      // added for this MID directly, or there is a sink already added with a
+      // MID, RSID pair for our MID and some RSID.
+      // Adding this criteria would cause one of these rules to be shadowed, so
+      // reject this new criteria.
+      if (known_mids_.find(criteria.mid()) != known_mids_.end()) {
+        RTC_LOG(LS_INFO) << criteria.ToString()
+                         << " would conflict with known mid";
+        return true;
+      }
+    } else {
+      // If the exact rule already exists, then reject this duplicate.
+      const auto sink_by_mid_and_rsid = sink_by_mid_and_rsid_.find(
+          std::make_pair(criteria.mid(), criteria.rsid()));
+      if (sink_by_mid_and_rsid != sink_by_mid_and_rsid_.end()) {
+        RTC_LOG(LS_INFO) << criteria.ToString()
+                         << " would conflict with existing sink = "
+                         << sink_by_mid_and_rsid->second
+                         << " by mid+rsid binding";
+        return true;
+      }
+      // If there is already a sink registered for the bare MID, then this
+      // criteria will never receive any packets because they will just be
+      // directed to that MID sink, so reject this new criteria.
+      const auto sink_by_mid = sink_by_mid_.find(criteria.mid());
+      if (sink_by_mid != sink_by_mid_.end()) {
+        RTC_LOG(LS_INFO) << criteria.ToString()
+                         << " would conflict with existing sink = "
+                         << sink_by_mid->second << " by mid binding";
+        return true;
+      }
+    }
+  }
+
+  for (uint32_t ssrc : criteria.ssrcs()) {
+    const auto sink_by_ssrc = sink_by_ssrc_.find(ssrc);
+    if (sink_by_ssrc != sink_by_ssrc_.end()) {
+      RTC_LOG(LS_INFO) << criteria.ToString()
+                       << " would conflict with existing sink = "
+                       << sink_by_ssrc->second << " binding by SSRC=" << ssrc;
+      return true;
+    }
+  }
+
+  // TODO(steveanton): May also sanity check payload types.
+
+  return false;
+}
+
+void RtpDemuxer::RefreshKnownMids() {
+  known_mids_.clear();
+
+  for (auto const& item : sink_by_mid_) {
+    const std::string& mid = item.first;
+    known_mids_.insert(mid);
+  }
+
+  for (auto const& item : sink_by_mid_and_rsid_) {
+    const std::string& mid = item.first.first;
+    known_mids_.insert(mid);
+  }
+}
+
+bool RtpDemuxer::AddSink(uint32_t ssrc, RtpPacketSinkInterface* sink) {
+  RtpDemuxerCriteria criteria;
+  criteria.ssrcs().insert(ssrc);
+  return AddSink(criteria, sink);
+}
+
+void RtpDemuxer::AddSink(absl::string_view rsid, RtpPacketSinkInterface* sink) {
+  RtpDemuxerCriteria criteria(absl::string_view() /* mid */, rsid);
+  AddSink(criteria, sink);
+}
+
+bool RtpDemuxer::RemoveSink(const RtpPacketSinkInterface* sink) {
+  RTC_DCHECK(sink);
+  size_t num_removed = RemoveFromMapByValue(&sink_by_mid_, sink) +
+                       RemoveFromMapByValue(&sink_by_ssrc_, sink) +
+                       RemoveFromMultimapByValue(&sinks_by_pt_, sink) +
+                       RemoveFromMapByValue(&sink_by_mid_and_rsid_, sink) +
+                       RemoveFromMapByValue(&sink_by_rsid_, sink);
+  RefreshKnownMids();
+  return num_removed > 0;
+}
+
+bool RtpDemuxer::OnRtpPacket(const RtpPacketReceived& packet) {
+  RtpPacketSinkInterface* sink = ResolveSink(packet);
+  if (sink != nullptr) {
+    sink->OnRtpPacket(packet);
+    return true;
+  }
+  return false;
+}
+
+RtpPacketSinkInterface* RtpDemuxer::ResolveSink(
+    const RtpPacketReceived& packet) {
+  // See the BUNDLE spec for high level reference to this algorithm:
+  // https://tools.ietf.org/html/draft-ietf-mmusic-sdp-bundle-negotiation-38#section-10.2
+
+  // RSID and RRID are routed to the same sinks. If an RSID is specified on a
+  // repair packet, it should be ignored and the RRID should be used.
+  std::string packet_mid, packet_rsid;
+  //bool has_mid = use_mid_ && packet.GetExtension<RtpMid>(&packet_mid);
+  bool has_rsid = packet.GetExtension<RepairedRtpStreamId>(&packet_rsid);
+  if (!has_rsid) {
+    has_rsid = packet.GetExtension<RtpStreamId>(&packet_rsid);
+  }
+  uint32_t ssrc = packet.Ssrc();
+
+  // Mid support is half-baked in branch 64. RtpStreamReceiverController only
+  // supports adding sinks by ssrc, so our mids will never show up in
+  // known_mids_, causing us to drop packets here.
+#if 0
+  // The BUNDLE spec says to drop any packets with unknown MIDs, even if the
+  // SSRC is known/latched.
+  if (has_mid && known_mids_.find(packet_mid) == known_mids_.end()) {
+    return nullptr;
+  }
+
+  // Cache information we learn about SSRCs and IDs. We need to do this even if
+  // there isn't a rule/sink yet because we might add an MID/RSID rule after
+  // learning an MID/RSID<->SSRC association.
+
+  std::string* mid = nullptr;
+  if (has_mid) {
+    mid_by_ssrc_[ssrc] = packet_mid;
+    mid = &packet_mid;
+  } else {
+    // If the packet does not include a MID header extension, check if there is
+    // a latched MID for the SSRC.
+    const auto it = mid_by_ssrc_.find(ssrc);
+    if (it != mid_by_ssrc_.end()) {
+      mid = &it->second;
+    }
+  }
+
+  std::string* rsid = nullptr;
+  if (has_rsid) {
+    rsid_by_ssrc_[ssrc] = packet_rsid;
+    rsid = &packet_rsid;
+  } else {
+    // If the packet does not include an RRID/RSID header extension, check if
+    // there is a latched RSID for the SSRC.
+    const auto it = rsid_by_ssrc_.find(ssrc);
+    if (it != rsid_by_ssrc_.end()) {
+      rsid = &it->second;
+    }
+  }
+
+  // If MID and/or RSID is specified, prioritize that for demuxing the packet.
+  // The motivation behind the BUNDLE algorithm is that we trust these are used
+  // deliberately by senders and are more likely to be correct than SSRC/payload
+  // type which are included with every packet.
+  // TODO(steveanton): According to the BUNDLE spec, new SSRC mappings are only
+  //                   accepted if the packet's extended sequence number is
+  //                   greater than that of the last SSRC mapping update.
+  //                   https://tools.ietf.org/html/rfc7941#section-4.2.6
+  if (mid != nullptr) {
+    RtpPacketSinkInterface* sink_by_mid = ResolveSinkByMid(*mid, ssrc);
+    if (sink_by_mid != nullptr) {
+      return sink_by_mid;
+    }
+
+    // RSID is scoped to a given MID if both are included.
+    if (rsid != nullptr) {
+      RtpPacketSinkInterface* sink_by_mid_rsid =
+          ResolveSinkByMidRsid(*mid, *rsid, ssrc);
+      if (sink_by_mid_rsid != nullptr) {
+        return sink_by_mid_rsid;
+      }
+    }
+
+    // At this point, there is at least one sink added for this MID and an RSID
+    // but either the packet does not have an RSID or it is for a different
+    // RSID. This falls outside the BUNDLE spec so drop the packet.
+    return nullptr;
+  }
+
+  // RSID can be used without MID as long as they are unique.
+  if (rsid != nullptr) {
+    RtpPacketSinkInterface* sink_by_rsid = ResolveSinkByRsid(*rsid, ssrc);
+    if (sink_by_rsid != nullptr) {
+      return sink_by_rsid;
+    }
+  }
+
+#endif
+  // We trust signaled SSRC more than payload type which is likely to conflict
+  // between streams.
+  const auto ssrc_sink_it = sink_by_ssrc_.find(ssrc);
+  if (ssrc_sink_it != sink_by_ssrc_.end()) {
+    return ssrc_sink_it->second;
+  }
+
+  // Legacy senders will only signal payload type, support that as last resort.
+  return ResolveSinkByPayloadType(packet.PayloadType(), ssrc);
+}
+
+RtpPacketSinkInterface* RtpDemuxer::ResolveSinkByMid(absl::string_view mid,
+                                                     uint32_t ssrc) {
+  const auto it = sink_by_mid_.find(mid);
+  if (it != sink_by_mid_.end()) {
+    RtpPacketSinkInterface* sink = it->second;
+    AddSsrcSinkBinding(ssrc, sink);
+    return sink;
+  }
+  return nullptr;
+}
+
+RtpPacketSinkInterface* RtpDemuxer::ResolveSinkByMidRsid(absl::string_view mid,
+                                                         absl::string_view rsid,
+                                                         uint32_t ssrc) {
+  const auto it = sink_by_mid_and_rsid_.find(
+      std::make_pair(std::string(mid), std::string(rsid)));
+  if (it != sink_by_mid_and_rsid_.end()) {
+    RtpPacketSinkInterface* sink = it->second;
+    AddSsrcSinkBinding(ssrc, sink);
+    return sink;
+  }
+  return nullptr;
+}
+
+RtpPacketSinkInterface* RtpDemuxer::ResolveSinkByRsid(absl::string_view rsid,
+                                                      uint32_t ssrc) {
+  const auto it = sink_by_rsid_.find(rsid);
+  if (it != sink_by_rsid_.end()) {
+    RtpPacketSinkInterface* sink = it->second;
+    AddSsrcSinkBinding(ssrc, sink);
+    return sink;
+  }
+  return nullptr;
+}
+
+RtpPacketSinkInterface* RtpDemuxer::ResolveSinkByPayloadType(
+    uint8_t payload_type,
+    uint32_t ssrc) {
+  const auto range = sinks_by_pt_.equal_range(payload_type);
+  if (range.first != range.second) {
+    auto it = range.first;
+    const auto end = range.second;
+    if (std::next(it) == end) {
+      RtpPacketSinkInterface* sink = it->second;
+      AddSsrcSinkBinding(ssrc, sink);
+      return sink;
+    }
+  }
+  return nullptr;
+}
+
+void RtpDemuxer::AddSsrcSinkBinding(uint32_t ssrc,
+                                    RtpPacketSinkInterface* sink) {
+  if (sink_by_ssrc_.size() >= kMaxSsrcBindings) {
+    RTC_LOG(LS_WARNING) << "New SSRC=" << ssrc
+                        << " sink binding ignored; limit of" << kMaxSsrcBindings
+                        << " bindings has been reached.";
+    return;
+  }
+
+  auto result = sink_by_ssrc_.emplace(ssrc, sink);
+  auto it = result.first;
+  bool inserted = result.second;
+  if (inserted) {
+    RTC_DLOG(LS_INFO) << "Added sink = " << sink
+                      << " binding with SSRC=" << ssrc;
+  } else if (it->second != sink) {
+    RTC_DLOG(LS_INFO) << "Updated sink = " << sink
+                      << " binding with SSRC=" << ssrc;
+    it->second = sink;
+  }
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/rtp_demuxer.h b/third_party/libwebrtc/call/rtp_demuxer.h
new file mode 100644
index 0000000000..53eeb0b6b6
--- /dev/null
+++ b/third_party/libwebrtc/call/rtp_demuxer.h
@@ -0,0 +1,218 @@
+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_RTP_DEMUXER_H_
+#define CALL_RTP_DEMUXER_H_
+
+#include <map>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "absl/strings/string_view.h"
+#include "rtc_base/containers/flat_map.h"
+#include "rtc_base/containers/flat_set.h"
+
+namespace webrtc {
+
+class RtpPacketReceived;
+class RtpPacketSinkInterface;
+
+// This struct describes the criteria that will be used to match packets to a
+// specific sink.
+class RtpDemuxerCriteria {
+ public:
+  explicit RtpDemuxerCriteria(absl::string_view mid,
+                              absl::string_view rsid = absl::string_view());
+  RtpDemuxerCriteria();
+  ~RtpDemuxerCriteria();
+
+  bool operator==(const RtpDemuxerCriteria& other) const;
+  bool operator!=(const RtpDemuxerCriteria& other) const;
+
+  // If not the empty string, will match packets with this MID.
+  const std::string& mid() const { return mid_; }
+
+  // Return string representation of demux criteria to facilitate logging
+  std::string ToString() const;
+
+  // If not the empty string, will match packets with this as their RTP stream
+  // ID or repaired RTP stream ID.
+  // Note that if both MID and RSID are specified, this will only match packets
+  // that have both specified (either through RTP header extensions, SSRC
+  // latching or RTCP).
+  const std::string& rsid() const { return rsid_; }
+
+  // The criteria will match packets with any of these SSRCs.
+  const flat_set<uint32_t>& ssrcs() const { return ssrcs_; }
+
+  // Writable accessor for directly modifying the list of ssrcs.
+  flat_set<uint32_t>& ssrcs() { return ssrcs_; }
+
+  // The criteria will match packets with any of these payload types.
+  const flat_set<uint8_t>& payload_types() const { return payload_types_; }
+
+  // Writable accessor for directly modifying the list of payload types.
+  flat_set<uint8_t>& payload_types() { return payload_types_; }
+
+ private:
+  // Intentionally private member variables to encourage specifying them via the
+  // constructor and consider them to be const as much as possible.
+  const std::string mid_;
+  const std::string rsid_;
+  flat_set<uint32_t> ssrcs_;
+  flat_set<uint8_t> payload_types_;
+};
+
+// This class represents the RTP demuxing, for a single RTP session (i.e., one
+// SSRC space, see RFC 7656). It isn't thread aware, leaving responsibility of
+// multithreading issues to the user of this class.
+// The demuxing algorithm follows the sketch given in the BUNDLE draft:
+// https://tools.ietf.org/html/draft-ietf-mmusic-sdp-bundle-negotiation-38#section-10.2
+// with modifications to support RTP stream IDs also.
+//
+// When a packet is received, the RtpDemuxer will route according to the
+// following rules:
+// 1. If the packet contains the MID header extension, and no sink has been
+//    added with that MID as a criteria, the packet is not routed.
+// 2. If the packet has the MID header extension, but no RSID or RRID extension,
+//    and the MID is bound to a sink, then bind its SSRC to the same sink and
+//    forward the packet to that sink. Note that rebinding to the same sink is
+//    not an error. (Later packets with that SSRC would therefore be forwarded
+//    to the same sink, whether they have the MID header extension or not.)
+// 3. If the packet has the MID header extension and either the RSID or RRID
+//    extension, and the MID, RSID (or RRID) pair is bound to a sink, then bind
+//    its SSRC to the same sink and forward the packet to that sink. Later
+//    packets with that SSRC will be forwarded to the same sink.
+// 4. If the packet has the RSID or RRID header extension, but no MID extension,
+//    and the RSID or RRID is bound to an RSID sink, then bind its SSRC to the
+//    same sink and forward the packet to that sink. Later packets with that
+//    SSRC will be forwarded to the same sink.
+// 5. If the packet's SSRC is bound to an SSRC through a previous call to
+//    AddSink, then forward the packet to that sink. Note that the RtpDemuxer
+//    will not verify the payload type even if included in the sink's criteria.
+//    The sink is expected to do the check in its handler.
+// 6. If the packet's payload type is bound to exactly one payload type sink
+//    through an earlier call to AddSink, then forward the packet to that sink.
+// 7. Otherwise, the packet is not routed.
+//
+// In summary, the routing algorithm will always try to first match MID and RSID
+// (including through SSRC binding), match SSRC directly as needed, and use
+// payload types only if all else fails.
+class RtpDemuxer {
+ public:
+  // Maximum number of unique SSRC bindings allowed. This limit is to prevent
+  // memory overuse attacks due to a malicious peer sending many packets with
+  // different SSRCs.
+  static constexpr int kMaxSsrcBindings = 1000;
+
+  // Returns a string that contains all the attributes of the given packet
+  // relevant for demuxing.
+  static std::string DescribePacket(const RtpPacketReceived& packet);
+
+  explicit RtpDemuxer(bool use_mid = true);
+  ~RtpDemuxer();
+
+  RtpDemuxer(const RtpDemuxer&) = delete;
+  void operator=(const RtpDemuxer&) = delete;
+
+  // Registers a sink that will be notified when RTP packets match its given
+  // criteria according to the algorithm described in the class description.
+  // Returns true if the sink was successfully added.
+  // Returns false in the following situations:
+  // - Only MID is specified and the MID is already registered.
+  // - Only RSID is specified and the RSID is already registered.
+  // - Both MID and RSID is specified and the (MID, RSID) pair is already
+  //   registered.
+  // - Any of the criteria SSRCs are already registered.
+  // If false is returned, no changes are made to the demuxer state.
+  bool AddSink(const RtpDemuxerCriteria& criteria,
+               RtpPacketSinkInterface* sink);
+
+  // Registers a sink. Multiple SSRCs may be mapped to the same sink, but
+  // each SSRC may only be mapped to one sink. The return value reports
+  // whether the association has been recorded or rejected. Rejection may occur
+  // if the SSRC has already been associated with a sink. The previously added
+  // sink is *not* forgotten.
+  bool AddSink(uint32_t ssrc, RtpPacketSinkInterface* sink);
+
+  // Registers a sink's association to an RSID. Only one sink may be associated
+  // with a given RSID. Null pointer is not allowed.
+  void AddSink(absl::string_view rsid, RtpPacketSinkInterface* sink);
+
+  // Removes a sink. Return value reports if anything was actually removed.
+  // Null pointer is not allowed.
+  bool RemoveSink(const RtpPacketSinkInterface* sink);
+
+  // Demuxes the given packet and forwards it to the chosen sink. Returns true
+  // if the packet was forwarded and false if the packet was dropped.
+  bool OnRtpPacket(const RtpPacketReceived& packet);
+
+ private:
+  // Returns true if adding a sink with the given criteria would cause conflicts
+  // with the existing criteria and should be rejected.
+  bool CriteriaWouldConflict(const RtpDemuxerCriteria& criteria) const;
+
+  // Runs the demux algorithm on the given packet and returns the sink that
+  // should receive the packet.
+  // Will record any SSRC<->ID associations along the way.
+  // If the packet should be dropped, this method returns null.
+  RtpPacketSinkInterface* ResolveSink(const RtpPacketReceived& packet);
+
+  // Used by the ResolveSink algorithm.
+  RtpPacketSinkInterface* ResolveSinkByMid(absl::string_view mid,
+                                           uint32_t ssrc);
+  RtpPacketSinkInterface* ResolveSinkByMidRsid(absl::string_view mid,
+                                               absl::string_view rsid,
+                                               uint32_t ssrc);
+  RtpPacketSinkInterface* ResolveSinkByRsid(absl::string_view rsid,
+                                            uint32_t ssrc);
+  RtpPacketSinkInterface* ResolveSinkByPayloadType(uint8_t payload_type,
+                                                   uint32_t ssrc);
+
+  // Regenerate the known_mids_ set from information in the sink_by_mid_ and
+  // sink_by_mid_and_rsid_ maps.
+  void RefreshKnownMids();
+
+  // Map each sink by its component attributes to facilitate quick lookups.
+  // Payload Type mapping is a multimap because if two sinks register for the
+  // same payload type, both AddSinks succeed but we must know not to demux on
+  // that attribute since it is ambiguous.
+  // Note: Mappings are only modified by AddSink/RemoveSink (except for
+  // SSRC mapping which receives all MID, payload type, or RSID to SSRC bindings
+  // discovered when demuxing packets).
+  flat_map<std::string, RtpPacketSinkInterface*> sink_by_mid_;
+  flat_map<uint32_t, RtpPacketSinkInterface*> sink_by_ssrc_;
+  std::multimap<uint8_t, RtpPacketSinkInterface*> sinks_by_pt_;
+  flat_map<std::pair<std::string, std::string>, RtpPacketSinkInterface*>
+      sink_by_mid_and_rsid_;
+  flat_map<std::string, RtpPacketSinkInterface*> sink_by_rsid_;
+
+  // Tracks all the MIDs that have been identified in added criteria. Used to
+  // determine if a packet should be dropped right away because the MID is
+  // unknown.
+  flat_set<std::string> known_mids_;
+
+  // Records learned mappings of MID --> SSRC and RSID --> SSRC as packets are
+  // received.
+  // This is stored separately from the sink mappings because if a sink is
+  // removed we want to still remember these associations.
+  flat_map<uint32_t, std::string> mid_by_ssrc_;
+  flat_map<uint32_t, std::string> rsid_by_ssrc_;
+
+  // Adds a binding from the SSRC to the given sink.
+  void AddSsrcSinkBinding(uint32_t ssrc, RtpPacketSinkInterface* sink);
+
+  const bool use_mid_;
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_RTP_DEMUXER_H_
diff --git a/third_party/libwebrtc/call/rtp_demuxer_unittest.cc b/third_party/libwebrtc/call/rtp_demuxer_unittest.cc
new file mode 100644
index 0000000000..2b394d3bff
--- /dev/null
+++ b/third_party/libwebrtc/call/rtp_demuxer_unittest.cc
@@ -0,0 +1,1287 @@
+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/rtp_demuxer.h"
+
+#include <memory>
+#include <set>
+#include <string>
+
+#include "absl/strings/string_view.h"
+#include "call/test/mock_rtp_packet_sink_interface.h"
+#include "modules/rtp_rtcp/include/rtp_header_extension_map.h"
+#include "modules/rtp_rtcp/source/rtp_header_extensions.h"
+#include "modules/rtp_rtcp/source/rtp_packet_received.h"
+#include "rtc_base/arraysize.h"
+#include "rtc_base/checks.h"
+#include "rtc_base/numerics/safe_conversions.h"
+#include "test/gmock.h"
+#include "test/gtest.h"
+
+namespace webrtc {
+
+namespace {
+
+using ::testing::_;
+using ::testing::AtLeast;
+using ::testing::InSequence;
+using ::testing::NiceMock;
+
+class RtpDemuxerTest : public ::testing::Test {
+ protected:
+  ~RtpDemuxerTest() {
+    for (auto* sink : sinks_to_tear_down_) {
+      demuxer_.RemoveSink(sink);
+    }
+  }
+
+  // These are convenience methods for calling demuxer.AddSink with different
+  // parameters and will ensure that the sink is automatically removed when the
+  // test case finishes.
+
+  bool AddSink(const RtpDemuxerCriteria& criteria,
+               RtpPacketSinkInterface* sink) {
+    bool added = demuxer_.AddSink(criteria, sink);
+    if (added) {
+      sinks_to_tear_down_.insert(sink);
+    }
+    return added;
+  }
+
+  bool AddSinkOnlySsrc(uint32_t ssrc, RtpPacketSinkInterface* sink) {
+    RtpDemuxerCriteria criteria;
+    criteria.ssrcs().insert(ssrc);
+    return AddSink(criteria, sink);
+  }
+
+  bool AddSinkOnlyRsid(absl::string_view rsid, RtpPacketSinkInterface* sink) {
+    RtpDemuxerCriteria criteria(absl::string_view(), rsid);
+    return AddSink(criteria, sink);
+  }
+
+  bool AddSinkOnlyMid(absl::string_view mid, RtpPacketSinkInterface* sink) {
+    RtpDemuxerCriteria criteria(mid);
+    return AddSink(criteria, sink);
+  }
+
+  bool AddSinkBothMidRsid(absl::string_view mid,
+                          absl::string_view rsid,
+                          RtpPacketSinkInterface* sink) {
+    RtpDemuxerCriteria criteria(mid, rsid);
+    return AddSink(criteria, sink);
+  }
+
+  bool RemoveSink(RtpPacketSinkInterface* sink) {
+    sinks_to_tear_down_.erase(sink);
+    return demuxer_.RemoveSink(sink);
+  }
+
+  // The CreatePacket* methods are helpers for creating new RTP packets with
+  // various attributes set. Tests should use the helper that provides the
+  // minimum information needed to exercise the behavior under test. Tests also
+  // should not rely on any behavior which is not clearly described in the
+  // helper name/arguments. Any additional settings that are not covered by the
+  // helper should be set manually on the packet once it has been returned.
+  // For example, most tests in this file do not care about the RTP sequence
+  // number, but to ensure that the returned packets are valid the helpers will
+  // auto-increment the sequence number starting with 1. Tests that rely on
+  // specific sequence number behavior should call SetSequenceNumber manually on
+  // the returned packet.
+
+  // Intended for use only by other CreatePacket* helpers.
+  std::unique_ptr<RtpPacketReceived> CreatePacket(
+      uint32_t ssrc,
+      RtpPacketReceived::ExtensionManager* extension_manager) {
+    auto packet = std::make_unique<RtpPacketReceived>(extension_manager);
+    packet->SetSsrc(ssrc);
+    packet->SetSequenceNumber(next_sequence_number_++);
+    return packet;
+  }
+
+  std::unique_ptr<RtpPacketReceived> CreatePacketWithSsrc(uint32_t ssrc) {
+    return CreatePacket(ssrc, nullptr);
+  }
+
+  std::unique_ptr<RtpPacketReceived> CreatePacketWithSsrcMid(
+      uint32_t ssrc,
+      absl::string_view mid) {
+    RtpPacketReceived::ExtensionManager extension_manager;
+    extension_manager.Register<RtpMid>(11);
+
+    auto packet = CreatePacket(ssrc, &extension_manager);
+    packet->SetExtension<RtpMid>(mid);
+    return packet;
+  }
+
+  std::unique_ptr<RtpPacketReceived> CreatePacketWithSsrcRsid(
+      uint32_t ssrc,
+      absl::string_view rsid) {
+    RtpPacketReceived::ExtensionManager extension_manager;
+    extension_manager.Register<RtpStreamId>(6);
+
+    auto packet = CreatePacket(ssrc, &extension_manager);
+    packet->SetExtension<RtpStreamId>(rsid);
+    return packet;
+  }
+
+  std::unique_ptr<RtpPacketReceived> CreatePacketWithSsrcRrid(
+      uint32_t ssrc,
+      absl::string_view rrid) {
+    RtpPacketReceived::ExtensionManager extension_manager;
+    extension_manager.Register<RepairedRtpStreamId>(7);
+
+    auto packet = CreatePacket(ssrc, &extension_manager);
+    packet->SetExtension<RepairedRtpStreamId>(rrid);
+    return packet;
+  }
+
+  std::unique_ptr<RtpPacketReceived> CreatePacketWithSsrcMidRsid(
+      uint32_t ssrc,
+      absl::string_view mid,
+      absl::string_view rsid) {
+    RtpPacketReceived::ExtensionManager extension_manager;
+    extension_manager.Register<RtpMid>(11);
+    extension_manager.Register<RtpStreamId>(6);
+
+    auto packet = CreatePacket(ssrc, &extension_manager);
+    packet->SetExtension<RtpMid>(mid);
+    packet->SetExtension<RtpStreamId>(rsid);
+    return packet;
+  }
+
+  std::unique_ptr<RtpPacketReceived> CreatePacketWithSsrcRsidRrid(
+      uint32_t ssrc,
+      absl::string_view rsid,
+      absl::string_view rrid) {
+    RtpPacketReceived::ExtensionManager extension_manager;
+    extension_manager.Register<RtpStreamId>(6);
+    extension_manager.Register<RepairedRtpStreamId>(7);
+
+    auto packet = CreatePacket(ssrc, &extension_manager);
+    packet->SetExtension<RtpStreamId>(rsid);
+    packet->SetExtension<RepairedRtpStreamId>(rrid);
+    return packet;
+  }
+
+  RtpDemuxer demuxer_;
+  std::set<RtpPacketSinkInterface*> sinks_to_tear_down_;
+  uint16_t next_sequence_number_ = 1;
+};
+
+class RtpDemuxerDeathTest : public RtpDemuxerTest {};
+
+MATCHER_P(SamePacketAs, other, "") {
+  return arg.Ssrc() == other.Ssrc() &&
+         arg.SequenceNumber() == other.SequenceNumber();
+}
+
+TEST_F(RtpDemuxerTest, CanAddSinkBySsrc) {
+  MockRtpPacketSink sink;
+  constexpr uint32_t ssrc = 1;
+
+  EXPECT_TRUE(AddSinkOnlySsrc(ssrc, &sink));
+}
+
+TEST_F(RtpDemuxerTest, AllowAddSinkWithOverlappingPayloadTypesIfDifferentMid) {
+  const std::string mid1 = "v";
+  const std::string mid2 = "a";
+  constexpr uint8_t pt1 = 30;
+  constexpr uint8_t pt2 = 31;
+  constexpr uint8_t pt3 = 32;
+
+  RtpDemuxerCriteria pt1_pt2(mid1);
+  pt1_pt2.payload_types() = {pt1, pt2};
+  MockRtpPacketSink sink1;
+  AddSink(pt1_pt2, &sink1);
+
+  RtpDemuxerCriteria pt1_pt3(mid2);
+  pt1_pt3.payload_types() = {pt1, pt3};
+  MockRtpPacketSink sink2;
+  EXPECT_TRUE(AddSink(pt1_pt3, &sink2));
+}
+
+TEST_F(RtpDemuxerTest, RejectAddSinkForSameMidOnly) {
+  const std::string mid = "mid";
+
+  MockRtpPacketSink sink;
+  AddSinkOnlyMid(mid, &sink);
+  EXPECT_FALSE(AddSinkOnlyMid(mid, &sink));
+}
+
+TEST_F(RtpDemuxerTest, RejectAddSinkForSameMidRsid) {
+  const std::string mid = "v";
+  const std::string rsid = "1";
+
+  MockRtpPacketSink sink1;
+  AddSinkBothMidRsid(mid, rsid, &sink1);
+
+  MockRtpPacketSink sink2;
+  EXPECT_FALSE(AddSinkBothMidRsid(mid, rsid, &sink2));
+}
+
+TEST_F(RtpDemuxerTest, RejectAddSinkForConflictingMidAndMidRsid) {
+  const std::string mid = "v";
+  const std::string rsid = "1";
+
+  MockRtpPacketSink mid_sink;
+  AddSinkOnlyMid(mid, &mid_sink);
+
+  // This sink would never get any packets routed to it because the above sink
+  // would receive them all.
+  MockRtpPacketSink mid_rsid_sink;
+  EXPECT_FALSE(AddSinkBothMidRsid(mid, rsid, &mid_rsid_sink));
+}
+
+TEST_F(RtpDemuxerTest, RejectAddSinkForConflictingMidRsidAndMid) {
+  const std::string mid = "v";
+  const std::string rsid = "";
+
+  MockRtpPacketSink mid_rsid_sink;
+  AddSinkBothMidRsid(mid, rsid, &mid_rsid_sink);
+
+  // This sink would shadow the above sink.
+  MockRtpPacketSink mid_sink;
+  EXPECT_FALSE(AddSinkOnlyMid(mid, &mid_sink));
+}
+
+TEST_F(RtpDemuxerTest, AddSinkFailsIfCalledForTwoSinksWithSameSsrc) {
+  MockRtpPacketSink sink_a;
+  MockRtpPacketSink sink_b;
+  constexpr uint32_t ssrc = 1;
+  ASSERT_TRUE(AddSinkOnlySsrc(ssrc, &sink_a));
+
+  EXPECT_FALSE(AddSinkOnlySsrc(ssrc, &sink_b));
+}
+
+TEST_F(RtpDemuxerTest, AddSinkFailsIfCalledTwiceEvenIfSameSinkWithSameSsrc) {
+  MockRtpPacketSink sink;
+  constexpr uint32_t ssrc = 1;
+  ASSERT_TRUE(AddSinkOnlySsrc(ssrc, &sink));
+
+  EXPECT_FALSE(AddSinkOnlySsrc(ssrc, &sink));
+}
+
+// TODO(steveanton): Currently fails because payload type validation is not
+// complete in AddSink (see note in rtp_demuxer.cc).
+TEST_F(RtpDemuxerTest, DISABLED_RejectAddSinkForSamePayloadTypes) {
+  constexpr uint8_t pt1 = 30;
+  constexpr uint8_t pt2 = 31;
+
+  RtpDemuxerCriteria pt1_pt2;
+  pt1_pt2.payload_types() = {pt1, pt2};
+  MockRtpPacketSink sink1;
+  AddSink(pt1_pt2, &sink1);
+
+  RtpDemuxerCriteria pt2_pt1;
+  pt2_pt1.payload_types() = {pt2, pt1};
+  MockRtpPacketSink sink2;
+  EXPECT_FALSE(AddSink(pt2_pt1, &sink2));
+}
+
+// Routing Tests
+
+TEST_F(RtpDemuxerTest, OnRtpPacketCalledOnCorrectSinkBySsrc) {
+  constexpr uint32_t ssrcs[] = {101, 202, 303};
+  MockRtpPacketSink sinks[arraysize(ssrcs)];
+  for (size_t i = 0; i < arraysize(ssrcs); i++) {
+    AddSinkOnlySsrc(ssrcs[i], &sinks[i]);
+  }
+
+  for (size_t i = 0; i < arraysize(ssrcs); i++) {
+    auto packet = CreatePacketWithSsrc(ssrcs[i]);
+    EXPECT_CALL(sinks[i], OnRtpPacket(SamePacketAs(*packet))).Times(1);
+    EXPECT_TRUE(demuxer_.OnRtpPacket(*packet));
+  }
+}
+
+TEST_F(RtpDemuxerTest, OnRtpPacketCalledOnCorrectSinkByRsid) {
+  const std::string rsids[] = {"a", "b", "c"};
+  MockRtpPacketSink sinks[arraysize(rsids)];
+  for (size_t i = 0; i < arraysize(rsids); i++) {
+    AddSinkOnlyRsid(rsids[i], &sinks[i]);
+  }
+
+  for (size_t i = 0; i < arraysize(rsids); i++) {
+    auto packet =
+        CreatePacketWithSsrcRsid(rtc::checked_cast<uint32_t>(i), rsids[i]);
+    EXPECT_CALL(sinks[i], OnRtpPacket(SamePacketAs(*packet))).Times(1);
+    EXPECT_TRUE(demuxer_.OnRtpPacket(*packet));
+  }
+}
+
+TEST_F(RtpDemuxerTest, OnRtpPacketCalledOnCorrectSinkByMid) {
+  const std::string mids[] = {"a", "v", "s"};
+  MockRtpPacketSink sinks[arraysize(mids)];
+  for (size_t i = 0; i < arraysize(mids); i++) {
+    AddSinkOnlyMid(mids[i], &sinks[i]);
+  }
+
+  for (size_t i = 0; i < arraysize(mids); i++) {
+    auto packet =
+        CreatePacketWithSsrcMid(rtc::checked_cast<uint32_t>(i), mids[i]);
+    EXPECT_CALL(sinks[i], OnRtpPacket(SamePacketAs(*packet))).Times(1);
+    EXPECT_TRUE(demuxer_.OnRtpPacket(*packet));
+  }
+}
+
+TEST_F(RtpDemuxerTest, OnRtpPacketCalledOnCorrectSinkByMidAndRsid) {
+  const std::string mid = "v";
+  const std::string rsid = "1";
+  constexpr uint32_t ssrc = 10;
+
+  MockRtpPacketSink sink;
+  AddSinkBothMidRsid(mid, rsid, &sink);
+
+  auto packet = CreatePacketWithSsrcMidRsid(ssrc, mid, rsid);
+  EXPECT_CALL(sink, OnRtpPacket(SamePacketAs(*packet))).Times(1);
+  EXPECT_TRUE(demuxer_.OnRtpPacket(*packet));
+}
+
+TEST_F(RtpDemuxerTest, OnRtpPacketCalledOnCorrectSinkByRepairedRsid) {
+  const std::string rrid = "1";
+  constexpr uint32_t ssrc = 10;
+
+  MockRtpPacketSink sink;
+  AddSinkOnlyRsid(rrid, &sink);
+
+  auto packet_with_rrid = CreatePacketWithSsrcRrid(ssrc, rrid);
+  EXPECT_CALL(sink, OnRtpPacket(SamePacketAs(*packet_with_rrid))).Times(1);
+  EXPECT_TRUE(demuxer_.OnRtpPacket(*packet_with_rrid));
+}
+
+TEST_F(RtpDemuxerTest, OnRtpPacketCalledOnCorrectSinkByPayloadType) {
+  constexpr uint32_t ssrc = 10;
+  constexpr uint8_t payload_type = 30;
+
+  MockRtpPacketSink sink;
+  RtpDemuxerCriteria criteria;
+  criteria.payload_types() = {payload_type};
+  AddSink(criteria, &sink);
+
+  auto packet = CreatePacketWithSsrc(ssrc);
+  packet->SetPayloadType(payload_type);
+  EXPECT_CALL(sink, OnRtpPacket(SamePacketAs(*packet))).Times(1);
+  EXPECT_TRUE(demuxer_.OnRtpPacket(*packet));
+}
+
+TEST_F(RtpDemuxerTest, PacketsDeliveredInRightOrder) {
+  constexpr uint32_t ssrc = 101;
+  MockRtpPacketSink sink;
+  AddSinkOnlySsrc(ssrc, &sink);
+
+  std::unique_ptr<RtpPacketReceived> packets[5];
+  for (size_t i = 0; i < arraysize(packets); i++) {
+    packets[i] = CreatePacketWithSsrc(ssrc);
+    packets[i]->SetSequenceNumber(rtc::checked_cast<uint16_t>(i));
+  }
+
+  InSequence sequence;
+  for (const auto& packet : packets) {
+    EXPECT_CALL(sink, OnRtpPacket(SamePacketAs(*packet))).Times(1);
+  }
+
+  for (const auto& packet : packets) {
+    EXPECT_TRUE(demuxer_.OnRtpPacket(*packet));
+  }
+}
+
+TEST_F(RtpDemuxerTest, SinkMappedToMultipleSsrcs) {
+  constexpr uint32_t ssrcs[] = {404, 505, 606};
+  MockRtpPacketSink sink;
+  for (uint32_t ssrc : ssrcs) {
+    AddSinkOnlySsrc(ssrc, &sink);
+  }
+
+  // The sink which is associated with multiple SSRCs gets the callback
+  // triggered for each of those SSRCs.
+  for (uint32_t ssrc : ssrcs) {
+    auto packet = CreatePacketWithSsrc(ssrc);
+    EXPECT_CALL(sink, OnRtpPacket(SamePacketAs(*packet))).Times(1);
+    EXPECT_TRUE(demuxer_.OnRtpPacket(*packet));
+  }
+}
+
+TEST_F(RtpDemuxerTest, NoCallbackOnSsrcSinkRemovedBeforeFirstPacket) {
+  constexpr uint32_t ssrc = 404;
+  MockRtpPacketSink sink;
+  AddSinkOnlySsrc(ssrc, &sink);
+
+  ASSERT_TRUE(RemoveSink(&sink));
+
+  // The removed sink does not get callbacks.
+  auto packet = CreatePacketWithSsrc(ssrc);
+  EXPECT_CALL(sink, OnRtpPacket(_)).Times(0);  // Not called.
+  EXPECT_FALSE(demuxer_.OnRtpPacket(*packet));
+}
+
+TEST_F(RtpDemuxerTest, NoCallbackOnSsrcSinkRemovedAfterFirstPacket) {
+  constexpr uint32_t ssrc = 404;
+  NiceMock<MockRtpPacketSink> sink;
+  AddSinkOnlySsrc(ssrc, &sink);
+
+  InSequence sequence;
+  for (size_t i = 0; i < 10; i++) {
+    ASSERT_TRUE(demuxer_.OnRtpPacket(*CreatePacketWithSsrc(ssrc)));
+  }
+
+  ASSERT_TRUE(RemoveSink(&sink));
+
+  // The removed sink does not get callbacks.
+  auto packet = CreatePacketWithSsrc(ssrc);
+  EXPECT_CALL(sink, OnRtpPacket(_)).Times(0);  // Not called.
+  EXPECT_FALSE(demuxer_.OnRtpPacket(*packet));
+}
+
+// An SSRC may only be mapped to a single sink. However, since configuration
+// of this associations might come from the network, we need to fail gracefully.
+TEST_F(RtpDemuxerTest, OnlyOneSinkPerSsrcGetsOnRtpPacketTriggered) {
+  MockRtpPacketSink sinks[3];
+  constexpr uint32_t ssrc = 404;
+  ASSERT_TRUE(AddSinkOnlySsrc(ssrc, &sinks[0]));
+  ASSERT_FALSE(AddSinkOnlySsrc(ssrc, &sinks[1]));
+  ASSERT_FALSE(AddSinkOnlySsrc(ssrc, &sinks[2]));
+
+  // The first sink associated with the SSRC remains active; other sinks
+  // were not really added, and so do not get OnRtpPacket() called.
+  auto packet = CreatePacketWithSsrc(ssrc);
+  EXPECT_CALL(sinks[0], OnRtpPacket(SamePacketAs(*packet))).Times(1);
+  EXPECT_CALL(sinks[1], OnRtpPacket(_)).Times(0);
+  EXPECT_CALL(sinks[2], OnRtpPacket(_)).Times(0);
+  ASSERT_TRUE(demuxer_.OnRtpPacket(*packet));
+}
+
+TEST_F(RtpDemuxerTest, NoRepeatedCallbackOnRepeatedAddSinkForSameSink) {
+  constexpr uint32_t ssrc = 111;
+  MockRtpPacketSink sink;
+
+  ASSERT_TRUE(AddSinkOnlySsrc(ssrc, &sink));
+  ASSERT_FALSE(AddSinkOnlySsrc(ssrc, &sink));
+
+  auto packet = CreatePacketWithSsrc(ssrc);
+  EXPECT_CALL(sink, OnRtpPacket(SamePacketAs(*packet))).Times(1);
+  EXPECT_TRUE(demuxer_.OnRtpPacket(*packet));
+}
+
+TEST_F(RtpDemuxerTest, RemoveSinkReturnsFalseForNeverAddedSink) {
+  MockRtpPacketSink sink;
+  EXPECT_FALSE(RemoveSink(&sink));
+}
+
+TEST_F(RtpDemuxerTest, RemoveSinkReturnsTrueForPreviouslyAddedSsrcSink) {
+  constexpr uint32_t ssrc = 101;
+  MockRtpPacketSink sink;
+  AddSinkOnlySsrc(ssrc, &sink);
+
+  EXPECT_TRUE(RemoveSink(&sink));
+}
+
+TEST_F(RtpDemuxerTest,
+       RemoveSinkReturnsTrueForUnresolvedPreviouslyAddedRsidSink) {
+  const std::string rsid = "a";
+  MockRtpPacketSink sink;
+  AddSinkOnlyRsid(rsid, &sink);
+
+  EXPECT_TRUE(RemoveSink(&sink));
+}
+
+TEST_F(RtpDemuxerTest,
+       RemoveSinkReturnsTrueForResolvedPreviouslyAddedRsidSink) {
+  const std::string rsid = "a";
+  constexpr uint32_t ssrc = 101;
+  NiceMock<MockRtpPacketSink> sink;
+  AddSinkOnlyRsid(rsid, &sink);
+  ASSERT_TRUE(demuxer_.OnRtpPacket(*CreatePacketWithSsrcRsid(ssrc, rsid)));
+
+  EXPECT_TRUE(RemoveSink(&sink));
+}
+
+TEST_F(RtpDemuxerTest, RsidLearnedAndLaterPacketsDeliveredWithOnlySsrc) {
+  MockRtpPacketSink sink;
+  const std::string rsid = "a";
+  AddSinkOnlyRsid(rsid, &sink);
+
+  // Create a sequence of RTP packets, where only the first one actually
+  // mentions the RSID.
+  std::unique_ptr<RtpPacketReceived> packets[5];
+  constexpr uint32_t rsid_ssrc = 111;
+  packets[0] = CreatePacketWithSsrcRsid(rsid_ssrc, rsid);
+  for (size_t i = 1; i < arraysize(packets); i++) {
+    packets[i] = CreatePacketWithSsrc(rsid_ssrc);
+  }
+
+  // The first packet associates the RSID with the SSRC, thereby allowing the
+  // demuxer to correctly demux all of the packets.
+  InSequence sequence;
+  for (const auto& packet : packets) {
+    EXPECT_CALL(sink, OnRtpPacket(SamePacketAs(*packet))).Times(1);
+  }
+  for (const auto& packet : packets) {
+    EXPECT_TRUE(demuxer_.OnRtpPacket(*packet));
+  }
+}
+
+TEST_F(RtpDemuxerTest, NoCallbackOnRsidSinkRemovedBeforeFirstPacket) {
+  MockRtpPacketSink sink;
+  const std::string rsid = "a";
+  AddSinkOnlyRsid(rsid, &sink);
+
+  // Sink removed - it won't get triggers even if packets with its RSID arrive.
+  ASSERT_TRUE(RemoveSink(&sink));
+
+  constexpr uint32_t ssrc = 111;
+  auto packet = CreatePacketWithSsrcRsid(ssrc, rsid);
+  EXPECT_CALL(sink, OnRtpPacket(_)).Times(0);  // Not called.
+  EXPECT_FALSE(demuxer_.OnRtpPacket(*packet));
+}
+
+TEST_F(RtpDemuxerTest, NoCallbackOnRsidSinkRemovedAfterFirstPacket) {
+  NiceMock<MockRtpPacketSink> sink;
+  const std::string rsid = "a";
+  AddSinkOnlyRsid(rsid, &sink);
+
+  InSequence sequence;
+  constexpr uint32_t ssrc = 111;
+  for (size_t i = 0; i < 10; i++) {
+    auto packet = CreatePacketWithSsrcRsid(ssrc, rsid);
+    ASSERT_TRUE(demuxer_.OnRtpPacket(*packet));
+  }
+
+  // Sink removed - it won't get triggers even if packets with its RSID arrive.
+  ASSERT_TRUE(RemoveSink(&sink));
+
+  auto packet = CreatePacketWithSsrcRsid(ssrc, rsid);
+  EXPECT_CALL(sink, OnRtpPacket(_)).Times(0);  // Not called.
+  EXPECT_FALSE(demuxer_.OnRtpPacket(*packet));
+}
+
+TEST_F(RtpDemuxerTest, NoCallbackOnMidSinkRemovedBeforeFirstPacket) {
+  const std::string mid = "v";
+  constexpr uint32_t ssrc = 10;
+
+  MockRtpPacketSink sink;
+  AddSinkOnlyMid(mid, &sink);
+  RemoveSink(&sink);
+
+  auto packet = CreatePacketWithSsrcMid(ssrc, mid);
+  EXPECT_CALL(sink, OnRtpPacket(_)).Times(0);
+  EXPECT_FALSE(demuxer_.OnRtpPacket(*packet));
+}
+
+TEST_F(RtpDemuxerTest, NoCallbackOnMidSinkRemovedAfterFirstPacket) {
+  const std::string mid = "v";
+  constexpr uint32_t ssrc = 10;
+
+  NiceMock<MockRtpPacketSink> sink;
+  AddSinkOnlyMid(mid, &sink);
+
+  auto p1 = CreatePacketWithSsrcMid(ssrc, mid);
+  demuxer_.OnRtpPacket(*p1);
+
+  RemoveSink(&sink);
+
+  auto p2 = CreatePacketWithSsrcMid(ssrc, mid);
+  EXPECT_CALL(sink, OnRtpPacket(_)).Times(0);
+  EXPECT_FALSE(demuxer_.OnRtpPacket(*p2));
+}
+
+TEST_F(RtpDemuxerTest, NoCallbackOnMidRsidSinkRemovedAfterFirstPacket) {
+  const std::string mid = "v";
+  const std::string rsid = "1";
+  constexpr uint32_t ssrc = 10;
+
+  NiceMock<MockRtpPacketSink> sink;
+  AddSinkBothMidRsid(mid, rsid, &sink);
+
+  auto p1 = CreatePacketWithSsrcMidRsid(ssrc, mid, rsid);
+  demuxer_.OnRtpPacket(*p1);
+
+  RemoveSink(&sink);
+
+  auto p2 = CreatePacketWithSsrcMidRsid(ssrc, mid, rsid);
+  EXPECT_CALL(sink, OnRtpPacket(_)).Times(0);
+  EXPECT_FALSE(demuxer_.OnRtpPacket(*p2));
+}
+
+// The RSID to SSRC mapping should be one-to-one. If we end up receiving
+// two (or more) packets with the same SSRC, but different RSIDs, we guarantee
+// delivery to one of them but not both.
+TEST_F(RtpDemuxerTest, FirstSsrcAssociatedWithAnRsidIsNotForgotten) {
+  // Each sink has a distinct RSID.
+  MockRtpPacketSink sink_a;
+  const std::string rsid_a = "a";
+  AddSinkOnlyRsid(rsid_a, &sink_a);
+
+  MockRtpPacketSink sink_b;
+  const std::string rsid_b = "b";
+  AddSinkOnlyRsid(rsid_b, &sink_b);
+
+  InSequence sequence;  // Verify that the order of delivery is unchanged.
+
+  constexpr uint32_t shared_ssrc = 100;
+
+  // First a packet with `rsid_a` is received, and `sink_a` is associated with
+  // its SSRC.
+  auto packet_a = CreatePacketWithSsrcRsid(shared_ssrc, rsid_a);
+  EXPECT_CALL(sink_a, OnRtpPacket(SamePacketAs(*packet_a))).Times(1);
+  EXPECT_TRUE(demuxer_.OnRtpPacket(*packet_a));
+
+  // Second, a packet with `rsid_b` is received. We guarantee that `sink_b`
+  // receives it.
+  auto packet_b = CreatePacketWithSsrcRsid(shared_ssrc, rsid_b);
+  EXPECT_CALL(sink_a, OnRtpPacket(_)).Times(0);
+  EXPECT_CALL(sink_b, OnRtpPacket(SamePacketAs(*packet_b))).Times(1);
+  EXPECT_TRUE(demuxer_.OnRtpPacket(*packet_b));
+
+  // Known edge-case; adding a new RSID association makes us re-examine all
+  // SSRCs. `sink_b` may or may not be associated with the SSRC now; we make
+  // no promises on that. However, since the RSID is specified and it cannot be
+  // found the packet should be dropped.
+  MockRtpPacketSink sink_c;
+  const std::string rsid_c = "c";
+  constexpr uint32_t some_other_ssrc = shared_ssrc + 1;
+  AddSinkOnlySsrc(some_other_ssrc, &sink_c);
+
+  auto packet_c = CreatePacketWithSsrcMid(shared_ssrc, rsid_c);
+  EXPECT_CALL(sink_a, OnRtpPacket(_)).Times(0);
+  EXPECT_CALL(sink_b, OnRtpPacket(_)).Times(0);
+  EXPECT_CALL(sink_c, OnRtpPacket(_)).Times(0);
+  EXPECT_FALSE(demuxer_.OnRtpPacket(*packet_c));
+}
+
+TEST_F(RtpDemuxerTest, MultipleRsidsOnSameSink) {
+  MockRtpPacketSink sink;
+  const std::string rsids[] = {"a", "b", "c"};
+
+  for (const std::string& rsid : rsids) {
+    AddSinkOnlyRsid(rsid, &sink);
+  }
+
+  InSequence sequence;
+  for (size_t i = 0; i < arraysize(rsids); i++) {
+    // Assign different SSRCs and sequence numbers to all packets.
+    const uint32_t ssrc = 1000 + static_cast<uint32_t>(i);
+    const uint16_t sequence_number = 50 + static_cast<uint16_t>(i);
+    auto packet = CreatePacketWithSsrcRsid(ssrc, rsids[i]);
+    packet->SetSequenceNumber(sequence_number);
+    EXPECT_CALL(sink, OnRtpPacket(SamePacketAs(*packet))).Times(1);
+    EXPECT_TRUE(demuxer_.OnRtpPacket(*packet));
+  }
+}
+
+// RSIDs are given higher priority than SSRC because we believe senders are less
+// likely to mislabel packets with RSID than mislabel them with SSRCs.
+TEST_F(RtpDemuxerTest, SinkWithBothRsidAndSsrcAssociations) {
+  MockRtpPacketSink sink;
+  constexpr uint32_t standalone_ssrc = 10101;
+  constexpr uint32_t rsid_ssrc = 20202;
+  const std::string rsid = "1";
+
+  AddSinkOnlySsrc(standalone_ssrc, &sink);
+  AddSinkOnlyRsid(rsid, &sink);
+
+  InSequence sequence;
+
+  auto ssrc_packet = CreatePacketWithSsrc(standalone_ssrc);
+  EXPECT_CALL(sink, OnRtpPacket(SamePacketAs(*ssrc_packet))).Times(1);
+  EXPECT_TRUE(demuxer_.OnRtpPacket(*ssrc_packet));
+
+  auto rsid_packet = CreatePacketWithSsrcRsid(rsid_ssrc, rsid);
+  EXPECT_CALL(sink, OnRtpPacket(SamePacketAs(*rsid_packet))).Times(1);
+  EXPECT_TRUE(demuxer_.OnRtpPacket(*rsid_packet));
+}
+
+// Packets are always guaranteed to be routed to only one sink.
+TEST_F(RtpDemuxerTest, AssociatingByRsidAndBySsrcCannotTriggerDoubleCall) {
+  constexpr uint32_t ssrc = 10101;
+  const std::string rsid = "a";
+
+  MockRtpPacketSink sink;
+  AddSinkOnlySsrc(ssrc, &sink);
+  AddSinkOnlyRsid(rsid, &sink);
+
+  auto packet = CreatePacketWithSsrcRsid(ssrc, rsid);
+  EXPECT_CALL(sink, OnRtpPacket(SamePacketAs(*packet))).Times(1);
+  EXPECT_TRUE(demuxer_.OnRtpPacket(*packet));
+}
+
+
+// If one sink is associated with SSRC x, and another sink with RSID y, then if
+// we receive a packet with both SSRC x and RSID y, route that to only the sink
+// for RSID y since we believe RSID tags to be more trustworthy than signaled
+// SSRCs.
+TEST_F(RtpDemuxerTest,
+       PacketFittingBothRsidSinkAndSsrcSinkGivenOnlyToRsidSink) {
+  constexpr uint32_t ssrc = 111;
+  MockRtpPacketSink ssrc_sink;
+  AddSinkOnlySsrc(ssrc, &ssrc_sink);
+
+  const std::string rsid = "a";
+  MockRtpPacketSink rsid_sink;
+  AddSinkOnlyRsid(rsid, &rsid_sink);
+
+  auto packet = CreatePacketWithSsrcRsid(ssrc, rsid);
+
+  EXPECT_CALL(ssrc_sink, OnRtpPacket(_)).Times(0);
+  EXPECT_CALL(rsid_sink, OnRtpPacket(SamePacketAs(*packet))).Times(1);
+  EXPECT_TRUE(demuxer_.OnRtpPacket(*packet));
+}
+
+// We're not expecting RSIDs to be resolved to SSRCs which were previously
+// mapped to sinks, and make no guarantees except for graceful handling.
+TEST_F(RtpDemuxerTest,
+       GracefullyHandleRsidBeingMappedToPrevouslyAssociatedSsrc) {
+  constexpr uint32_t ssrc = 111;
+  NiceMock<MockRtpPacketSink> ssrc_sink;
+  AddSinkOnlySsrc(ssrc, &ssrc_sink);
+
+  const std::string rsid = "a";
+  NiceMock<MockRtpPacketSink> rsid_sink;
+  AddSinkOnlyRsid(rsid, &rsid_sink);
+
+  // The SSRC was mapped to an SSRC sink, but was even active (packets flowed
+  // over it).
+  auto packet = CreatePacketWithSsrcRsid(ssrc, rsid);
+  demuxer_.OnRtpPacket(*packet);
+
+  // If the SSRC sink is ever removed, the RSID sink *might* receive indications
+  // of packets, and observers *might* be informed. Only graceful handling
+  // is guaranteed.
+  RemoveSink(&ssrc_sink);
+  EXPECT_CALL(rsid_sink, OnRtpPacket(SamePacketAs(*packet))).Times(AtLeast(0));
+  EXPECT_TRUE(demuxer_.OnRtpPacket(*packet));
+}
+
+// Tests that when one MID sink is configured, packets that include the MID
+// extension will get routed to that sink and any packets that use the same
+// SSRC as one of those packets later will also get routed to the sink, even
+// if a new SSRC is introduced for the same MID.
+TEST_F(RtpDemuxerTest, RoutedByMidWhenSsrcAdded) {
+  const std::string mid = "v";
+  NiceMock<MockRtpPacketSink> sink;
+  AddSinkOnlyMid(mid, &sink);
+
+  constexpr uint32_t ssrc1 = 10;
+  constexpr uint32_t ssrc2 = 11;
+
+  auto packet_ssrc1_mid = CreatePacketWithSsrcMid(ssrc1, mid);
+  demuxer_.OnRtpPacket(*packet_ssrc1_mid);
+  auto packet_ssrc2_mid = CreatePacketWithSsrcMid(ssrc2, mid);
+  demuxer_.OnRtpPacket(*packet_ssrc2_mid);
+
+  auto packet_ssrc1_only = CreatePacketWithSsrc(ssrc1);
+  EXPECT_CALL(sink, OnRtpPacket(SamePacketAs(*packet_ssrc1_only))).Times(1);
+  EXPECT_TRUE(demuxer_.OnRtpPacket(*packet_ssrc1_only));
+
+  auto packet_ssrc2_only = CreatePacketWithSsrc(ssrc2);
+  EXPECT_CALL(sink, OnRtpPacket(SamePacketAs(*packet_ssrc2_only))).Times(1);
+  EXPECT_TRUE(demuxer_.OnRtpPacket(*packet_ssrc2_only));
+}
+
+TEST_F(RtpDemuxerTest, DontLearnMidSsrcBindingBeforeSinkAdded) {
+  const std::string mid = "v";
+  constexpr uint32_t ssrc = 10;
+
+  auto packet_ssrc_mid = CreatePacketWithSsrcMid(ssrc, mid);
+  ASSERT_FALSE(demuxer_.OnRtpPacket(*packet_ssrc_mid));
+
+  MockRtpPacketSink sink;
+  AddSinkOnlyMid(mid, &sink);
+
+  auto packet_ssrc_only = CreatePacketWithSsrc(ssrc);
+  EXPECT_CALL(sink, OnRtpPacket(_)).Times(0);
+  EXPECT_FALSE(demuxer_.OnRtpPacket(*packet_ssrc_only));
+}
+
+TEST_F(RtpDemuxerTest, DontForgetMidSsrcBindingWhenSinkRemoved) {
+  const std::string mid = "v";
+  constexpr uint32_t ssrc = 10;
+
+  NiceMock<MockRtpPacketSink> sink1;
+  AddSinkOnlyMid(mid, &sink1);
+
+  auto packet_with_mid = CreatePacketWithSsrcMid(ssrc, mid);
+  demuxer_.OnRtpPacket(*packet_with_mid);
+
+  RemoveSink(&sink1);
+
+  MockRtpPacketSink sink2;
+  AddSinkOnlyMid(mid, &sink2);
+
+  auto packet_with_ssrc = CreatePacketWithSsrc(ssrc);
+  EXPECT_CALL(sink2, OnRtpPacket(SamePacketAs(*packet_with_ssrc)));
+  EXPECT_TRUE(demuxer_.OnRtpPacket(*packet_with_ssrc));
+}
+
+// If a sink is added with only a MID, then any packet with that MID no matter
+// the RSID should be routed to that sink.
+TEST_F(RtpDemuxerTest, RoutedByMidWithAnyRsid) {
+  const std::string mid = "v";
+  const std::string rsid1 = "1";
+  const std::string rsid2 = "2";
+  constexpr uint32_t ssrc1 = 10;
+  constexpr uint32_t ssrc2 = 11;
+
+  MockRtpPacketSink sink;
+  AddSinkOnlyMid(mid, &sink);
+
+  InSequence sequence;
+
+  auto packet_ssrc1_rsid1 = CreatePacketWithSsrcMidRsid(ssrc1, mid, rsid1);
+  EXPECT_CALL(sink, OnRtpPacket(SamePacketAs(*packet_ssrc1_rsid1))).Times(1);
+  EXPECT_TRUE(demuxer_.OnRtpPacket(*packet_ssrc1_rsid1));
+
+  auto packet_ssrc2_rsid2 = CreatePacketWithSsrcMidRsid(ssrc2, mid, rsid2);
+  EXPECT_CALL(sink, OnRtpPacket(SamePacketAs(*packet_ssrc2_rsid2))).Times(1);
+  EXPECT_TRUE(demuxer_.OnRtpPacket(*packet_ssrc2_rsid2));
+}
+
+// These two tests verify that for a sink added with a MID, RSID pair, if the
+// MID and RSID are learned in separate packets (e.g., because the header
+// extensions are sent separately), then a later packet with just SSRC will get
+// routed to that sink.
+// The first test checks that the functionality works when MID is learned first.
+// The second test checks that the functionality works when RSID is learned
+// first.
+TEST_F(RtpDemuxerTest, LearnMidThenRsidSeparatelyAndRouteBySsrc) {
+  const std::string mid = "v";
+  const std::string rsid = "1";
+  constexpr uint32_t ssrc = 10;
+
+  NiceMock<MockRtpPacketSink> sink;
+  AddSinkBothMidRsid(mid, rsid, &sink);
+
+  auto packet_with_mid = CreatePacketWithSsrcMid(ssrc, mid);
+  ASSERT_FALSE(demuxer_.OnRtpPacket(*packet_with_mid));
+
+  auto packet_with_rsid = CreatePacketWithSsrcRsid(ssrc, rsid);
+  ASSERT_TRUE(demuxer_.OnRtpPacket(*packet_with_rsid));
+
+  auto packet_with_ssrc = CreatePacketWithSsrc(ssrc);
+  EXPECT_CALL(sink, OnRtpPacket(SamePacketAs(*packet_with_ssrc))).Times(1);
+  EXPECT_TRUE(demuxer_.OnRtpPacket(*packet_with_ssrc));
+}
+
+TEST_F(RtpDemuxerTest, LearnRsidThenMidSeparatelyAndRouteBySsrc) {
+  const std::string mid = "v";
+  const std::string rsid = "1";
+  constexpr uint32_t ssrc = 10;
+
+  NiceMock<MockRtpPacketSink> sink;
+  AddSinkBothMidRsid(mid, rsid, &sink);
+
+  auto packet_with_rsid = CreatePacketWithSsrcRsid(ssrc, rsid);
+  ASSERT_FALSE(demuxer_.OnRtpPacket(*packet_with_rsid));
+
+  auto packet_with_mid = CreatePacketWithSsrcMid(ssrc, mid);
+  ASSERT_TRUE(demuxer_.OnRtpPacket(*packet_with_mid));
+
+  auto packet_with_ssrc = CreatePacketWithSsrc(ssrc);
+  EXPECT_CALL(sink, OnRtpPacket(SamePacketAs(*packet_with_ssrc))).Times(1);
+  EXPECT_TRUE(demuxer_.OnRtpPacket(*packet_with_ssrc));
+}
+
+TEST_F(RtpDemuxerTest, DontLearnMidRsidBindingBeforeSinkAdded) {
+  const std::string mid = "v";
+  const std::string rsid = "1";
+  constexpr uint32_t ssrc = 10;
+
+  auto packet_with_both = CreatePacketWithSsrcMidRsid(ssrc, mid, rsid);
+  ASSERT_FALSE(demuxer_.OnRtpPacket(*packet_with_both));
+
+  MockRtpPacketSink sink;
+  AddSinkBothMidRsid(mid, rsid, &sink);
+
+  auto packet_with_ssrc = CreatePacketWithSsrc(ssrc);
+  EXPECT_CALL(sink, OnRtpPacket(_)).Times(0);
+  EXPECT_FALSE(demuxer_.OnRtpPacket(*packet_with_ssrc));
+}
+
+TEST_F(RtpDemuxerTest, DontForgetMidRsidBindingWhenSinkRemoved) {
+  const std::string mid = "v";
+  const std::string rsid = "1";
+  constexpr uint32_t ssrc = 10;
+
+  NiceMock<MockRtpPacketSink> sink1;
+  AddSinkBothMidRsid(mid, rsid, &sink1);
+
+  auto packet_with_both = CreatePacketWithSsrcMidRsid(ssrc, mid, rsid);
+  demuxer_.OnRtpPacket(*packet_with_both);
+
+  RemoveSink(&sink1);
+
+  MockRtpPacketSink sink2;
+  AddSinkBothMidRsid(mid, rsid, &sink2);
+
+  auto packet_with_ssrc = CreatePacketWithSsrc(ssrc);
+  EXPECT_CALL(sink2, OnRtpPacket(SamePacketAs(*packet_with_ssrc)));
+  EXPECT_TRUE(demuxer_.OnRtpPacket(*packet_with_ssrc));
+}
+
+TEST_F(RtpDemuxerTest, LearnMidRsidBindingAfterSinkAdded) {
+  const std::string mid = "v";
+  const std::string rsid = "1";
+  constexpr uint32_t ssrc = 10;
+
+  NiceMock<MockRtpPacketSink> sink;
+  AddSinkBothMidRsid(mid, rsid, &sink);
+
+  auto packet_with_both = CreatePacketWithSsrcMidRsid(ssrc, mid, rsid);
+  demuxer_.OnRtpPacket(*packet_with_both);
+
+  auto packet_with_ssrc = CreatePacketWithSsrc(ssrc);
+  EXPECT_CALL(sink, OnRtpPacket(SamePacketAs(*packet_with_ssrc)));
+  EXPECT_TRUE(demuxer_.OnRtpPacket(*packet_with_ssrc));
+}
+
+TEST_F(RtpDemuxerTest, DropByPayloadTypeIfNoSink) {
+  constexpr uint8_t payload_type = 30;
+  constexpr uint32_t ssrc = 10;
+
+  auto packet = CreatePacketWithSsrc(ssrc);
+  packet->SetPayloadType(payload_type);
+  EXPECT_FALSE(demuxer_.OnRtpPacket(*packet));
+}
+
+// For legacy applications, it's possible for us to demux if the payload type is
+// unique. But if multiple sinks are registered with different MIDs and the same
+// payload types, then we cannot route a packet with just payload type because
+// it is ambiguous which sink it should be sent to.
+TEST_F(RtpDemuxerTest, DropByPayloadTypeIfAddedInMultipleSinks) {
+  const std::string mid1 = "v";
+  const std::string mid2 = "a";
+  constexpr uint8_t payload_type = 30;
+  constexpr uint32_t ssrc = 10;
+
+  RtpDemuxerCriteria mid1_pt(mid1);
+  mid1_pt.payload_types() = {payload_type};
+  MockRtpPacketSink sink1;
+  AddSink(mid1_pt, &sink1);
+
+  RtpDemuxerCriteria mid2_pt(mid2);
+  mid2_pt.payload_types() = {payload_type};
+  MockRtpPacketSink sink2;
+  AddSink(mid2_pt, &sink2);
+
+  auto packet = CreatePacketWithSsrc(ssrc);
+  packet->SetPayloadType(payload_type);
+
+  EXPECT_CALL(sink1, OnRtpPacket(_)).Times(0);
+  EXPECT_CALL(sink2, OnRtpPacket(_)).Times(0);
+  EXPECT_FALSE(demuxer_.OnRtpPacket(*packet));
+}
+
+// If two sinks are added with different MIDs but the same payload types, then
+// we cannot demux on the payload type only unless one of the sinks is removed.
+TEST_F(RtpDemuxerTest, RoutedByPayloadTypeIfAmbiguousSinkRemoved) {
+  const std::string mid1 = "v";
+  const std::string mid2 = "a";
+  constexpr uint8_t payload_type = 30;
+  constexpr uint32_t ssrc = 10;
+
+  RtpDemuxerCriteria mid1_pt(mid1);
+  mid1_pt.payload_types().insert(payload_type);
+  MockRtpPacketSink sink1;
+  AddSink(mid1_pt, &sink1);
+
+  RtpDemuxerCriteria mid2_pt(mid2);
+  mid2_pt.payload_types().insert(payload_type);
+  MockRtpPacketSink sink2;
+  AddSink(mid2_pt, &sink2);
+
+  RemoveSink(&sink1);
+
+  auto packet = CreatePacketWithSsrc(ssrc);
+  packet->SetPayloadType(payload_type);
+
+  EXPECT_CALL(sink1, OnRtpPacket(_)).Times(0);
+  EXPECT_CALL(sink2, OnRtpPacket(SamePacketAs(*packet))).Times(1);
+
+  EXPECT_TRUE(demuxer_.OnRtpPacket(*packet));
+}
+
+TEST_F(RtpDemuxerTest, RoutedByPayloadTypeLatchesSsrc) {
+  constexpr uint8_t payload_type = 30;
+  constexpr uint32_t ssrc = 10;
+
+  RtpDemuxerCriteria pt;
+  pt.payload_types().insert(payload_type);
+  NiceMock<MockRtpPacketSink> sink;
+  AddSink(pt, &sink);
+
+  auto packet_with_pt = CreatePacketWithSsrc(ssrc);
+  packet_with_pt->SetPayloadType(payload_type);
+  ASSERT_TRUE(demuxer_.OnRtpPacket(*packet_with_pt));
+
+  auto packet_with_ssrc = CreatePacketWithSsrc(ssrc);
+  EXPECT_CALL(sink, OnRtpPacket(SamePacketAs(*packet_with_ssrc))).Times(1);
+  EXPECT_TRUE(demuxer_.OnRtpPacket(*packet_with_ssrc));
+}
+
+// RSIDs are scoped within MID, so if two sinks are registered with the same
+// RSIDs but different MIDs, then packets containing both extensions should be
+// routed to the correct one.
+TEST_F(RtpDemuxerTest, PacketWithSameRsidDifferentMidRoutedToProperSink) {
+  const std::string mid1 = "mid1";
+  const std::string mid2 = "mid2";
+  const std::string rsid = "rsid";
+  constexpr uint32_t ssrc1 = 10;
+  constexpr uint32_t ssrc2 = 11;
+
+  NiceMock<MockRtpPacketSink> mid1_sink;
+  AddSinkBothMidRsid(mid1, rsid, &mid1_sink);
+
+  MockRtpPacketSink mid2_sink;
+  AddSinkBothMidRsid(mid2, rsid, &mid2_sink);
+
+  auto packet_mid1 = CreatePacketWithSsrcMidRsid(ssrc1, mid1, rsid);
+  ASSERT_TRUE(demuxer_.OnRtpPacket(*packet_mid1));
+
+  auto packet_mid2 = CreatePacketWithSsrcMidRsid(ssrc2, mid2, rsid);
+  EXPECT_CALL(mid2_sink, OnRtpPacket(SamePacketAs(*packet_mid2))).Times(1);
+  EXPECT_TRUE(demuxer_.OnRtpPacket(*packet_mid2));
+}
+
+// If a sink is first bound to a given SSRC by signaling but later a new sink is
+// bound to a given MID by a later signaling, then when a packet arrives with
+// both the SSRC and MID, then the signaled MID sink should take precedence.
+TEST_F(RtpDemuxerTest, SignaledMidShouldOverwriteSignaledSsrc) {
+  constexpr uint32_t ssrc = 11;
+  const std::string mid = "mid";
+
+  MockRtpPacketSink ssrc_sink;
+  AddSinkOnlySsrc(ssrc, &ssrc_sink);
+
+  MockRtpPacketSink mid_sink;
+  AddSinkOnlyMid(mid, &mid_sink);
+
+  auto p = CreatePacketWithSsrcMid(ssrc, mid);
+  EXPECT_CALL(ssrc_sink, OnRtpPacket(_)).Times(0);
+  EXPECT_CALL(mid_sink, OnRtpPacket(SamePacketAs(*p))).Times(1);
+  EXPECT_TRUE(demuxer_.OnRtpPacket(*p));
+}
+
+// Extends the previous test to also ensure that later packets that do not
+// specify MID are still routed to the MID sink rather than the overwritten SSRC
+// sink.
+TEST_F(RtpDemuxerTest, SignaledMidShouldOverwriteSignalledSsrcPersistent) {
+  constexpr uint32_t ssrc = 11;
+  const std::string mid = "mid";
+
+  MockRtpPacketSink ssrc_sink;
+  AddSinkOnlySsrc(ssrc, &ssrc_sink);
+
+  NiceMock<MockRtpPacketSink> mid_sink;
+  AddSinkOnlyMid(mid, &mid_sink);
+
+  EXPECT_CALL(ssrc_sink, OnRtpPacket(_)).Times(0);
+
+  auto packet_with_mid = CreatePacketWithSsrcMid(ssrc, mid);
+  demuxer_.OnRtpPacket(*packet_with_mid);
+
+  auto packet_without_mid = CreatePacketWithSsrc(ssrc);
+  EXPECT_CALL(mid_sink, OnRtpPacket(SamePacketAs(*packet_without_mid)))
+      .Times(1);
+  EXPECT_TRUE(demuxer_.OnRtpPacket(*packet_without_mid));
+}
+
+TEST_F(RtpDemuxerTest, RouteByPayloadTypeMultipleMatch) {
+  constexpr uint32_t ssrc = 10;
+  constexpr uint8_t pt1 = 30;
+  constexpr uint8_t pt2 = 31;
+
+  MockRtpPacketSink sink;
+  RtpDemuxerCriteria criteria;
+  criteria.payload_types() = {pt1, pt2};
+  AddSink(criteria, &sink);
+
+  auto packet_with_pt1 = CreatePacketWithSsrc(ssrc);
+  packet_with_pt1->SetPayloadType(pt1);
+  EXPECT_CALL(sink, OnRtpPacket(SamePacketAs(*packet_with_pt1)));
+  EXPECT_TRUE(demuxer_.OnRtpPacket(*packet_with_pt1));
+
+  auto packet_with_pt2 = CreatePacketWithSsrc(ssrc);
+  packet_with_pt2->SetPayloadType(pt2);
+  EXPECT_CALL(sink, OnRtpPacket(SamePacketAs(*packet_with_pt2)));
+  EXPECT_TRUE(demuxer_.OnRtpPacket(*packet_with_pt2));
+}
+
+TEST_F(RtpDemuxerTest, DontDemuxOnMidAloneIfAddedWithRsid) {
+  const std::string mid = "v";
+  const std::string rsid = "1";
+  constexpr uint32_t ssrc = 10;
+
+  MockRtpPacketSink sink;
+  AddSinkBothMidRsid(mid, rsid, &sink);
+
+  EXPECT_CALL(sink, OnRtpPacket(_)).Times(0);
+
+  auto packet = CreatePacketWithSsrcMid(ssrc, mid);
+  EXPECT_FALSE(demuxer_.OnRtpPacket(*packet));
+}
+
+TEST_F(RtpDemuxerTest, DemuxBySsrcEvenWithMidAndRsid) {
+  const std::string mid = "v";
+  const std::string rsid = "1";
+  constexpr uint32_t ssrc = 10;
+
+  RtpDemuxerCriteria criteria(mid, rsid);
+  criteria.ssrcs().insert(ssrc);
+  MockRtpPacketSink sink;
+  AddSink(criteria, &sink);
+
+  auto packet = CreatePacketWithSsrc(ssrc);
+  EXPECT_CALL(sink, OnRtpPacket(SamePacketAs(*packet))).Times(1);
+  EXPECT_TRUE(demuxer_.OnRtpPacket(*packet));
+}
+
+// In slight deviation from the BUNDLE spec, if we match a sink according to
+// SSRC, then we do not verify payload type against the criteria and defer to
+// the sink to check that it is correct.
+TEST_F(RtpDemuxerTest, DoNotCheckPayloadTypeIfMatchedByOtherCriteria) {
+  constexpr uint32_t ssrc = 10;
+  constexpr uint8_t payload_type = 30;
+  constexpr uint8_t different_payload_type = payload_type + 1;
+
+  RtpDemuxerCriteria criteria;
+  criteria.ssrcs().insert(ssrc);
+  criteria.payload_types().insert(payload_type);
+  MockRtpPacketSink sink;
+  AddSink(criteria, &sink);
+
+  auto packet = CreatePacketWithSsrc(ssrc);
+  packet->SetPayloadType(different_payload_type);
+  EXPECT_CALL(sink, OnRtpPacket(SamePacketAs(*packet))).Times(1);
+  EXPECT_TRUE(demuxer_.OnRtpPacket(*packet));
+}
+
+// If a repair packet includes an RSID it should be ignored and the packet
+// should be routed by its RRID.
+TEST_F(RtpDemuxerTest, PacketWithRsidAndRridRoutedByRrid) {
+  const std::string rsid = "1";
+  const std::string rrid = "1r";
+  constexpr uint32_t ssrc = 10;
+
+  MockRtpPacketSink sink_rsid;
+  AddSinkOnlyRsid(rsid, &sink_rsid);
+
+  MockRtpPacketSink sink_rrid;
+  AddSinkOnlyRsid(rrid, &sink_rrid);
+
+  auto packet = CreatePacketWithSsrcRsidRrid(ssrc, rsid, rrid);
+  EXPECT_CALL(sink_rsid, OnRtpPacket(_)).Times(0);
+  EXPECT_CALL(sink_rrid, OnRtpPacket(SamePacketAs(*packet))).Times(1);
+  EXPECT_TRUE(demuxer_.OnRtpPacket(*packet));
+}
+
+// Same test as above but checks that the latched SSRC routes to the RRID sink.
+TEST_F(RtpDemuxerTest, PacketWithRsidAndRridLatchesSsrcToRrid) {
+  const std::string rsid = "1";
+  const std::string rrid = "1r";
+  constexpr uint32_t ssrc = 10;
+
+  MockRtpPacketSink sink_rsid;
+  AddSinkOnlyRsid(rsid, &sink_rsid);
+
+  NiceMock<MockRtpPacketSink> sink_rrid;
+  AddSinkOnlyRsid(rrid, &sink_rrid);
+
+  auto packet_rsid_rrid = CreatePacketWithSsrcRsidRrid(ssrc, rsid, rrid);
+  demuxer_.OnRtpPacket(*packet_rsid_rrid);
+
+  auto packet_ssrc_only = CreatePacketWithSsrc(ssrc);
+  EXPECT_CALL(sink_rsid, OnRtpPacket(_)).Times(0);
+  EXPECT_CALL(sink_rrid, OnRtpPacket(SamePacketAs(*packet_ssrc_only))).Times(1);
+  EXPECT_TRUE(demuxer_.OnRtpPacket(*packet_ssrc_only));
+}
+
+// Tests that a packet which includes MID and RSID is dropped and not routed by
+// SSRC if the MID and RSID do not match an added sink.
+TEST_F(RtpDemuxerTest, PacketWithMidAndUnknownRsidIsNotRoutedBySsrc) {
+  constexpr uint32_t ssrc = 10;
+  const std::string mid = "v";
+  const std::string rsid = "1";
+  const std::string wrong_rsid = "2";
+
+  RtpDemuxerCriteria criteria(mid, rsid);
+  criteria.ssrcs().insert(ssrc);
+  MockRtpPacketSink sink;
+  AddSink(criteria, &sink);
+
+  auto packet = CreatePacketWithSsrcMidRsid(ssrc, mid, wrong_rsid);
+  EXPECT_CALL(sink, OnRtpPacket(_)).Times(0);
+  EXPECT_FALSE(demuxer_.OnRtpPacket(*packet));
+}
+
+// Tests that a packet which includes MID and RSID is dropped and not routed by
+// payload type if the MID and RSID do not match an added sink.
+TEST_F(RtpDemuxerTest, PacketWithMidAndUnknownRsidIsNotRoutedByPayloadType) {
+  constexpr uint32_t ssrc = 10;
+  const std::string mid = "v";
+  const std::string rsid = "1";
+  const std::string wrong_rsid = "2";
+  constexpr uint8_t payload_type = 30;
+
+  RtpDemuxerCriteria criteria(mid, rsid);
+  criteria.payload_types().insert(payload_type);
+  MockRtpPacketSink sink;
+  AddSink(criteria, &sink);
+
+  auto packet = CreatePacketWithSsrcMidRsid(ssrc, mid, wrong_rsid);
+  packet->SetPayloadType(payload_type);
+  EXPECT_CALL(sink, OnRtpPacket(_)).Times(0);
+  EXPECT_FALSE(demuxer_.OnRtpPacket(*packet));
+}
+
+TEST_F(RtpDemuxerTest, MidMustNotExceedMaximumLength) {
+  MockRtpPacketSink sink1;
+  std::string mid1(BaseRtpStringExtension::kMaxValueSizeBytes + 1, 'a');
+  // Adding the sink should pass even though the supplied mid is too long.
+  // The mid will be truncated though.
+  EXPECT_TRUE(AddSinkOnlyMid(mid1, &sink1));
+
+  // Adding a second sink with a mid that matches the truncated mid that was
+  // just added, should fail.
+  MockRtpPacketSink sink2;
+  std::string mid2(mid1.substr(0, BaseRtpStringExtension::kMaxValueSizeBytes));
+  EXPECT_FALSE(AddSinkOnlyMid(mid2, &sink2));
+  EXPECT_FALSE(RemoveSink(&sink2));
+
+  // Remove the original sink.
+  EXPECT_TRUE(RemoveSink(&sink1));
+}
+
+#if RTC_DCHECK_IS_ON && GTEST_HAS_DEATH_TEST && !defined(WEBRTC_ANDROID)
+
+TEST_F(RtpDemuxerDeathTest, CriteriaMustBeNonEmpty) {
+  MockRtpPacketSink sink;
+  RtpDemuxerCriteria criteria;
+  EXPECT_DEATH(AddSink(criteria, &sink), "");
+}
+
+TEST_F(RtpDemuxerDeathTest, RsidMustBeAlphaNumeric) {
+  MockRtpPacketSink sink;
+  EXPECT_DEATH(AddSinkOnlyRsid("a_3", &sink), "");
+}
+
+TEST_F(RtpDemuxerDeathTest, MidMustBeToken) {
+  MockRtpPacketSink sink;
+  EXPECT_DEATH(AddSinkOnlyMid("a(3)", &sink), "");
+}
+
+TEST_F(RtpDemuxerDeathTest, RsidMustNotExceedMaximumLength) {
+  MockRtpPacketSink sink;
+  std::string rsid(BaseRtpStringExtension::kMaxValueSizeBytes + 1, 'a');
+  EXPECT_DEATH(AddSinkOnlyRsid(rsid, &sink), "");
+}
+
+#endif
+
+}  // namespace
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/rtp_interfaces_gn/moz.build b/third_party/libwebrtc/call/rtp_interfaces_gn/moz.build
new file mode 100644
index 0000000000..8e64b72341
--- /dev/null
+++ b/third_party/libwebrtc/call/rtp_interfaces_gn/moz.build
@@ -0,0 +1,232 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+  ### This moz.build was AUTOMATICALLY GENERATED from a GN config,  ###
+  ### DO NOT edit it by hand.                                       ###
+
+COMPILE_FLAGS["OS_INCLUDES"] = []
+AllowCompilerWarnings()
+
+DEFINES["ABSL_ALLOCATOR_NOTHROW"] = "1"
+DEFINES["RTC_DAV1D_IN_INTERNAL_DECODER_FACTORY"] = True
+DEFINES["RTC_ENABLE_VP9"] = True
+DEFINES["WEBRTC_ENABLE_PROTOBUF"] = "0"
+DEFINES["WEBRTC_LIBRARY_IMPL"] = True
+DEFINES["WEBRTC_MOZILLA_BUILD"] = True
+DEFINES["WEBRTC_NON_STATIC_TRACE_EVENT_HANDLERS"] = "0"
+DEFINES["WEBRTC_STRICT_FIELD_TRIALS"] = "0"
+
+FINAL_LIBRARY = "webrtc"
+
+
+LOCAL_INCLUDES += [
+    "!/ipc/ipdl/_ipdlheaders",
+    "!/third_party/libwebrtc/gen",
+    "/ipc/chromium/src",
+    "/third_party/libwebrtc/",
+    "/third_party/libwebrtc/third_party/abseil-cpp/",
+    "/tools/profiler/public"
+]
+
+UNIFIED_SOURCES += [
+    "/third_party/libwebrtc/call/rtp_config.cc"
+]
+
+if not CONFIG["MOZ_DEBUG"]:
+
+    DEFINES["DYNAMIC_ANNOTATIONS_ENABLED"] = "0"
+    DEFINES["NDEBUG"] = True
+    DEFINES["NVALGRIND"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1":
+
+    DEFINES["DYNAMIC_ANNOTATIONS_ENABLED"] = "1"
+
+if CONFIG["OS_TARGET"] == "Android":
+
+    DEFINES["ANDROID"] = True
+    DEFINES["ANDROID_NDK_VERSION_ROLL"] = "r22_1"
+    DEFINES["HAVE_SYS_UIO_H"] = True
+    DEFINES["WEBRTC_ANDROID"] = True
+    DEFINES["WEBRTC_ANDROID_OPENSLES"] = True
+    DEFINES["WEBRTC_LINUX"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_GNU_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+    OS_LIBS += [
+        "log"
+    ]
+
+if CONFIG["OS_TARGET"] == "Darwin":
+
+    DEFINES["WEBRTC_MAC"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_LIBCPP_HAS_NO_ALIGNED_ALLOCATION"] = True
+    DEFINES["__ASSERT_MACROS_DEFINE_VERSIONS_WITHOUT_UNDERSCORES"] = "0"
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+if CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["USE_AURA"] = "1"
+    DEFINES["USE_GLIB"] = "1"
+    DEFINES["USE_NSS_CERTS"] = "1"
+    DEFINES["USE_OZONE"] = "1"
+    DEFINES["USE_UDEV"] = True
+    DEFINES["WEBRTC_LINUX"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_FILE_OFFSET_BITS"] = "64"
+    DEFINES["_LARGEFILE64_SOURCE"] = True
+    DEFINES["_LARGEFILE_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+    OS_LIBS += [
+        "rt"
+    ]
+
+if CONFIG["OS_TARGET"] == "OpenBSD":
+
+    DEFINES["USE_GLIB"] = "1"
+    DEFINES["USE_OZONE"] = "1"
+    DEFINES["USE_X11"] = "1"
+    DEFINES["WEBRTC_BSD"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_FILE_OFFSET_BITS"] = "64"
+    DEFINES["_LARGEFILE64_SOURCE"] = True
+    DEFINES["_LARGEFILE_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+if CONFIG["OS_TARGET"] == "WINNT":
+
+    DEFINES["CERT_CHAIN_PARA_HAS_EXTRA_FIELDS"] = True
+    DEFINES["NOMINMAX"] = True
+    DEFINES["NTDDI_VERSION"] = "0x0A000000"
+    DEFINES["PSAPI_VERSION"] = "2"
+    DEFINES["UNICODE"] = True
+    DEFINES["USE_AURA"] = "1"
+    DEFINES["WEBRTC_WIN"] = True
+    DEFINES["WIN32"] = True
+    DEFINES["WIN32_LEAN_AND_MEAN"] = True
+    DEFINES["WINAPI_FAMILY"] = "WINAPI_FAMILY_DESKTOP_APP"
+    DEFINES["WINVER"] = "0x0A00"
+    DEFINES["_ATL_NO_OPENGL"] = True
+    DEFINES["_CRT_RAND_S"] = True
+    DEFINES["_CRT_SECURE_NO_DEPRECATE"] = True
+    DEFINES["_ENABLE_EXTENDED_ALIGNED_STORAGE"] = True
+    DEFINES["_HAS_EXCEPTIONS"] = "0"
+    DEFINES["_HAS_NODISCARD"] = True
+    DEFINES["_SCL_SECURE_NO_DEPRECATE"] = True
+    DEFINES["_SECURE_ATL"] = True
+    DEFINES["_UNICODE"] = True
+    DEFINES["_WIN32_WINNT"] = "0x0A00"
+    DEFINES["_WINDOWS"] = True
+    DEFINES["__STD_C"] = True
+
+    OS_LIBS += [
+        "crypt32",
+        "iphlpapi",
+        "secur32",
+        "winmm"
+    ]
+
+if CONFIG["CPU_ARCH"] == "aarch64":
+
+    DEFINES["WEBRTC_ARCH_ARM64"] = True
+    DEFINES["WEBRTC_HAS_NEON"] = True
+
+if CONFIG["CPU_ARCH"] == "arm":
+
+    CXXFLAGS += [
+        "-mfpu=neon"
+    ]
+
+    DEFINES["WEBRTC_ARCH_ARM"] = True
+    DEFINES["WEBRTC_ARCH_ARM_V7"] = True
+    DEFINES["WEBRTC_HAS_NEON"] = True
+
+if CONFIG["CPU_ARCH"] == "mips32":
+
+    DEFINES["MIPS32_LE"] = True
+    DEFINES["MIPS_FPU_LE"] = True
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "mips64":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86":
+
+    DEFINES["WEBRTC_ENABLE_AVX2"] = True
+
+if CONFIG["CPU_ARCH"] == "x86_64":
+
+    DEFINES["WEBRTC_ENABLE_AVX2"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Android":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Darwin":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "OpenBSD":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "WINNT":
+
+    DEFINES["_HAS_ITERATOR_DEBUGGING"] = "0"
+
+if CONFIG["MOZ_X11"] == "1" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["USE_X11"] = "1"
+
+if CONFIG["CPU_ARCH"] == "arm" and CONFIG["OS_TARGET"] == "Android":
+
+    OS_LIBS += [
+        "android_support",
+        "unwind"
+    ]
+
+if CONFIG["CPU_ARCH"] == "x86" and CONFIG["OS_TARGET"] == "Android":
+
+    CXXFLAGS += [
+        "-msse2"
+    ]
+
+    OS_LIBS += [
+        "android_support"
+    ]
+
+if CONFIG["CPU_ARCH"] == "aarch64" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "arm" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86" and CONFIG["OS_TARGET"] == "Linux":
+
+    CXXFLAGS += [
+        "-msse2"
+    ]
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86_64" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+Library("rtp_interfaces_gn")
diff --git a/third_party/libwebrtc/call/rtp_packet_sink_interface.h b/third_party/libwebrtc/call/rtp_packet_sink_interface.h
new file mode 100644
index 0000000000..ffbd58c398
--- /dev/null
+++ b/third_party/libwebrtc/call/rtp_packet_sink_interface.h
@@ -0,0 +1,26 @@
+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+#ifndef CALL_RTP_PACKET_SINK_INTERFACE_H_
+#define CALL_RTP_PACKET_SINK_INTERFACE_H_
+
+namespace webrtc {
+
+class RtpPacketReceived;
+
+// This class represents a receiver of already parsed RTP packets.
+class RtpPacketSinkInterface {
+ public:
+  virtual ~RtpPacketSinkInterface() = default;
+  virtual void OnRtpPacket(const RtpPacketReceived& packet) = 0;
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_RTP_PACKET_SINK_INTERFACE_H_
diff --git a/third_party/libwebrtc/call/rtp_payload_params.cc b/third_party/libwebrtc/call/rtp_payload_params.cc
new file mode 100644
index 0000000000..6ff7549901
--- /dev/null
+++ b/third_party/libwebrtc/call/rtp_payload_params.cc
@@ -0,0 +1,750 @@
+/*
+ *  Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/rtp_payload_params.h"
+
+#include <stddef.h>
+
+#include <algorithm>
+
+#include "absl/container/inlined_vector.h"
+#include "absl/strings/match.h"
+#include "absl/types/variant.h"
+#include "api/video/video_timing.h"
+#include "modules/video_coding/codecs/h264/include/h264_globals.h"
+#include "modules/video_coding/codecs/interface/common_constants.h"
+#include "modules/video_coding/codecs/vp8/include/vp8_globals.h"
+#include "modules/video_coding/codecs/vp9/include/vp9_globals.h"
+#include "modules/video_coding/frame_dependencies_calculator.h"
+#include "rtc_base/arraysize.h"
+#include "rtc_base/checks.h"
+#include "rtc_base/logging.h"
+#include "rtc_base/random.h"
+#include "rtc_base/time_utils.h"
+
+namespace webrtc {
+namespace {
+
+constexpr int kMaxSimulatedSpatialLayers = 3;
+
+void PopulateRtpWithCodecSpecifics(const CodecSpecificInfo& info,
+                                   absl::optional<int> spatial_index,
+                                   RTPVideoHeader* rtp) {
+  rtp->codec = info.codecType;
+  rtp->is_last_frame_in_picture = info.end_of_picture;
+  switch (info.codecType) {
+    case kVideoCodecVP8: {
+      auto& vp8_header = rtp->video_type_header.emplace<RTPVideoHeaderVP8>();
+      vp8_header.InitRTPVideoHeaderVP8();
+      vp8_header.nonReference = info.codecSpecific.VP8.nonReference;
+      vp8_header.temporalIdx = info.codecSpecific.VP8.temporalIdx;
+      vp8_header.layerSync = info.codecSpecific.VP8.layerSync;
+      vp8_header.keyIdx = info.codecSpecific.VP8.keyIdx;
+      rtp->simulcastIdx = spatial_index.value_or(0);
+      return;
+    }
+    case kVideoCodecVP9: {
+      auto& vp9_header = rtp->video_type_header.emplace<RTPVideoHeaderVP9>();
+      vp9_header.InitRTPVideoHeaderVP9();
+      vp9_header.inter_pic_predicted =
+          info.codecSpecific.VP9.inter_pic_predicted;
+      vp9_header.flexible_mode = info.codecSpecific.VP9.flexible_mode;
+      vp9_header.ss_data_available = info.codecSpecific.VP9.ss_data_available;
+      vp9_header.non_ref_for_inter_layer_pred =
+          info.codecSpecific.VP9.non_ref_for_inter_layer_pred;
+      vp9_header.temporal_idx = info.codecSpecific.VP9.temporal_idx;
+      vp9_header.temporal_up_switch = info.codecSpecific.VP9.temporal_up_switch;
+      vp9_header.inter_layer_predicted =
+          info.codecSpecific.VP9.inter_layer_predicted;
+      vp9_header.gof_idx = info.codecSpecific.VP9.gof_idx;
+      vp9_header.num_spatial_layers = info.codecSpecific.VP9.num_spatial_layers;
+      vp9_header.first_active_layer = info.codecSpecific.VP9.first_active_layer;
+      if (vp9_header.num_spatial_layers > 1) {
+        vp9_header.spatial_idx = spatial_index.value_or(kNoSpatialIdx);
+      } else {
+        vp9_header.spatial_idx = kNoSpatialIdx;
+      }
+      if (info.codecSpecific.VP9.ss_data_available) {
+        vp9_header.spatial_layer_resolution_present =
+            info.codecSpecific.VP9.spatial_layer_resolution_present;
+        if (info.codecSpecific.VP9.spatial_layer_resolution_present) {
+          for (size_t i = 0; i < info.codecSpecific.VP9.num_spatial_layers;
+               ++i) {
+            vp9_header.width[i] = info.codecSpecific.VP9.width[i];
+            vp9_header.height[i] = info.codecSpecific.VP9.height[i];
+          }
+        }
+        vp9_header.gof.CopyGofInfoVP9(info.codecSpecific.VP9.gof);
+      }
+
+      vp9_header.num_ref_pics = info.codecSpecific.VP9.num_ref_pics;
+      for (int i = 0; i < info.codecSpecific.VP9.num_ref_pics; ++i) {
+        vp9_header.pid_diff[i] = info.codecSpecific.VP9.p_diff[i];
+      }
+      vp9_header.end_of_picture = info.end_of_picture;
+      return;
+    }
+    case kVideoCodecH264: {
+      auto& h264_header = rtp->video_type_header.emplace<RTPVideoHeaderH264>();
+      h264_header.packetization_mode =
+          info.codecSpecific.H264.packetization_mode;
+      rtp->simulcastIdx = spatial_index.value_or(0);
+      return;
+    }
+    case kVideoCodecMultiplex:
+    case kVideoCodecGeneric:
+      rtp->codec = kVideoCodecGeneric;
+      rtp->simulcastIdx = spatial_index.value_or(0);
+      return;
+    default:
+      return;
+  }
+}
+
+void SetVideoTiming(const EncodedImage& image, VideoSendTiming* timing) {
+  if (image.timing_.flags == VideoSendTiming::TimingFrameFlags::kInvalid ||
+      image.timing_.flags == VideoSendTiming::TimingFrameFlags::kNotTriggered) {
+    timing->flags = VideoSendTiming::TimingFrameFlags::kInvalid;
+    return;
+  }
+
+  timing->encode_start_delta_ms = VideoSendTiming::GetDeltaCappedMs(
+      image.capture_time_ms_, image.timing_.encode_start_ms);
+  timing->encode_finish_delta_ms = VideoSendTiming::GetDeltaCappedMs(
+      image.capture_time_ms_, image.timing_.encode_finish_ms);
+  timing->packetization_finish_delta_ms = 0;
+  timing->pacer_exit_delta_ms = 0;
+  timing->network_timestamp_delta_ms = 0;
+  timing->network2_timestamp_delta_ms = 0;
+  timing->flags = image.timing_.flags;
+}
+
+// Returns structure that aligns with simulated generic info. The templates
+// allow to produce valid dependency descriptor for any stream where
+// `num_spatial_layers` * `num_temporal_layers` <= 32 (limited by
+// https://aomediacodec.github.io/av1-rtp-spec/#a82-syntax, see
+// template_fdiffs()). The set of the templates is not tuned for any paricular
+// structure thus dependency descriptor would use more bytes on the wire than
+// with tuned templates.
+FrameDependencyStructure MinimalisticStructure(int num_spatial_layers,
+                                               int num_temporal_layers) {
+  RTC_DCHECK_LE(num_spatial_layers, DependencyDescriptor::kMaxSpatialIds);
+  RTC_DCHECK_LE(num_temporal_layers, DependencyDescriptor::kMaxTemporalIds);
+  RTC_DCHECK_LE(num_spatial_layers * num_temporal_layers, 32);
+  FrameDependencyStructure structure;
+  structure.num_decode_targets = num_spatial_layers * num_temporal_layers;
+  structure.num_chains = num_spatial_layers;
+  structure.templates.reserve(num_spatial_layers * num_temporal_layers);
+  for (int sid = 0; sid < num_spatial_layers; ++sid) {
+    for (int tid = 0; tid < num_temporal_layers; ++tid) {
+      FrameDependencyTemplate a_template;
+      a_template.spatial_id = sid;
+      a_template.temporal_id = tid;
+      for (int s = 0; s < num_spatial_layers; ++s) {
+        for (int t = 0; t < num_temporal_layers; ++t) {
+          // Prefer kSwitch indication for frames that is part of the decode
+          // target because dependency descriptor information generated in this
+          // class use kSwitch indications more often that kRequired, increasing
+          // the chance of a good (or complete) template match.
+          a_template.decode_target_indications.push_back(
+              sid <= s && tid <= t ? DecodeTargetIndication::kSwitch
+                                   : DecodeTargetIndication::kNotPresent);
+        }
+      }
+      a_template.frame_diffs.push_back(tid == 0 ? num_spatial_layers *
+                                                      num_temporal_layers
+                                                : num_spatial_layers);
+      a_template.chain_diffs.assign(structure.num_chains, 1);
+      structure.templates.push_back(a_template);
+
+      structure.decode_target_protected_by_chain.push_back(sid);
+    }
+  }
+  return structure;
+}
+}  // namespace
+
+RtpPayloadParams::RtpPayloadParams(const uint32_t ssrc,
+                                   const RtpPayloadState* state,
+                                   const FieldTrialsView& trials)
+    : ssrc_(ssrc),
+      generic_picture_id_experiment_(
+          absl::StartsWith(trials.Lookup("WebRTC-GenericPictureId"),
+                           "Enabled")),
+      simulate_generic_structure_(absl::StartsWith(
+          trials.Lookup("WebRTC-GenericCodecDependencyDescriptor"),
+          "Enabled")) {
+  for (auto& spatial_layer : last_shared_frame_id_)
+    spatial_layer.fill(-1);
+
+  chain_last_frame_id_.fill(-1);
+  buffer_id_to_frame_id_.fill(-1);
+
+  Random random(rtc::TimeMicros());
+  state_.picture_id =
+      state ? state->picture_id : (random.Rand<int16_t>() & 0x7FFF);
+  state_.tl0_pic_idx = state ? state->tl0_pic_idx : (random.Rand<uint8_t>());
+}
+
+RtpPayloadParams::RtpPayloadParams(const RtpPayloadParams& other) = default;
+
+RtpPayloadParams::~RtpPayloadParams() {}
+
+RTPVideoHeader RtpPayloadParams::GetRtpVideoHeader(
+    const EncodedImage& image,
+    const CodecSpecificInfo* codec_specific_info,
+    int64_t shared_frame_id) {
+  RTPVideoHeader rtp_video_header;
+  if (codec_specific_info) {
+    PopulateRtpWithCodecSpecifics(*codec_specific_info, image.SpatialIndex(),
+                                  &rtp_video_header);
+  }
+  rtp_video_header.frame_type = image._frameType;
+  rtp_video_header.rotation = image.rotation_;
+  rtp_video_header.content_type = image.content_type_;
+  rtp_video_header.playout_delay = image.playout_delay_;
+  rtp_video_header.width = image._encodedWidth;
+  rtp_video_header.height = image._encodedHeight;
+  rtp_video_header.color_space = image.ColorSpace()
+                                     ? absl::make_optional(*image.ColorSpace())
+                                     : absl::nullopt;
+  rtp_video_header.video_frame_tracking_id = image.VideoFrameTrackingId();
+  SetVideoTiming(image, &rtp_video_header.video_timing);
+
+  const bool is_keyframe = image._frameType == VideoFrameType::kVideoFrameKey;
+  const bool first_frame_in_picture =
+      (codec_specific_info && codec_specific_info->codecType == kVideoCodecVP9)
+          ? codec_specific_info->codecSpecific.VP9.first_frame_in_picture
+          : true;
+
+  SetCodecSpecific(&rtp_video_header, first_frame_in_picture);
+
+  SetGeneric(codec_specific_info, shared_frame_id, is_keyframe,
+             &rtp_video_header);
+
+  return rtp_video_header;
+}
+
+uint32_t RtpPayloadParams::ssrc() const {
+  return ssrc_;
+}
+
+RtpPayloadState RtpPayloadParams::state() const {
+  return state_;
+}
+
+void RtpPayloadParams::SetCodecSpecific(RTPVideoHeader* rtp_video_header,
+                                        bool first_frame_in_picture) {
+  // Always set picture id. Set tl0_pic_idx iff temporal index is set.
+  if (first_frame_in_picture) {
+    state_.picture_id = (static_cast<uint16_t>(state_.picture_id) + 1) & 0x7FFF;
+  }
+  if (rtp_video_header->codec == kVideoCodecVP8) {
+    auto& vp8_header =
+        absl::get<RTPVideoHeaderVP8>(rtp_video_header->video_type_header);
+    vp8_header.pictureId = state_.picture_id;
+
+    if (vp8_header.temporalIdx != kNoTemporalIdx) {
+      if (vp8_header.temporalIdx == 0) {
+        ++state_.tl0_pic_idx;
+      }
+      vp8_header.tl0PicIdx = state_.tl0_pic_idx;
+    }
+  }
+  if (rtp_video_header->codec == kVideoCodecVP9) {
+    auto& vp9_header =
+        absl::get<RTPVideoHeaderVP9>(rtp_video_header->video_type_header);
+    vp9_header.picture_id = state_.picture_id;
+
+    // Note that in the case that we have no temporal layers but we do have
+    // spatial layers, packets will carry layering info with a temporal_idx of
+    // zero, and we then have to set and increment tl0_pic_idx.
+    if (vp9_header.temporal_idx != kNoTemporalIdx ||
+        vp9_header.spatial_idx != kNoSpatialIdx) {
+      if (first_frame_in_picture &&
+          (vp9_header.temporal_idx == 0 ||
+           vp9_header.temporal_idx == kNoTemporalIdx)) {
+        ++state_.tl0_pic_idx;
+      }
+      vp9_header.tl0_pic_idx = state_.tl0_pic_idx;
+    }
+  }
+  if (generic_picture_id_experiment_ &&
+      rtp_video_header->codec == kVideoCodecGeneric) {
+    rtp_video_header->video_type_header.emplace<RTPVideoHeaderLegacyGeneric>()
+        .picture_id = state_.picture_id;
+  }
+}
+
+RTPVideoHeader::GenericDescriptorInfo
+RtpPayloadParams::GenericDescriptorFromFrameInfo(
+    const GenericFrameInfo& frame_info,
+    int64_t frame_id) {
+  RTPVideoHeader::GenericDescriptorInfo generic;
+  generic.frame_id = frame_id;
+  generic.dependencies = dependencies_calculator_.FromBuffersUsage(
+      frame_id, frame_info.encoder_buffers);
+  generic.chain_diffs =
+      chains_calculator_.From(frame_id, frame_info.part_of_chain);
+  generic.spatial_index = frame_info.spatial_id;
+  generic.temporal_index = frame_info.temporal_id;
+  generic.decode_target_indications = frame_info.decode_target_indications;
+  generic.active_decode_targets = frame_info.active_decode_targets;
+  return generic;
+}
+
+void RtpPayloadParams::SetGeneric(const CodecSpecificInfo* codec_specific_info,
+                                  int64_t frame_id,
+                                  bool is_keyframe,
+                                  RTPVideoHeader* rtp_video_header) {
+  if (codec_specific_info && codec_specific_info->generic_frame_info &&
+      !codec_specific_info->generic_frame_info->encoder_buffers.empty()) {
+    if (is_keyframe) {
+      // Key frame resets all chains it is in.
+      chains_calculator_.Reset(
+          codec_specific_info->generic_frame_info->part_of_chain);
+    }
+    rtp_video_header->generic = GenericDescriptorFromFrameInfo(
+        *codec_specific_info->generic_frame_info, frame_id);
+    return;
+  }
+
+  switch (rtp_video_header->codec) {
+    case VideoCodecType::kVideoCodecGeneric:
+      GenericToGeneric(frame_id, is_keyframe, rtp_video_header);
+      return;
+    case VideoCodecType::kVideoCodecVP8:
+      if (codec_specific_info) {
+        Vp8ToGeneric(codec_specific_info->codecSpecific.VP8, frame_id,
+                     is_keyframe, rtp_video_header);
+      }
+      return;
+    case VideoCodecType::kVideoCodecVP9:
+      if (codec_specific_info != nullptr) {
+        Vp9ToGeneric(codec_specific_info->codecSpecific.VP9, frame_id,
+                     *rtp_video_header);
+      }
+      return;
+    case VideoCodecType::kVideoCodecAV1:
+      // TODO(philipel): Implement AV1 to generic descriptor.
+      return;
+    case VideoCodecType::kVideoCodecH264:
+      if (codec_specific_info) {
+        H264ToGeneric(codec_specific_info->codecSpecific.H264, frame_id,
+                      is_keyframe, rtp_video_header);
+      }
+      return;
+    case VideoCodecType::kVideoCodecMultiplex:
+      return;
+  }
+  RTC_DCHECK_NOTREACHED() << "Unsupported codec.";
+}
+
+absl::optional<FrameDependencyStructure> RtpPayloadParams::GenericStructure(
+    const CodecSpecificInfo* codec_specific_info) {
+  if (codec_specific_info == nullptr) {
+    return absl::nullopt;
+  }
+  // This helper shouldn't be used when template structure is specified
+  // explicetly.
+  RTC_DCHECK(!codec_specific_info->template_structure.has_value());
+  switch (codec_specific_info->codecType) {
+    case VideoCodecType::kVideoCodecGeneric:
+      if (simulate_generic_structure_) {
+        return MinimalisticStructure(/*num_spatial_layers=*/1,
+                                     /*num_temporal_layer=*/1);
+      }
+      return absl::nullopt;
+    case VideoCodecType::kVideoCodecVP8:
+      return MinimalisticStructure(/*num_spatial_layers=*/1,
+                                   /*num_temporal_layer=*/kMaxTemporalStreams);
+    case VideoCodecType::kVideoCodecVP9: {
+      absl::optional<FrameDependencyStructure> structure =
+          MinimalisticStructure(
+              /*num_spatial_layers=*/kMaxSimulatedSpatialLayers,
+              /*num_temporal_layer=*/kMaxTemporalStreams);
+      const CodecSpecificInfoVP9& vp9 = codec_specific_info->codecSpecific.VP9;
+      if (vp9.ss_data_available && vp9.spatial_layer_resolution_present) {
+        RenderResolution first_valid;
+        RenderResolution last_valid;
+        for (size_t i = 0; i < vp9.num_spatial_layers; ++i) {
+          RenderResolution r(vp9.width[i], vp9.height[i]);
+          if (r.Valid()) {
+            if (!first_valid.Valid()) {
+              first_valid = r;
+            }
+            last_valid = r;
+          }
+          structure->resolutions.push_back(r);
+        }
+        if (!last_valid.Valid()) {
+          // No valid resolution found. Do not send resolutions.
+          structure->resolutions.clear();
+        } else {
+          structure->resolutions.resize(kMaxSimulatedSpatialLayers, last_valid);
+          // VP9 encoder wrapper may disable first few spatial layers by
+          // setting invalid resolution (0,0). `structure->resolutions`
+          // doesn't support invalid resolution, so reset them to something
+          // valid.
+          for (RenderResolution& r : structure->resolutions) {
+            if (!r.Valid()) {
+              r = first_valid;
+            }
+          }
+        }
+      }
+      return structure;
+    }
+    case VideoCodecType::kVideoCodecAV1:
+    case VideoCodecType::kVideoCodecH264:
+    case VideoCodecType::kVideoCodecMultiplex:
+      return absl::nullopt;
+  }
+  RTC_DCHECK_NOTREACHED() << "Unsupported codec.";
+}
+
+void RtpPayloadParams::GenericToGeneric(int64_t shared_frame_id,
+                                        bool is_keyframe,
+                                        RTPVideoHeader* rtp_video_header) {
+  RTPVideoHeader::GenericDescriptorInfo& generic =
+      rtp_video_header->generic.emplace();
+
+  generic.frame_id = shared_frame_id;
+  generic.decode_target_indications.push_back(DecodeTargetIndication::kSwitch);
+
+  if (is_keyframe) {
+    generic.chain_diffs.push_back(0);
+    last_shared_frame_id_[0].fill(-1);
+  } else {
+    int64_t frame_id = last_shared_frame_id_[0][0];
+    RTC_DCHECK_NE(frame_id, -1);
+    RTC_DCHECK_LT(frame_id, shared_frame_id);
+    generic.chain_diffs.push_back(shared_frame_id - frame_id);
+    generic.dependencies.push_back(frame_id);
+  }
+
+  last_shared_frame_id_[0][0] = shared_frame_id;
+}
+
+void RtpPayloadParams::H264ToGeneric(const CodecSpecificInfoH264& h264_info,
+                                     int64_t shared_frame_id,
+                                     bool is_keyframe,
+                                     RTPVideoHeader* rtp_video_header) {
+  const int temporal_index =
+      h264_info.temporal_idx != kNoTemporalIdx ? h264_info.temporal_idx : 0;
+
+  if (temporal_index >= RtpGenericFrameDescriptor::kMaxTemporalLayers) {
+    RTC_LOG(LS_WARNING) << "Temporal and/or spatial index is too high to be "
+                           "used with generic frame descriptor.";
+    return;
+  }
+
+  RTPVideoHeader::GenericDescriptorInfo& generic =
+      rtp_video_header->generic.emplace();
+
+  generic.frame_id = shared_frame_id;
+  generic.temporal_index = temporal_index;
+
+  if (is_keyframe) {
+    RTC_DCHECK_EQ(temporal_index, 0);
+    last_shared_frame_id_[/*spatial index*/ 0].fill(-1);
+    last_shared_frame_id_[/*spatial index*/ 0][temporal_index] =
+        shared_frame_id;
+    return;
+  }
+
+  if (h264_info.base_layer_sync) {
+    int64_t tl0_frame_id = last_shared_frame_id_[/*spatial index*/ 0][0];
+
+    for (int i = 1; i < RtpGenericFrameDescriptor::kMaxTemporalLayers; ++i) {
+      if (last_shared_frame_id_[/*spatial index*/ 0][i] < tl0_frame_id) {
+        last_shared_frame_id_[/*spatial index*/ 0][i] = -1;
+      }
+    }
+
+    RTC_DCHECK_GE(tl0_frame_id, 0);
+    RTC_DCHECK_LT(tl0_frame_id, shared_frame_id);
+    generic.dependencies.push_back(tl0_frame_id);
+  } else {
+    for (int i = 0; i <= temporal_index; ++i) {
+      int64_t frame_id = last_shared_frame_id_[/*spatial index*/ 0][i];
+
+      if (frame_id != -1) {
+        RTC_DCHECK_LT(frame_id, shared_frame_id);
+        generic.dependencies.push_back(frame_id);
+      }
+    }
+  }
+
+  last_shared_frame_id_[/*spatial_index*/ 0][temporal_index] = shared_frame_id;
+}
+
+void RtpPayloadParams::Vp8ToGeneric(const CodecSpecificInfoVP8& vp8_info,
+                                    int64_t shared_frame_id,
+                                    bool is_keyframe,
+                                    RTPVideoHeader* rtp_video_header) {
+  const auto& vp8_header =
+      absl::get<RTPVideoHeaderVP8>(rtp_video_header->video_type_header);
+  const int spatial_index = 0;
+  const int temporal_index =
+      vp8_header.temporalIdx != kNoTemporalIdx ? vp8_header.temporalIdx : 0;
+
+  if (temporal_index >= RtpGenericFrameDescriptor::kMaxTemporalLayers ||
+      spatial_index >= RtpGenericFrameDescriptor::kMaxSpatialLayers) {
+    RTC_LOG(LS_WARNING) << "Temporal and/or spatial index is too high to be "
+                           "used with generic frame descriptor.";
+    return;
+  }
+
+  RTPVideoHeader::GenericDescriptorInfo& generic =
+      rtp_video_header->generic.emplace();
+
+  generic.frame_id = shared_frame_id;
+  generic.spatial_index = spatial_index;
+  generic.temporal_index = temporal_index;
+
+  // Generate decode target indications.
+  RTC_DCHECK_LT(temporal_index, kMaxTemporalStreams);
+  generic.decode_target_indications.resize(kMaxTemporalStreams);
+  auto it = std::fill_n(generic.decode_target_indications.begin(),
+                        temporal_index, DecodeTargetIndication::kNotPresent);
+  std::fill(it, generic.decode_target_indications.end(),
+            DecodeTargetIndication::kSwitch);
+
+  // Frame dependencies.
+  if (vp8_info.useExplicitDependencies) {
+    SetDependenciesVp8New(vp8_info, shared_frame_id, is_keyframe,
+                          vp8_header.layerSync, &generic);
+  } else {
+    SetDependenciesVp8Deprecated(vp8_info, shared_frame_id, is_keyframe,
+                                 spatial_index, temporal_index,
+                                 vp8_header.layerSync, &generic);
+  }
+
+  // Calculate chains.
+  generic.chain_diffs = {
+      (is_keyframe || chain_last_frame_id_[0] < 0)
+          ? 0
+          : static_cast<int>(shared_frame_id - chain_last_frame_id_[0])};
+  if (temporal_index == 0) {
+    chain_last_frame_id_[0] = shared_frame_id;
+  }
+}
+
+void RtpPayloadParams::Vp9ToGeneric(const CodecSpecificInfoVP9& vp9_info,
+                                    int64_t shared_frame_id,
+                                    RTPVideoHeader& rtp_video_header) {
+  const auto& vp9_header =
+      absl::get<RTPVideoHeaderVP9>(rtp_video_header.video_type_header);
+  const int num_spatial_layers = kMaxSimulatedSpatialLayers;
+  const int num_active_spatial_layers = vp9_header.num_spatial_layers;
+  const int num_temporal_layers = kMaxTemporalStreams;
+  static_assert(num_spatial_layers <=
+                RtpGenericFrameDescriptor::kMaxSpatialLayers);
+  static_assert(num_temporal_layers <=
+                RtpGenericFrameDescriptor::kMaxTemporalLayers);
+  static_assert(num_spatial_layers <= DependencyDescriptor::kMaxSpatialIds);
+  static_assert(num_temporal_layers <= DependencyDescriptor::kMaxTemporalIds);
+
+  int spatial_index =
+      vp9_header.spatial_idx != kNoSpatialIdx ? vp9_header.spatial_idx : 0;
+  int temporal_index =
+      vp9_header.temporal_idx != kNoTemporalIdx ? vp9_header.temporal_idx : 0;
+
+  if (spatial_index >= num_spatial_layers ||
+      temporal_index >= num_temporal_layers ||
+      num_active_spatial_layers > num_spatial_layers) {
+    // Prefer to generate no generic layering than an inconsistent one.
+    return;
+  }
+
+  RTPVideoHeader::GenericDescriptorInfo& result =
+      rtp_video_header.generic.emplace();
+
+  result.frame_id = shared_frame_id;
+  result.spatial_index = spatial_index;
+  result.temporal_index = temporal_index;
+
+  result.decode_target_indications.reserve(num_spatial_layers *
+                                           num_temporal_layers);
+  for (int sid = 0; sid < num_spatial_layers; ++sid) {
+    for (int tid = 0; tid < num_temporal_layers; ++tid) {
+      DecodeTargetIndication dti;
+      if (sid < spatial_index || tid < temporal_index) {
+        dti = DecodeTargetIndication::kNotPresent;
+      } else if (spatial_index != sid &&
+                 vp9_header.non_ref_for_inter_layer_pred) {
+        dti = DecodeTargetIndication::kNotPresent;
+      } else if (sid == spatial_index && tid == temporal_index) {
+        // Assume that if frame is decodable, all of its own layer is decodable.
+        dti = DecodeTargetIndication::kSwitch;
+      } else if (sid == spatial_index && vp9_header.temporal_up_switch) {
+        dti = DecodeTargetIndication::kSwitch;
+      } else if (!vp9_header.inter_pic_predicted) {
+        // Key frame or spatial upswitch
+        dti = DecodeTargetIndication::kSwitch;
+      } else {
+        // Make no other assumptions. That should be safe, though suboptimal.
+        // To provide more accurate dti, encoder wrapper should fill in
+        // CodecSpecificInfo::generic_frame_info
+        dti = DecodeTargetIndication::kRequired;
+      }
+      result.decode_target_indications.push_back(dti);
+    }
+  }
+
+  // Calculate frame dependencies.
+  static constexpr int kPictureDiffLimit = 128;
+  if (last_vp9_frame_id_.empty()) {
+    // Create the array only if it is ever used.
+    last_vp9_frame_id_.resize(kPictureDiffLimit);
+  }
+  if (vp9_header.inter_layer_predicted && spatial_index > 0) {
+    result.dependencies.push_back(
+        last_vp9_frame_id_[vp9_header.picture_id % kPictureDiffLimit]
+                          [spatial_index - 1]);
+  }
+  if (vp9_header.inter_pic_predicted) {
+    for (size_t i = 0; i < vp9_header.num_ref_pics; ++i) {
+      // picture_id is 15 bit number that wraps around. Though undeflow may
+      // produce picture that exceeds 2^15, it is ok because in this
+      // code block only last 7 bits of the picture_id are used.
+      uint16_t depend_on = vp9_header.picture_id - vp9_header.pid_diff[i];
+      result.dependencies.push_back(
+          last_vp9_frame_id_[depend_on % kPictureDiffLimit][spatial_index]);
+    }
+  }
+  last_vp9_frame_id_[vp9_header.picture_id % kPictureDiffLimit][spatial_index] =
+      shared_frame_id;
+
+  result.active_decode_targets =
+      ((uint32_t{1} << num_temporal_layers * num_active_spatial_layers) - 1);
+
+  // Calculate chains, asuming chain includes all frames with temporal_id = 0
+  if (!vp9_header.inter_pic_predicted && !vp9_header.inter_layer_predicted) {
+    // Assume frames without dependencies also reset chains.
+    for (int sid = spatial_index; sid < num_spatial_layers; ++sid) {
+      chain_last_frame_id_[sid] = -1;
+    }
+  }
+  result.chain_diffs.resize(num_spatial_layers, 0);
+  for (int sid = 0; sid < num_active_spatial_layers; ++sid) {
+    if (chain_last_frame_id_[sid] == -1) {
+      result.chain_diffs[sid] = 0;
+      continue;
+    }
+    result.chain_diffs[sid] = shared_frame_id - chain_last_frame_id_[sid];
+  }
+
+  if (temporal_index == 0) {
+    chain_last_frame_id_[spatial_index] = shared_frame_id;
+    if (!vp9_header.non_ref_for_inter_layer_pred) {
+      for (int sid = spatial_index + 1; sid < num_spatial_layers; ++sid) {
+        chain_last_frame_id_[sid] = shared_frame_id;
+      }
+    }
+  }
+}
+
+void RtpPayloadParams::SetDependenciesVp8Deprecated(
+    const CodecSpecificInfoVP8& vp8_info,
+    int64_t shared_frame_id,
+    bool is_keyframe,
+    int spatial_index,
+    int temporal_index,
+    bool layer_sync,
+    RTPVideoHeader::GenericDescriptorInfo* generic) {
+  RTC_DCHECK(!vp8_info.useExplicitDependencies);
+  RTC_DCHECK(!new_version_used_.has_value() || !new_version_used_.value());
+  new_version_used_ = false;
+
+  if (is_keyframe) {
+    RTC_DCHECK_EQ(temporal_index, 0);
+    last_shared_frame_id_[spatial_index].fill(-1);
+    last_shared_frame_id_[spatial_index][temporal_index] = shared_frame_id;
+    return;
+  }
+
+  if (layer_sync) {
+    int64_t tl0_frame_id = last_shared_frame_id_[spatial_index][0];
+
+    for (int i = 1; i < RtpGenericFrameDescriptor::kMaxTemporalLayers; ++i) {
+      if (last_shared_frame_id_[spatial_index][i] < tl0_frame_id) {
+        last_shared_frame_id_[spatial_index][i] = -1;
+      }
+    }
+
+    RTC_DCHECK_GE(tl0_frame_id, 0);
+    RTC_DCHECK_LT(tl0_frame_id, shared_frame_id);
+    generic->dependencies.push_back(tl0_frame_id);
+  } else {
+    for (int i = 0; i <= temporal_index; ++i) {
+      int64_t frame_id = last_shared_frame_id_[spatial_index][i];
+
+      if (frame_id != -1) {
+        RTC_DCHECK_LT(frame_id, shared_frame_id);
+        generic->dependencies.push_back(frame_id);
+      }
+    }
+  }
+
+  last_shared_frame_id_[spatial_index][temporal_index] = shared_frame_id;
+}
+
+void RtpPayloadParams::SetDependenciesVp8New(
+    const CodecSpecificInfoVP8& vp8_info,
+    int64_t shared_frame_id,
+    bool is_keyframe,
+    bool layer_sync,
+    RTPVideoHeader::GenericDescriptorInfo* generic) {
+  RTC_DCHECK(vp8_info.useExplicitDependencies);
+  RTC_DCHECK(!new_version_used_.has_value() || new_version_used_.value());
+  new_version_used_ = true;
+
+  if (is_keyframe) {
+    RTC_DCHECK_EQ(vp8_info.referencedBuffersCount, 0u);
+    buffer_id_to_frame_id_.fill(shared_frame_id);
+    return;
+  }
+
+  constexpr size_t kBuffersCountVp8 = CodecSpecificInfoVP8::kBuffersCount;
+
+  RTC_DCHECK_GT(vp8_info.referencedBuffersCount, 0u);
+  RTC_DCHECK_LE(vp8_info.referencedBuffersCount,
+                arraysize(vp8_info.referencedBuffers));
+
+  for (size_t i = 0; i < vp8_info.referencedBuffersCount; ++i) {
+    const size_t referenced_buffer = vp8_info.referencedBuffers[i];
+    RTC_DCHECK_LT(referenced_buffer, kBuffersCountVp8);
+    RTC_DCHECK_LT(referenced_buffer, buffer_id_to_frame_id_.size());
+
+    const int64_t dependency_frame_id =
+        buffer_id_to_frame_id_[referenced_buffer];
+    RTC_DCHECK_GE(dependency_frame_id, 0);
+    RTC_DCHECK_LT(dependency_frame_id, shared_frame_id);
+
+    const bool is_new_dependency =
+        std::find(generic->dependencies.begin(), generic->dependencies.end(),
+                  dependency_frame_id) == generic->dependencies.end();
+    if (is_new_dependency) {
+      generic->dependencies.push_back(dependency_frame_id);
+    }
+  }
+
+  RTC_DCHECK_LE(vp8_info.updatedBuffersCount, kBuffersCountVp8);
+  for (size_t i = 0; i < vp8_info.updatedBuffersCount; ++i) {
+    const size_t updated_id = vp8_info.updatedBuffers[i];
+    buffer_id_to_frame_id_[updated_id] = shared_frame_id;
+  }
+
+  RTC_DCHECK_LE(buffer_id_to_frame_id_.size(), kBuffersCountVp8);
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/rtp_payload_params.h b/third_party/libwebrtc/call/rtp_payload_params.h
new file mode 100644
index 0000000000..5feee11ab0
--- /dev/null
+++ b/third_party/libwebrtc/call/rtp_payload_params.h
@@ -0,0 +1,134 @@
+/*
+ *  Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_RTP_PAYLOAD_PARAMS_H_
+#define CALL_RTP_PAYLOAD_PARAMS_H_
+
+#include <array>
+#include <vector>
+
+#include "absl/types/optional.h"
+#include "api/field_trials_view.h"
+#include "api/video_codecs/video_encoder.h"
+#include "call/rtp_config.h"
+#include "modules/rtp_rtcp/source/rtp_generic_frame_descriptor.h"
+#include "modules/rtp_rtcp/source/rtp_video_header.h"
+#include "modules/video_coding/chain_diff_calculator.h"
+#include "modules/video_coding/frame_dependencies_calculator.h"
+#include "modules/video_coding/include/video_codec_interface.h"
+
+namespace webrtc {
+
+// State for setting picture id and tl0 pic idx, for VP8 and VP9
+// TODO(nisse): Make these properties not codec specific.
+class RtpPayloadParams final {
+ public:
+  RtpPayloadParams(uint32_t ssrc,
+                   const RtpPayloadState* state,
+                   const FieldTrialsView& trials);
+  RtpPayloadParams(const RtpPayloadParams& other);
+  ~RtpPayloadParams();
+
+  RTPVideoHeader GetRtpVideoHeader(const EncodedImage& image,
+                                   const CodecSpecificInfo* codec_specific_info,
+                                   int64_t shared_frame_id);
+
+  // Returns structure that aligns with simulated generic info generated by
+  // `GetRtpVideoHeader` for the `codec_specific_info`
+  absl::optional<FrameDependencyStructure> GenericStructure(
+      const CodecSpecificInfo* codec_specific_info);
+
+  uint32_t ssrc() const;
+
+  RtpPayloadState state() const;
+
+ private:
+  void SetCodecSpecific(RTPVideoHeader* rtp_video_header,
+                        bool first_frame_in_picture);
+  RTPVideoHeader::GenericDescriptorInfo GenericDescriptorFromFrameInfo(
+      const GenericFrameInfo& frame_info,
+      int64_t frame_id);
+  void SetGeneric(const CodecSpecificInfo* codec_specific_info,
+                  int64_t frame_id,
+                  bool is_keyframe,
+                  RTPVideoHeader* rtp_video_header);
+
+  void Vp8ToGeneric(const CodecSpecificInfoVP8& vp8_info,
+                    int64_t shared_frame_id,
+                    bool is_keyframe,
+                    RTPVideoHeader* rtp_video_header);
+
+  void Vp9ToGeneric(const CodecSpecificInfoVP9& vp9_info,
+                    int64_t shared_frame_id,
+                    RTPVideoHeader& rtp_video_header);
+
+  void H264ToGeneric(const CodecSpecificInfoH264& h264_info,
+                     int64_t shared_frame_id,
+                     bool is_keyframe,
+                     RTPVideoHeader* rtp_video_header);
+
+  void GenericToGeneric(int64_t shared_frame_id,
+                        bool is_keyframe,
+                        RTPVideoHeader* rtp_video_header);
+
+  // TODO(bugs.webrtc.org/10242): Delete SetDependenciesVp8Deprecated() and move
+  // the logic in SetDependenciesVp8New() into Vp8ToGeneric() once all hardware
+  // wrappers have been updated.
+  void SetDependenciesVp8Deprecated(
+      const CodecSpecificInfoVP8& vp8_info,
+      int64_t shared_frame_id,
+      bool is_keyframe,
+      int spatial_index,
+      int temporal_index,
+      bool layer_sync,
+      RTPVideoHeader::GenericDescriptorInfo* generic);
+  void SetDependenciesVp8New(const CodecSpecificInfoVP8& vp8_info,
+                             int64_t shared_frame_id,
+                             bool is_keyframe,
+                             bool layer_sync,
+                             RTPVideoHeader::GenericDescriptorInfo* generic);
+
+  FrameDependenciesCalculator dependencies_calculator_;
+  ChainDiffCalculator chains_calculator_;
+  // TODO(bugs.webrtc.org/10242): Remove once all encoder-wrappers are updated.
+  // Holds the last shared frame id for a given (spatial, temporal) layer.
+  std::array<std::array<int64_t, RtpGenericFrameDescriptor::kMaxTemporalLayers>,
+             RtpGenericFrameDescriptor::kMaxSpatialLayers>
+      last_shared_frame_id_;
+  // circular buffer of frame ids for the last 128 vp9 pictures.
+  // ids for the `picture_id` are stored at the index `picture_id % 128`.
+  std::vector<std::array<int64_t, RtpGenericFrameDescriptor::kMaxSpatialLayers>>
+      last_vp9_frame_id_;
+  // Last frame id for each chain
+  std::array<int64_t, RtpGenericFrameDescriptor::kMaxSpatialLayers>
+      chain_last_frame_id_;
+
+  // TODO(eladalon): When additional codecs are supported,
+  // set kMaxCodecBuffersCount to the max() of these codecs' buffer count.
+  static constexpr size_t kMaxCodecBuffersCount =
+      CodecSpecificInfoVP8::kBuffersCount;
+
+  // Maps buffer IDs to the frame-ID stored in them.
+  std::array<int64_t, kMaxCodecBuffersCount> buffer_id_to_frame_id_;
+
+  // Until we remove SetDependenciesVp8Deprecated(), we should make sure
+  // that, for a given object, we either always use
+  // SetDependenciesVp8Deprecated(), or always use SetDependenciesVp8New().
+  // TODO(bugs.webrtc.org/10242): Remove.
+  absl::optional<bool> new_version_used_;
+
+  const uint32_t ssrc_;
+  RtpPayloadState state_;
+
+  const bool generic_picture_id_experiment_;
+  const bool simulate_generic_structure_;
+};
+}  // namespace webrtc
+#endif  // CALL_RTP_PAYLOAD_PARAMS_H_
diff --git a/third_party/libwebrtc/call/rtp_payload_params_unittest.cc b/third_party/libwebrtc/call/rtp_payload_params_unittest.cc
new file mode 100644
index 0000000000..6a54ac8f9f
--- /dev/null
+++ b/third_party/libwebrtc/call/rtp_payload_params_unittest.cc
@@ -0,0 +1,1180 @@
+/*
+ *  Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/rtp_payload_params.h"
+
+#include <string.h>
+
+#include <map>
+#include <set>
+
+#include "absl/container/inlined_vector.h"
+#include "absl/types/optional.h"
+#include "absl/types/variant.h"
+#include "api/transport/field_trial_based_config.h"
+#include "api/video/video_content_type.h"
+#include "api/video/video_rotation.h"
+#include "modules/video_coding/codecs/h264/include/h264_globals.h"
+#include "modules/video_coding/codecs/interface/common_constants.h"
+#include "modules/video_coding/codecs/vp8/include/vp8_globals.h"
+#include "modules/video_coding/codecs/vp9/include/vp9_globals.h"
+#include "modules/video_coding/include/video_codec_interface.h"
+#include "test/explicit_key_value_config.h"
+#include "test/gmock.h"
+#include "test/gtest.h"
+#include "test/scoped_key_value_config.h"
+
+namespace webrtc {
+namespace {
+
+using ::testing::AllOf;
+using ::testing::Each;
+using ::testing::ElementsAre;
+using ::testing::Eq;
+using ::testing::Field;
+using ::testing::IsEmpty;
+using ::testing::Optional;
+using ::testing::SizeIs;
+
+using GenericDescriptorInfo = RTPVideoHeader::GenericDescriptorInfo;
+
+const uint32_t kSsrc1 = 12345;
+const uint32_t kSsrc2 = 23456;
+const int16_t kPictureId = 123;
+const int16_t kTl0PicIdx = 20;
+const uint8_t kTemporalIdx = 1;
+const int16_t kInitialPictureId1 = 222;
+const int16_t kInitialTl0PicIdx1 = 99;
+const int64_t kDontCare = 0;
+
+TEST(RtpPayloadParamsTest, InfoMappedToRtpVideoHeader_Vp8) {
+  RtpPayloadState state2;
+  state2.picture_id = kPictureId;
+  state2.tl0_pic_idx = kTl0PicIdx;
+  std::map<uint32_t, RtpPayloadState> states = {{kSsrc2, state2}};
+
+  RtpPayloadParams params(kSsrc2, &state2, FieldTrialBasedConfig());
+  EncodedImage encoded_image;
+  encoded_image.rotation_ = kVideoRotation_90;
+  encoded_image.content_type_ = VideoContentType::SCREENSHARE;
+  encoded_image.SetSpatialIndex(1);
+
+  CodecSpecificInfo codec_info;
+  codec_info.codecType = kVideoCodecVP8;
+  codec_info.codecSpecific.VP8.temporalIdx = 0;
+  codec_info.codecSpecific.VP8.keyIdx = kNoKeyIdx;
+  codec_info.codecSpecific.VP8.layerSync = false;
+  codec_info.codecSpecific.VP8.nonReference = true;
+
+  RTPVideoHeader header =
+      params.GetRtpVideoHeader(encoded_image, &codec_info, kDontCare);
+
+  codec_info.codecType = kVideoCodecVP8;
+  codec_info.codecSpecific.VP8.temporalIdx = 1;
+  codec_info.codecSpecific.VP8.layerSync = true;
+
+  header = params.GetRtpVideoHeader(encoded_image, &codec_info, 1);
+
+  EXPECT_EQ(kVideoRotation_90, header.rotation);
+  EXPECT_EQ(VideoContentType::SCREENSHARE, header.content_type);
+  EXPECT_EQ(1, header.simulcastIdx);
+  EXPECT_EQ(kVideoCodecVP8, header.codec);
+  const auto& vp8_header =
+      absl::get<RTPVideoHeaderVP8>(header.video_type_header);
+  EXPECT_EQ(kPictureId + 2, vp8_header.pictureId);
+  EXPECT_EQ(kTemporalIdx, vp8_header.temporalIdx);
+  EXPECT_EQ(kTl0PicIdx + 1, vp8_header.tl0PicIdx);
+  EXPECT_EQ(kNoKeyIdx, vp8_header.keyIdx);
+  EXPECT_TRUE(vp8_header.layerSync);
+  EXPECT_TRUE(vp8_header.nonReference);
+}
+
+TEST(RtpPayloadParamsTest, InfoMappedToRtpVideoHeader_Vp9) {
+  RtpPayloadState state;
+  state.picture_id = kPictureId;
+  state.tl0_pic_idx = kTl0PicIdx;
+  RtpPayloadParams params(kSsrc1, &state, FieldTrialBasedConfig());
+
+  EncodedImage encoded_image;
+  encoded_image.rotation_ = kVideoRotation_90;
+  encoded_image.content_type_ = VideoContentType::SCREENSHARE;
+  encoded_image.SetSpatialIndex(0);
+  CodecSpecificInfo codec_info;
+  codec_info.codecType = kVideoCodecVP9;
+  codec_info.codecSpecific.VP9.num_spatial_layers = 3;
+  codec_info.codecSpecific.VP9.first_frame_in_picture = true;
+  codec_info.codecSpecific.VP9.temporal_idx = 2;
+  codec_info.end_of_picture = false;
+
+  RTPVideoHeader header =
+      params.GetRtpVideoHeader(encoded_image, &codec_info, kDontCare);
+
+  EXPECT_EQ(kVideoRotation_90, header.rotation);
+  EXPECT_EQ(VideoContentType::SCREENSHARE, header.content_type);
+  EXPECT_EQ(kVideoCodecVP9, header.codec);
+  EXPECT_FALSE(header.color_space);
+  const auto& vp9_header =
+      absl::get<RTPVideoHeaderVP9>(header.video_type_header);
+  EXPECT_EQ(kPictureId + 1, vp9_header.picture_id);
+  EXPECT_EQ(kTl0PicIdx, vp9_header.tl0_pic_idx);
+  EXPECT_EQ(vp9_header.temporal_idx, codec_info.codecSpecific.VP9.temporal_idx);
+  EXPECT_EQ(vp9_header.spatial_idx, encoded_image.SpatialIndex());
+  EXPECT_EQ(vp9_header.num_spatial_layers,
+            codec_info.codecSpecific.VP9.num_spatial_layers);
+  EXPECT_EQ(vp9_header.end_of_picture, codec_info.end_of_picture);
+
+  // Next spatial layer.
+  codec_info.codecSpecific.VP9.first_frame_in_picture = false;
+  codec_info.end_of_picture = true;
+
+  encoded_image.SetSpatialIndex(1);
+  ColorSpace color_space(
+      ColorSpace::PrimaryID::kSMPTE170M, ColorSpace::TransferID::kSMPTE170M,
+      ColorSpace::MatrixID::kSMPTE170M, ColorSpace::RangeID::kFull);
+  encoded_image.SetColorSpace(color_space);
+  header = params.GetRtpVideoHeader(encoded_image, &codec_info, kDontCare);
+
+  EXPECT_EQ(kVideoRotation_90, header.rotation);
+  EXPECT_EQ(VideoContentType::SCREENSHARE, header.content_type);
+  EXPECT_EQ(kVideoCodecVP9, header.codec);
+  EXPECT_EQ(absl::make_optional(color_space), header.color_space);
+  EXPECT_EQ(kPictureId + 1, vp9_header.picture_id);
+  EXPECT_EQ(kTl0PicIdx, vp9_header.tl0_pic_idx);
+  EXPECT_EQ(vp9_header.temporal_idx, codec_info.codecSpecific.VP9.temporal_idx);
+  EXPECT_EQ(vp9_header.spatial_idx, encoded_image.SpatialIndex());
+  EXPECT_EQ(vp9_header.num_spatial_layers,
+            codec_info.codecSpecific.VP9.num_spatial_layers);
+  EXPECT_EQ(vp9_header.end_of_picture, codec_info.end_of_picture);
+}
+
+TEST(RtpPayloadParamsTest, PictureIdIsSetForVp8) {
+  RtpPayloadState state;
+  state.picture_id = kInitialPictureId1;
+  state.tl0_pic_idx = kInitialTl0PicIdx1;
+
+  EncodedImage encoded_image;
+  CodecSpecificInfo codec_info;
+  codec_info.codecType = kVideoCodecVP8;
+
+  RtpPayloadParams params(kSsrc1, &state, FieldTrialBasedConfig());
+  RTPVideoHeader header =
+      params.GetRtpVideoHeader(encoded_image, &codec_info, kDontCare);
+  EXPECT_EQ(kVideoCodecVP8, header.codec);
+  EXPECT_EQ(kInitialPictureId1 + 1,
+            absl::get<RTPVideoHeaderVP8>(header.video_type_header).pictureId);
+
+  // State should hold latest used picture id and tl0_pic_idx.
+  state = params.state();
+  EXPECT_EQ(kInitialPictureId1 + 1, state.picture_id);
+  EXPECT_EQ(kInitialTl0PicIdx1 + 1, state.tl0_pic_idx);
+}
+
+TEST(RtpPayloadParamsTest, PictureIdWraps) {
+  RtpPayloadState state;
+  state.picture_id = kMaxTwoBytePictureId;
+  state.tl0_pic_idx = kInitialTl0PicIdx1;
+
+  EncodedImage encoded_image;
+  CodecSpecificInfo codec_info;
+  codec_info.codecType = kVideoCodecVP8;
+  codec_info.codecSpecific.VP8.temporalIdx = kNoTemporalIdx;
+
+  RtpPayloadParams params(kSsrc1, &state, FieldTrialBasedConfig());
+  RTPVideoHeader header =
+      params.GetRtpVideoHeader(encoded_image, &codec_info, kDontCare);
+  EXPECT_EQ(kVideoCodecVP8, header.codec);
+  EXPECT_EQ(0,
+            absl::get<RTPVideoHeaderVP8>(header.video_type_header).pictureId);
+
+  // State should hold latest used picture id and tl0_pic_idx.
+  EXPECT_EQ(0, params.state().picture_id);  // Wrapped.
+  EXPECT_EQ(kInitialTl0PicIdx1, params.state().tl0_pic_idx);
+}
+
+TEST(RtpPayloadParamsTest, CreatesGenericDescriptorForVp8) {
+  constexpr auto kSwitch = DecodeTargetIndication::kSwitch;
+  constexpr auto kNotPresent = DecodeTargetIndication::kNotPresent;
+
+  RtpPayloadState state;
+  RtpPayloadParams params(kSsrc1, &state, FieldTrialBasedConfig());
+
+  EncodedImage key_frame_image;
+  key_frame_image._frameType = VideoFrameType::kVideoFrameKey;
+  CodecSpecificInfo key_frame_info;
+  key_frame_info.codecType = kVideoCodecVP8;
+  key_frame_info.codecSpecific.VP8.temporalIdx = 0;
+  RTPVideoHeader key_frame_header = params.GetRtpVideoHeader(
+      key_frame_image, &key_frame_info, /*shared_frame_id=*/123);
+
+  EncodedImage delta_t1_image;
+  delta_t1_image._frameType = VideoFrameType::kVideoFrameDelta;
+  CodecSpecificInfo delta_t1_info;
+  delta_t1_info.codecType = kVideoCodecVP8;
+  delta_t1_info.codecSpecific.VP8.temporalIdx = 1;
+  RTPVideoHeader delta_t1_header = params.GetRtpVideoHeader(
+      delta_t1_image, &delta_t1_info, /*shared_frame_id=*/124);
+
+  EncodedImage delta_t0_image;
+  delta_t0_image._frameType = VideoFrameType::kVideoFrameDelta;
+  CodecSpecificInfo delta_t0_info;
+  delta_t0_info.codecType = kVideoCodecVP8;
+  delta_t0_info.codecSpecific.VP8.temporalIdx = 0;
+  RTPVideoHeader delta_t0_header = params.GetRtpVideoHeader(
+      delta_t0_image, &delta_t0_info, /*shared_frame_id=*/125);
+
+  EXPECT_THAT(
+      key_frame_header,
+      AllOf(Field(&RTPVideoHeader::codec, kVideoCodecVP8),
+            Field(&RTPVideoHeader::frame_type, VideoFrameType::kVideoFrameKey),
+            Field(&RTPVideoHeader::generic,
+                  Optional(AllOf(
+                      Field(&GenericDescriptorInfo::frame_id, 123),
+                      Field(&GenericDescriptorInfo::spatial_index, 0),
+                      Field(&GenericDescriptorInfo::temporal_index, 0),
+                      Field(&GenericDescriptorInfo::decode_target_indications,
+                            ElementsAre(kSwitch, kSwitch, kSwitch, kSwitch)),
+                      Field(&GenericDescriptorInfo::dependencies, IsEmpty()),
+                      Field(&GenericDescriptorInfo::chain_diffs,
+                            ElementsAre(0)))))));
+
+  EXPECT_THAT(
+      delta_t1_header,
+      AllOf(
+          Field(&RTPVideoHeader::codec, kVideoCodecVP8),
+          Field(&RTPVideoHeader::frame_type, VideoFrameType::kVideoFrameDelta),
+          Field(
+              &RTPVideoHeader::generic,
+              Optional(AllOf(
+                  Field(&GenericDescriptorInfo::frame_id, 124),
+                  Field(&GenericDescriptorInfo::spatial_index, 0),
+                  Field(&GenericDescriptorInfo::temporal_index, 1),
+                  Field(&GenericDescriptorInfo::decode_target_indications,
+                        ElementsAre(kNotPresent, kSwitch, kSwitch, kSwitch)),
+                  Field(&GenericDescriptorInfo::dependencies, ElementsAre(123)),
+                  Field(&GenericDescriptorInfo::chain_diffs,
+                        ElementsAre(1)))))));
+
+  EXPECT_THAT(
+      delta_t0_header,
+      AllOf(
+          Field(&RTPVideoHeader::codec, kVideoCodecVP8),
+          Field(&RTPVideoHeader::frame_type, VideoFrameType::kVideoFrameDelta),
+          Field(
+              &RTPVideoHeader::generic,
+              Optional(AllOf(
+                  Field(&GenericDescriptorInfo::frame_id, 125),
+                  Field(&GenericDescriptorInfo::spatial_index, 0),
+                  Field(&GenericDescriptorInfo::temporal_index, 0),
+                  Field(&GenericDescriptorInfo::decode_target_indications,
+                        ElementsAre(kSwitch, kSwitch, kSwitch, kSwitch)),
+                  Field(&GenericDescriptorInfo::dependencies, ElementsAre(123)),
+                  Field(&GenericDescriptorInfo::chain_diffs,
+                        ElementsAre(2)))))));
+}
+
+TEST(RtpPayloadParamsTest, Tl0PicIdxUpdatedForVp8) {
+  RtpPayloadState state;
+  state.picture_id = kInitialPictureId1;
+  state.tl0_pic_idx = kInitialTl0PicIdx1;
+
+  EncodedImage encoded_image;
+  // Modules are sending for this test.
+  // OnEncodedImage, temporalIdx: 1.
+  CodecSpecificInfo codec_info;
+  codec_info.codecType = kVideoCodecVP8;
+  codec_info.codecSpecific.VP8.temporalIdx = 1;
+
+  RtpPayloadParams params(kSsrc1, &state, FieldTrialBasedConfig());
+  RTPVideoHeader header =
+      params.GetRtpVideoHeader(encoded_image, &codec_info, kDontCare);
+
+  EXPECT_EQ(kVideoCodecVP8, header.codec);
+  const auto& vp8_header =
+      absl::get<RTPVideoHeaderVP8>(header.video_type_header);
+  EXPECT_EQ(kInitialPictureId1 + 1, vp8_header.pictureId);
+  EXPECT_EQ(kInitialTl0PicIdx1, vp8_header.tl0PicIdx);
+
+  // OnEncodedImage, temporalIdx: 0.
+  codec_info.codecSpecific.VP8.temporalIdx = 0;
+
+  header = params.GetRtpVideoHeader(encoded_image, &codec_info, kDontCare);
+  EXPECT_EQ(kVideoCodecVP8, header.codec);
+  EXPECT_EQ(kInitialPictureId1 + 2, vp8_header.pictureId);
+  EXPECT_EQ(kInitialTl0PicIdx1 + 1, vp8_header.tl0PicIdx);
+
+  // State should hold latest used picture id and tl0_pic_idx.
+  EXPECT_EQ(kInitialPictureId1 + 2, params.state().picture_id);
+  EXPECT_EQ(kInitialTl0PicIdx1 + 1, params.state().tl0_pic_idx);
+}
+
+TEST(RtpPayloadParamsTest, Tl0PicIdxUpdatedForVp9) {
+  RtpPayloadState state;
+  state.picture_id = kInitialPictureId1;
+  state.tl0_pic_idx = kInitialTl0PicIdx1;
+
+  EncodedImage encoded_image;
+  // Modules are sending for this test.
+  // OnEncodedImage, temporalIdx: 1.
+  CodecSpecificInfo codec_info;
+  codec_info.codecType = kVideoCodecVP9;
+  codec_info.codecSpecific.VP9.temporal_idx = 1;
+  codec_info.codecSpecific.VP9.first_frame_in_picture = true;
+
+  RtpPayloadParams params(kSsrc1, &state, FieldTrialBasedConfig());
+  RTPVideoHeader header =
+      params.GetRtpVideoHeader(encoded_image, &codec_info, kDontCare);
+
+  EXPECT_EQ(kVideoCodecVP9, header.codec);
+  const auto& vp9_header =
+      absl::get<RTPVideoHeaderVP9>(header.video_type_header);
+  EXPECT_EQ(kInitialPictureId1 + 1, vp9_header.picture_id);
+  EXPECT_EQ(kInitialTl0PicIdx1, vp9_header.tl0_pic_idx);
+
+  // OnEncodedImage, temporalIdx: 0.
+  codec_info.codecSpecific.VP9.temporal_idx = 0;
+
+  header = params.GetRtpVideoHeader(encoded_image, &codec_info, kDontCare);
+
+  EXPECT_EQ(kVideoCodecVP9, header.codec);
+  EXPECT_EQ(kInitialPictureId1 + 2, vp9_header.picture_id);
+  EXPECT_EQ(kInitialTl0PicIdx1 + 1, vp9_header.tl0_pic_idx);
+
+  // OnEncodedImage, first_frame_in_picture = false
+  codec_info.codecSpecific.VP9.first_frame_in_picture = false;
+
+  header = params.GetRtpVideoHeader(encoded_image, &codec_info, kDontCare);
+
+  EXPECT_EQ(kVideoCodecVP9, header.codec);
+  EXPECT_EQ(kInitialPictureId1 + 2, vp9_header.picture_id);
+  EXPECT_EQ(kInitialTl0PicIdx1 + 1, vp9_header.tl0_pic_idx);
+
+  // State should hold latest used picture id and tl0_pic_idx.
+  EXPECT_EQ(kInitialPictureId1 + 2, params.state().picture_id);
+  EXPECT_EQ(kInitialTl0PicIdx1 + 1, params.state().tl0_pic_idx);
+}
+
+TEST(RtpPayloadParamsTest, PictureIdForOldGenericFormat) {
+  test::ScopedKeyValueConfig field_trials("WebRTC-GenericPictureId/Enabled/");
+  RtpPayloadState state{};
+
+  EncodedImage encoded_image;
+  CodecSpecificInfo codec_info;
+  codec_info.codecType = kVideoCodecGeneric;
+  encoded_image._frameType = VideoFrameType::kVideoFrameKey;
+
+  RtpPayloadParams params(kSsrc1, &state, field_trials);
+  RTPVideoHeader header =
+      params.GetRtpVideoHeader(encoded_image, &codec_info, 10);
+
+  EXPECT_EQ(kVideoCodecGeneric, header.codec);
+  const auto* generic =
+      absl::get_if<RTPVideoHeaderLegacyGeneric>(&header.video_type_header);
+  ASSERT_TRUE(generic);
+  EXPECT_EQ(0, generic->picture_id);
+
+  encoded_image._frameType = VideoFrameType::kVideoFrameDelta;
+  header = params.GetRtpVideoHeader(encoded_image, &codec_info, 20);
+  generic =
+      absl::get_if<RTPVideoHeaderLegacyGeneric>(&header.video_type_header);
+  ASSERT_TRUE(generic);
+  EXPECT_EQ(1, generic->picture_id);
+}
+
+TEST(RtpPayloadParamsTest, GenericDescriptorForGenericCodec) {
+  RtpPayloadState state;
+
+  EncodedImage encoded_image;
+  encoded_image._frameType = VideoFrameType::kVideoFrameKey;
+  CodecSpecificInfo codec_info;
+  codec_info.codecType = kVideoCodecGeneric;
+
+  RtpPayloadParams params(kSsrc1, &state, FieldTrialBasedConfig());
+  RTPVideoHeader header =
+      params.GetRtpVideoHeader(encoded_image, &codec_info, 0);
+
+  EXPECT_THAT(header.codec, Eq(kVideoCodecGeneric));
+
+  ASSERT_TRUE(header.generic);
+  EXPECT_THAT(header.generic->frame_id, Eq(0));
+  EXPECT_THAT(header.generic->spatial_index, Eq(0));
+  EXPECT_THAT(header.generic->temporal_index, Eq(0));
+  EXPECT_THAT(header.generic->decode_target_indications,
+              ElementsAre(DecodeTargetIndication::kSwitch));
+  EXPECT_THAT(header.generic->dependencies, IsEmpty());
+  EXPECT_THAT(header.generic->chain_diffs, ElementsAre(0));
+
+  encoded_image._frameType = VideoFrameType::kVideoFrameDelta;
+  header = params.GetRtpVideoHeader(encoded_image, &codec_info, 3);
+  ASSERT_TRUE(header.generic);
+  EXPECT_THAT(header.generic->frame_id, Eq(3));
+  EXPECT_THAT(header.generic->spatial_index, Eq(0));
+  EXPECT_THAT(header.generic->temporal_index, Eq(0));
+  EXPECT_THAT(header.generic->dependencies, ElementsAre(0));
+  EXPECT_THAT(header.generic->decode_target_indications,
+              ElementsAre(DecodeTargetIndication::kSwitch));
+  EXPECT_THAT(header.generic->chain_diffs, ElementsAre(3));
+}
+
+TEST(RtpPayloadParamsTest, SetsGenericFromGenericFrameInfo) {
+  RtpPayloadState state;
+  EncodedImage encoded_image;
+  CodecSpecificInfo codec_info;
+
+  RtpPayloadParams params(kSsrc1, &state, FieldTrialBasedConfig());
+
+  encoded_image._frameType = VideoFrameType::kVideoFrameKey;
+  codec_info.generic_frame_info =
+      GenericFrameInfo::Builder().S(1).T(0).Dtis("S").Build();
+  codec_info.generic_frame_info->encoder_buffers = {
+      {/*id=*/0, /*referenced=*/false, /*updated=*/true}};
+  codec_info.generic_frame_info->part_of_chain = {true, false};
+  RTPVideoHeader key_header =
+      params.GetRtpVideoHeader(encoded_image, &codec_info, /*frame_id=*/1);
+
+  ASSERT_TRUE(key_header.generic);
+  EXPECT_EQ(key_header.generic->spatial_index, 1);
+  EXPECT_EQ(key_header.generic->temporal_index, 0);
+  EXPECT_EQ(key_header.generic->frame_id, 1);
+  EXPECT_THAT(key_header.generic->dependencies, IsEmpty());
+  EXPECT_THAT(key_header.generic->decode_target_indications,
+              ElementsAre(DecodeTargetIndication::kSwitch));
+  EXPECT_THAT(key_header.generic->chain_diffs, SizeIs(2));
+
+  encoded_image._frameType = VideoFrameType::kVideoFrameDelta;
+  codec_info.generic_frame_info =
+      GenericFrameInfo::Builder().S(2).T(3).Dtis("D").Build();
+  codec_info.generic_frame_info->encoder_buffers = {
+      {/*id=*/0, /*referenced=*/true, /*updated=*/false}};
+  codec_info.generic_frame_info->part_of_chain = {false, false};
+  RTPVideoHeader delta_header =
+      params.GetRtpVideoHeader(encoded_image, &codec_info, /*frame_id=*/3);
+
+  ASSERT_TRUE(delta_header.generic);
+  EXPECT_EQ(delta_header.generic->spatial_index, 2);
+  EXPECT_EQ(delta_header.generic->temporal_index, 3);
+  EXPECT_EQ(delta_header.generic->frame_id, 3);
+  EXPECT_THAT(delta_header.generic->dependencies, ElementsAre(1));
+  EXPECT_THAT(delta_header.generic->decode_target_indications,
+              ElementsAre(DecodeTargetIndication::kDiscardable));
+  EXPECT_THAT(delta_header.generic->chain_diffs, SizeIs(2));
+}
+
+class RtpPayloadParamsVp8ToGenericTest : public ::testing::Test {
+ public:
+  enum LayerSync { kNoSync, kSync };
+
+  RtpPayloadParamsVp8ToGenericTest()
+      : state_(), params_(123, &state_, trials_config_) {}
+
+  void ConvertAndCheck(int temporal_index,
+                       int64_t shared_frame_id,
+                       VideoFrameType frame_type,
+                       LayerSync layer_sync,
+                       const std::set<int64_t>& expected_deps,
+                       uint16_t width = 0,
+                       uint16_t height = 0) {
+    EncodedImage encoded_image;
+    encoded_image._frameType = frame_type;
+    encoded_image._encodedWidth = width;
+    encoded_image._encodedHeight = height;
+
+    CodecSpecificInfo codec_info;
+    codec_info.codecType = kVideoCodecVP8;
+    codec_info.codecSpecific.VP8.temporalIdx = temporal_index;
+    codec_info.codecSpecific.VP8.layerSync = layer_sync == kSync;
+
+    RTPVideoHeader header =
+        params_.GetRtpVideoHeader(encoded_image, &codec_info, shared_frame_id);
+
+    ASSERT_TRUE(header.generic);
+    EXPECT_EQ(header.generic->spatial_index, 0);
+
+    EXPECT_EQ(header.generic->frame_id, shared_frame_id);
+    EXPECT_EQ(header.generic->temporal_index, temporal_index);
+    std::set<int64_t> actual_deps(header.generic->dependencies.begin(),
+                                  header.generic->dependencies.end());
+    EXPECT_EQ(expected_deps, actual_deps);
+
+    EXPECT_EQ(header.width, width);
+    EXPECT_EQ(header.height, height);
+  }
+
+ protected:
+  FieldTrialBasedConfig trials_config_;
+  RtpPayloadState state_;
+  RtpPayloadParams params_;
+};
+
+TEST_F(RtpPayloadParamsVp8ToGenericTest, Keyframe) {
+  ConvertAndCheck(0, 0, VideoFrameType::kVideoFrameKey, kNoSync, {}, 480, 360);
+  ConvertAndCheck(0, 1, VideoFrameType::kVideoFrameDelta, kNoSync, {0});
+  ConvertAndCheck(0, 2, VideoFrameType::kVideoFrameKey, kNoSync, {}, 480, 360);
+}
+
+TEST_F(RtpPayloadParamsVp8ToGenericTest, TooHighTemporalIndex) {
+  ConvertAndCheck(0, 0, VideoFrameType::kVideoFrameKey, kNoSync, {}, 480, 360);
+
+  EncodedImage encoded_image;
+  encoded_image._frameType = VideoFrameType::kVideoFrameDelta;
+  CodecSpecificInfo codec_info;
+  codec_info.codecType = kVideoCodecVP8;
+  codec_info.codecSpecific.VP8.temporalIdx =
+      RtpGenericFrameDescriptor::kMaxTemporalLayers;
+  codec_info.codecSpecific.VP8.layerSync = false;
+
+  RTPVideoHeader header =
+      params_.GetRtpVideoHeader(encoded_image, &codec_info, 1);
+  EXPECT_FALSE(header.generic);
+}
+
+TEST_F(RtpPayloadParamsVp8ToGenericTest, LayerSync) {
+  // 02120212 pattern
+  ConvertAndCheck(0, 0, VideoFrameType::kVideoFrameKey, kNoSync, {}, 480, 360);
+  ConvertAndCheck(2, 1, VideoFrameType::kVideoFrameDelta, kNoSync, {0});
+  ConvertAndCheck(1, 2, VideoFrameType::kVideoFrameDelta, kNoSync, {0});
+  ConvertAndCheck(2, 3, VideoFrameType::kVideoFrameDelta, kNoSync, {0, 1, 2});
+
+  ConvertAndCheck(0, 4, VideoFrameType::kVideoFrameDelta, kNoSync, {0});
+  ConvertAndCheck(2, 5, VideoFrameType::kVideoFrameDelta, kNoSync, {2, 3, 4});
+  ConvertAndCheck(1, 6, VideoFrameType::kVideoFrameDelta, kSync,
+                  {4});  // layer sync
+  ConvertAndCheck(2, 7, VideoFrameType::kVideoFrameDelta, kNoSync, {4, 5, 6});
+}
+
+TEST_F(RtpPayloadParamsVp8ToGenericTest, FrameIdGaps) {
+  // 0101 pattern
+  ConvertAndCheck(0, 0, VideoFrameType::kVideoFrameKey, kNoSync, {}, 480, 360);
+  ConvertAndCheck(1, 1, VideoFrameType::kVideoFrameDelta, kNoSync, {0});
+
+  ConvertAndCheck(0, 5, VideoFrameType::kVideoFrameDelta, kNoSync, {0});
+  ConvertAndCheck(1, 10, VideoFrameType::kVideoFrameDelta, kNoSync, {1, 5});
+
+  ConvertAndCheck(0, 15, VideoFrameType::kVideoFrameDelta, kNoSync, {5});
+  ConvertAndCheck(1, 20, VideoFrameType::kVideoFrameDelta, kNoSync, {10, 15});
+}
+
+TEST(RtpPayloadParamsVp9ToGenericTest, NoScalability) {
+  RtpPayloadState state;
+  RtpPayloadParams params(/*ssrc=*/123, &state, FieldTrialBasedConfig());
+
+  EncodedImage encoded_image;
+  CodecSpecificInfo codec_info;
+  codec_info.codecType = kVideoCodecVP9;
+  codec_info.codecSpecific.VP9.num_spatial_layers = 1;
+  codec_info.codecSpecific.VP9.temporal_idx = kNoTemporalIdx;
+  codec_info.codecSpecific.VP9.first_frame_in_picture = true;
+  codec_info.end_of_picture = true;
+
+  // Key frame.
+  encoded_image._frameType = VideoFrameType::kVideoFrameKey;
+  codec_info.codecSpecific.VP9.inter_pic_predicted = false;
+  codec_info.codecSpecific.VP9.num_ref_pics = 0;
+  RTPVideoHeader header = params.GetRtpVideoHeader(encoded_image, &codec_info,
+                                                   /*shared_frame_id=*/1);
+
+  ASSERT_TRUE(header.generic);
+  EXPECT_EQ(header.generic->spatial_index, 0);
+  EXPECT_EQ(header.generic->temporal_index, 0);
+  EXPECT_EQ(header.generic->frame_id, 1);
+  ASSERT_THAT(header.generic->decode_target_indications, Not(IsEmpty()));
+  EXPECT_EQ(header.generic->decode_target_indications[0],
+            DecodeTargetIndication::kSwitch);
+  EXPECT_THAT(header.generic->dependencies, IsEmpty());
+  ASSERT_THAT(header.generic->chain_diffs, Not(IsEmpty()));
+  EXPECT_EQ(header.generic->chain_diffs[0], 0);
+
+  // Delta frame.
+  encoded_image._frameType = VideoFrameType::kVideoFrameDelta;
+  codec_info.codecSpecific.VP9.inter_pic_predicted = true;
+  codec_info.codecSpecific.VP9.num_ref_pics = 1;
+  codec_info.codecSpecific.VP9.p_diff[0] = 1;
+  header = params.GetRtpVideoHeader(encoded_image, &codec_info,
+                                    /*shared_frame_id=*/3);
+
+  ASSERT_TRUE(header.generic);
+  EXPECT_EQ(header.generic->spatial_index, 0);
+  EXPECT_EQ(header.generic->temporal_index, 0);
+  EXPECT_EQ(header.generic->frame_id, 3);
+  ASSERT_THAT(header.generic->decode_target_indications, Not(IsEmpty()));
+  EXPECT_EQ(header.generic->decode_target_indications[0],
+            DecodeTargetIndication::kSwitch);
+  EXPECT_THAT(header.generic->dependencies, ElementsAre(1));
+  ASSERT_THAT(header.generic->chain_diffs, Not(IsEmpty()));
+  // previous frame in the chain was frame#1,
+  EXPECT_EQ(header.generic->chain_diffs[0], 3 - 1);
+}
+
+TEST(RtpPayloadParamsVp9ToGenericTest, TemporalScalabilityWith2Layers) {
+  // Test with 2 temporal layers structure that is not used by webrtc:
+  //    1---3   5
+  //   /   /   /   ...
+  //  0---2---4---
+  RtpPayloadState state;
+  RtpPayloadParams params(/*ssrc=*/123, &state, FieldTrialBasedConfig());
+
+  EncodedImage image;
+  CodecSpecificInfo info;
+  info.codecType = kVideoCodecVP9;
+  info.codecSpecific.VP9.num_spatial_layers = 1;
+  info.codecSpecific.VP9.first_frame_in_picture = true;
+  info.end_of_picture = true;
+
+  RTPVideoHeader headers[6];
+  // Key frame.
+  image._frameType = VideoFrameType::kVideoFrameKey;
+  info.codecSpecific.VP9.inter_pic_predicted = false;
+  info.codecSpecific.VP9.num_ref_pics = 0;
+  info.codecSpecific.VP9.temporal_up_switch = true;
+  info.codecSpecific.VP9.temporal_idx = 0;
+  headers[0] = params.GetRtpVideoHeader(image, &info, /*shared_frame_id=*/1);
+
+  // Delta frames.
+  info.codecSpecific.VP9.inter_pic_predicted = true;
+  image._frameType = VideoFrameType::kVideoFrameDelta;
+
+  info.codecSpecific.VP9.temporal_up_switch = true;
+  info.codecSpecific.VP9.temporal_idx = 1;
+  info.codecSpecific.VP9.num_ref_pics = 1;
+  info.codecSpecific.VP9.p_diff[0] = 1;
+  headers[1] = params.GetRtpVideoHeader(image, &info, /*shared_frame_id=*/3);
+
+  info.codecSpecific.VP9.temporal_up_switch = false;
+  info.codecSpecific.VP9.temporal_idx = 0;
+  info.codecSpecific.VP9.num_ref_pics = 1;
+  info.codecSpecific.VP9.p_diff[0] = 2;
+  headers[2] = params.GetRtpVideoHeader(image, &info, /*shared_frame_id=*/5);
+
+  info.codecSpecific.VP9.temporal_up_switch = false;
+  info.codecSpecific.VP9.temporal_idx = 1;
+  info.codecSpecific.VP9.num_ref_pics = 2;
+  info.codecSpecific.VP9.p_diff[0] = 1;
+  info.codecSpecific.VP9.p_diff[1] = 2;
+  headers[3] = params.GetRtpVideoHeader(image, &info, /*shared_frame_id=*/7);
+
+  info.codecSpecific.VP9.temporal_up_switch = true;
+  info.codecSpecific.VP9.temporal_idx = 0;
+  info.codecSpecific.VP9.num_ref_pics = 1;
+  info.codecSpecific.VP9.p_diff[0] = 2;
+  headers[4] = params.GetRtpVideoHeader(image, &info, /*shared_frame_id=*/9);
+
+  info.codecSpecific.VP9.temporal_up_switch = true;
+  info.codecSpecific.VP9.temporal_idx = 1;
+  info.codecSpecific.VP9.num_ref_pics = 1;
+  info.codecSpecific.VP9.p_diff[0] = 1;
+  headers[5] = params.GetRtpVideoHeader(image, &info, /*shared_frame_id=*/11);
+
+  ASSERT_TRUE(headers[0].generic);
+  int num_decode_targets = headers[0].generic->decode_target_indications.size();
+  int num_chains = headers[0].generic->chain_diffs.size();
+  ASSERT_GE(num_decode_targets, 2);
+  ASSERT_GE(num_chains, 1);
+
+  for (int frame_idx = 0; frame_idx < 6; ++frame_idx) {
+    const RTPVideoHeader& header = headers[frame_idx];
+    ASSERT_TRUE(header.generic);
+    EXPECT_EQ(header.generic->spatial_index, 0);
+    EXPECT_EQ(header.generic->temporal_index, frame_idx % 2);
+    EXPECT_EQ(header.generic->frame_id, 1 + 2 * frame_idx);
+    ASSERT_THAT(header.generic->decode_target_indications,
+                SizeIs(num_decode_targets));
+    ASSERT_THAT(header.generic->chain_diffs, SizeIs(num_chains));
+    // Expect only T0 frames are needed for the 1st decode target.
+    if (header.generic->temporal_index == 0) {
+      EXPECT_NE(header.generic->decode_target_indications[0],
+                DecodeTargetIndication::kNotPresent);
+    } else {
+      EXPECT_EQ(header.generic->decode_target_indications[0],
+                DecodeTargetIndication::kNotPresent);
+    }
+    // Expect all frames are needed for the 2nd decode target.
+    EXPECT_NE(header.generic->decode_target_indications[1],
+              DecodeTargetIndication::kNotPresent);
+  }
+
+  // Expect switch at every beginning of the pattern.
+  EXPECT_THAT(headers[0].generic->decode_target_indications[0],
+              DecodeTargetIndication::kSwitch);
+  EXPECT_THAT(headers[0].generic->decode_target_indications[1],
+              DecodeTargetIndication::kSwitch);
+  EXPECT_THAT(headers[4].generic->decode_target_indications[0],
+              DecodeTargetIndication::kSwitch);
+  EXPECT_THAT(headers[4].generic->decode_target_indications[1],
+              DecodeTargetIndication::kSwitch);
+
+  EXPECT_THAT(headers[0].generic->dependencies, IsEmpty());          // T0, 1
+  EXPECT_THAT(headers[1].generic->dependencies, ElementsAre(1));     // T1, 3
+  EXPECT_THAT(headers[2].generic->dependencies, ElementsAre(1));     // T0, 5
+  EXPECT_THAT(headers[3].generic->dependencies, ElementsAre(5, 3));  // T1, 7
+  EXPECT_THAT(headers[4].generic->dependencies, ElementsAre(5));     // T0, 9
+  EXPECT_THAT(headers[5].generic->dependencies, ElementsAre(9));     // T1, 11
+
+  EXPECT_THAT(headers[0].generic->chain_diffs[0], Eq(0));
+  EXPECT_THAT(headers[1].generic->chain_diffs[0], Eq(2));
+  EXPECT_THAT(headers[2].generic->chain_diffs[0], Eq(4));
+  EXPECT_THAT(headers[3].generic->chain_diffs[0], Eq(2));
+  EXPECT_THAT(headers[4].generic->chain_diffs[0], Eq(4));
+  EXPECT_THAT(headers[5].generic->chain_diffs[0], Eq(2));
+}
+
+TEST(RtpPayloadParamsVp9ToGenericTest, TemporalScalabilityWith3Layers) {
+  // Test with 3 temporal layers structure that is not used by webrtc, but used
+  // by chromium: https://imgur.com/pURAGvp
+  RtpPayloadState state;
+  RtpPayloadParams params(/*ssrc=*/123, &state, FieldTrialBasedConfig());
+
+  EncodedImage image;
+  CodecSpecificInfo info;
+  info.codecType = kVideoCodecVP9;
+  info.codecSpecific.VP9.num_spatial_layers = 1;
+  info.codecSpecific.VP9.first_frame_in_picture = true;
+  info.end_of_picture = true;
+
+  RTPVideoHeader headers[9];
+  // Key frame.
+  image._frameType = VideoFrameType::kVideoFrameKey;
+  info.codecSpecific.VP9.inter_pic_predicted = false;
+  info.codecSpecific.VP9.num_ref_pics = 0;
+  info.codecSpecific.VP9.temporal_up_switch = true;
+  info.codecSpecific.VP9.temporal_idx = 0;
+  headers[0] = params.GetRtpVideoHeader(image, &info, /*shared_frame_id=*/1);
+
+  // Delta frames.
+  info.codecSpecific.VP9.inter_pic_predicted = true;
+  image._frameType = VideoFrameType::kVideoFrameDelta;
+
+  info.codecSpecific.VP9.temporal_up_switch = true;
+  info.codecSpecific.VP9.temporal_idx = 2;
+  info.codecSpecific.VP9.num_ref_pics = 1;
+  info.codecSpecific.VP9.p_diff[0] = 1;
+  headers[1] = params.GetRtpVideoHeader(image, &info, /*shared_frame_id=*/3);
+
+  info.codecSpecific.VP9.temporal_up_switch = true;
+  info.codecSpecific.VP9.temporal_idx = 1;
+  info.codecSpecific.VP9.num_ref_pics = 1;
+  info.codecSpecific.VP9.p_diff[0] = 2;
+  headers[2] = params.GetRtpVideoHeader(image, &info, /*shared_frame_id=*/5);
+
+  info.codecSpecific.VP9.temporal_up_switch = true;
+  info.codecSpecific.VP9.temporal_idx = 2;
+  info.codecSpecific.VP9.num_ref_pics = 1;
+  info.codecSpecific.VP9.p_diff[0] = 1;
+  headers[3] = params.GetRtpVideoHeader(image, &info, /*shared_frame_id=*/7);
+
+  info.codecSpecific.VP9.temporal_up_switch = false;
+  info.codecSpecific.VP9.temporal_idx = 0;
+  info.codecSpecific.VP9.num_ref_pics = 1;
+  info.codecSpecific.VP9.p_diff[0] = 4;
+  headers[4] = params.GetRtpVideoHeader(image, &info, /*shared_frame_id=*/9);
+
+  info.codecSpecific.VP9.temporal_up_switch = true;
+  info.codecSpecific.VP9.temporal_idx = 2;
+  info.codecSpecific.VP9.num_ref_pics = 2;
+  info.codecSpecific.VP9.p_diff[0] = 1;
+  info.codecSpecific.VP9.p_diff[1] = 3;
+  headers[5] = params.GetRtpVideoHeader(image, &info, /*shared_frame_id=*/11);
+
+  info.codecSpecific.VP9.temporal_up_switch = false;
+  info.codecSpecific.VP9.temporal_idx = 1;
+  info.codecSpecific.VP9.num_ref_pics = 2;
+  info.codecSpecific.VP9.p_diff[0] = 2;
+  info.codecSpecific.VP9.p_diff[1] = 4;
+  headers[6] = params.GetRtpVideoHeader(image, &info, /*shared_frame_id=*/13);
+
+  info.codecSpecific.VP9.temporal_up_switch = true;
+  info.codecSpecific.VP9.temporal_idx = 2;
+  info.codecSpecific.VP9.num_ref_pics = 1;
+  info.codecSpecific.VP9.p_diff[0] = 1;
+  headers[7] = params.GetRtpVideoHeader(image, &info, /*shared_frame_id=*/15);
+
+  info.codecSpecific.VP9.temporal_up_switch = true;
+  info.codecSpecific.VP9.temporal_idx = 0;
+  info.codecSpecific.VP9.num_ref_pics = 1;
+  info.codecSpecific.VP9.p_diff[0] = 4;
+  headers[8] = params.GetRtpVideoHeader(image, &info, /*shared_frame_id=*/17);
+
+  ASSERT_TRUE(headers[0].generic);
+  int num_decode_targets = headers[0].generic->decode_target_indications.size();
+  int num_chains = headers[0].generic->chain_diffs.size();
+  ASSERT_GE(num_decode_targets, 3);
+  ASSERT_GE(num_chains, 1);
+
+  for (int frame_idx = 0; frame_idx < 9; ++frame_idx) {
+    const RTPVideoHeader& header = headers[frame_idx];
+    ASSERT_TRUE(header.generic);
+    EXPECT_EQ(header.generic->spatial_index, 0);
+    EXPECT_EQ(header.generic->frame_id, 1 + 2 * frame_idx);
+    ASSERT_THAT(header.generic->decode_target_indications,
+                SizeIs(num_decode_targets));
+    ASSERT_THAT(header.generic->chain_diffs, SizeIs(num_chains));
+    // Expect only T0 frames are needed for the 1st decode target.
+    if (header.generic->temporal_index == 0) {
+      EXPECT_NE(header.generic->decode_target_indications[0],
+                DecodeTargetIndication::kNotPresent);
+    } else {
+      EXPECT_EQ(header.generic->decode_target_indications[0],
+                DecodeTargetIndication::kNotPresent);
+    }
+    // Expect only T0 and T1 frames are needed for the 2nd decode target.
+    if (header.generic->temporal_index <= 1) {
+      EXPECT_NE(header.generic->decode_target_indications[1],
+                DecodeTargetIndication::kNotPresent);
+    } else {
+      EXPECT_EQ(header.generic->decode_target_indications[1],
+                DecodeTargetIndication::kNotPresent);
+    }
+    // Expect all frames are needed for the 3rd decode target.
+    EXPECT_NE(header.generic->decode_target_indications[2],
+              DecodeTargetIndication::kNotPresent);
+  }
+
+  EXPECT_EQ(headers[0].generic->temporal_index, 0);
+  EXPECT_EQ(headers[1].generic->temporal_index, 2);
+  EXPECT_EQ(headers[2].generic->temporal_index, 1);
+  EXPECT_EQ(headers[3].generic->temporal_index, 2);
+  EXPECT_EQ(headers[4].generic->temporal_index, 0);
+  EXPECT_EQ(headers[5].generic->temporal_index, 2);
+  EXPECT_EQ(headers[6].generic->temporal_index, 1);
+  EXPECT_EQ(headers[7].generic->temporal_index, 2);
+  EXPECT_EQ(headers[8].generic->temporal_index, 0);
+
+  // Expect switch at every beginning of the pattern.
+  EXPECT_THAT(headers[0].generic->decode_target_indications,
+              Each(DecodeTargetIndication::kSwitch));
+  EXPECT_THAT(headers[8].generic->decode_target_indications[0],
+              DecodeTargetIndication::kSwitch);
+  EXPECT_THAT(headers[8].generic->decode_target_indications[1],
+              DecodeTargetIndication::kSwitch);
+  EXPECT_THAT(headers[8].generic->decode_target_indications[2],
+              DecodeTargetIndication::kSwitch);
+
+  EXPECT_THAT(headers[0].generic->dependencies, IsEmpty());          // T0, 1
+  EXPECT_THAT(headers[1].generic->dependencies, ElementsAre(1));     // T2, 3
+  EXPECT_THAT(headers[2].generic->dependencies, ElementsAre(1));     // T1, 5
+  EXPECT_THAT(headers[3].generic->dependencies, ElementsAre(5));     // T2, 7
+  EXPECT_THAT(headers[4].generic->dependencies, ElementsAre(1));     // T0, 9
+  EXPECT_THAT(headers[5].generic->dependencies, ElementsAre(9, 5));  // T2, 11
+  EXPECT_THAT(headers[6].generic->dependencies, ElementsAre(9, 5));  // T1, 13
+  EXPECT_THAT(headers[7].generic->dependencies, ElementsAre(13));    // T2, 15
+  EXPECT_THAT(headers[8].generic->dependencies, ElementsAre(9));     // T0, 17
+
+  EXPECT_THAT(headers[0].generic->chain_diffs[0], Eq(0));
+  EXPECT_THAT(headers[1].generic->chain_diffs[0], Eq(2));
+  EXPECT_THAT(headers[2].generic->chain_diffs[0], Eq(4));
+  EXPECT_THAT(headers[3].generic->chain_diffs[0], Eq(6));
+  EXPECT_THAT(headers[4].generic->chain_diffs[0], Eq(8));
+  EXPECT_THAT(headers[5].generic->chain_diffs[0], Eq(2));
+  EXPECT_THAT(headers[6].generic->chain_diffs[0], Eq(4));
+  EXPECT_THAT(headers[7].generic->chain_diffs[0], Eq(6));
+  EXPECT_THAT(headers[8].generic->chain_diffs[0], Eq(8));
+}
+
+TEST(RtpPayloadParamsVp9ToGenericTest, SpatialScalabilityKSvc) {
+  //  1---3--
+  //  |     ...
+  //  0---2--
+  RtpPayloadState state;
+  RtpPayloadParams params(/*ssrc=*/123, &state, FieldTrialBasedConfig());
+
+  EncodedImage image;
+  CodecSpecificInfo info;
+  info.codecType = kVideoCodecVP9;
+  info.codecSpecific.VP9.num_spatial_layers = 2;
+  info.codecSpecific.VP9.first_frame_in_picture = true;
+
+  RTPVideoHeader headers[4];
+  // Key frame.
+  image._frameType = VideoFrameType::kVideoFrameKey;
+  image.SetSpatialIndex(0);
+  info.codecSpecific.VP9.inter_pic_predicted = false;
+  info.codecSpecific.VP9.inter_layer_predicted = false;
+  info.codecSpecific.VP9.non_ref_for_inter_layer_pred = false;
+  info.codecSpecific.VP9.num_ref_pics = 0;
+  info.codecSpecific.VP9.first_frame_in_picture = true;
+  info.end_of_picture = false;
+  headers[0] = params.GetRtpVideoHeader(image, &info, /*shared_frame_id=*/1);
+
+  image.SetSpatialIndex(1);
+  info.codecSpecific.VP9.inter_layer_predicted = true;
+  info.codecSpecific.VP9.non_ref_for_inter_layer_pred = true;
+  info.codecSpecific.VP9.first_frame_in_picture = false;
+  info.end_of_picture = true;
+  headers[1] = params.GetRtpVideoHeader(image, &info, /*shared_frame_id=*/3);
+
+  // Delta frames.
+  info.codecSpecific.VP9.inter_pic_predicted = true;
+  image._frameType = VideoFrameType::kVideoFrameDelta;
+  info.codecSpecific.VP9.num_ref_pics = 1;
+  info.codecSpecific.VP9.p_diff[0] = 1;
+
+  image.SetSpatialIndex(0);
+  info.codecSpecific.VP9.inter_layer_predicted = false;
+  info.codecSpecific.VP9.non_ref_for_inter_layer_pred = true;
+  info.codecSpecific.VP9.first_frame_in_picture = true;
+  info.end_of_picture = false;
+  headers[2] = params.GetRtpVideoHeader(image, &info, /*shared_frame_id=*/5);
+
+  image.SetSpatialIndex(1);
+  info.codecSpecific.VP9.inter_layer_predicted = false;
+  info.codecSpecific.VP9.non_ref_for_inter_layer_pred = true;
+  info.codecSpecific.VP9.first_frame_in_picture = false;
+  info.end_of_picture = true;
+  headers[3] = params.GetRtpVideoHeader(image, &info, /*shared_frame_id=*/7);
+
+  ASSERT_TRUE(headers[0].generic);
+  int num_decode_targets = headers[0].generic->decode_target_indications.size();
+  // Rely on implementation detail there are always kMaxTemporalStreams temporal
+  // layers assumed, in particular assume Decode Target#0 matches layer S0T0,
+  // and Decode Target#kMaxTemporalStreams matches layer S1T0.
+  ASSERT_GE(num_decode_targets, kMaxTemporalStreams * 2);
+  int num_chains = headers[0].generic->chain_diffs.size();
+  ASSERT_GE(num_chains, 2);
+
+  for (int frame_idx = 0; frame_idx < 4; ++frame_idx) {
+    const RTPVideoHeader& header = headers[frame_idx];
+    ASSERT_TRUE(header.generic);
+    EXPECT_EQ(header.generic->spatial_index, frame_idx % 2);
+    EXPECT_EQ(header.generic->temporal_index, 0);
+    EXPECT_EQ(header.generic->frame_id, 1 + 2 * frame_idx);
+    ASSERT_THAT(header.generic->decode_target_indications,
+                SizeIs(num_decode_targets));
+    ASSERT_THAT(header.generic->chain_diffs, SizeIs(num_chains));
+  }
+
+  // Expect S0 key frame is switch for both Decode Targets.
+  EXPECT_EQ(headers[0].generic->decode_target_indications[0],
+            DecodeTargetIndication::kSwitch);
+  EXPECT_EQ(headers[0].generic->decode_target_indications[kMaxTemporalStreams],
+            DecodeTargetIndication::kSwitch);
+  // S1 key frame is only needed for the 2nd Decode Targets.
+  EXPECT_EQ(headers[1].generic->decode_target_indications[0],
+            DecodeTargetIndication::kNotPresent);
+  EXPECT_NE(headers[1].generic->decode_target_indications[kMaxTemporalStreams],
+            DecodeTargetIndication::kNotPresent);
+  // Delta frames are only needed for their own Decode Targets.
+  EXPECT_NE(headers[2].generic->decode_target_indications[0],
+            DecodeTargetIndication::kNotPresent);
+  EXPECT_EQ(headers[2].generic->decode_target_indications[kMaxTemporalStreams],
+            DecodeTargetIndication::kNotPresent);
+  EXPECT_EQ(headers[3].generic->decode_target_indications[0],
+            DecodeTargetIndication::kNotPresent);
+  EXPECT_NE(headers[3].generic->decode_target_indications[kMaxTemporalStreams],
+            DecodeTargetIndication::kNotPresent);
+
+  EXPECT_THAT(headers[0].generic->dependencies, IsEmpty());       // S0, 1
+  EXPECT_THAT(headers[1].generic->dependencies, ElementsAre(1));  // S1, 3
+  EXPECT_THAT(headers[2].generic->dependencies, ElementsAre(1));  // S0, 5
+  EXPECT_THAT(headers[3].generic->dependencies, ElementsAre(3));  // S1, 7
+
+  EXPECT_THAT(headers[0].generic->chain_diffs[0], Eq(0));
+  EXPECT_THAT(headers[0].generic->chain_diffs[1], Eq(0));
+  EXPECT_THAT(headers[1].generic->chain_diffs[0], Eq(2));
+  EXPECT_THAT(headers[1].generic->chain_diffs[1], Eq(2));
+  EXPECT_THAT(headers[2].generic->chain_diffs[0], Eq(4));
+  EXPECT_THAT(headers[2].generic->chain_diffs[1], Eq(2));
+  EXPECT_THAT(headers[3].generic->chain_diffs[0], Eq(2));
+  EXPECT_THAT(headers[3].generic->chain_diffs[1], Eq(4));
+}
+
+TEST(RtpPayloadParamsVp9ToGenericTest,
+     IncreaseNumberOfSpatialLayersOnDeltaFrame) {
+  // S1     5--
+  //        | ...
+  // S0 1---3--
+  RtpPayloadState state;
+  RtpPayloadParams params(/*ssrc=*/123, &state, FieldTrialBasedConfig());
+
+  EncodedImage image;
+  CodecSpecificInfo info;
+  info.codecType = kVideoCodecVP9;
+  info.codecSpecific.VP9.num_spatial_layers = 1;
+  info.codecSpecific.VP9.first_frame_in_picture = true;
+
+  RTPVideoHeader headers[3];
+  // Key frame.
+  image._frameType = VideoFrameType::kVideoFrameKey;
+  image.SetSpatialIndex(0);
+  info.codecSpecific.VP9.inter_pic_predicted = false;
+  info.codecSpecific.VP9.inter_layer_predicted = false;
+  info.codecSpecific.VP9.non_ref_for_inter_layer_pred = true;
+  info.codecSpecific.VP9.num_ref_pics = 0;
+  info.codecSpecific.VP9.first_frame_in_picture = true;
+  info.end_of_picture = true;
+  headers[0] = params.GetRtpVideoHeader(image, &info, /*shared_frame_id=*/1);
+
+  // S0 delta frame.
+  image._frameType = VideoFrameType::kVideoFrameDelta;
+  info.codecSpecific.VP9.num_spatial_layers = 2;
+  info.codecSpecific.VP9.non_ref_for_inter_layer_pred = false;
+  info.codecSpecific.VP9.first_frame_in_picture = true;
+  info.codecSpecific.VP9.inter_pic_predicted = true;
+  info.codecSpecific.VP9.num_ref_pics = 1;
+  info.codecSpecific.VP9.p_diff[0] = 1;
+  info.end_of_picture = false;
+  headers[1] = params.GetRtpVideoHeader(image, &info, /*shared_frame_id=*/3);
+
+  // S1 delta frame.
+  image.SetSpatialIndex(1);
+  info.codecSpecific.VP9.inter_layer_predicted = true;
+  info.codecSpecific.VP9.non_ref_for_inter_layer_pred = true;
+  info.codecSpecific.VP9.first_frame_in_picture = false;
+  info.codecSpecific.VP9.inter_pic_predicted = false;
+  info.end_of_picture = true;
+  headers[2] = params.GetRtpVideoHeader(image, &info, /*shared_frame_id=*/5);
+
+  ASSERT_TRUE(headers[0].generic);
+  int num_decode_targets = headers[0].generic->decode_target_indications.size();
+  int num_chains = headers[0].generic->chain_diffs.size();
+  // Rely on implementation detail there are always kMaxTemporalStreams temporal
+  // layers. In particular assume Decode Target#0 matches layer S0T0, and
+  // Decode Target#kMaxTemporalStreams matches layer S1T0.
+  static constexpr int kS0T0 = 0;
+  static constexpr int kS1T0 = kMaxTemporalStreams;
+  ASSERT_GE(num_decode_targets, 2);
+  ASSERT_GE(num_chains, 2);
+
+  for (int frame_idx = 0; frame_idx < 3; ++frame_idx) {
+    const RTPVideoHeader& header = headers[frame_idx];
+    ASSERT_TRUE(header.generic);
+    EXPECT_EQ(header.generic->temporal_index, 0);
+    EXPECT_EQ(header.generic->frame_id, 1 + 2 * frame_idx);
+    ASSERT_THAT(header.generic->decode_target_indications,
+                SizeIs(num_decode_targets));
+    ASSERT_THAT(header.generic->chain_diffs, SizeIs(num_chains));
+  }
+
+  EXPECT_TRUE(headers[0].generic->active_decode_targets[kS0T0]);
+  EXPECT_FALSE(headers[0].generic->active_decode_targets[kS1T0]);
+
+  EXPECT_TRUE(headers[1].generic->active_decode_targets[kS0T0]);
+  EXPECT_TRUE(headers[1].generic->active_decode_targets[kS1T0]);
+
+  EXPECT_TRUE(headers[2].generic->active_decode_targets[kS0T0]);
+  EXPECT_TRUE(headers[2].generic->active_decode_targets[kS1T0]);
+
+  EXPECT_EQ(headers[0].generic->decode_target_indications[kS0T0],
+            DecodeTargetIndication::kSwitch);
+
+  EXPECT_EQ(headers[1].generic->decode_target_indications[kS0T0],
+            DecodeTargetIndication::kSwitch);
+
+  EXPECT_EQ(headers[2].generic->decode_target_indications[kS0T0],
+            DecodeTargetIndication::kNotPresent);
+  EXPECT_EQ(headers[2].generic->decode_target_indications[kS1T0],
+            DecodeTargetIndication::kSwitch);
+
+  EXPECT_THAT(headers[0].generic->dependencies, IsEmpty());       // S0, 1
+  EXPECT_THAT(headers[1].generic->dependencies, ElementsAre(1));  // S0, 3
+  EXPECT_THAT(headers[2].generic->dependencies, ElementsAre(3));  // S1, 5
+
+  EXPECT_EQ(headers[0].generic->chain_diffs[0], 0);
+
+  EXPECT_EQ(headers[1].generic->chain_diffs[0], 2);
+  EXPECT_EQ(headers[1].generic->chain_diffs[1], 0);
+
+  EXPECT_EQ(headers[2].generic->chain_diffs[0], 2);
+  EXPECT_EQ(headers[2].generic->chain_diffs[1], 2);
+}
+
+class RtpPayloadParamsH264ToGenericTest : public ::testing::Test {
+ public:
+  enum LayerSync { kNoSync, kSync };
+
+  RtpPayloadParamsH264ToGenericTest()
+      : state_(), params_(123, &state_, trials_config_) {}
+
+  void ConvertAndCheck(int temporal_index,
+                       int64_t shared_frame_id,
+                       VideoFrameType frame_type,
+                       LayerSync layer_sync,
+                       const std::set<int64_t>& expected_deps,
+                       uint16_t width = 0,
+                       uint16_t height = 0) {
+    EncodedImage encoded_image;
+    encoded_image._frameType = frame_type;
+    encoded_image._encodedWidth = width;
+    encoded_image._encodedHeight = height;
+
+    CodecSpecificInfo codec_info;
+    codec_info.codecType = kVideoCodecH264;
+    codec_info.codecSpecific.H264.temporal_idx = temporal_index;
+    codec_info.codecSpecific.H264.base_layer_sync = layer_sync == kSync;
+
+    RTPVideoHeader header =
+        params_.GetRtpVideoHeader(encoded_image, &codec_info, shared_frame_id);
+
+    ASSERT_TRUE(header.generic);
+    EXPECT_EQ(header.generic->spatial_index, 0);
+
+    EXPECT_EQ(header.generic->frame_id, shared_frame_id);
+    EXPECT_EQ(header.generic->temporal_index, temporal_index);
+    std::set<int64_t> actual_deps(header.generic->dependencies.begin(),
+                                  header.generic->dependencies.end());
+    EXPECT_EQ(expected_deps, actual_deps);
+
+    EXPECT_EQ(header.width, width);
+    EXPECT_EQ(header.height, height);
+  }
+
+ protected:
+  FieldTrialBasedConfig trials_config_;
+  RtpPayloadState state_;
+  RtpPayloadParams params_;
+};
+
+TEST_F(RtpPayloadParamsH264ToGenericTest, Keyframe) {
+  ConvertAndCheck(0, 0, VideoFrameType::kVideoFrameKey, kNoSync, {}, 480, 360);
+  ConvertAndCheck(0, 1, VideoFrameType::kVideoFrameDelta, kNoSync, {0});
+  ConvertAndCheck(0, 2, VideoFrameType::kVideoFrameKey, kNoSync, {}, 480, 360);
+}
+
+TEST_F(RtpPayloadParamsH264ToGenericTest, TooHighTemporalIndex) {
+  ConvertAndCheck(0, 0, VideoFrameType::kVideoFrameKey, kNoSync, {}, 480, 360);
+
+  EncodedImage encoded_image;
+  encoded_image._frameType = VideoFrameType::kVideoFrameDelta;
+  CodecSpecificInfo codec_info;
+  codec_info.codecType = kVideoCodecH264;
+  codec_info.codecSpecific.H264.temporal_idx =
+      RtpGenericFrameDescriptor::kMaxTemporalLayers;
+  codec_info.codecSpecific.H264.base_layer_sync = false;
+
+  RTPVideoHeader header =
+      params_.GetRtpVideoHeader(encoded_image, &codec_info, 1);
+  EXPECT_FALSE(header.generic);
+}
+
+TEST_F(RtpPayloadParamsH264ToGenericTest, LayerSync) {
+  // 02120212 pattern
+  ConvertAndCheck(0, 0, VideoFrameType::kVideoFrameKey, kNoSync, {}, 480, 360);
+  ConvertAndCheck(2, 1, VideoFrameType::kVideoFrameDelta, kNoSync, {0});
+  ConvertAndCheck(1, 2, VideoFrameType::kVideoFrameDelta, kNoSync, {0});
+  ConvertAndCheck(2, 3, VideoFrameType::kVideoFrameDelta, kNoSync, {0, 1, 2});
+
+  ConvertAndCheck(0, 4, VideoFrameType::kVideoFrameDelta, kNoSync, {0});
+  ConvertAndCheck(2, 5, VideoFrameType::kVideoFrameDelta, kNoSync, {2, 3, 4});
+  ConvertAndCheck(1, 6, VideoFrameType::kVideoFrameDelta, kSync,
+                  {4});  // layer sync
+  ConvertAndCheck(2, 7, VideoFrameType::kVideoFrameDelta, kNoSync, {4, 5, 6});
+}
+
+TEST_F(RtpPayloadParamsH264ToGenericTest, FrameIdGaps) {
+  // 0101 pattern
+  ConvertAndCheck(0, 0, VideoFrameType::kVideoFrameKey, kNoSync, {}, 480, 360);
+  ConvertAndCheck(1, 1, VideoFrameType::kVideoFrameDelta, kNoSync, {0});
+
+  ConvertAndCheck(0, 5, VideoFrameType::kVideoFrameDelta, kNoSync, {0});
+  ConvertAndCheck(1, 10, VideoFrameType::kVideoFrameDelta, kNoSync, {1, 5});
+
+  ConvertAndCheck(0, 15, VideoFrameType::kVideoFrameDelta, kNoSync, {5});
+  ConvertAndCheck(1, 20, VideoFrameType::kVideoFrameDelta, kNoSync, {10, 15});
+}
+
+}  // namespace
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/rtp_receiver_gn/moz.build b/third_party/libwebrtc/call/rtp_receiver_gn/moz.build
new file mode 100644
index 0000000000..481a02fe55
--- /dev/null
+++ b/third_party/libwebrtc/call/rtp_receiver_gn/moz.build
@@ -0,0 +1,234 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+  ### This moz.build was AUTOMATICALLY GENERATED from a GN config,  ###
+  ### DO NOT edit it by hand.                                       ###
+
+COMPILE_FLAGS["OS_INCLUDES"] = []
+AllowCompilerWarnings()
+
+DEFINES["ABSL_ALLOCATOR_NOTHROW"] = "1"
+DEFINES["RTC_DAV1D_IN_INTERNAL_DECODER_FACTORY"] = True
+DEFINES["RTC_ENABLE_VP9"] = True
+DEFINES["WEBRTC_ENABLE_PROTOBUF"] = "0"
+DEFINES["WEBRTC_LIBRARY_IMPL"] = True
+DEFINES["WEBRTC_MOZILLA_BUILD"] = True
+DEFINES["WEBRTC_NON_STATIC_TRACE_EVENT_HANDLERS"] = "0"
+DEFINES["WEBRTC_STRICT_FIELD_TRIALS"] = "0"
+
+FINAL_LIBRARY = "webrtc"
+
+
+LOCAL_INCLUDES += [
+    "!/ipc/ipdl/_ipdlheaders",
+    "!/third_party/libwebrtc/gen",
+    "/ipc/chromium/src",
+    "/third_party/libwebrtc/",
+    "/third_party/libwebrtc/third_party/abseil-cpp/",
+    "/tools/profiler/public"
+]
+
+UNIFIED_SOURCES += [
+    "/third_party/libwebrtc/call/rtp_demuxer.cc",
+    "/third_party/libwebrtc/call/rtp_stream_receiver_controller.cc",
+    "/third_party/libwebrtc/call/rtx_receive_stream.cc"
+]
+
+if not CONFIG["MOZ_DEBUG"]:
+
+    DEFINES["DYNAMIC_ANNOTATIONS_ENABLED"] = "0"
+    DEFINES["NDEBUG"] = True
+    DEFINES["NVALGRIND"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1":
+
+    DEFINES["DYNAMIC_ANNOTATIONS_ENABLED"] = "1"
+
+if CONFIG["OS_TARGET"] == "Android":
+
+    DEFINES["ANDROID"] = True
+    DEFINES["ANDROID_NDK_VERSION_ROLL"] = "r22_1"
+    DEFINES["HAVE_SYS_UIO_H"] = True
+    DEFINES["WEBRTC_ANDROID"] = True
+    DEFINES["WEBRTC_ANDROID_OPENSLES"] = True
+    DEFINES["WEBRTC_LINUX"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_GNU_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+    OS_LIBS += [
+        "log"
+    ]
+
+if CONFIG["OS_TARGET"] == "Darwin":
+
+    DEFINES["WEBRTC_MAC"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_LIBCPP_HAS_NO_ALIGNED_ALLOCATION"] = True
+    DEFINES["__ASSERT_MACROS_DEFINE_VERSIONS_WITHOUT_UNDERSCORES"] = "0"
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+if CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["USE_AURA"] = "1"
+    DEFINES["USE_GLIB"] = "1"
+    DEFINES["USE_NSS_CERTS"] = "1"
+    DEFINES["USE_OZONE"] = "1"
+    DEFINES["USE_UDEV"] = True
+    DEFINES["WEBRTC_LINUX"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_FILE_OFFSET_BITS"] = "64"
+    DEFINES["_LARGEFILE64_SOURCE"] = True
+    DEFINES["_LARGEFILE_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+    OS_LIBS += [
+        "rt"
+    ]
+
+if CONFIG["OS_TARGET"] == "OpenBSD":
+
+    DEFINES["USE_GLIB"] = "1"
+    DEFINES["USE_OZONE"] = "1"
+    DEFINES["USE_X11"] = "1"
+    DEFINES["WEBRTC_BSD"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_FILE_OFFSET_BITS"] = "64"
+    DEFINES["_LARGEFILE64_SOURCE"] = True
+    DEFINES["_LARGEFILE_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+if CONFIG["OS_TARGET"] == "WINNT":
+
+    DEFINES["CERT_CHAIN_PARA_HAS_EXTRA_FIELDS"] = True
+    DEFINES["NOMINMAX"] = True
+    DEFINES["NTDDI_VERSION"] = "0x0A000000"
+    DEFINES["PSAPI_VERSION"] = "2"
+    DEFINES["UNICODE"] = True
+    DEFINES["USE_AURA"] = "1"
+    DEFINES["WEBRTC_WIN"] = True
+    DEFINES["WIN32"] = True
+    DEFINES["WIN32_LEAN_AND_MEAN"] = True
+    DEFINES["WINAPI_FAMILY"] = "WINAPI_FAMILY_DESKTOP_APP"
+    DEFINES["WINVER"] = "0x0A00"
+    DEFINES["_ATL_NO_OPENGL"] = True
+    DEFINES["_CRT_RAND_S"] = True
+    DEFINES["_CRT_SECURE_NO_DEPRECATE"] = True
+    DEFINES["_ENABLE_EXTENDED_ALIGNED_STORAGE"] = True
+    DEFINES["_HAS_EXCEPTIONS"] = "0"
+    DEFINES["_HAS_NODISCARD"] = True
+    DEFINES["_SCL_SECURE_NO_DEPRECATE"] = True
+    DEFINES["_SECURE_ATL"] = True
+    DEFINES["_UNICODE"] = True
+    DEFINES["_WIN32_WINNT"] = "0x0A00"
+    DEFINES["_WINDOWS"] = True
+    DEFINES["__STD_C"] = True
+
+    OS_LIBS += [
+        "crypt32",
+        "iphlpapi",
+        "secur32",
+        "winmm"
+    ]
+
+if CONFIG["CPU_ARCH"] == "aarch64":
+
+    DEFINES["WEBRTC_ARCH_ARM64"] = True
+    DEFINES["WEBRTC_HAS_NEON"] = True
+
+if CONFIG["CPU_ARCH"] == "arm":
+
+    CXXFLAGS += [
+        "-mfpu=neon"
+    ]
+
+    DEFINES["WEBRTC_ARCH_ARM"] = True
+    DEFINES["WEBRTC_ARCH_ARM_V7"] = True
+    DEFINES["WEBRTC_HAS_NEON"] = True
+
+if CONFIG["CPU_ARCH"] == "mips32":
+
+    DEFINES["MIPS32_LE"] = True
+    DEFINES["MIPS_FPU_LE"] = True
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "mips64":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86":
+
+    DEFINES["WEBRTC_ENABLE_AVX2"] = True
+
+if CONFIG["CPU_ARCH"] == "x86_64":
+
+    DEFINES["WEBRTC_ENABLE_AVX2"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Android":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Darwin":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "OpenBSD":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "WINNT":
+
+    DEFINES["_HAS_ITERATOR_DEBUGGING"] = "0"
+
+if CONFIG["MOZ_X11"] == "1" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["USE_X11"] = "1"
+
+if CONFIG["CPU_ARCH"] == "arm" and CONFIG["OS_TARGET"] == "Android":
+
+    OS_LIBS += [
+        "android_support",
+        "unwind"
+    ]
+
+if CONFIG["CPU_ARCH"] == "x86" and CONFIG["OS_TARGET"] == "Android":
+
+    CXXFLAGS += [
+        "-msse2"
+    ]
+
+    OS_LIBS += [
+        "android_support"
+    ]
+
+if CONFIG["CPU_ARCH"] == "aarch64" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "arm" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86" and CONFIG["OS_TARGET"] == "Linux":
+
+    CXXFLAGS += [
+        "-msse2"
+    ]
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86_64" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+Library("rtp_receiver_gn")
diff --git a/third_party/libwebrtc/call/rtp_sender_gn/moz.build b/third_party/libwebrtc/call/rtp_sender_gn/moz.build
new file mode 100644
index 0000000000..f823d8ea77
--- /dev/null
+++ b/third_party/libwebrtc/call/rtp_sender_gn/moz.build
@@ -0,0 +1,234 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+  ### This moz.build was AUTOMATICALLY GENERATED from a GN config,  ###
+  ### DO NOT edit it by hand.                                       ###
+
+COMPILE_FLAGS["OS_INCLUDES"] = []
+AllowCompilerWarnings()
+
+DEFINES["ABSL_ALLOCATOR_NOTHROW"] = "1"
+DEFINES["RTC_DAV1D_IN_INTERNAL_DECODER_FACTORY"] = True
+DEFINES["RTC_ENABLE_VP9"] = True
+DEFINES["WEBRTC_ENABLE_PROTOBUF"] = "0"
+DEFINES["WEBRTC_LIBRARY_IMPL"] = True
+DEFINES["WEBRTC_MOZILLA_BUILD"] = True
+DEFINES["WEBRTC_NON_STATIC_TRACE_EVENT_HANDLERS"] = "0"
+DEFINES["WEBRTC_STRICT_FIELD_TRIALS"] = "0"
+
+FINAL_LIBRARY = "webrtc"
+
+
+LOCAL_INCLUDES += [
+    "!/ipc/ipdl/_ipdlheaders",
+    "!/third_party/libwebrtc/gen",
+    "/ipc/chromium/src",
+    "/third_party/libwebrtc/",
+    "/third_party/libwebrtc/third_party/abseil-cpp/",
+    "/tools/profiler/public"
+]
+
+UNIFIED_SOURCES += [
+    "/third_party/libwebrtc/call/rtp_payload_params.cc",
+    "/third_party/libwebrtc/call/rtp_transport_controller_send.cc",
+    "/third_party/libwebrtc/call/rtp_video_sender.cc"
+]
+
+if not CONFIG["MOZ_DEBUG"]:
+
+    DEFINES["DYNAMIC_ANNOTATIONS_ENABLED"] = "0"
+    DEFINES["NDEBUG"] = True
+    DEFINES["NVALGRIND"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1":
+
+    DEFINES["DYNAMIC_ANNOTATIONS_ENABLED"] = "1"
+
+if CONFIG["OS_TARGET"] == "Android":
+
+    DEFINES["ANDROID"] = True
+    DEFINES["ANDROID_NDK_VERSION_ROLL"] = "r22_1"
+    DEFINES["HAVE_SYS_UIO_H"] = True
+    DEFINES["WEBRTC_ANDROID"] = True
+    DEFINES["WEBRTC_ANDROID_OPENSLES"] = True
+    DEFINES["WEBRTC_LINUX"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_GNU_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+    OS_LIBS += [
+        "log"
+    ]
+
+if CONFIG["OS_TARGET"] == "Darwin":
+
+    DEFINES["WEBRTC_MAC"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_LIBCPP_HAS_NO_ALIGNED_ALLOCATION"] = True
+    DEFINES["__ASSERT_MACROS_DEFINE_VERSIONS_WITHOUT_UNDERSCORES"] = "0"
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+if CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["USE_AURA"] = "1"
+    DEFINES["USE_GLIB"] = "1"
+    DEFINES["USE_NSS_CERTS"] = "1"
+    DEFINES["USE_OZONE"] = "1"
+    DEFINES["USE_UDEV"] = True
+    DEFINES["WEBRTC_LINUX"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_FILE_OFFSET_BITS"] = "64"
+    DEFINES["_LARGEFILE64_SOURCE"] = True
+    DEFINES["_LARGEFILE_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+    OS_LIBS += [
+        "rt"
+    ]
+
+if CONFIG["OS_TARGET"] == "OpenBSD":
+
+    DEFINES["USE_GLIB"] = "1"
+    DEFINES["USE_OZONE"] = "1"
+    DEFINES["USE_X11"] = "1"
+    DEFINES["WEBRTC_BSD"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_FILE_OFFSET_BITS"] = "64"
+    DEFINES["_LARGEFILE64_SOURCE"] = True
+    DEFINES["_LARGEFILE_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+if CONFIG["OS_TARGET"] == "WINNT":
+
+    DEFINES["CERT_CHAIN_PARA_HAS_EXTRA_FIELDS"] = True
+    DEFINES["NOMINMAX"] = True
+    DEFINES["NTDDI_VERSION"] = "0x0A000000"
+    DEFINES["PSAPI_VERSION"] = "2"
+    DEFINES["UNICODE"] = True
+    DEFINES["USE_AURA"] = "1"
+    DEFINES["WEBRTC_WIN"] = True
+    DEFINES["WIN32"] = True
+    DEFINES["WIN32_LEAN_AND_MEAN"] = True
+    DEFINES["WINAPI_FAMILY"] = "WINAPI_FAMILY_DESKTOP_APP"
+    DEFINES["WINVER"] = "0x0A00"
+    DEFINES["_ATL_NO_OPENGL"] = True
+    DEFINES["_CRT_RAND_S"] = True
+    DEFINES["_CRT_SECURE_NO_DEPRECATE"] = True
+    DEFINES["_ENABLE_EXTENDED_ALIGNED_STORAGE"] = True
+    DEFINES["_HAS_EXCEPTIONS"] = "0"
+    DEFINES["_HAS_NODISCARD"] = True
+    DEFINES["_SCL_SECURE_NO_DEPRECATE"] = True
+    DEFINES["_SECURE_ATL"] = True
+    DEFINES["_UNICODE"] = True
+    DEFINES["_WIN32_WINNT"] = "0x0A00"
+    DEFINES["_WINDOWS"] = True
+    DEFINES["__STD_C"] = True
+
+    OS_LIBS += [
+        "crypt32",
+        "iphlpapi",
+        "secur32",
+        "winmm"
+    ]
+
+if CONFIG["CPU_ARCH"] == "aarch64":
+
+    DEFINES["WEBRTC_ARCH_ARM64"] = True
+    DEFINES["WEBRTC_HAS_NEON"] = True
+
+if CONFIG["CPU_ARCH"] == "arm":
+
+    CXXFLAGS += [
+        "-mfpu=neon"
+    ]
+
+    DEFINES["WEBRTC_ARCH_ARM"] = True
+    DEFINES["WEBRTC_ARCH_ARM_V7"] = True
+    DEFINES["WEBRTC_HAS_NEON"] = True
+
+if CONFIG["CPU_ARCH"] == "mips32":
+
+    DEFINES["MIPS32_LE"] = True
+    DEFINES["MIPS_FPU_LE"] = True
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "mips64":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86":
+
+    DEFINES["WEBRTC_ENABLE_AVX2"] = True
+
+if CONFIG["CPU_ARCH"] == "x86_64":
+
+    DEFINES["WEBRTC_ENABLE_AVX2"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Android":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Darwin":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "OpenBSD":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "WINNT":
+
+    DEFINES["_HAS_ITERATOR_DEBUGGING"] = "0"
+
+if CONFIG["MOZ_X11"] == "1" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["USE_X11"] = "1"
+
+if CONFIG["CPU_ARCH"] == "arm" and CONFIG["OS_TARGET"] == "Android":
+
+    OS_LIBS += [
+        "android_support",
+        "unwind"
+    ]
+
+if CONFIG["CPU_ARCH"] == "x86" and CONFIG["OS_TARGET"] == "Android":
+
+    CXXFLAGS += [
+        "-msse2"
+    ]
+
+    OS_LIBS += [
+        "android_support"
+    ]
+
+if CONFIG["CPU_ARCH"] == "aarch64" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "arm" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86" and CONFIG["OS_TARGET"] == "Linux":
+
+    CXXFLAGS += [
+        "-msse2"
+    ]
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86_64" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+Library("rtp_sender_gn")
diff --git a/third_party/libwebrtc/call/rtp_stream_receiver_controller.cc b/third_party/libwebrtc/call/rtp_stream_receiver_controller.cc
new file mode 100644
index 0000000000..993a4fc76e
--- /dev/null
+++ b/third_party/libwebrtc/call/rtp_stream_receiver_controller.cc
@@ -0,0 +1,71 @@
+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/rtp_stream_receiver_controller.h"
+
+#include <memory>
+
+#include "rtc_base/logging.h"
+
+namespace webrtc {
+
+RtpStreamReceiverController::Receiver::Receiver(
+    RtpStreamReceiverController* controller,
+    uint32_t ssrc,
+    RtpPacketSinkInterface* sink)
+    : controller_(controller), sink_(sink) {
+  const bool sink_added = controller_->AddSink(ssrc, sink_);
+  if (!sink_added) {
+    RTC_LOG(LS_ERROR)
+        << "RtpStreamReceiverController::Receiver::Receiver: Sink "
+           "could not be added for SSRC="
+        << ssrc << ".";
+  }
+}
+
+RtpStreamReceiverController::Receiver::~Receiver() {
+  // This may fail, if corresponding AddSink in the constructor failed.
+  controller_->RemoveSink(sink_);
+}
+
+RtpStreamReceiverController::RtpStreamReceiverController() {}
+
+RtpStreamReceiverController::~RtpStreamReceiverController() = default;
+
+std::unique_ptr<RtpStreamReceiverInterface>
+RtpStreamReceiverController::CreateReceiver(uint32_t ssrc,
+                                            RtpPacketSinkInterface* sink) {
+  return std::make_unique<Receiver>(this, ssrc, sink);
+}
+
+bool RtpStreamReceiverController::OnRtpPacket(const RtpPacketReceived& packet) {
+  RTC_DCHECK_RUN_ON(&demuxer_sequence_);
+  return demuxer_.OnRtpPacket(packet);
+}
+
+void RtpStreamReceiverController::OnRecoveredPacket(
+    const RtpPacketReceived& packet) {
+  RTC_DCHECK_RUN_ON(&demuxer_sequence_);
+  demuxer_.OnRtpPacket(packet);
+}
+
+bool RtpStreamReceiverController::AddSink(uint32_t ssrc,
+                                          RtpPacketSinkInterface* sink) {
+  RTC_DCHECK_RUN_ON(&demuxer_sequence_);
+  return demuxer_.AddSink(ssrc, sink);
+}
+
+bool RtpStreamReceiverController::RemoveSink(
+    const RtpPacketSinkInterface* sink) {
+  RTC_DCHECK_RUN_ON(&demuxer_sequence_);
+  return demuxer_.RemoveSink(sink);
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/rtp_stream_receiver_controller.h b/third_party/libwebrtc/call/rtp_stream_receiver_controller.h
new file mode 100644
index 0000000000..1040632639
--- /dev/null
+++ b/third_party/libwebrtc/call/rtp_stream_receiver_controller.h
@@ -0,0 +1,80 @@
+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+#ifndef CALL_RTP_STREAM_RECEIVER_CONTROLLER_H_
+#define CALL_RTP_STREAM_RECEIVER_CONTROLLER_H_
+
+#include <memory>
+
+#include "api/sequence_checker.h"
+#include "call/rtp_demuxer.h"
+#include "call/rtp_stream_receiver_controller_interface.h"
+#include "modules/rtp_rtcp/include/recovered_packet_receiver.h"
+
+namespace webrtc {
+
+class RtpPacketReceived;
+
+// This class represents the RTP receive parsing and demuxing, for a
+// single RTP session.
+// TODO(bugs.webrtc.org/7135): Add RTCP processing, we should aim to terminate
+// RTCP and not leave any RTCP processing to individual receive streams.
+class RtpStreamReceiverController : public RtpStreamReceiverControllerInterface,
+                                    public RecoveredPacketReceiver {
+ public:
+  RtpStreamReceiverController();
+  ~RtpStreamReceiverController() override;
+
+  // Implements RtpStreamReceiverControllerInterface.
+  std::unique_ptr<RtpStreamReceiverInterface> CreateReceiver(
+      uint32_t ssrc,
+      RtpPacketSinkInterface* sink) override;
+
+  // TODO(bugs.webrtc.org/7135): Not yet responsible for parsing.
+  bool OnRtpPacket(const RtpPacketReceived& packet);
+
+  // Implements RecoveredPacketReceiver.
+  // Responsible for demuxing recovered FLEXFEC packets.
+  void OnRecoveredPacket(const RtpPacketReceived& packet) override;
+
+ private:
+  class Receiver : public RtpStreamReceiverInterface {
+   public:
+    Receiver(RtpStreamReceiverController* controller,
+             uint32_t ssrc,
+             RtpPacketSinkInterface* sink);
+
+    ~Receiver() override;
+
+   private:
+    RtpStreamReceiverController* const controller_;
+    RtpPacketSinkInterface* const sink_;
+  };
+
+  // Thread-safe wrappers for the corresponding RtpDemuxer methods.
+  bool AddSink(uint32_t ssrc, RtpPacketSinkInterface* sink);
+  bool RemoveSink(const RtpPacketSinkInterface* sink);
+
+  // TODO(bugs.webrtc.org/11993): We expect construction and all methods to be
+  // called on the same thread/tq. Currently this is the worker thread
+  // (including OnRtpPacket) but a more natural fit would be the network thread.
+  // Using a sequence checker to ensure that usage is correct but at the same
+  // time not require a specific thread/tq, an instance of this class + the
+  // associated functionality should be easily moved from one execution context
+  // to another (i.e. when network packets don't hop to the worker thread inside
+  // of Call).
+  SequenceChecker demuxer_sequence_;
+  // At this level the demuxer is only configured to demux by SSRC, so don't
+  // worry about MIDs (MIDs are handled by upper layers).
+  RtpDemuxer demuxer_ RTC_GUARDED_BY(&demuxer_sequence_){false /*use_mid*/};
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_RTP_STREAM_RECEIVER_CONTROLLER_H_
diff --git a/third_party/libwebrtc/call/rtp_stream_receiver_controller_interface.h b/third_party/libwebrtc/call/rtp_stream_receiver_controller_interface.h
new file mode 100644
index 0000000000..793d0bc145
--- /dev/null
+++ b/third_party/libwebrtc/call/rtp_stream_receiver_controller_interface.h
@@ -0,0 +1,43 @@
+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+#ifndef CALL_RTP_STREAM_RECEIVER_CONTROLLER_INTERFACE_H_
+#define CALL_RTP_STREAM_RECEIVER_CONTROLLER_INTERFACE_H_
+
+#include <memory>
+
+#include "call/rtp_packet_sink_interface.h"
+
+namespace webrtc {
+
+// An RtpStreamReceiver is responsible for the rtp-specific but
+// media-independent state needed for receiving an RTP stream.
+// TODO(bugs.webrtc.org/7135): Currently, only owns the association between ssrc
+// and the stream's RtpPacketSinkInterface. Ownership of corresponding objects
+// from modules/rtp_rtcp/ should move to this class (or rather, the
+// corresponding implementation class). We should add methods for getting rtp
+// receive stats, and for sending RTCP messages related to the receive stream.
+class RtpStreamReceiverInterface {
+ public:
+  virtual ~RtpStreamReceiverInterface() {}
+};
+
+// This class acts as a factory for RtpStreamReceiver objects.
+class RtpStreamReceiverControllerInterface {
+ public:
+  virtual ~RtpStreamReceiverControllerInterface() {}
+
+  virtual std::unique_ptr<RtpStreamReceiverInterface> CreateReceiver(
+      uint32_t ssrc,
+      RtpPacketSinkInterface* sink) = 0;
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_RTP_STREAM_RECEIVER_CONTROLLER_INTERFACE_H_
diff --git a/third_party/libwebrtc/call/rtp_transport_config.h b/third_party/libwebrtc/call/rtp_transport_config.h
new file mode 100644
index 0000000000..6c94f7d911
--- /dev/null
+++ b/third_party/libwebrtc/call/rtp_transport_config.h
@@ -0,0 +1,53 @@
+/*
+ *  Copyright (c) 2021 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_RTP_TRANSPORT_CONFIG_H_
+#define CALL_RTP_TRANSPORT_CONFIG_H_
+
+#include <memory>
+
+#include "api/field_trials_view.h"
+#include "api/network_state_predictor.h"
+#include "api/rtc_event_log/rtc_event_log.h"
+#include "api/transport/bitrate_settings.h"
+#include "api/transport/network_control.h"
+#include "rtc_base/task_queue.h"
+
+namespace webrtc {
+
+struct RtpTransportConfig {
+  // Bitrate config used until valid bitrate estimates are calculated. Also
+  // used to cap total bitrate used. This comes from the remote connection.
+  BitrateConstraints bitrate_config;
+
+  // RtcEventLog to use for this call. Required.
+  // Use webrtc::RtcEventLog::CreateNull() for a null implementation.
+  RtcEventLog* event_log = nullptr;
+
+  // Task Queue Factory to be used in this call. Required.
+  TaskQueueFactory* task_queue_factory = nullptr;
+
+  // NetworkStatePredictor to use for this call.
+  NetworkStatePredictorFactoryInterface* network_state_predictor_factory =
+      nullptr;
+
+  // Network controller factory to use for this call.
+  NetworkControllerFactoryInterface* network_controller_factory = nullptr;
+
+  // Key-value mapping of internal configurations to apply,
+  // e.g. field trials.
+  const FieldTrialsView* trials = nullptr;
+
+  // The burst interval of the pacer, see TaskQueuePacedSender constructor.
+  absl::optional<TimeDelta> pacer_burst_interval;
+};
+}  // namespace webrtc
+
+#endif  // CALL_RTP_TRANSPORT_CONFIG_H_
diff --git a/third_party/libwebrtc/call/rtp_transport_controller_send.cc b/third_party/libwebrtc/call/rtp_transport_controller_send.cc
new file mode 100644
index 0000000000..940dff7894
--- /dev/null
+++ b/third_party/libwebrtc/call/rtp_transport_controller_send.cc
@@ -0,0 +1,723 @@
+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+#include "call/rtp_transport_controller_send.h"
+
+#include <memory>
+#include <utility>
+#include <vector>
+
+#include "absl/strings/match.h"
+#include "absl/strings/string_view.h"
+#include "absl/types/optional.h"
+#include "api/task_queue/pending_task_safety_flag.h"
+#include "api/transport/goog_cc_factory.h"
+#include "api/transport/network_types.h"
+#include "api/units/data_rate.h"
+#include "api/units/time_delta.h"
+#include "api/units/timestamp.h"
+#include "call/rtp_video_sender.h"
+#include "logging/rtc_event_log/events/rtc_event_remote_estimate.h"
+#include "logging/rtc_event_log/events/rtc_event_route_change.h"
+#include "modules/rtp_rtcp/source/rtcp_packet/transport_feedback.h"
+#include "rtc_base/checks.h"
+#include "rtc_base/logging.h"
+#include "rtc_base/rate_limiter.h"
+
+namespace webrtc {
+namespace {
+static const int64_t kRetransmitWindowSizeMs = 500;
+static const size_t kMaxOverheadBytes = 500;
+
+constexpr TimeDelta kPacerQueueUpdateInterval = TimeDelta::Millis(25);
+
+TargetRateConstraints ConvertConstraints(int min_bitrate_bps,
+                                         int max_bitrate_bps,
+                                         int start_bitrate_bps,
+                                         Clock* clock) {
+  TargetRateConstraints msg;
+  msg.at_time = Timestamp::Millis(clock->TimeInMilliseconds());
+  msg.min_data_rate = min_bitrate_bps >= 0
+                          ? DataRate::BitsPerSec(min_bitrate_bps)
+                          : DataRate::Zero();
+  msg.max_data_rate = max_bitrate_bps > 0
+                          ? DataRate::BitsPerSec(max_bitrate_bps)
+                          : DataRate::Infinity();
+  if (start_bitrate_bps > 0)
+    msg.starting_rate = DataRate::BitsPerSec(start_bitrate_bps);
+  return msg;
+}
+
+TargetRateConstraints ConvertConstraints(const BitrateConstraints& contraints,
+                                         Clock* clock) {
+  return ConvertConstraints(contraints.min_bitrate_bps,
+                            contraints.max_bitrate_bps,
+                            contraints.start_bitrate_bps, clock);
+}
+
+bool IsEnabled(const FieldTrialsView& trials, absl::string_view key) {
+  return absl::StartsWith(trials.Lookup(key), "Enabled");
+}
+
+bool IsRelayed(const rtc::NetworkRoute& route) {
+  return route.local.uses_turn() || route.remote.uses_turn();
+}
+}  // namespace
+
+RtpTransportControllerSend::PacerSettings::PacerSettings(
+    const FieldTrialsView& trials)
+    : holdback_window("holdback_window", TimeDelta::Millis(5)),
+      holdback_packets("holdback_packets", 3) {
+  ParseFieldTrial({&holdback_window, &holdback_packets},
+                  trials.Lookup("WebRTC-TaskQueuePacer"));
+}
+
+RtpTransportControllerSend::RtpTransportControllerSend(
+    Clock* clock,
+    const RtpTransportConfig& config)
+    : clock_(clock),
+      event_log_(config.event_log),
+      task_queue_factory_(config.task_queue_factory),
+      bitrate_configurator_(config.bitrate_config),
+      pacer_started_(false),
+      pacer_settings_(*config.trials),
+      pacer_(clock,
+             &packet_router_,
+             *config.trials,
+             config.task_queue_factory,
+             pacer_settings_.holdback_window.Get(),
+             pacer_settings_.holdback_packets.Get(),
+             config.pacer_burst_interval),
+      observer_(nullptr),
+      controller_factory_override_(config.network_controller_factory),
+      controller_factory_fallback_(
+          std::make_unique<GoogCcNetworkControllerFactory>(
+              config.network_state_predictor_factory)),
+      process_interval_(controller_factory_fallback_->GetProcessInterval()),
+      last_report_block_time_(Timestamp::Millis(clock_->TimeInMilliseconds())),
+      reset_feedback_on_route_change_(
+          !IsEnabled(*config.trials, "WebRTC-Bwe-NoFeedbackReset")),
+      add_pacing_to_cwin_(
+          IsEnabled(*config.trials,
+                    "WebRTC-AddPacingToCongestionWindowPushback")),
+      relay_bandwidth_cap_("relay_cap", DataRate::PlusInfinity()),
+      transport_overhead_bytes_per_packet_(0),
+      network_available_(false),
+      congestion_window_size_(DataSize::PlusInfinity()),
+      is_congested_(false),
+      retransmission_rate_limiter_(clock, kRetransmitWindowSizeMs),
+      task_queue_(*config.trials,
+                  "rtp_send_controller",
+                  config.task_queue_factory),
+      field_trials_(*config.trials) {
+  ParseFieldTrial({&relay_bandwidth_cap_},
+                  config.trials->Lookup("WebRTC-Bwe-NetworkRouteConstraints"));
+  initial_config_.constraints =
+      ConvertConstraints(config.bitrate_config, clock_);
+  initial_config_.event_log = config.event_log;
+  initial_config_.key_value_config = config.trials;
+  RTC_DCHECK(config.bitrate_config.start_bitrate_bps > 0);
+
+  pacer_.SetPacingRates(
+      DataRate::BitsPerSec(config.bitrate_config.start_bitrate_bps),
+      DataRate::Zero());
+}
+
+RtpTransportControllerSend::~RtpTransportControllerSend() {
+  RTC_DCHECK_RUN_ON(&main_thread_);
+  RTC_DCHECK(video_rtp_senders_.empty());
+  if (task_queue_.IsCurrent()) {
+    // If these repeated tasks run on a task queue owned by
+    // `task_queue_`, they are stopped when the task queue is deleted.
+    // Otherwise, stop them here.
+    pacer_queue_update_task_.Stop();
+    controller_task_.Stop();
+  }
+}
+
+RtpVideoSenderInterface* RtpTransportControllerSend::CreateRtpVideoSender(
+    const std::map<uint32_t, RtpState>& suspended_ssrcs,
+    const std::map<uint32_t, RtpPayloadState>& states,
+    const RtpConfig& rtp_config,
+    int rtcp_report_interval_ms,
+    Transport* send_transport,
+    const RtpSenderObservers& observers,
+    RtcEventLog* event_log,
+    std::unique_ptr<FecController> fec_controller,
+    const RtpSenderFrameEncryptionConfig& frame_encryption_config,
+    rtc::scoped_refptr<FrameTransformerInterface> frame_transformer) {
+  RTC_DCHECK_RUN_ON(&main_thread_);
+  video_rtp_senders_.push_back(std::make_unique<RtpVideoSender>(
+      clock_, suspended_ssrcs, states, rtp_config, rtcp_report_interval_ms,
+      send_transport, observers,
+      // TODO(holmer): Remove this circular dependency by injecting
+      // the parts of RtpTransportControllerSendInterface that are really used.
+      this, event_log, &retransmission_rate_limiter_, std::move(fec_controller),
+      frame_encryption_config.frame_encryptor,
+      frame_encryption_config.crypto_options, std::move(frame_transformer),
+      field_trials_, task_queue_factory_));
+  return video_rtp_senders_.back().get();
+}
+
+void RtpTransportControllerSend::DestroyRtpVideoSender(
+    RtpVideoSenderInterface* rtp_video_sender) {
+  RTC_DCHECK_RUN_ON(&main_thread_);
+  std::vector<std::unique_ptr<RtpVideoSenderInterface>>::iterator it =
+      video_rtp_senders_.end();
+  for (it = video_rtp_senders_.begin(); it != video_rtp_senders_.end(); ++it) {
+    if (it->get() == rtp_video_sender) {
+      break;
+    }
+  }
+  RTC_DCHECK(it != video_rtp_senders_.end());
+  video_rtp_senders_.erase(it);
+}
+
+void RtpTransportControllerSend::UpdateControlState() {
+  absl::optional<TargetTransferRate> update = control_handler_->GetUpdate();
+  if (!update)
+    return;
+  retransmission_rate_limiter_.SetMaxRate(update->target_rate.bps());
+  // We won't create control_handler_ until we have an observers.
+  RTC_DCHECK(observer_ != nullptr);
+  observer_->OnTargetTransferRate(*update);
+}
+
+void RtpTransportControllerSend::UpdateCongestedState() {
+  bool congested = transport_feedback_adapter_.GetOutstandingData() >=
+                   congestion_window_size_;
+  if (congested != is_congested_) {
+    is_congested_ = congested;
+    pacer_.SetCongested(congested);
+  }
+}
+
+MaybeWorkerThread* RtpTransportControllerSend::GetWorkerQueue() {
+  return &task_queue_;
+}
+
+PacketRouter* RtpTransportControllerSend::packet_router() {
+  return &packet_router_;
+}
+
+NetworkStateEstimateObserver*
+RtpTransportControllerSend::network_state_estimate_observer() {
+  return this;
+}
+
+TransportFeedbackObserver*
+RtpTransportControllerSend::transport_feedback_observer() {
+  return this;
+}
+
+RtpPacketSender* RtpTransportControllerSend::packet_sender() {
+  return &pacer_;
+}
+
+void RtpTransportControllerSend::SetAllocatedSendBitrateLimits(
+    BitrateAllocationLimits limits) {
+  RTC_DCHECK_RUN_ON(&task_queue_);
+  streams_config_.min_total_allocated_bitrate = limits.min_allocatable_rate;
+  streams_config_.max_padding_rate = limits.max_padding_rate;
+  streams_config_.max_total_allocated_bitrate = limits.max_allocatable_rate;
+  UpdateStreamsConfig();
+}
+void RtpTransportControllerSend::SetPacingFactor(float pacing_factor) {
+  RTC_DCHECK_RUN_ON(&task_queue_);
+  streams_config_.pacing_factor = pacing_factor;
+  UpdateStreamsConfig();
+}
+void RtpTransportControllerSend::SetQueueTimeLimit(int limit_ms) {
+  pacer_.SetQueueTimeLimit(TimeDelta::Millis(limit_ms));
+}
+StreamFeedbackProvider*
+RtpTransportControllerSend::GetStreamFeedbackProvider() {
+  return &feedback_demuxer_;
+}
+
+void RtpTransportControllerSend::RegisterTargetTransferRateObserver(
+    TargetTransferRateObserver* observer) {
+  task_queue_.RunOrPost([this, observer] {
+    RTC_DCHECK_RUN_ON(&task_queue_);
+    RTC_DCHECK(observer_ == nullptr);
+    observer_ = observer;
+    observer_->OnStartRateUpdate(*initial_config_.constraints.starting_rate);
+    MaybeCreateControllers();
+  });
+}
+
+bool RtpTransportControllerSend::IsRelevantRouteChange(
+    const rtc::NetworkRoute& old_route,
+    const rtc::NetworkRoute& new_route) const {
+  // TODO(bugs.webrtc.org/11438): Experiment with using more information/
+  // other conditions.
+  bool connected_changed = old_route.connected != new_route.connected;
+  bool route_ids_changed =
+      old_route.local.network_id() != new_route.local.network_id() ||
+      old_route.remote.network_id() != new_route.remote.network_id();
+  if (relay_bandwidth_cap_->IsFinite()) {
+    bool relaying_changed = IsRelayed(old_route) != IsRelayed(new_route);
+    return connected_changed || route_ids_changed || relaying_changed;
+  } else {
+    return connected_changed || route_ids_changed;
+  }
+}
+
+void RtpTransportControllerSend::OnNetworkRouteChanged(
+    absl::string_view transport_name,
+    const rtc::NetworkRoute& network_route) {
+  // Check if the network route is connected.
+
+  if (!network_route.connected) {
+    // TODO(honghaiz): Perhaps handle this in SignalChannelNetworkState and
+    // consider merging these two methods.
+    return;
+  }
+
+  absl::optional<BitrateConstraints> relay_constraint_update =
+      ApplyOrLiftRelayCap(IsRelayed(network_route));
+
+  // Check whether the network route has changed on each transport.
+  auto result = network_routes_.insert(
+      // Explicit conversion of transport_name to std::string here is necessary
+      // to support some platforms that cannot yet deal with implicit
+      // conversion in these types of situations.
+      std::make_pair(std::string(transport_name), network_route));
+  auto kv = result.first;
+  bool inserted = result.second;
+  if (inserted || !(kv->second == network_route)) {
+    RTC_LOG(LS_INFO) << "Network route changed on transport " << transport_name
+                     << ": new_route = " << network_route.DebugString();
+    if (!inserted) {
+      RTC_LOG(LS_INFO) << "old_route = " << kv->second.DebugString();
+    }
+  }
+
+  if (inserted) {
+    if (relay_constraint_update.has_value()) {
+      UpdateBitrateConstraints(*relay_constraint_update);
+    }
+    task_queue_.RunOrPost([this, network_route] {
+      RTC_DCHECK_RUN_ON(&task_queue_);
+      transport_overhead_bytes_per_packet_ = network_route.packet_overhead;
+    });
+    // No need to reset BWE if this is the first time the network connects.
+    return;
+  }
+
+  const rtc::NetworkRoute old_route = kv->second;
+  kv->second = network_route;
+
+  // Check if enough conditions of the new/old route has changed
+  // to trigger resetting of bitrates (and a probe).
+  if (IsRelevantRouteChange(old_route, network_route)) {
+    BitrateConstraints bitrate_config = bitrate_configurator_.GetConfig();
+    RTC_LOG(LS_INFO) << "Reset bitrates to min: "
+                     << bitrate_config.min_bitrate_bps
+                     << " bps, start: " << bitrate_config.start_bitrate_bps
+                     << " bps,  max: " << bitrate_config.max_bitrate_bps
+                     << " bps.";
+    RTC_DCHECK_GT(bitrate_config.start_bitrate_bps, 0);
+
+    if (event_log_) {
+      event_log_->Log(std::make_unique<RtcEventRouteChange>(
+          network_route.connected, network_route.packet_overhead));
+    }
+    NetworkRouteChange msg;
+    msg.at_time = Timestamp::Millis(clock_->TimeInMilliseconds());
+    msg.constraints = ConvertConstraints(bitrate_config, clock_);
+    task_queue_.RunOrPost([this, msg, network_route] {
+      RTC_DCHECK_RUN_ON(&task_queue_);
+      transport_overhead_bytes_per_packet_ = network_route.packet_overhead;
+      if (reset_feedback_on_route_change_) {
+        transport_feedback_adapter_.SetNetworkRoute(network_route);
+      }
+      if (controller_) {
+        PostUpdates(controller_->OnNetworkRouteChange(msg));
+      } else {
+        UpdateInitialConstraints(msg.constraints);
+      }
+      is_congested_ = false;
+      pacer_.SetCongested(false);
+    });
+  }
+}
+void RtpTransportControllerSend::OnNetworkAvailability(bool network_available) {
+  RTC_DCHECK_RUN_ON(&main_thread_);
+  RTC_LOG(LS_VERBOSE) << "SignalNetworkState "
+                      << (network_available ? "Up" : "Down");
+  NetworkAvailability msg;
+  msg.at_time = Timestamp::Millis(clock_->TimeInMilliseconds());
+  msg.network_available = network_available;
+  task_queue_.RunOrPost([this, msg]() {
+    RTC_DCHECK_RUN_ON(&task_queue_);
+    if (network_available_ == msg.network_available)
+      return;
+    network_available_ = msg.network_available;
+    if (network_available_) {
+      pacer_.Resume();
+    } else {
+      pacer_.Pause();
+    }
+    is_congested_ = false;
+    pacer_.SetCongested(false);
+
+    if (controller_) {
+      control_handler_->SetNetworkAvailability(network_available_);
+      PostUpdates(controller_->OnNetworkAvailability(msg));
+      UpdateControlState();
+    } else {
+      MaybeCreateControllers();
+    }
+  });
+
+  for (auto& rtp_sender : video_rtp_senders_) {
+    rtp_sender->OnNetworkAvailability(network_available);
+  }
+}
+RtcpBandwidthObserver* RtpTransportControllerSend::GetBandwidthObserver() {
+  return this;
+}
+int64_t RtpTransportControllerSend::GetPacerQueuingDelayMs() const {
+  return pacer_.OldestPacketWaitTime().ms();
+}
+absl::optional<Timestamp> RtpTransportControllerSend::GetFirstPacketTime()
+    const {
+  return pacer_.FirstSentPacketTime();
+}
+void RtpTransportControllerSend::EnablePeriodicAlrProbing(bool enable) {
+  task_queue_.RunOrPost([this, enable]() {
+    RTC_DCHECK_RUN_ON(&task_queue_);
+    streams_config_.requests_alr_probing = enable;
+    UpdateStreamsConfig();
+  });
+}
+void RtpTransportControllerSend::OnSentPacket(
+    const rtc::SentPacket& sent_packet) {
+  // Normally called on the network thread !
+
+  // We can not use SafeTask here if we are using an owned task queue, because
+  // the safety flag will be destroyed when RtpTransportControllerSend is
+  // destroyed on the worker thread. But we must use SafeTask if we are using
+  // the worker thread, since the worker thread outlive
+  // RtpTransportControllerSend.
+  task_queue_.TaskQueueForPost()->PostTask(
+      task_queue_.MaybeSafeTask(safety_.flag(), [this, sent_packet]() {
+        RTC_DCHECK_RUN_ON(&task_queue_);
+        absl::optional<SentPacket> packet_msg =
+            transport_feedback_adapter_.ProcessSentPacket(sent_packet);
+        if (packet_msg) {
+          // Only update outstanding data if:
+          // 1. Packet feedback is used.
+          // 2. The packet has not yet received an acknowledgement.
+          // 3. It is not a retransmission of an earlier packet.
+          UpdateCongestedState();
+          if (controller_)
+            PostUpdates(controller_->OnSentPacket(*packet_msg));
+        }
+      }));
+}
+
+void RtpTransportControllerSend::OnReceivedPacket(
+    const ReceivedPacket& packet_msg) {
+  task_queue_.RunOrPost([this, packet_msg]() {
+    RTC_DCHECK_RUN_ON(&task_queue_);
+    if (controller_)
+      PostUpdates(controller_->OnReceivedPacket(packet_msg));
+  });
+}
+
+void RtpTransportControllerSend::UpdateBitrateConstraints(
+    const BitrateConstraints& updated) {
+  TargetRateConstraints msg = ConvertConstraints(updated, clock_);
+  task_queue_.RunOrPost([this, msg]() {
+    RTC_DCHECK_RUN_ON(&task_queue_);
+    if (controller_) {
+      PostUpdates(controller_->OnTargetRateConstraints(msg));
+    } else {
+      UpdateInitialConstraints(msg);
+    }
+  });
+}
+
+void RtpTransportControllerSend::SetSdpBitrateParameters(
+    const BitrateConstraints& constraints) {
+  absl::optional<BitrateConstraints> updated =
+      bitrate_configurator_.UpdateWithSdpParameters(constraints);
+  if (updated.has_value()) {
+    UpdateBitrateConstraints(*updated);
+  } else {
+    RTC_LOG(LS_VERBOSE)
+        << "WebRTC.RtpTransportControllerSend.SetSdpBitrateParameters: "
+           "nothing to update";
+  }
+}
+
+void RtpTransportControllerSend::SetClientBitratePreferences(
+    const BitrateSettings& preferences) {
+  absl::optional<BitrateConstraints> updated =
+      bitrate_configurator_.UpdateWithClientPreferences(preferences);
+  if (updated.has_value()) {
+    UpdateBitrateConstraints(*updated);
+  } else {
+    RTC_LOG(LS_VERBOSE)
+        << "WebRTC.RtpTransportControllerSend.SetClientBitratePreferences: "
+           "nothing to update";
+  }
+}
+
+absl::optional<BitrateConstraints>
+RtpTransportControllerSend::ApplyOrLiftRelayCap(bool is_relayed) {
+  DataRate cap = is_relayed ? relay_bandwidth_cap_ : DataRate::PlusInfinity();
+  return bitrate_configurator_.UpdateWithRelayCap(cap);
+}
+
+void RtpTransportControllerSend::OnTransportOverheadChanged(
+    size_t transport_overhead_bytes_per_packet) {
+  RTC_DCHECK_RUN_ON(&main_thread_);
+  if (transport_overhead_bytes_per_packet >= kMaxOverheadBytes) {
+    RTC_LOG(LS_ERROR) << "Transport overhead exceeds " << kMaxOverheadBytes;
+    return;
+  }
+
+  pacer_.SetTransportOverhead(
+      DataSize::Bytes(transport_overhead_bytes_per_packet));
+
+  // TODO(holmer): Call AudioRtpSenders when they have been moved to
+  // RtpTransportControllerSend.
+  for (auto& rtp_video_sender : video_rtp_senders_) {
+    rtp_video_sender->OnTransportOverheadChanged(
+        transport_overhead_bytes_per_packet);
+  }
+}
+
+void RtpTransportControllerSend::AccountForAudioPacketsInPacedSender(
+    bool account_for_audio) {
+  pacer_.SetAccountForAudioPackets(account_for_audio);
+}
+
+void RtpTransportControllerSend::IncludeOverheadInPacedSender() {
+  pacer_.SetIncludeOverhead();
+}
+
+void RtpTransportControllerSend::EnsureStarted() {
+  if (!pacer_started_) {
+    pacer_started_ = true;
+    pacer_.EnsureStarted();
+  }
+}
+
+void RtpTransportControllerSend::OnReceivedEstimatedBitrate(uint32_t bitrate) {
+  RemoteBitrateReport msg;
+  msg.receive_time = Timestamp::Millis(clock_->TimeInMilliseconds());
+  msg.bandwidth = DataRate::BitsPerSec(bitrate);
+  task_queue_.RunOrPost([this, msg]() {
+    RTC_DCHECK_RUN_ON(&task_queue_);
+    if (controller_)
+      PostUpdates(controller_->OnRemoteBitrateReport(msg));
+  });
+}
+
+void RtpTransportControllerSend::OnReceivedRtcpReceiverReport(
+    const ReportBlockList& report_blocks,
+    int64_t rtt_ms,
+    int64_t now_ms) {
+  task_queue_.RunOrPost([this, report_blocks, now_ms, rtt_ms]() {
+    RTC_DCHECK_RUN_ON(&task_queue_);
+    OnReceivedRtcpReceiverReportBlocks(report_blocks, now_ms);
+    RoundTripTimeUpdate report;
+    report.receive_time = Timestamp::Millis(now_ms);
+    report.round_trip_time = TimeDelta::Millis(rtt_ms);
+    report.smoothed = false;
+    if (controller_ && !report.round_trip_time.IsZero())
+      PostUpdates(controller_->OnRoundTripTimeUpdate(report));
+  });
+}
+
+void RtpTransportControllerSend::OnAddPacket(
+    const RtpPacketSendInfo& packet_info) {
+  Timestamp creation_time = Timestamp::Millis(clock_->TimeInMilliseconds());
+
+  task_queue_.RunOrPost([this, packet_info, creation_time]() {
+    RTC_DCHECK_RUN_ON(&task_queue_);
+    feedback_demuxer_.AddPacket(packet_info);
+    transport_feedback_adapter_.AddPacket(
+        packet_info, transport_overhead_bytes_per_packet_, creation_time);
+  });
+}
+
+void RtpTransportControllerSend::OnTransportFeedback(
+    const rtcp::TransportFeedback& feedback) {
+  auto feedback_time = Timestamp::Millis(clock_->TimeInMilliseconds());
+  task_queue_.RunOrPost([this, feedback, feedback_time]() {
+    RTC_DCHECK_RUN_ON(&task_queue_);
+    feedback_demuxer_.OnTransportFeedback(feedback);
+    absl::optional<TransportPacketsFeedback> feedback_msg =
+        transport_feedback_adapter_.ProcessTransportFeedback(feedback,
+                                                             feedback_time);
+    if (feedback_msg) {
+      if (controller_)
+        PostUpdates(controller_->OnTransportPacketsFeedback(*feedback_msg));
+
+      // Only update outstanding data if any packet is first time acked.
+      UpdateCongestedState();
+    }
+  });
+}
+
+void RtpTransportControllerSend::OnRemoteNetworkEstimate(
+    NetworkStateEstimate estimate) {
+  if (event_log_) {
+    event_log_->Log(std::make_unique<RtcEventRemoteEstimate>(
+        estimate.link_capacity_lower, estimate.link_capacity_upper));
+  }
+  estimate.update_time = Timestamp::Millis(clock_->TimeInMilliseconds());
+  task_queue_.RunOrPost([this, estimate] {
+    RTC_DCHECK_RUN_ON(&task_queue_);
+    if (controller_)
+      PostUpdates(controller_->OnNetworkStateEstimate(estimate));
+  });
+}
+
+void RtpTransportControllerSend::MaybeCreateControllers() {
+  RTC_DCHECK(!controller_);
+  RTC_DCHECK(!control_handler_);
+
+  if (!network_available_ || !observer_)
+    return;
+  control_handler_ = std::make_unique<CongestionControlHandler>();
+
+  initial_config_.constraints.at_time =
+      Timestamp::Millis(clock_->TimeInMilliseconds());
+  initial_config_.stream_based_config = streams_config_;
+
+  // TODO(srte): Use fallback controller if no feedback is available.
+  if (controller_factory_override_) {
+    RTC_LOG(LS_INFO) << "Creating overridden congestion controller";
+    controller_ = controller_factory_override_->Create(initial_config_);
+    process_interval_ = controller_factory_override_->GetProcessInterval();
+  } else {
+    RTC_LOG(LS_INFO) << "Creating fallback congestion controller";
+    controller_ = controller_factory_fallback_->Create(initial_config_);
+    process_interval_ = controller_factory_fallback_->GetProcessInterval();
+  }
+  UpdateControllerWithTimeInterval();
+  StartProcessPeriodicTasks();
+}
+
+void RtpTransportControllerSend::UpdateInitialConstraints(
+    TargetRateConstraints new_contraints) {
+  if (!new_contraints.starting_rate)
+    new_contraints.starting_rate = initial_config_.constraints.starting_rate;
+  RTC_DCHECK(new_contraints.starting_rate);
+  initial_config_.constraints = new_contraints;
+}
+
+void RtpTransportControllerSend::StartProcessPeriodicTasks() {
+  RTC_DCHECK_RUN_ON(&task_queue_);
+  if (!pacer_queue_update_task_.Running()) {
+    pacer_queue_update_task_ = RepeatingTaskHandle::DelayedStart(
+        task_queue_.TaskQueueForDelayedTasks(), kPacerQueueUpdateInterval,
+        [this]() {
+          RTC_DCHECK_RUN_ON(&task_queue_);
+          TimeDelta expected_queue_time = pacer_.ExpectedQueueTime();
+          control_handler_->SetPacerQueue(expected_queue_time);
+          UpdateControlState();
+          return kPacerQueueUpdateInterval;
+        });
+  }
+  controller_task_.Stop();
+  if (process_interval_.IsFinite()) {
+    controller_task_ = RepeatingTaskHandle::DelayedStart(
+        task_queue_.TaskQueueForDelayedTasks(), process_interval_, [this]() {
+          RTC_DCHECK_RUN_ON(&task_queue_);
+          UpdateControllerWithTimeInterval();
+          return process_interval_;
+        });
+  }
+}
+
+void RtpTransportControllerSend::UpdateControllerWithTimeInterval() {
+  RTC_DCHECK(controller_);
+  ProcessInterval msg;
+  msg.at_time = Timestamp::Millis(clock_->TimeInMilliseconds());
+  if (add_pacing_to_cwin_)
+    msg.pacer_queue = pacer_.QueueSizeData();
+  PostUpdates(controller_->OnProcessInterval(msg));
+}
+
+void RtpTransportControllerSend::UpdateStreamsConfig() {
+  streams_config_.at_time = Timestamp::Millis(clock_->TimeInMilliseconds());
+  if (controller_)
+    PostUpdates(controller_->OnStreamsConfig(streams_config_));
+}
+
+void RtpTransportControllerSend::PostUpdates(NetworkControlUpdate update) {
+  if (update.congestion_window) {
+    congestion_window_size_ = *update.congestion_window;
+    UpdateCongestedState();
+  }
+  if (update.pacer_config) {
+    pacer_.SetPacingRates(update.pacer_config->data_rate(),
+                          update.pacer_config->pad_rate());
+  }
+  if (!update.probe_cluster_configs.empty()) {
+    pacer_.CreateProbeClusters(std::move(update.probe_cluster_configs));
+  }
+  if (update.target_rate) {
+    control_handler_->SetTargetRate(*update.target_rate);
+    UpdateControlState();
+  }
+}
+
+void RtpTransportControllerSend::OnReceivedRtcpReceiverReportBlocks(
+    const ReportBlockList& report_blocks,
+    int64_t now_ms) {
+  if (report_blocks.empty())
+    return;
+
+  int total_packets_lost_delta = 0;
+  int total_packets_delta = 0;
+
+  // Compute the packet loss from all report blocks.
+  for (const RTCPReportBlock& report_block : report_blocks) {
+    auto it = last_report_blocks_.find(report_block.source_ssrc);
+    if (it != last_report_blocks_.end()) {
+      auto number_of_packets = report_block.extended_highest_sequence_number -
+                               it->second.extended_highest_sequence_number;
+      total_packets_delta += number_of_packets;
+      auto lost_delta = report_block.packets_lost - it->second.packets_lost;
+      total_packets_lost_delta += lost_delta;
+    }
+    last_report_blocks_[report_block.source_ssrc] = report_block;
+  }
+  // Can only compute delta if there has been previous blocks to compare to. If
+  // not, total_packets_delta will be unchanged and there's nothing more to do.
+  if (!total_packets_delta)
+    return;
+  int packets_received_delta = total_packets_delta - total_packets_lost_delta;
+  // To detect lost packets, at least one packet has to be received. This check
+  // is needed to avoid bandwith detection update in
+  // VideoSendStreamTest.SuspendBelowMinBitrate
+
+  if (packets_received_delta < 1)
+    return;
+  Timestamp now = Timestamp::Millis(now_ms);
+  TransportLossReport msg;
+  msg.packets_lost_delta = total_packets_lost_delta;
+  msg.packets_received_delta = packets_received_delta;
+  msg.receive_time = now;
+  msg.start_time = last_report_block_time_;
+  msg.end_time = now;
+  if (controller_)
+    PostUpdates(controller_->OnTransportLossReport(msg));
+  last_report_block_time_ = now;
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/rtp_transport_controller_send.h b/third_party/libwebrtc/call/rtp_transport_controller_send.h
new file mode 100644
index 0000000000..51bda73445
--- /dev/null
+++ b/third_party/libwebrtc/call/rtp_transport_controller_send.h
@@ -0,0 +1,214 @@
+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_RTP_TRANSPORT_CONTROLLER_SEND_H_
+#define CALL_RTP_TRANSPORT_CONTROLLER_SEND_H_
+
+#include <atomic>
+#include <map>
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "absl/strings/string_view.h"
+#include "api/network_state_predictor.h"
+#include "api/sequence_checker.h"
+#include "api/task_queue/task_queue_base.h"
+#include "api/task_queue/task_queue_factory.h"
+#include "api/transport/network_control.h"
+#include "api/units/data_rate.h"
+#include "call/rtp_bitrate_configurator.h"
+#include "call/rtp_transport_config.h"
+#include "call/rtp_transport_controller_send_interface.h"
+#include "call/rtp_video_sender.h"
+#include "modules/congestion_controller/rtp/control_handler.h"
+#include "modules/congestion_controller/rtp/transport_feedback_adapter.h"
+#include "modules/congestion_controller/rtp/transport_feedback_demuxer.h"
+#include "modules/pacing/packet_router.h"
+#include "modules/pacing/rtp_packet_pacer.h"
+#include "modules/pacing/task_queue_paced_sender.h"
+#include "modules/utility/maybe_worker_thread.h"
+#include "rtc_base/network_route.h"
+#include "rtc_base/race_checker.h"
+#include "rtc_base/task_queue.h"
+#include "rtc_base/task_utils/repeating_task.h"
+
+namespace webrtc {
+class Clock;
+class FrameEncryptorInterface;
+class RtcEventLog;
+
+class RtpTransportControllerSend final
+    : public RtpTransportControllerSendInterface,
+      public RtcpBandwidthObserver,
+      public TransportFeedbackObserver,
+      public NetworkStateEstimateObserver {
+ public:
+  RtpTransportControllerSend(Clock* clock, const RtpTransportConfig& config);
+  ~RtpTransportControllerSend() override;
+
+  RtpTransportControllerSend(const RtpTransportControllerSend&) = delete;
+  RtpTransportControllerSend& operator=(const RtpTransportControllerSend&) =
+      delete;
+
+  // TODO(tommi): Change to std::unique_ptr<>.
+  RtpVideoSenderInterface* CreateRtpVideoSender(
+      const std::map<uint32_t, RtpState>& suspended_ssrcs,
+      const std::map<uint32_t, RtpPayloadState>&
+          states,  // move states into RtpTransportControllerSend
+      const RtpConfig& rtp_config,
+      int rtcp_report_interval_ms,
+      Transport* send_transport,
+      const RtpSenderObservers& observers,
+      RtcEventLog* event_log,
+      std::unique_ptr<FecController> fec_controller,
+      const RtpSenderFrameEncryptionConfig& frame_encryption_config,
+      rtc::scoped_refptr<FrameTransformerInterface> frame_transformer) override;
+  void DestroyRtpVideoSender(
+      RtpVideoSenderInterface* rtp_video_sender) override;
+
+  // Implements RtpTransportControllerSendInterface
+  MaybeWorkerThread* GetWorkerQueue() override;
+  PacketRouter* packet_router() override;
+
+  NetworkStateEstimateObserver* network_state_estimate_observer() override;
+  TransportFeedbackObserver* transport_feedback_observer() override;
+  RtpPacketSender* packet_sender() override;
+
+  void SetAllocatedSendBitrateLimits(BitrateAllocationLimits limits) override;
+
+  void SetPacingFactor(float pacing_factor) override;
+  void SetQueueTimeLimit(int limit_ms) override;
+  StreamFeedbackProvider* GetStreamFeedbackProvider() override;
+  void RegisterTargetTransferRateObserver(
+      TargetTransferRateObserver* observer) override;
+  void OnNetworkRouteChanged(absl::string_view transport_name,
+                             const rtc::NetworkRoute& network_route) override;
+  void OnNetworkAvailability(bool network_available) override;
+  RtcpBandwidthObserver* GetBandwidthObserver() override;
+  int64_t GetPacerQueuingDelayMs() const override;
+  absl::optional<Timestamp> GetFirstPacketTime() const override;
+  void EnablePeriodicAlrProbing(bool enable) override;
+  void OnSentPacket(const rtc::SentPacket& sent_packet) override;
+  void OnReceivedPacket(const ReceivedPacket& packet_msg) override;
+
+  void SetSdpBitrateParameters(const BitrateConstraints& constraints) override;
+  void SetClientBitratePreferences(const BitrateSettings& preferences) override;
+
+  void OnTransportOverheadChanged(
+      size_t transport_overhead_bytes_per_packet) override;
+
+  void AccountForAudioPacketsInPacedSender(bool account_for_audio) override;
+  void IncludeOverheadInPacedSender() override;
+  void EnsureStarted() override;
+
+  // Implements RtcpBandwidthObserver interface
+  void OnReceivedEstimatedBitrate(uint32_t bitrate) override;
+  void OnReceivedRtcpReceiverReport(const ReportBlockList& report_blocks,
+                                    int64_t rtt,
+                                    int64_t now_ms) override;
+
+  // Implements TransportFeedbackObserver interface
+  void OnAddPacket(const RtpPacketSendInfo& packet_info) override;
+  void OnTransportFeedback(const rtcp::TransportFeedback& feedback) override;
+
+  // Implements NetworkStateEstimateObserver interface
+  void OnRemoteNetworkEstimate(NetworkStateEstimate estimate) override;
+
+ private:
+  struct PacerSettings {
+    explicit PacerSettings(const FieldTrialsView& trials);
+
+    FieldTrialParameter<TimeDelta> holdback_window;
+    FieldTrialParameter<int> holdback_packets;
+  };
+
+  void MaybeCreateControllers() RTC_RUN_ON(task_queue_);
+  void UpdateInitialConstraints(TargetRateConstraints new_contraints)
+      RTC_RUN_ON(task_queue_);
+
+  void StartProcessPeriodicTasks() RTC_RUN_ON(task_queue_);
+  void UpdateControllerWithTimeInterval() RTC_RUN_ON(task_queue_);
+
+  absl::optional<BitrateConstraints> ApplyOrLiftRelayCap(bool is_relayed);
+  bool IsRelevantRouteChange(const rtc::NetworkRoute& old_route,
+                             const rtc::NetworkRoute& new_route) const;
+  void UpdateBitrateConstraints(const BitrateConstraints& updated);
+  void UpdateStreamsConfig() RTC_RUN_ON(task_queue_);
+  void OnReceivedRtcpReceiverReportBlocks(const ReportBlockList& report_blocks,
+                                          int64_t now_ms)
+      RTC_RUN_ON(task_queue_);
+  void PostUpdates(NetworkControlUpdate update) RTC_RUN_ON(task_queue_);
+  void UpdateControlState() RTC_RUN_ON(task_queue_);
+  void UpdateCongestedState() RTC_RUN_ON(task_queue_);
+
+  Clock* const clock_;
+  RtcEventLog* const event_log_;
+  TaskQueueFactory* const task_queue_factory_;
+  SequenceChecker main_thread_;
+  PacketRouter packet_router_;
+  std::vector<std::unique_ptr<RtpVideoSenderInterface>> video_rtp_senders_
+      RTC_GUARDED_BY(&main_thread_);
+  RtpBitrateConfigurator bitrate_configurator_;
+  std::map<std::string, rtc::NetworkRoute> network_routes_;
+  bool pacer_started_;
+  const PacerSettings pacer_settings_;
+  TaskQueuePacedSender pacer_;
+
+  TargetTransferRateObserver* observer_ RTC_GUARDED_BY(task_queue_);
+  TransportFeedbackDemuxer feedback_demuxer_;
+
+  TransportFeedbackAdapter transport_feedback_adapter_
+      RTC_GUARDED_BY(task_queue_);
+
+  NetworkControllerFactoryInterface* const controller_factory_override_
+      RTC_PT_GUARDED_BY(task_queue_);
+  const std::unique_ptr<NetworkControllerFactoryInterface>
+      controller_factory_fallback_ RTC_PT_GUARDED_BY(task_queue_);
+
+  std::unique_ptr<CongestionControlHandler> control_handler_
+      RTC_GUARDED_BY(task_queue_) RTC_PT_GUARDED_BY(task_queue_);
+
+  std::unique_ptr<NetworkControllerInterface> controller_
+      RTC_GUARDED_BY(task_queue_) RTC_PT_GUARDED_BY(task_queue_);
+
+  TimeDelta process_interval_ RTC_GUARDED_BY(task_queue_);
+
+  std::map<uint32_t, RTCPReportBlock> last_report_blocks_
+      RTC_GUARDED_BY(task_queue_);
+  Timestamp last_report_block_time_ RTC_GUARDED_BY(task_queue_);
+
+  NetworkControllerConfig initial_config_ RTC_GUARDED_BY(task_queue_);
+  StreamsConfig streams_config_ RTC_GUARDED_BY(task_queue_);
+
+  const bool reset_feedback_on_route_change_;
+  const bool add_pacing_to_cwin_;
+  FieldTrialParameter<DataRate> relay_bandwidth_cap_;
+
+  size_t transport_overhead_bytes_per_packet_ RTC_GUARDED_BY(task_queue_);
+  bool network_available_ RTC_GUARDED_BY(task_queue_);
+  RepeatingTaskHandle pacer_queue_update_task_ RTC_GUARDED_BY(task_queue_);
+  RepeatingTaskHandle controller_task_ RTC_GUARDED_BY(task_queue_);
+
+  DataSize congestion_window_size_ RTC_GUARDED_BY(task_queue_);
+  bool is_congested_ RTC_GUARDED_BY(task_queue_);
+
+  // Protected by internal locks.
+  RateLimiter retransmission_rate_limiter_;
+
+  ScopedTaskSafety safety_;
+  MaybeWorkerThread task_queue_;
+
+  const FieldTrialsView& field_trials_;
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_RTP_TRANSPORT_CONTROLLER_SEND_H_
diff --git a/third_party/libwebrtc/call/rtp_transport_controller_send_factory.h b/third_party/libwebrtc/call/rtp_transport_controller_send_factory.h
new file mode 100644
index 0000000000..6349302e45
--- /dev/null
+++ b/third_party/libwebrtc/call/rtp_transport_controller_send_factory.h
@@ -0,0 +1,34 @@
+/*
+ *  Copyright (c) 2021 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_RTP_TRANSPORT_CONTROLLER_SEND_FACTORY_H_
+#define CALL_RTP_TRANSPORT_CONTROLLER_SEND_FACTORY_H_
+
+#include <memory>
+#include <utility>
+
+#include "call/rtp_transport_controller_send.h"
+#include "call/rtp_transport_controller_send_factory_interface.h"
+
+namespace webrtc {
+class RtpTransportControllerSendFactory
+    : public RtpTransportControllerSendFactoryInterface {
+ public:
+  std::unique_ptr<RtpTransportControllerSendInterface> Create(
+      const RtpTransportConfig& config,
+      Clock* clock) override {
+    RTC_CHECK(config.trials);
+    return std::make_unique<RtpTransportControllerSend>(clock, config);
+  }
+
+  virtual ~RtpTransportControllerSendFactory() {}
+};
+}  // namespace webrtc
+#endif  // CALL_RTP_TRANSPORT_CONTROLLER_SEND_FACTORY_H_
diff --git a/third_party/libwebrtc/call/rtp_transport_controller_send_factory_interface.h b/third_party/libwebrtc/call/rtp_transport_controller_send_factory_interface.h
new file mode 100644
index 0000000000..0f4c36c221
--- /dev/null
+++ b/third_party/libwebrtc/call/rtp_transport_controller_send_factory_interface.h
@@ -0,0 +1,30 @@
+/*
+ *  Copyright (c) 2021 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+#ifndef CALL_RTP_TRANSPORT_CONTROLLER_SEND_FACTORY_INTERFACE_H_
+#define CALL_RTP_TRANSPORT_CONTROLLER_SEND_FACTORY_INTERFACE_H_
+
+#include <memory>
+
+#include "call/rtp_transport_config.h"
+#include "call/rtp_transport_controller_send_interface.h"
+
+namespace webrtc {
+// A factory used for dependency injection on the send side of the transport
+// controller.
+class RtpTransportControllerSendFactoryInterface {
+ public:
+  virtual std::unique_ptr<RtpTransportControllerSendInterface> Create(
+      const RtpTransportConfig& config,
+      Clock* clock) = 0;
+
+  virtual ~RtpTransportControllerSendFactoryInterface() {}
+};
+}  // namespace webrtc
+#endif  // CALL_RTP_TRANSPORT_CONTROLLER_SEND_FACTORY_INTERFACE_H_
diff --git a/third_party/libwebrtc/call/rtp_transport_controller_send_interface.h b/third_party/libwebrtc/call/rtp_transport_controller_send_interface.h
new file mode 100644
index 0000000000..44df5aa736
--- /dev/null
+++ b/third_party/libwebrtc/call/rtp_transport_controller_send_interface.h
@@ -0,0 +1,166 @@
+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_RTP_TRANSPORT_CONTROLLER_SEND_INTERFACE_H_
+#define CALL_RTP_TRANSPORT_CONTROLLER_SEND_INTERFACE_H_
+#include <stddef.h>
+#include <stdint.h>
+
+#include <map>
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "absl/strings/string_view.h"
+#include "absl/types/optional.h"
+#include "api/crypto/crypto_options.h"
+#include "api/fec_controller.h"
+#include "api/frame_transformer_interface.h"
+#include "api/rtc_event_log/rtc_event_log.h"
+#include "api/transport/bitrate_settings.h"
+#include "api/units/timestamp.h"
+#include "call/rtp_config.h"
+#include "common_video/frame_counts.h"
+#include "modules/rtp_rtcp/include/report_block_data.h"
+#include "modules/rtp_rtcp/include/rtcp_statistics.h"
+#include "modules/rtp_rtcp/include/rtp_packet_sender.h"
+#include "modules/rtp_rtcp/include/rtp_rtcp_defines.h"
+#include "modules/rtp_rtcp/source/rtp_packet_received.h"
+
+namespace rtc {
+struct SentPacket;
+struct NetworkRoute;
+class TaskQueue;
+}  // namespace rtc
+namespace webrtc {
+
+class FrameEncryptorInterface;
+class MaybeWorkerThread;
+class TargetTransferRateObserver;
+class Transport;
+class PacketRouter;
+class RtpVideoSenderInterface;
+class RtcpBandwidthObserver;
+class RtpPacketSender;
+
+struct RtpSenderObservers {
+  RtcpRttStats* rtcp_rtt_stats;
+  RtcpIntraFrameObserver* intra_frame_callback;
+  RtcpLossNotificationObserver* rtcp_loss_notification_observer;
+  ReportBlockDataObserver* report_block_data_observer;
+  StreamDataCountersCallback* rtp_stats;
+  BitrateStatisticsObserver* bitrate_observer;
+  FrameCountObserver* frame_count_observer;
+  RtcpPacketTypeCounterObserver* rtcp_type_observer;
+  SendSideDelayObserver* send_delay_observer;
+  SendPacketObserver* send_packet_observer;
+};
+
+struct RtpSenderFrameEncryptionConfig {
+  FrameEncryptorInterface* frame_encryptor = nullptr;
+  CryptoOptions crypto_options;
+};
+
+// An RtpTransportController should own everything related to the RTP
+// transport to/from a remote endpoint. We should have separate
+// interfaces for send and receive side, even if they are implemented
+// by the same class. This is an ongoing refactoring project. At some
+// point, this class should be promoted to a public api under
+// webrtc/api/rtp/.
+//
+// For a start, this object is just a collection of the objects needed
+// by the VideoSendStream constructor. The plan is to move ownership
+// of all RTP-related objects here, and add methods to create per-ssrc
+// objects which would then be passed to VideoSendStream. Eventually,
+// direct accessors like packet_router() should be removed.
+//
+// This should also have a reference to the underlying
+// webrtc::Transport(s). Currently, webrtc::Transport is implemented by
+// WebRtcVideoChannel and WebRtcVoiceMediaChannel, and owned by
+// WebrtcSession. Video and audio always uses different transport
+// objects, even in the common case where they are bundled over the
+// same underlying transport.
+//
+// Extracting the logic of the webrtc::Transport from BaseChannel and
+// subclasses into a separate class seems to be a prerequesite for
+// moving the transport here.
+class RtpTransportControllerSendInterface {
+ public:
+  virtual ~RtpTransportControllerSendInterface() {}
+  // TODO(webrtc:14502): Remove MaybeWorkerThread when experiment has been
+  // evaluated.
+  virtual MaybeWorkerThread* GetWorkerQueue() = 0;
+  virtual PacketRouter* packet_router() = 0;
+
+  virtual RtpVideoSenderInterface* CreateRtpVideoSender(
+      const std::map<uint32_t, RtpState>& suspended_ssrcs,
+      // TODO(holmer): Move states into RtpTransportControllerSend.
+      const std::map<uint32_t, RtpPayloadState>& states,
+      const RtpConfig& rtp_config,
+      int rtcp_report_interval_ms,
+      Transport* send_transport,
+      const RtpSenderObservers& observers,
+      RtcEventLog* event_log,
+      std::unique_ptr<FecController> fec_controller,
+      const RtpSenderFrameEncryptionConfig& frame_encryption_config,
+      rtc::scoped_refptr<FrameTransformerInterface> frame_transformer) = 0;
+  virtual void DestroyRtpVideoSender(
+      RtpVideoSenderInterface* rtp_video_sender) = 0;
+
+  virtual NetworkStateEstimateObserver* network_state_estimate_observer() = 0;
+  virtual TransportFeedbackObserver* transport_feedback_observer() = 0;
+
+  virtual RtpPacketSender* packet_sender() = 0;
+
+  // SetAllocatedSendBitrateLimits sets bitrates limits imposed by send codec
+  // settings.
+  virtual void SetAllocatedSendBitrateLimits(
+      BitrateAllocationLimits limits) = 0;
+
+  virtual void SetPacingFactor(float pacing_factor) = 0;
+  virtual void SetQueueTimeLimit(int limit_ms) = 0;
+
+  virtual StreamFeedbackProvider* GetStreamFeedbackProvider() = 0;
+  virtual void RegisterTargetTransferRateObserver(
+      TargetTransferRateObserver* observer) = 0;
+  virtual void OnNetworkRouteChanged(
+      absl::string_view transport_name,
+      const rtc::NetworkRoute& network_route) = 0;
+  virtual void OnNetworkAvailability(bool network_available) = 0;
+  virtual RtcpBandwidthObserver* GetBandwidthObserver() = 0;
+  virtual int64_t GetPacerQueuingDelayMs() const = 0;
+  virtual absl::optional<Timestamp> GetFirstPacketTime() const = 0;
+  virtual void EnablePeriodicAlrProbing(bool enable) = 0;
+
+  // Called when a packet has been sent.
+  // The call should arrive on the network thread, but may not in all cases
+  // (some tests don't adhere to this). Implementations today should not block
+  // the calling thread or make assumptions about the thread context.
+  virtual void OnSentPacket(const rtc::SentPacket& sent_packet) = 0;
+
+  virtual void OnReceivedPacket(const ReceivedPacket& received_packet) = 0;
+
+  virtual void SetSdpBitrateParameters(
+      const BitrateConstraints& constraints) = 0;
+  virtual void SetClientBitratePreferences(
+      const BitrateSettings& preferences) = 0;
+
+  virtual void OnTransportOverheadChanged(
+      size_t transport_overhead_per_packet) = 0;
+
+  virtual void AccountForAudioPacketsInPacedSender(bool account_for_audio) = 0;
+  virtual void IncludeOverheadInPacedSender() = 0;
+
+  virtual void EnsureStarted() = 0;
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_RTP_TRANSPORT_CONTROLLER_SEND_INTERFACE_H_
diff --git a/third_party/libwebrtc/call/rtp_video_sender.cc b/third_party/libwebrtc/call/rtp_video_sender.cc
new file mode 100644
index 0000000000..de19b97c66
--- /dev/null
+++ b/third_party/libwebrtc/call/rtp_video_sender.cc
@@ -0,0 +1,1027 @@
+/*
+ *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/rtp_video_sender.h"
+
+#include <algorithm>
+#include <memory>
+#include <string>
+#include <utility>
+
+#include "absl/algorithm/container.h"
+#include "absl/strings/match.h"
+#include "absl/strings/string_view.h"
+#include "api/array_view.h"
+#include "api/task_queue/task_queue_factory.h"
+#include "api/transport/field_trial_based_config.h"
+#include "api/video_codecs/video_codec.h"
+#include "call/rtp_transport_controller_send_interface.h"
+#include "modules/pacing/packet_router.h"
+#include "modules/rtp_rtcp/include/rtp_rtcp_defines.h"
+#include "modules/rtp_rtcp/source/rtp_rtcp_impl2.h"
+#include "modules/rtp_rtcp/source/rtp_sender.h"
+#include "modules/utility/maybe_worker_thread.h"
+#include "modules/video_coding/include/video_codec_interface.h"
+#include "rtc_base/checks.h"
+#include "rtc_base/logging.h"
+#include "rtc_base/task_queue.h"
+#include "rtc_base/trace_event.h"
+
+namespace webrtc {
+
+namespace webrtc_internal_rtp_video_sender {
+
+RtpStreamSender::RtpStreamSender(
+    std::unique_ptr<ModuleRtpRtcpImpl2> rtp_rtcp,
+    std::unique_ptr<RTPSenderVideo> sender_video,
+    std::unique_ptr<VideoFecGenerator> fec_generator)
+    : rtp_rtcp(std::move(rtp_rtcp)),
+      sender_video(std::move(sender_video)),
+      fec_generator(std::move(fec_generator)) {}
+
+RtpStreamSender::~RtpStreamSender() = default;
+
+}  // namespace webrtc_internal_rtp_video_sender
+
+namespace {
+static const int kMinSendSidePacketHistorySize = 600;
+// We don't do MTU discovery, so assume that we have the standard ethernet MTU.
+static const size_t kPathMTU = 1500;
+
+using webrtc_internal_rtp_video_sender::RtpStreamSender;
+
+bool PayloadTypeSupportsSkippingFecPackets(absl::string_view payload_name,
+                                           const FieldTrialsView& trials) {
+  const VideoCodecType codecType =
+      PayloadStringToCodecType(std::string(payload_name));
+  if (codecType == kVideoCodecVP8 || codecType == kVideoCodecVP9) {
+    return true;
+  }
+  if (codecType == kVideoCodecGeneric &&
+      absl::StartsWith(trials.Lookup("WebRTC-GenericPictureId"), "Enabled")) {
+    return true;
+  }
+  return false;
+}
+
+bool ShouldDisableRedAndUlpfec(bool flexfec_enabled,
+                               const RtpConfig& rtp_config,
+                               const FieldTrialsView& trials) {
+  // Consistency of NACK and RED+ULPFEC parameters is checked in this function.
+  const bool nack_enabled = rtp_config.nack.rtp_history_ms > 0;
+
+  // Shorthands.
+  auto IsRedEnabled = [&]() { return rtp_config.ulpfec.red_payload_type >= 0; };
+  auto IsUlpfecEnabled = [&]() {
+    return rtp_config.ulpfec.ulpfec_payload_type >= 0;
+  };
+
+  bool should_disable_red_and_ulpfec = false;
+
+  if (absl::StartsWith(trials.Lookup("WebRTC-DisableUlpFecExperiment"),
+                       "Enabled")) {
+    RTC_LOG(LS_INFO) << "Experiment to disable sending ULPFEC is enabled.";
+    should_disable_red_and_ulpfec = true;
+  }
+
+  // If enabled, FlexFEC takes priority over RED+ULPFEC.
+  if (flexfec_enabled) {
+    if (IsUlpfecEnabled()) {
+      RTC_LOG(LS_INFO)
+          << "Both FlexFEC and ULPFEC are configured. Disabling ULPFEC.";
+    }
+    should_disable_red_and_ulpfec = true;
+  }
+
+  // Payload types without picture ID cannot determine that a stream is complete
+  // without retransmitting FEC, so using ULPFEC + NACK for H.264 (for instance)
+  // is a waste of bandwidth since FEC packets still have to be transmitted.
+  // Note that this is not the case with FlexFEC.
+  if (nack_enabled && IsUlpfecEnabled() &&
+      !PayloadTypeSupportsSkippingFecPackets(rtp_config.payload_name, trials)) {
+    RTC_LOG(LS_WARNING)
+        << "Transmitting payload type without picture ID using "
+           "NACK+ULPFEC is a waste of bandwidth since ULPFEC packets "
+           "also have to be retransmitted. Disabling ULPFEC.";
+    should_disable_red_and_ulpfec = true;
+  }
+
+  // Verify payload types.
+  if (IsUlpfecEnabled() ^ IsRedEnabled()) {
+    RTC_LOG(LS_WARNING)
+        << "Only RED or only ULPFEC enabled, but not both. Disabling both.";
+    should_disable_red_and_ulpfec = true;
+  }
+
+  return should_disable_red_and_ulpfec;
+}
+
+// TODO(brandtr): Update this function when we support multistream protection.
+std::unique_ptr<VideoFecGenerator> MaybeCreateFecGenerator(
+    Clock* clock,
+    const RtpConfig& rtp,
+    const std::map<uint32_t, RtpState>& suspended_ssrcs,
+    int simulcast_index,
+    const FieldTrialsView& trials) {
+  // If flexfec is configured that takes priority.
+  if (rtp.flexfec.payload_type >= 0) {
+    RTC_DCHECK_GE(rtp.flexfec.payload_type, 0);
+    RTC_DCHECK_LE(rtp.flexfec.payload_type, 127);
+    if (rtp.flexfec.ssrc == 0) {
+      RTC_LOG(LS_WARNING) << "FlexFEC is enabled, but no FlexFEC SSRC given. "
+                             "Therefore disabling FlexFEC.";
+      return nullptr;
+    }
+    if (rtp.flexfec.protected_media_ssrcs.empty()) {
+      RTC_LOG(LS_WARNING)
+          << "FlexFEC is enabled, but no protected media SSRC given. "
+             "Therefore disabling FlexFEC.";
+      return nullptr;
+    }
+
+    if (rtp.flexfec.protected_media_ssrcs.size() > 1) {
+      RTC_LOG(LS_WARNING)
+          << "The supplied FlexfecConfig contained multiple protected "
+             "media streams, but our implementation currently only "
+             "supports protecting a single media stream. "
+             "To avoid confusion, disabling FlexFEC completely.";
+      return nullptr;
+    }
+
+    if (absl::c_find(rtp.flexfec.protected_media_ssrcs,
+                     rtp.ssrcs[simulcast_index]) ==
+        rtp.flexfec.protected_media_ssrcs.end()) {
+      // Media SSRC not among flexfec protected SSRCs.
+      return nullptr;
+    }
+
+    const RtpState* rtp_state = nullptr;
+    auto it = suspended_ssrcs.find(rtp.flexfec.ssrc);
+    if (it != suspended_ssrcs.end()) {
+      rtp_state = &it->second;
+    }
+
+    RTC_DCHECK_EQ(1U, rtp.flexfec.protected_media_ssrcs.size());
+    return std::make_unique<FlexfecSender>(
+        rtp.flexfec.payload_type, rtp.flexfec.ssrc,
+        rtp.flexfec.protected_media_ssrcs[0], rtp.mid, rtp.extensions,
+        RTPSender::FecExtensionSizes(), rtp_state, clock);
+  } else if (rtp.ulpfec.red_payload_type >= 0 &&
+             rtp.ulpfec.ulpfec_payload_type >= 0 &&
+             !ShouldDisableRedAndUlpfec(/*flexfec_enabled=*/false, rtp,
+                                        trials)) {
+    // Flexfec not configured, but ulpfec is and is not disabled.
+    return std::make_unique<UlpfecGenerator>(
+        rtp.ulpfec.red_payload_type, rtp.ulpfec.ulpfec_payload_type, clock);
+  }
+
+  // Not a single FEC is given.
+  return nullptr;
+}
+
+std::vector<RtpStreamSender> CreateRtpStreamSenders(
+    Clock* clock,
+    const RtpConfig& rtp_config,
+    const RtpSenderObservers& observers,
+    int rtcp_report_interval_ms,
+    Transport* send_transport,
+    RtcpBandwidthObserver* bandwidth_callback,
+    RtpTransportControllerSendInterface* transport,
+    const std::map<uint32_t, RtpState>& suspended_ssrcs,
+    RtcEventLog* event_log,
+    RateLimiter* retransmission_rate_limiter,
+    FrameEncryptorInterface* frame_encryptor,
+    const CryptoOptions& crypto_options,
+    rtc::scoped_refptr<FrameTransformerInterface> frame_transformer,
+    const FieldTrialsView& trials,
+    TaskQueueFactory* task_queue_factory) {
+  RTC_DCHECK_GT(rtp_config.ssrcs.size(), 0);
+  RTC_DCHECK(task_queue_factory);
+
+  RtpRtcpInterface::Configuration configuration;
+  configuration.clock = clock;
+  configuration.audio = false;
+  configuration.receiver_only = false;
+  configuration.outgoing_transport = send_transport;
+  configuration.intra_frame_callback = observers.intra_frame_callback;
+  configuration.rtcp_loss_notification_observer =
+      observers.rtcp_loss_notification_observer;
+  configuration.bandwidth_callback = bandwidth_callback;
+  configuration.network_state_estimate_observer =
+      transport->network_state_estimate_observer();
+  configuration.transport_feedback_callback =
+      transport->transport_feedback_observer();
+  configuration.rtt_stats = observers.rtcp_rtt_stats;
+  configuration.rtcp_packet_type_counter_observer =
+      observers.rtcp_type_observer;
+  configuration.report_block_data_observer =
+      observers.report_block_data_observer;
+  configuration.paced_sender = transport->packet_sender();
+  configuration.send_bitrate_observer = observers.bitrate_observer;
+  configuration.send_side_delay_observer = observers.send_delay_observer;
+  configuration.send_packet_observer = observers.send_packet_observer;
+  configuration.event_log = event_log;
+  configuration.retransmission_rate_limiter = retransmission_rate_limiter;
+  configuration.rtp_stats_callback = observers.rtp_stats;
+  configuration.frame_encryptor = frame_encryptor;
+  configuration.require_frame_encryption =
+      crypto_options.sframe.require_frame_encryption;
+  configuration.extmap_allow_mixed = rtp_config.extmap_allow_mixed;
+  configuration.rtcp_report_interval_ms = rtcp_report_interval_ms;
+  configuration.field_trials = &trials;
+
+  std::vector<RtpStreamSender> rtp_streams;
+
+  RTC_DCHECK(rtp_config.rtx.ssrcs.empty() ||
+             rtp_config.rtx.ssrcs.size() == rtp_config.ssrcs.size());
+
+  // Some streams could have been disabled, but the rids are still there.
+  // This will occur when simulcast has been disabled for a codec (e.g. VP9)
+  RTC_DCHECK(rtp_config.rids.empty() ||
+             rtp_config.rids.size() >= rtp_config.ssrcs.size());
+
+  for (size_t i = 0; i < rtp_config.ssrcs.size(); ++i) {
+    RTPSenderVideo::Config video_config;
+    configuration.local_media_ssrc = rtp_config.ssrcs[i];
+
+    std::unique_ptr<VideoFecGenerator> fec_generator =
+        MaybeCreateFecGenerator(clock, rtp_config, suspended_ssrcs, i, trials);
+    configuration.fec_generator = fec_generator.get();
+
+    configuration.rtx_send_ssrc =
+        rtp_config.GetRtxSsrcAssociatedWithMediaSsrc(rtp_config.ssrcs[i]);
+    RTC_DCHECK_EQ(configuration.rtx_send_ssrc.has_value(),
+                  !rtp_config.rtx.ssrcs.empty());
+
+    configuration.rid = (i < rtp_config.rids.size()) ? rtp_config.rids[i] : "";
+
+    configuration.need_rtp_packet_infos = rtp_config.lntf.enabled;
+
+    std::unique_ptr<ModuleRtpRtcpImpl2> rtp_rtcp(
+        ModuleRtpRtcpImpl2::Create(configuration));
+    rtp_rtcp->SetSendingStatus(false);
+    rtp_rtcp->SetSendingMediaStatus(false);
+    rtp_rtcp->SetRTCPStatus(RtcpMode::kCompound);
+    // Set NACK.
+    rtp_rtcp->SetStorePacketsStatus(true, kMinSendSidePacketHistorySize);
+
+    video_config.clock = configuration.clock;
+    video_config.rtp_sender = rtp_rtcp->RtpSender();
+    video_config.frame_encryptor = frame_encryptor;
+    video_config.require_frame_encryption =
+        crypto_options.sframe.require_frame_encryption;
+    video_config.enable_retransmit_all_layers = false;
+    video_config.field_trials = &trials;
+
+    const bool using_flexfec =
+        fec_generator &&
+        fec_generator->GetFecType() == VideoFecGenerator::FecType::kFlexFec;
+    const bool should_disable_red_and_ulpfec =
+        ShouldDisableRedAndUlpfec(using_flexfec, rtp_config, trials);
+    if (!should_disable_red_and_ulpfec &&
+        rtp_config.ulpfec.red_payload_type != -1) {
+      video_config.red_payload_type = rtp_config.ulpfec.red_payload_type;
+    }
+    if (fec_generator) {
+      video_config.fec_type = fec_generator->GetFecType();
+      video_config.fec_overhead_bytes = fec_generator->MaxPacketOverhead();
+    }
+    video_config.frame_transformer = frame_transformer;
+    video_config.task_queue_factory = task_queue_factory;
+    auto sender_video = std::make_unique<RTPSenderVideo>(video_config);
+    rtp_streams.emplace_back(std::move(rtp_rtcp), std::move(sender_video),
+                             std::move(fec_generator));
+  }
+  return rtp_streams;
+}
+
+absl::optional<VideoCodecType> GetVideoCodecType(const RtpConfig& config) {
+  if (config.raw_payload) {
+    return absl::nullopt;
+  }
+  return PayloadStringToCodecType(config.payload_name);
+}
+bool TransportSeqNumExtensionConfigured(const RtpConfig& config) {
+  return absl::c_any_of(config.extensions, [](const RtpExtension& ext) {
+    return ext.uri == RtpExtension::kTransportSequenceNumberUri;
+  });
+}
+
+// Returns true when some coded video sequence can be decoded starting with
+// this frame without requiring any previous frames.
+// e.g. it is the same as a key frame when spatial scalability is not used.
+// When spatial scalability is used, then it is true for layer frames of
+// a key frame without inter-layer dependencies.
+bool IsFirstFrameOfACodedVideoSequence(
+    const EncodedImage& encoded_image,
+    const CodecSpecificInfo* codec_specific_info) {
+  if (encoded_image._frameType != VideoFrameType::kVideoFrameKey) {
+    return false;
+  }
+
+  if (codec_specific_info != nullptr) {
+    if (codec_specific_info->generic_frame_info.has_value()) {
+      // This function is used before
+      // `codec_specific_info->generic_frame_info->frame_diffs` are calculated,
+      // so need to use a more complicated way to check for presence of the
+      // dependencies.
+      return absl::c_none_of(
+          codec_specific_info->generic_frame_info->encoder_buffers,
+          [](const CodecBufferUsage& buffer) { return buffer.referenced; });
+    }
+
+    if (codec_specific_info->codecType == VideoCodecType::kVideoCodecVP8 ||
+        codec_specific_info->codecType == VideoCodecType::kVideoCodecH264 ||
+        codec_specific_info->codecType == VideoCodecType::kVideoCodecGeneric) {
+      // These codecs do not support intra picture dependencies, so a frame
+      // marked as a key frame should be a key frame.
+      return true;
+    }
+  }
+
+  // Without depenedencies described in generic format do an educated guess.
+  // It might be wrong for VP9 with spatial layer 0 skipped or higher spatial
+  // layer not depending on the spatial layer 0. This corner case is unimportant
+  // for current usage of this helper function.
+
+  // Use <= to accept both 0 (i.e. the first) and nullopt (i.e. the only).
+  return encoded_image.SpatialIndex() <= 0;
+}
+
+}  // namespace
+
+RtpVideoSender::RtpVideoSender(
+    Clock* clock,
+    const std::map<uint32_t, RtpState>& suspended_ssrcs,
+    const std::map<uint32_t, RtpPayloadState>& states,
+    const RtpConfig& rtp_config,
+    int rtcp_report_interval_ms,
+    Transport* send_transport,
+    const RtpSenderObservers& observers,
+    RtpTransportControllerSendInterface* transport,
+    RtcEventLog* event_log,
+    RateLimiter* retransmission_limiter,
+    std::unique_ptr<FecController> fec_controller,
+    FrameEncryptorInterface* frame_encryptor,
+    const CryptoOptions& crypto_options,
+    rtc::scoped_refptr<FrameTransformerInterface> frame_transformer,
+    const FieldTrialsView& field_trials,
+    TaskQueueFactory* task_queue_factory)
+    : field_trials_(field_trials),
+      use_frame_rate_for_overhead_(absl::StartsWith(
+          field_trials_.Lookup("WebRTC-Video-UseFrameRateForOverhead"),
+          "Enabled")),
+      has_packet_feedback_(TransportSeqNumExtensionConfigured(rtp_config)),
+      active_(false),
+      fec_controller_(std::move(fec_controller)),
+      fec_allowed_(true),
+      rtp_streams_(CreateRtpStreamSenders(clock,
+                                          rtp_config,
+                                          observers,
+                                          rtcp_report_interval_ms,
+                                          send_transport,
+                                          transport->GetBandwidthObserver(),
+                                          transport,
+                                          suspended_ssrcs,
+                                          event_log,
+                                          retransmission_limiter,
+                                          frame_encryptor,
+                                          crypto_options,
+                                          std::move(frame_transformer),
+                                          field_trials_,
+                                          task_queue_factory)),
+      rtp_config_(rtp_config),
+      codec_type_(GetVideoCodecType(rtp_config)),
+      transport_(transport),
+      transport_overhead_bytes_per_packet_(0),
+      encoder_target_rate_bps_(0),
+      frame_counts_(rtp_config.ssrcs.size()),
+      frame_count_observer_(observers.frame_count_observer) {
+  transport_checker_.Detach();
+  RTC_DCHECK_EQ(rtp_config_.ssrcs.size(), rtp_streams_.size());
+  if (has_packet_feedback_)
+    transport_->IncludeOverheadInPacedSender();
+  // SSRCs are assumed to be sorted in the same order as `rtp_modules`.
+  for (uint32_t ssrc : rtp_config_.ssrcs) {
+    // Restore state if it previously existed.
+    const RtpPayloadState* state = nullptr;
+    auto it = states.find(ssrc);
+    if (it != states.end()) {
+      state = &it->second;
+      shared_frame_id_ = std::max(shared_frame_id_, state->shared_frame_id);
+    }
+    params_.push_back(RtpPayloadParams(ssrc, state, field_trials_));
+  }
+
+  // RTP/RTCP initialization.
+
+  for (size_t i = 0; i < rtp_config_.extensions.size(); ++i) {
+    const std::string& extension = rtp_config_.extensions[i].uri;
+    int id = rtp_config_.extensions[i].id;
+    RTC_DCHECK(RtpExtension::IsSupportedForVideo(extension));
+    for (const RtpStreamSender& stream : rtp_streams_) {
+      stream.rtp_rtcp->RegisterRtpHeaderExtension(extension, id);
+    }
+  }
+
+  ConfigureSsrcs(suspended_ssrcs);
+
+  if (!rtp_config_.mid.empty()) {
+    for (const RtpStreamSender& stream : rtp_streams_) {
+      stream.rtp_rtcp->SetMid(rtp_config_.mid);
+    }
+  }
+
+  bool fec_enabled = false;
+  for (const RtpStreamSender& stream : rtp_streams_) {
+    // Simulcast has one module for each layer. Set the CNAME on all modules.
+    stream.rtp_rtcp->SetCNAME(rtp_config_.c_name.c_str());
+    stream.rtp_rtcp->SetMaxRtpPacketSize(rtp_config_.max_packet_size);
+    stream.rtp_rtcp->RegisterSendPayloadFrequency(rtp_config_.payload_type,
+                                                  kVideoPayloadTypeFrequency);
+    if (stream.fec_generator != nullptr) {
+      fec_enabled = true;
+    }
+  }
+  // Currently, both ULPFEC and FlexFEC use the same FEC rate calculation logic,
+  // so enable that logic if either of those FEC schemes are enabled.
+  fec_controller_->SetProtectionMethod(fec_enabled, NackEnabled());
+
+  fec_controller_->SetProtectionCallback(this);
+
+  // Construction happens on the worker thread (see Call::CreateVideoSendStream)
+  // but subseqeuent calls to the RTP state will happen on one of two threads:
+  // * The pacer thread for actually sending packets.
+  // * The transport thread when tearing down and quering GetRtpState().
+  // Detach thread checkers.
+  for (const RtpStreamSender& stream : rtp_streams_) {
+    stream.rtp_rtcp->OnPacketSendingThreadSwitched();
+  }
+}
+
+RtpVideoSender::~RtpVideoSender() {
+  // TODO(bugs.webrtc.org/13517): Remove once RtpVideoSender gets deleted on the
+  // transport task queue.
+  transport_checker_.Detach();
+
+  SetActiveModulesLocked(
+      std::vector<bool>(rtp_streams_.size(), /*active=*/false));
+
+  RTC_DCHECK(!registered_for_feedback_);
+}
+
+void RtpVideoSender::Stop() {
+  RTC_DCHECK_RUN_ON(&transport_checker_);
+  MutexLock lock(&mutex_);
+  if (!active_)
+    return;
+
+  const std::vector<bool> active_modules(rtp_streams_.size(), false);
+  SetActiveModulesLocked(active_modules);
+}
+
+void RtpVideoSender::SetActiveModules(const std::vector<bool>& active_modules) {
+  RTC_DCHECK_RUN_ON(&transport_checker_);
+  MutexLock lock(&mutex_);
+  return SetActiveModulesLocked(active_modules);
+}
+
+void RtpVideoSender::SetActiveModulesLocked(
+    const std::vector<bool>& active_modules) {
+  RTC_DCHECK_RUN_ON(&transport_checker_);
+  RTC_DCHECK_EQ(rtp_streams_.size(), active_modules.size());
+  active_ = false;
+  for (size_t i = 0; i < active_modules.size(); ++i) {
+    if (active_modules[i]) {
+      active_ = true;
+    }
+
+    RtpRtcpInterface& rtp_module = *rtp_streams_[i].rtp_rtcp;
+    const bool was_active = rtp_module.Sending();
+    const bool should_be_active = active_modules[i];
+
+    // Sends a kRtcpByeCode when going from true to false.
+    rtp_module.SetSendingStatus(active_modules[i]);
+
+    if (was_active && !should_be_active) {
+      // Disabling media, remove from packet router map to reduce size and
+      // prevent any stray packets in the pacer from asynchronously arriving
+      // to a disabled module.
+      transport_->packet_router()->RemoveSendRtpModule(&rtp_module);
+
+      // Clear the pacer queue of any packets pertaining to this module.
+      transport_->packet_sender()->RemovePacketsForSsrc(rtp_module.SSRC());
+      if (rtp_module.RtxSsrc().has_value()) {
+        transport_->packet_sender()->RemovePacketsForSsrc(
+            *rtp_module.RtxSsrc());
+      }
+      if (rtp_module.FlexfecSsrc().has_value()) {
+        transport_->packet_sender()->RemovePacketsForSsrc(
+            *rtp_module.FlexfecSsrc());
+      }
+    }
+
+    // If set to false this module won't send media.
+    rtp_module.SetSendingMediaStatus(active_modules[i]);
+
+    if (!was_active && should_be_active) {
+      // Turning on media, register with packet router.
+      transport_->packet_router()->AddSendRtpModule(&rtp_module,
+                                                    /*remb_candidate=*/true);
+    }
+  }
+  if (!active_) {
+    auto* feedback_provider = transport_->GetStreamFeedbackProvider();
+    if (registered_for_feedback_) {
+      feedback_provider->DeRegisterStreamFeedbackObserver(this);
+      registered_for_feedback_ = false;
+    }
+  } else if (!registered_for_feedback_) {
+    auto* feedback_provider = transport_->GetStreamFeedbackProvider();
+    feedback_provider->RegisterStreamFeedbackObserver(rtp_config_.ssrcs, this);
+    registered_for_feedback_ = true;
+  }
+}
+
+bool RtpVideoSender::IsActive() {
+  RTC_DCHECK_RUN_ON(&transport_checker_);
+  MutexLock lock(&mutex_);
+  return IsActiveLocked();
+}
+
+bool RtpVideoSender::IsActiveLocked() {
+  return active_ && !rtp_streams_.empty();
+}
+
+EncodedImageCallback::Result RtpVideoSender::OnEncodedImage(
+    const EncodedImage& encoded_image,
+    const CodecSpecificInfo* codec_specific_info) {
+  fec_controller_->UpdateWithEncodedData(encoded_image.size(),
+                                         encoded_image._frameType);
+  MutexLock lock(&mutex_);
+  RTC_DCHECK(!rtp_streams_.empty());
+  if (!active_)
+    return Result(Result::ERROR_SEND_FAILED);
+
+  shared_frame_id_++;
+  size_t stream_index = 0;
+  if (codec_specific_info &&
+      (codec_specific_info->codecType == kVideoCodecVP8 ||
+       codec_specific_info->codecType == kVideoCodecH264 ||
+       codec_specific_info->codecType == kVideoCodecGeneric)) {
+    // Map spatial index to simulcast.
+    stream_index = encoded_image.SpatialIndex().value_or(0);
+  }
+  RTC_DCHECK_LT(stream_index, rtp_streams_.size());
+
+  uint32_t rtp_timestamp =
+      encoded_image.Timestamp() +
+      rtp_streams_[stream_index].rtp_rtcp->StartTimestamp();
+
+  // RTCPSender has it's own copy of the timestamp offset, added in
+  // RTCPSender::BuildSR, hence we must not add the in the offset for this call.
+  // TODO(nisse): Delete RTCPSender:timestamp_offset_, and see if we can confine
+  // knowledge of the offset to a single place.
+  if (!rtp_streams_[stream_index].rtp_rtcp->OnSendingRtpFrame(
+          encoded_image.Timestamp(), encoded_image.capture_time_ms_,
+          rtp_config_.payload_type,
+          encoded_image._frameType == VideoFrameType::kVideoFrameKey)) {
+    // The payload router could be active but this module isn't sending.
+    return Result(Result::ERROR_SEND_FAILED);
+  }
+
+  absl::optional<int64_t> expected_retransmission_time_ms;
+  if (encoded_image.RetransmissionAllowed()) {
+    expected_retransmission_time_ms =
+        rtp_streams_[stream_index].rtp_rtcp->ExpectedRetransmissionTimeMs();
+  }
+
+  if (IsFirstFrameOfACodedVideoSequence(encoded_image, codec_specific_info)) {
+    // In order to use the dependency descriptor RTP header extension:
+    //  - Pass along any `FrameDependencyStructure` templates produced by the
+    //    encoder adapter.
+    //  - If none were produced the `RtpPayloadParams::*ToGeneric` for the
+    //    particular codec have simulated a dependency structure, so provide a
+    //    minimal set of templates.
+    //  - Otherwise, don't pass along any templates at all which will disable
+    //    the generation of a dependency descriptor.
+    RTPSenderVideo& sender_video = *rtp_streams_[stream_index].sender_video;
+    if (codec_specific_info && codec_specific_info->template_structure) {
+      sender_video.SetVideoStructure(&*codec_specific_info->template_structure);
+    } else if (absl::optional<FrameDependencyStructure> structure =
+                   params_[stream_index].GenericStructure(
+                       codec_specific_info)) {
+      sender_video.SetVideoStructure(&*structure);
+    } else {
+      sender_video.SetVideoStructure(nullptr);
+    }
+  }
+
+  bool send_result = rtp_streams_[stream_index].sender_video->SendEncodedImage(
+      rtp_config_.payload_type, codec_type_, rtp_timestamp, encoded_image,
+      params_[stream_index].GetRtpVideoHeader(
+          encoded_image, codec_specific_info, shared_frame_id_),
+      expected_retransmission_time_ms);
+  if (frame_count_observer_) {
+    FrameCounts& counts = frame_counts_[stream_index];
+    if (encoded_image._frameType == VideoFrameType::kVideoFrameKey) {
+      ++counts.key_frames;
+    } else if (encoded_image._frameType == VideoFrameType::kVideoFrameDelta) {
+      ++counts.delta_frames;
+    } else {
+      RTC_DCHECK(encoded_image._frameType == VideoFrameType::kEmptyFrame);
+    }
+    frame_count_observer_->FrameCountUpdated(counts,
+                                             rtp_config_.ssrcs[stream_index]);
+  }
+  if (!send_result)
+    return Result(Result::ERROR_SEND_FAILED);
+
+  return Result(Result::OK, rtp_timestamp);
+}
+
+void RtpVideoSender::OnBitrateAllocationUpdated(
+    const VideoBitrateAllocation& bitrate) {
+  RTC_DCHECK_RUN_ON(&transport_checker_);
+  MutexLock lock(&mutex_);
+  if (IsActiveLocked()) {
+    if (rtp_streams_.size() == 1) {
+      // If spatial scalability is enabled, it is covered by a single stream.
+      rtp_streams_[0].rtp_rtcp->SetVideoBitrateAllocation(bitrate);
+    } else {
+      std::vector<absl::optional<VideoBitrateAllocation>> layer_bitrates =
+          bitrate.GetSimulcastAllocations();
+      // Simulcast is in use, split the VideoBitrateAllocation into one struct
+      // per rtp stream, moving over the temporal layer allocation.
+      for (size_t i = 0; i < rtp_streams_.size(); ++i) {
+        // The next spatial layer could be used if the current one is
+        // inactive.
+        if (layer_bitrates[i]) {
+          rtp_streams_[i].rtp_rtcp->SetVideoBitrateAllocation(
+              *layer_bitrates[i]);
+        } else {
+          // Signal a 0 bitrate on a simulcast stream.
+          rtp_streams_[i].rtp_rtcp->SetVideoBitrateAllocation(
+              VideoBitrateAllocation());
+        }
+      }
+    }
+  }
+}
+void RtpVideoSender::OnVideoLayersAllocationUpdated(
+    const VideoLayersAllocation& allocation) {
+  MutexLock lock(&mutex_);
+  if (IsActiveLocked()) {
+    for (size_t i = 0; i < rtp_streams_.size(); ++i) {
+      VideoLayersAllocation stream_allocation = allocation;
+      stream_allocation.rtp_stream_index = i;
+      rtp_streams_[i].sender_video->SetVideoLayersAllocation(
+          std::move(stream_allocation));
+      // Only send video frames on the rtp module if the encoder is configured
+      // to send. This is to prevent stray frames to be sent after an encoder
+      // has been reconfigured.
+      rtp_streams_[i].rtp_rtcp->SetSendingMediaStatus(
+          absl::c_any_of(allocation.active_spatial_layers,
+                         [&i](const VideoLayersAllocation::SpatialLayer layer) {
+                           return layer.rtp_stream_index == static_cast<int>(i);
+                         }));
+    }
+  }
+}
+
+bool RtpVideoSender::NackEnabled() const {
+  const bool nack_enabled = rtp_config_.nack.rtp_history_ms > 0;
+  return nack_enabled;
+}
+
+uint32_t RtpVideoSender::GetPacketizationOverheadRate() const {
+  uint32_t packetization_overhead_bps = 0;
+  for (size_t i = 0; i < rtp_streams_.size(); ++i) {
+    if (rtp_streams_[i].rtp_rtcp->SendingMedia()) {
+      packetization_overhead_bps +=
+          rtp_streams_[i].sender_video->PacketizationOverheadBps();
+    }
+  }
+  return packetization_overhead_bps;
+}
+
+void RtpVideoSender::DeliverRtcp(const uint8_t* packet, size_t length) {
+  // Runs on a network thread.
+  for (const RtpStreamSender& stream : rtp_streams_)
+    stream.rtp_rtcp->IncomingRtcpPacket(packet, length);
+}
+
+void RtpVideoSender::ConfigureSsrcs(
+    const std::map<uint32_t, RtpState>& suspended_ssrcs) {
+  // Configure regular SSRCs.
+  RTC_CHECK(ssrc_to_rtp_module_.empty());
+  for (size_t i = 0; i < rtp_config_.ssrcs.size(); ++i) {
+    uint32_t ssrc = rtp_config_.ssrcs[i];
+    RtpRtcpInterface* const rtp_rtcp = rtp_streams_[i].rtp_rtcp.get();
+
+    // Restore RTP state if previous existed.
+    auto it = suspended_ssrcs.find(ssrc);
+    if (it != suspended_ssrcs.end())
+      rtp_rtcp->SetRtpState(it->second);
+
+    ssrc_to_rtp_module_[ssrc] = rtp_rtcp;
+  }
+
+  // Set up RTX if available.
+  if (rtp_config_.rtx.ssrcs.empty())
+    return;
+
+  RTC_DCHECK_EQ(rtp_config_.rtx.ssrcs.size(), rtp_config_.ssrcs.size());
+  for (size_t i = 0; i < rtp_config_.rtx.ssrcs.size(); ++i) {
+    uint32_t ssrc = rtp_config_.rtx.ssrcs[i];
+    RtpRtcpInterface* const rtp_rtcp = rtp_streams_[i].rtp_rtcp.get();
+    auto it = suspended_ssrcs.find(ssrc);
+    if (it != suspended_ssrcs.end())
+      rtp_rtcp->SetRtxState(it->second);
+  }
+
+  // Configure RTX payload types.
+  RTC_DCHECK_GE(rtp_config_.rtx.payload_type, 0);
+  for (const RtpStreamSender& stream : rtp_streams_) {
+    stream.rtp_rtcp->SetRtxSendPayloadType(rtp_config_.rtx.payload_type,
+                                           rtp_config_.payload_type);
+    stream.rtp_rtcp->SetRtxSendStatus(kRtxRetransmitted |
+                                      kRtxRedundantPayloads);
+  }
+  if (rtp_config_.ulpfec.red_payload_type != -1 &&
+      rtp_config_.ulpfec.red_rtx_payload_type != -1) {
+    for (const RtpStreamSender& stream : rtp_streams_) {
+      stream.rtp_rtcp->SetRtxSendPayloadType(
+          rtp_config_.ulpfec.red_rtx_payload_type,
+          rtp_config_.ulpfec.red_payload_type);
+    }
+  }
+}
+
+void RtpVideoSender::OnNetworkAvailability(bool network_available) {
+  for (const RtpStreamSender& stream : rtp_streams_) {
+    stream.rtp_rtcp->SetRTCPStatus(network_available ? rtp_config_.rtcp_mode
+                                                     : RtcpMode::kOff);
+  }
+}
+
+std::map<uint32_t, RtpState> RtpVideoSender::GetRtpStates() const {
+  std::map<uint32_t, RtpState> rtp_states;
+
+  for (size_t i = 0; i < rtp_config_.ssrcs.size(); ++i) {
+    uint32_t ssrc = rtp_config_.ssrcs[i];
+    RTC_DCHECK_EQ(ssrc, rtp_streams_[i].rtp_rtcp->SSRC());
+    rtp_states[ssrc] = rtp_streams_[i].rtp_rtcp->GetRtpState();
+
+    // Only happens during shutdown, when RTP module is already inactive,
+    // so OK to call fec generator here.
+    if (rtp_streams_[i].fec_generator) {
+      absl::optional<RtpState> fec_state =
+          rtp_streams_[i].fec_generator->GetRtpState();
+      if (fec_state) {
+        uint32_t ssrc = rtp_config_.flexfec.ssrc;
+        rtp_states[ssrc] = *fec_state;
+      }
+    }
+  }
+
+  for (size_t i = 0; i < rtp_config_.rtx.ssrcs.size(); ++i) {
+    uint32_t ssrc = rtp_config_.rtx.ssrcs[i];
+    rtp_states[ssrc] = rtp_streams_[i].rtp_rtcp->GetRtxState();
+  }
+
+  return rtp_states;
+}
+
+std::map<uint32_t, RtpPayloadState> RtpVideoSender::GetRtpPayloadStates()
+    const {
+  MutexLock lock(&mutex_);
+  std::map<uint32_t, RtpPayloadState> payload_states;
+  for (const auto& param : params_) {
+    payload_states[param.ssrc()] = param.state();
+    payload_states[param.ssrc()].shared_frame_id = shared_frame_id_;
+  }
+  return payload_states;
+}
+
+void RtpVideoSender::OnTransportOverheadChanged(
+    size_t transport_overhead_bytes_per_packet) {
+  MutexLock lock(&mutex_);
+  transport_overhead_bytes_per_packet_ = transport_overhead_bytes_per_packet;
+
+  size_t max_rtp_packet_size =
+      std::min(rtp_config_.max_packet_size,
+               kPathMTU - transport_overhead_bytes_per_packet_);
+  for (const RtpStreamSender& stream : rtp_streams_) {
+    stream.rtp_rtcp->SetMaxRtpPacketSize(max_rtp_packet_size);
+  }
+}
+
+void RtpVideoSender::OnBitrateUpdated(BitrateAllocationUpdate update,
+                                      int framerate) {
+  // Substract overhead from bitrate.
+  MutexLock lock(&mutex_);
+  size_t num_active_streams = 0;
+  size_t overhead_bytes_per_packet = 0;
+  for (const auto& stream : rtp_streams_) {
+    if (stream.rtp_rtcp->SendingMedia()) {
+      overhead_bytes_per_packet += stream.rtp_rtcp->ExpectedPerPacketOverhead();
+      ++num_active_streams;
+    }
+  }
+  if (num_active_streams > 1) {
+    overhead_bytes_per_packet /= num_active_streams;
+  }
+
+  DataSize packet_overhead = DataSize::Bytes(
+      overhead_bytes_per_packet + transport_overhead_bytes_per_packet_);
+  DataSize max_total_packet_size = DataSize::Bytes(
+      rtp_config_.max_packet_size + transport_overhead_bytes_per_packet_);
+  uint32_t payload_bitrate_bps = update.target_bitrate.bps();
+  if (has_packet_feedback_) {
+    DataRate overhead_rate =
+        CalculateOverheadRate(update.target_bitrate, max_total_packet_size,
+                              packet_overhead, Frequency::Hertz(framerate));
+    // TODO(srte): We probably should not accept 0 payload bitrate here.
+    payload_bitrate_bps = rtc::saturated_cast<uint32_t>(payload_bitrate_bps -
+                                                        overhead_rate.bps());
+  }
+
+  // Get the encoder target rate. It is the estimated network rate -
+  // protection overhead.
+  // TODO(srte): We should multiply with 255 here.
+  encoder_target_rate_bps_ = fec_controller_->UpdateFecRates(
+      payload_bitrate_bps, framerate,
+      rtc::saturated_cast<uint8_t>(update.packet_loss_ratio * 256),
+      loss_mask_vector_, update.round_trip_time.ms());
+  if (!fec_allowed_) {
+    encoder_target_rate_bps_ = payload_bitrate_bps;
+    // fec_controller_->UpdateFecRates() was still called so as to allow
+    // `fec_controller_` to update whatever internal state it might have,
+    // since `fec_allowed_` may be toggled back on at any moment.
+  }
+
+  // Subtract packetization overhead from the encoder target. If target rate
+  // is really low, cap the overhead at 50%. This also avoids the case where
+  // `encoder_target_rate_bps_` is 0 due to encoder pause event while the
+  // packetization rate is positive since packets are still flowing.
+  uint32_t packetization_rate_bps =
+      std::min(GetPacketizationOverheadRate(), encoder_target_rate_bps_ / 2);
+  encoder_target_rate_bps_ -= packetization_rate_bps;
+
+  loss_mask_vector_.clear();
+
+  uint32_t encoder_overhead_rate_bps = 0;
+  if (has_packet_feedback_) {
+    // TODO(srte): The packet size should probably be the same as in the
+    // CalculateOverheadRate call above (just max_total_packet_size), it doesn't
+    // make sense to use different packet rates for different overhead
+    // calculations.
+    DataRate encoder_overhead_rate = CalculateOverheadRate(
+        DataRate::BitsPerSec(encoder_target_rate_bps_),
+        max_total_packet_size - DataSize::Bytes(overhead_bytes_per_packet),
+        packet_overhead, Frequency::Hertz(framerate));
+    encoder_overhead_rate_bps = std::min(
+        encoder_overhead_rate.bps<uint32_t>(),
+        update.target_bitrate.bps<uint32_t>() - encoder_target_rate_bps_);
+  }
+  const uint32_t media_rate = encoder_target_rate_bps_ +
+                              encoder_overhead_rate_bps +
+                              packetization_rate_bps;
+  RTC_DCHECK_GE(update.target_bitrate, DataRate::BitsPerSec(media_rate));
+  // `protection_bitrate_bps_` includes overhead.
+  protection_bitrate_bps_ = update.target_bitrate.bps() - media_rate;
+}
+
+uint32_t RtpVideoSender::GetPayloadBitrateBps() const {
+  return encoder_target_rate_bps_;
+}
+
+uint32_t RtpVideoSender::GetProtectionBitrateBps() const {
+  return protection_bitrate_bps_;
+}
+
+std::vector<RtpSequenceNumberMap::Info> RtpVideoSender::GetSentRtpPacketInfos(
+    uint32_t ssrc,
+    rtc::ArrayView<const uint16_t> sequence_numbers) const {
+  for (const auto& rtp_stream : rtp_streams_) {
+    if (ssrc == rtp_stream.rtp_rtcp->SSRC()) {
+      return rtp_stream.rtp_rtcp->GetSentRtpPacketInfos(sequence_numbers);
+    }
+  }
+  return std::vector<RtpSequenceNumberMap::Info>();
+}
+
+int RtpVideoSender::ProtectionRequest(const FecProtectionParams* delta_params,
+                                      const FecProtectionParams* key_params,
+                                      uint32_t* sent_video_rate_bps,
+                                      uint32_t* sent_nack_rate_bps,
+                                      uint32_t* sent_fec_rate_bps) {
+  *sent_video_rate_bps = 0;
+  *sent_nack_rate_bps = 0;
+  *sent_fec_rate_bps = 0;
+  for (const RtpStreamSender& stream : rtp_streams_) {
+      stream.rtp_rtcp->SetFecProtectionParams(*delta_params, *key_params);
+
+      auto send_bitrate = stream.rtp_rtcp->GetSendRates();
+      *sent_video_rate_bps += send_bitrate[RtpPacketMediaType::kVideo].bps();
+      *sent_fec_rate_bps +=
+          send_bitrate[RtpPacketMediaType::kForwardErrorCorrection].bps();
+      *sent_nack_rate_bps +=
+          send_bitrate[RtpPacketMediaType::kRetransmission].bps();
+  }
+  return 0;
+}
+
+void RtpVideoSender::SetFecAllowed(bool fec_allowed) {
+  MutexLock lock(&mutex_);
+  fec_allowed_ = fec_allowed;
+}
+
+void RtpVideoSender::OnPacketFeedbackVector(
+    std::vector<StreamPacketInfo> packet_feedback_vector) {
+  if (fec_controller_->UseLossVectorMask()) {
+    MutexLock lock(&mutex_);
+    for (const StreamPacketInfo& packet : packet_feedback_vector) {
+      loss_mask_vector_.push_back(!packet.received);
+    }
+  }
+
+  // Map from SSRC to all acked packets for that RTP module.
+  std::map<uint32_t, std::vector<uint16_t>> acked_packets_per_ssrc;
+  for (const StreamPacketInfo& packet : packet_feedback_vector) {
+    if (packet.received && packet.ssrc) {
+      acked_packets_per_ssrc[*packet.ssrc].push_back(
+          packet.rtp_sequence_number);
+    }
+  }
+
+  // Map from SSRC to vector of RTP sequence numbers that are indicated as
+  // lost by feedback, without being trailed by any received packets.
+  std::map<uint32_t, std::vector<uint16_t>> early_loss_detected_per_ssrc;
+
+  for (const StreamPacketInfo& packet : packet_feedback_vector) {
+    // Only include new media packets, not retransmissions/padding/fec.
+    if (!packet.received && packet.ssrc && !packet.is_retransmission) {
+      // Last known lost packet, might not be detectable as lost by remote
+      // jitter buffer.
+      early_loss_detected_per_ssrc[*packet.ssrc].push_back(
+          packet.rtp_sequence_number);
+    } else {
+      // Packet received, so any loss prior to this is already detectable.
+      early_loss_detected_per_ssrc.erase(*packet.ssrc);
+    }
+  }
+
+  for (const auto& kv : early_loss_detected_per_ssrc) {
+    const uint32_t ssrc = kv.first;
+    auto it = ssrc_to_rtp_module_.find(ssrc);
+    RTC_CHECK(it != ssrc_to_rtp_module_.end());
+    RTPSender* rtp_sender = it->second->RtpSender();
+    for (uint16_t sequence_number : kv.second) {
+      rtp_sender->ReSendPacket(sequence_number);
+    }
+  }
+
+  for (const auto& kv : acked_packets_per_ssrc) {
+    const uint32_t ssrc = kv.first;
+    auto it = ssrc_to_rtp_module_.find(ssrc);
+    if (it == ssrc_to_rtp_module_.end()) {
+      // No media, likely FEC or padding. Ignore since there's no RTP history to
+      // clean up anyway.
+      continue;
+    }
+    rtc::ArrayView<const uint16_t> rtp_sequence_numbers(kv.second);
+    it->second->OnPacketsAcknowledged(rtp_sequence_numbers);
+  }
+}
+
+void RtpVideoSender::SetEncodingData(size_t width,
+                                     size_t height,
+                                     size_t num_temporal_layers) {
+  fec_controller_->SetEncodingData(width, height, num_temporal_layers,
+                                   rtp_config_.max_packet_size);
+}
+
+DataRate RtpVideoSender::CalculateOverheadRate(DataRate data_rate,
+                                               DataSize packet_size,
+                                               DataSize overhead_per_packet,
+                                               Frequency framerate) const {
+  Frequency packet_rate = data_rate / packet_size;
+  if (use_frame_rate_for_overhead_) {
+    framerate = std::max(framerate, Frequency::Hertz(1));
+    DataSize frame_size = data_rate / framerate;
+    int packets_per_frame = ceil(frame_size / packet_size);
+    packet_rate = packets_per_frame * framerate;
+  }
+  return packet_rate.RoundUpTo(Frequency::Hertz(1)) * overhead_per_packet;
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/rtp_video_sender.h b/third_party/libwebrtc/call/rtp_video_sender.h
new file mode 100644
index 0000000000..9666b89916
--- /dev/null
+++ b/third_party/libwebrtc/call/rtp_video_sender.h
@@ -0,0 +1,218 @@
+/*
+ *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_RTP_VIDEO_SENDER_H_
+#define CALL_RTP_VIDEO_SENDER_H_
+
+#include <map>
+#include <memory>
+#include <unordered_set>
+#include <vector>
+
+#include "absl/types/optional.h"
+#include "api/array_view.h"
+#include "api/call/transport.h"
+#include "api/fec_controller.h"
+#include "api/fec_controller_override.h"
+#include "api/field_trials_view.h"
+#include "api/rtc_event_log/rtc_event_log.h"
+#include "api/sequence_checker.h"
+#include "api/task_queue/task_queue_base.h"
+#include "api/task_queue/task_queue_factory.h"
+#include "api/video_codecs/video_encoder.h"
+#include "call/rtp_config.h"
+#include "call/rtp_payload_params.h"
+#include "call/rtp_transport_controller_send_interface.h"
+#include "call/rtp_video_sender_interface.h"
+#include "modules/rtp_rtcp/include/flexfec_sender.h"
+#include "modules/rtp_rtcp/source/rtp_rtcp_impl2.h"
+#include "modules/rtp_rtcp/source/rtp_sender.h"
+#include "modules/rtp_rtcp/source/rtp_sender_video.h"
+#include "modules/rtp_rtcp/source/rtp_sequence_number_map.h"
+#include "modules/rtp_rtcp/source/rtp_video_header.h"
+#include "rtc_base/rate_limiter.h"
+#include "rtc_base/synchronization/mutex.h"
+#include "rtc_base/thread_annotations.h"
+
+namespace webrtc {
+
+class FrameEncryptorInterface;
+class RtpTransportControllerSendInterface;
+
+namespace webrtc_internal_rtp_video_sender {
+// RTP state for a single simulcast stream. Internal to the implementation of
+// RtpVideoSender.
+struct RtpStreamSender {
+  RtpStreamSender(std::unique_ptr<ModuleRtpRtcpImpl2> rtp_rtcp,
+                  std::unique_ptr<RTPSenderVideo> sender_video,
+                  std::unique_ptr<VideoFecGenerator> fec_generator);
+  ~RtpStreamSender();
+
+  RtpStreamSender(RtpStreamSender&&) = default;
+  RtpStreamSender& operator=(RtpStreamSender&&) = default;
+
+  // Note: Needs pointer stability.
+  std::unique_ptr<ModuleRtpRtcpImpl2> rtp_rtcp;
+  std::unique_ptr<RTPSenderVideo> sender_video;
+  std::unique_ptr<VideoFecGenerator> fec_generator;
+};
+
+}  // namespace webrtc_internal_rtp_video_sender
+
+// RtpVideoSender routes outgoing data to the correct sending RTP module, based
+// on the simulcast layer in RTPVideoHeader.
+class RtpVideoSender : public RtpVideoSenderInterface,
+                       public VCMProtectionCallback,
+                       public StreamFeedbackObserver {
+ public:
+  // Rtp modules are assumed to be sorted in simulcast index order.
+  RtpVideoSender(
+      Clock* clock,
+      const std::map<uint32_t, RtpState>& suspended_ssrcs,
+      const std::map<uint32_t, RtpPayloadState>& states,
+      const RtpConfig& rtp_config,
+      int rtcp_report_interval_ms,
+      Transport* send_transport,
+      const RtpSenderObservers& observers,
+      RtpTransportControllerSendInterface* transport,
+      RtcEventLog* event_log,
+      RateLimiter* retransmission_limiter,  // move inside RtpTransport
+      std::unique_ptr<FecController> fec_controller,
+      FrameEncryptorInterface* frame_encryptor,
+      const CryptoOptions& crypto_options,  // move inside RtpTransport
+      rtc::scoped_refptr<FrameTransformerInterface> frame_transformer,
+      const FieldTrialsView& field_trials,
+      TaskQueueFactory* task_queue_factory);
+  ~RtpVideoSender() override;
+
+  RtpVideoSender(const RtpVideoSender&) = delete;
+  RtpVideoSender& operator=(const RtpVideoSender&) = delete;
+
+  // Sets the sending status of the rtp modules and appropriately sets the
+  // payload router to active if any rtp modules are active.
+  void SetActiveModules(const std::vector<bool>& active_modules)
+      RTC_LOCKS_EXCLUDED(mutex_) override;
+  void Stop() RTC_LOCKS_EXCLUDED(mutex_) override;
+  bool IsActive() RTC_LOCKS_EXCLUDED(mutex_) override;
+
+  void OnNetworkAvailability(bool network_available)
+      RTC_LOCKS_EXCLUDED(mutex_) override;
+  std::map<uint32_t, RtpState> GetRtpStates() const
+      RTC_LOCKS_EXCLUDED(mutex_) override;
+  std::map<uint32_t, RtpPayloadState> GetRtpPayloadStates() const
+      RTC_LOCKS_EXCLUDED(mutex_) override;
+
+  void DeliverRtcp(const uint8_t* packet, size_t length)
+      RTC_LOCKS_EXCLUDED(mutex_) override;
+
+  // Implements webrtc::VCMProtectionCallback.
+  int ProtectionRequest(const FecProtectionParams* delta_params,
+                        const FecProtectionParams* key_params,
+                        uint32_t* sent_video_rate_bps,
+                        uint32_t* sent_nack_rate_bps,
+                        uint32_t* sent_fec_rate_bps)
+      RTC_LOCKS_EXCLUDED(mutex_) override;
+
+  // Implements FecControllerOverride.
+  void SetFecAllowed(bool fec_allowed) RTC_LOCKS_EXCLUDED(mutex_) override;
+
+  // Implements EncodedImageCallback.
+  // Returns 0 if the packet was routed / sent, -1 otherwise.
+  EncodedImageCallback::Result OnEncodedImage(
+      const EncodedImage& encoded_image,
+      const CodecSpecificInfo* codec_specific_info)
+      RTC_LOCKS_EXCLUDED(mutex_) override;
+
+  void OnBitrateAllocationUpdated(const VideoBitrateAllocation& bitrate)
+      RTC_LOCKS_EXCLUDED(mutex_) override;
+  void OnVideoLayersAllocationUpdated(
+      const VideoLayersAllocation& layers) override;
+  void OnTransportOverheadChanged(size_t transport_overhead_bytes_per_packet)
+      RTC_LOCKS_EXCLUDED(mutex_) override;
+  void OnBitrateUpdated(BitrateAllocationUpdate update, int framerate)
+      RTC_LOCKS_EXCLUDED(mutex_) override;
+  uint32_t GetPayloadBitrateBps() const RTC_LOCKS_EXCLUDED(mutex_) override;
+  uint32_t GetProtectionBitrateBps() const RTC_LOCKS_EXCLUDED(mutex_) override;
+  void SetEncodingData(size_t width, size_t height, size_t num_temporal_layers)
+      RTC_LOCKS_EXCLUDED(mutex_) override;
+
+  std::vector<RtpSequenceNumberMap::Info> GetSentRtpPacketInfos(
+      uint32_t ssrc,
+      rtc::ArrayView<const uint16_t> sequence_numbers) const
+      RTC_LOCKS_EXCLUDED(mutex_) override;
+
+  // From StreamFeedbackObserver.
+  void OnPacketFeedbackVector(
+      std::vector<StreamPacketInfo> packet_feedback_vector)
+      RTC_LOCKS_EXCLUDED(mutex_) override;
+
+ private:
+  bool IsActiveLocked() RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
+  void SetActiveModulesLocked(const std::vector<bool>& active_modules)
+      RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
+  void UpdateModuleSendingState() RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
+  void ConfigureProtection();
+  void ConfigureSsrcs(const std::map<uint32_t, RtpState>& suspended_ssrcs);
+  bool NackEnabled() const;
+  uint32_t GetPacketizationOverheadRate() const;
+  DataRate CalculateOverheadRate(DataRate data_rate,
+                                 DataSize packet_size,
+                                 DataSize overhead_per_packet,
+                                 Frequency framerate) const;
+
+  const FieldTrialsView& field_trials_;
+  const bool use_frame_rate_for_overhead_;
+  const bool has_packet_feedback_;
+
+  // Semantically equivalent to checking for `transport_->GetWorkerQueue()`
+  // but some tests need to be updated to call from the correct context.
+  RTC_NO_UNIQUE_ADDRESS SequenceChecker transport_checker_;
+
+  // TODO(bugs.webrtc.org/13517): Remove mutex_ once RtpVideoSender runs on the
+  // transport task queue.
+  mutable Mutex mutex_;
+  bool active_ RTC_GUARDED_BY(mutex_);
+  bool registered_for_feedback_ RTC_GUARDED_BY(transport_checker_) = false;
+
+  const std::unique_ptr<FecController> fec_controller_;
+  bool fec_allowed_ RTC_GUARDED_BY(mutex_);
+
+  // Rtp modules are assumed to be sorted in simulcast index order.
+  const std::vector<webrtc_internal_rtp_video_sender::RtpStreamSender>
+      rtp_streams_;
+  const RtpConfig rtp_config_;
+  const absl::optional<VideoCodecType> codec_type_;
+  RtpTransportControllerSendInterface* const transport_;
+
+  // When using the generic descriptor we want all simulcast streams to share
+  // one frame id space (so that the SFU can switch stream without having to
+  // rewrite the frame id), therefore `shared_frame_id` has to live in a place
+  // where we are aware of all the different streams.
+  int64_t shared_frame_id_ = 0;
+  std::vector<RtpPayloadParams> params_ RTC_GUARDED_BY(mutex_);
+
+  size_t transport_overhead_bytes_per_packet_ RTC_GUARDED_BY(mutex_);
+  uint32_t protection_bitrate_bps_;
+  uint32_t encoder_target_rate_bps_;
+
+  std::vector<bool> loss_mask_vector_ RTC_GUARDED_BY(mutex_);
+
+  std::vector<FrameCounts> frame_counts_ RTC_GUARDED_BY(mutex_);
+  FrameCountObserver* const frame_count_observer_;
+
+  // Effectively const map from SSRC to RtpRtcp, for all media SSRCs.
+  // This map is set at construction time and never changed, but it's
+  // non-trivial to make it properly const.
+  std::map<uint32_t, RtpRtcpInterface*> ssrc_to_rtp_module_;
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_RTP_VIDEO_SENDER_H_
diff --git a/third_party/libwebrtc/call/rtp_video_sender_interface.h b/third_party/libwebrtc/call/rtp_video_sender_interface.h
new file mode 100644
index 0000000000..3f2877155a
--- /dev/null
+++ b/third_party/libwebrtc/call/rtp_video_sender_interface.h
@@ -0,0 +1,69 @@
+/*
+ *  Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_RTP_VIDEO_SENDER_INTERFACE_H_
+#define CALL_RTP_VIDEO_SENDER_INTERFACE_H_
+
+#include <map>
+#include <vector>
+
+#include "absl/types/optional.h"
+#include "api/array_view.h"
+#include "api/call/bitrate_allocation.h"
+#include "api/fec_controller_override.h"
+#include "api/video/video_layers_allocation.h"
+#include "call/rtp_config.h"
+#include "modules/rtp_rtcp/include/rtp_rtcp_defines.h"
+#include "modules/rtp_rtcp/source/rtp_sequence_number_map.h"
+#include "modules/video_coding/include/video_codec_interface.h"
+
+namespace webrtc {
+class VideoBitrateAllocation;
+struct FecProtectionParams;
+
+class RtpVideoSenderInterface : public EncodedImageCallback,
+                                public FecControllerOverride {
+ public:
+  // Sets the sending status of the rtp modules and appropriately sets the
+  // RtpVideoSender to active if any rtp modules are active.
+  // A module will only send packet if beeing active.
+  virtual void SetActiveModules(const std::vector<bool>& active_modules) = 0;
+  // Set the sending status of all rtp modules to inactive.
+  virtual void Stop() = 0;
+  virtual bool IsActive() = 0;
+
+  virtual void OnNetworkAvailability(bool network_available) = 0;
+  virtual std::map<uint32_t, RtpState> GetRtpStates() const = 0;
+  virtual std::map<uint32_t, RtpPayloadState> GetRtpPayloadStates() const = 0;
+
+  virtual void DeliverRtcp(const uint8_t* packet, size_t length) = 0;
+
+  virtual void OnBitrateAllocationUpdated(
+      const VideoBitrateAllocation& bitrate) = 0;
+  virtual void OnVideoLayersAllocationUpdated(
+      const VideoLayersAllocation& allocation) = 0;
+  virtual void OnBitrateUpdated(BitrateAllocationUpdate update,
+                                int framerate) = 0;
+  virtual void OnTransportOverheadChanged(
+      size_t transport_overhead_bytes_per_packet) = 0;
+  virtual uint32_t GetPayloadBitrateBps() const = 0;
+  virtual uint32_t GetProtectionBitrateBps() const = 0;
+  virtual void SetEncodingData(size_t width,
+                               size_t height,
+                               size_t num_temporal_layers) = 0;
+  virtual std::vector<RtpSequenceNumberMap::Info> GetSentRtpPacketInfos(
+      uint32_t ssrc,
+      rtc::ArrayView<const uint16_t> sequence_numbers) const = 0;
+
+  // Implements FecControllerOverride.
+  void SetFecAllowed(bool fec_allowed) override = 0;
+};
+}  // namespace webrtc
+#endif  // CALL_RTP_VIDEO_SENDER_INTERFACE_H_
diff --git a/third_party/libwebrtc/call/rtp_video_sender_unittest.cc b/third_party/libwebrtc/call/rtp_video_sender_unittest.cc
new file mode 100644
index 0000000000..da2bed649b
--- /dev/null
+++ b/third_party/libwebrtc/call/rtp_video_sender_unittest.cc
@@ -0,0 +1,1178 @@
+/*
+ *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/rtp_video_sender.h"
+
+#include <atomic>
+#include <memory>
+#include <string>
+#include <utility>
+
+#include "absl/functional/any_invocable.h"
+#include "call/rtp_transport_controller_send.h"
+#include "modules/rtp_rtcp/include/rtp_rtcp_defines.h"
+#include "modules/rtp_rtcp/source/byte_io.h"
+#include "modules/rtp_rtcp/source/rtcp_packet/nack.h"
+#include "modules/rtp_rtcp/source/rtp_dependency_descriptor_extension.h"
+#include "modules/rtp_rtcp/source/rtp_packet.h"
+#include "modules/video_coding/fec_controller_default.h"
+#include "modules/video_coding/include/video_codec_interface.h"
+#include "rtc_base/rate_limiter.h"
+#include "test/gmock.h"
+#include "test/gtest.h"
+#include "test/mock_frame_transformer.h"
+#include "test/mock_transport.h"
+#include "test/scenario/scenario.h"
+#include "test/scoped_key_value_config.h"
+#include "test/time_controller/simulated_time_controller.h"
+#include "video/send_delay_stats.h"
+#include "video/send_statistics_proxy.h"
+
+namespace webrtc {
+namespace {
+
+using ::testing::_;
+using ::testing::NiceMock;
+using ::testing::SaveArg;
+using ::testing::SizeIs;
+
+const int8_t kPayloadType = 96;
+const uint32_t kSsrc1 = 12345;
+const uint32_t kSsrc2 = 23456;
+const uint32_t kRtxSsrc1 = 34567;
+const uint32_t kRtxSsrc2 = 45678;
+const int16_t kInitialPictureId1 = 222;
+const int16_t kInitialPictureId2 = 44;
+const int16_t kInitialTl0PicIdx1 = 99;
+const int16_t kInitialTl0PicIdx2 = 199;
+const int64_t kRetransmitWindowSizeMs = 500;
+const int kTransportsSequenceExtensionId = 7;
+const int kDependencyDescriptorExtensionId = 8;
+
+class MockRtcpIntraFrameObserver : public RtcpIntraFrameObserver {
+ public:
+  MOCK_METHOD(void, OnReceivedIntraFrameRequest, (uint32_t), (override));
+};
+
+RtpSenderObservers CreateObservers(
+    RtcpRttStats* rtcp_rtt_stats,
+    RtcpIntraFrameObserver* intra_frame_callback,
+    ReportBlockDataObserver* report_block_data_observer,
+    StreamDataCountersCallback* rtp_stats,
+    BitrateStatisticsObserver* bitrate_observer,
+    FrameCountObserver* frame_count_observer,
+    RtcpPacketTypeCounterObserver* rtcp_type_observer,
+    SendSideDelayObserver* send_delay_observer,
+    SendPacketObserver* send_packet_observer) {
+  RtpSenderObservers observers;
+  observers.rtcp_rtt_stats = rtcp_rtt_stats;
+  observers.intra_frame_callback = intra_frame_callback;
+  observers.rtcp_loss_notification_observer = nullptr;
+  observers.report_block_data_observer = report_block_data_observer;
+  observers.rtp_stats = rtp_stats;
+  observers.bitrate_observer = bitrate_observer;
+  observers.frame_count_observer = frame_count_observer;
+  observers.rtcp_type_observer = rtcp_type_observer;
+  observers.send_delay_observer = send_delay_observer;
+  observers.send_packet_observer = send_packet_observer;
+  return observers;
+}
+
+BitrateConstraints GetBitrateConfig() {
+  BitrateConstraints bitrate_config;
+  bitrate_config.min_bitrate_bps = 30000;
+  bitrate_config.start_bitrate_bps = 300000;
+  bitrate_config.max_bitrate_bps = 3000000;
+  return bitrate_config;
+}
+
+VideoSendStream::Config CreateVideoSendStreamConfig(
+    Transport* transport,
+    const std::vector<uint32_t>& ssrcs,
+    const std::vector<uint32_t>& rtx_ssrcs,
+    int payload_type) {
+  VideoSendStream::Config config(transport);
+  config.rtp.ssrcs = ssrcs;
+  config.rtp.rtx.ssrcs = rtx_ssrcs;
+  config.rtp.payload_type = payload_type;
+  config.rtp.rtx.payload_type = payload_type + 1;
+  config.rtp.nack.rtp_history_ms = 1000;
+  config.rtp.extensions.emplace_back(RtpExtension::kTransportSequenceNumberUri,
+                                     kTransportsSequenceExtensionId);
+  config.rtp.extensions.emplace_back(RtpDependencyDescriptorExtension::Uri(),
+                                     kDependencyDescriptorExtensionId);
+  config.rtp.extmap_allow_mixed = true;
+  return config;
+}
+
+class RtpVideoSenderTestFixture {
+ public:
+  RtpVideoSenderTestFixture(
+      const std::vector<uint32_t>& ssrcs,
+      const std::vector<uint32_t>& rtx_ssrcs,
+      int payload_type,
+      const std::map<uint32_t, RtpPayloadState>& suspended_payload_states,
+      FrameCountObserver* frame_count_observer,
+      rtc::scoped_refptr<FrameTransformerInterface> frame_transformer,
+      const FieldTrialsView* field_trials = nullptr)
+      : time_controller_(Timestamp::Millis(1000000)),
+        config_(CreateVideoSendStreamConfig(&transport_,
+                                            ssrcs,
+                                            rtx_ssrcs,
+                                            payload_type)),
+        send_delay_stats_(time_controller_.GetClock()),
+        bitrate_config_(GetBitrateConfig()),
+        transport_controller_(
+            time_controller_.GetClock(),
+            RtpTransportConfig{
+                .bitrate_config = bitrate_config_,
+                .event_log = &event_log_,
+                .task_queue_factory = time_controller_.GetTaskQueueFactory(),
+                .trials = field_trials ? field_trials : &field_trials_,
+            }),
+        stats_proxy_(time_controller_.GetClock(),
+                     config_,
+                     VideoEncoderConfig::ContentType::kRealtimeVideo,
+                     field_trials ? *field_trials : field_trials_),
+        retransmission_rate_limiter_(time_controller_.GetClock(),
+                                     kRetransmitWindowSizeMs) {
+    transport_controller_.EnsureStarted();
+    std::map<uint32_t, RtpState> suspended_ssrcs;
+    router_ = std::make_unique<RtpVideoSender>(
+        time_controller_.GetClock(), suspended_ssrcs, suspended_payload_states,
+        config_.rtp, config_.rtcp_report_interval_ms, &transport_,
+        CreateObservers(nullptr, &encoder_feedback_, &stats_proxy_,
+                        &stats_proxy_, &stats_proxy_, frame_count_observer,
+                        &stats_proxy_, &stats_proxy_, &send_delay_stats_),
+        &transport_controller_, &event_log_, &retransmission_rate_limiter_,
+        std::make_unique<FecControllerDefault>(time_controller_.GetClock()),
+        nullptr, CryptoOptions{}, frame_transformer,
+        field_trials ? *field_trials : field_trials_,
+        time_controller_.GetTaskQueueFactory());
+  }
+
+  RtpVideoSenderTestFixture(
+      const std::vector<uint32_t>& ssrcs,
+      const std::vector<uint32_t>& rtx_ssrcs,
+      int payload_type,
+      const std::map<uint32_t, RtpPayloadState>& suspended_payload_states,
+      FrameCountObserver* frame_count_observer,
+      const FieldTrialsView* field_trials = nullptr)
+      : RtpVideoSenderTestFixture(ssrcs,
+                                  rtx_ssrcs,
+                                  payload_type,
+                                  suspended_payload_states,
+                                  frame_count_observer,
+                                  /*frame_transformer=*/nullptr,
+                                  field_trials) {}
+
+  RtpVideoSenderTestFixture(
+      const std::vector<uint32_t>& ssrcs,
+      const std::vector<uint32_t>& rtx_ssrcs,
+      int payload_type,
+      const std::map<uint32_t, RtpPayloadState>& suspended_payload_states,
+      const FieldTrialsView* field_trials = nullptr)
+      : RtpVideoSenderTestFixture(ssrcs,
+                                  rtx_ssrcs,
+                                  payload_type,
+                                  suspended_payload_states,
+                                  /*frame_count_observer=*/nullptr,
+                                  /*frame_transformer=*/nullptr,
+                                  field_trials) {}
+
+  ~RtpVideoSenderTestFixture() { Stop(); }
+
+  RtpVideoSender* router() { return router_.get(); }
+  MockTransport& transport() { return transport_; }
+  void AdvanceTime(TimeDelta delta) { time_controller_.AdvanceTime(delta); }
+
+  void Stop() {
+    RunOnTransportQueue([&]() { router_->Stop(); });
+  }
+
+  void SetActiveModules(const std::vector<bool>& active_modules) {
+    RunOnTransportQueue([&]() { router_->SetActiveModules(active_modules); });
+  }
+
+  // Several RtpVideoSender methods expect to be called on the task queue as
+  // owned by the send transport. While the SequenceChecker may pick up the
+  // default thread as the transport queue, explicit checks for the transport
+  // queue (not just using a SequenceChecker) aren't possible unless such a
+  // queue is actually active. So RunOnTransportQueue is a convenience function
+  // that allow for running a `task` on the transport queue, similar to
+  // SendTask().
+  void RunOnTransportQueue(absl::AnyInvocable<void() &&> task) {
+    transport_controller_.GetWorkerQueue()->RunOrPost(std::move(task));
+    AdvanceTime(TimeDelta::Zero());
+  }
+
+ private:
+  test::ScopedKeyValueConfig field_trials_;
+  NiceMock<MockTransport> transport_;
+  NiceMock<MockRtcpIntraFrameObserver> encoder_feedback_;
+  GlobalSimulatedTimeController time_controller_;
+  RtcEventLogNull event_log_;
+  VideoSendStream::Config config_;
+  SendDelayStats send_delay_stats_;
+  BitrateConstraints bitrate_config_;
+  RtpTransportControllerSend transport_controller_;
+  SendStatisticsProxy stats_proxy_;
+  RateLimiter retransmission_rate_limiter_;
+  std::unique_ptr<RtpVideoSender> router_;
+};
+
+BitrateAllocationUpdate CreateBitrateAllocationUpdate(int target_bitrate_bps) {
+  BitrateAllocationUpdate update;
+  update.target_bitrate = DataRate::BitsPerSec(target_bitrate_bps);
+  update.round_trip_time = TimeDelta::Zero();
+  return update;
+}
+
+}  // namespace
+
+TEST(RtpVideoSenderTest, SendOnOneModule) {
+  constexpr uint8_t kPayload = 'a';
+  EncodedImage encoded_image;
+  encoded_image.SetTimestamp(1);
+  encoded_image.capture_time_ms_ = 2;
+  encoded_image._frameType = VideoFrameType::kVideoFrameKey;
+  encoded_image.SetEncodedData(EncodedImageBuffer::Create(&kPayload, 1));
+
+  RtpVideoSenderTestFixture test({kSsrc1}, {kRtxSsrc1}, kPayloadType, {});
+  EXPECT_NE(EncodedImageCallback::Result::OK,
+            test.router()->OnEncodedImage(encoded_image, nullptr).error);
+
+  test.SetActiveModules({true});
+  EXPECT_EQ(EncodedImageCallback::Result::OK,
+            test.router()->OnEncodedImage(encoded_image, nullptr).error);
+
+  test.SetActiveModules({false});
+  EXPECT_NE(EncodedImageCallback::Result::OK,
+            test.router()->OnEncodedImage(encoded_image, nullptr).error);
+
+  test.SetActiveModules({true});
+  EXPECT_EQ(EncodedImageCallback::Result::OK,
+            test.router()->OnEncodedImage(encoded_image, nullptr).error);
+}
+
+TEST(RtpVideoSenderTest, SendSimulcastSetActive) {
+  constexpr uint8_t kPayload = 'a';
+  EncodedImage encoded_image_1;
+  encoded_image_1.SetTimestamp(1);
+  encoded_image_1.capture_time_ms_ = 2;
+  encoded_image_1._frameType = VideoFrameType::kVideoFrameKey;
+  encoded_image_1.SetEncodedData(EncodedImageBuffer::Create(&kPayload, 1));
+
+  RtpVideoSenderTestFixture test({kSsrc1, kSsrc2}, {kRtxSsrc1, kRtxSsrc2},
+                                 kPayloadType, {});
+
+  CodecSpecificInfo codec_info;
+  codec_info.codecType = kVideoCodecVP8;
+
+  test.SetActiveModules({true, true});
+  EXPECT_EQ(EncodedImageCallback::Result::OK,
+            test.router()->OnEncodedImage(encoded_image_1, &codec_info).error);
+
+  EncodedImage encoded_image_2(encoded_image_1);
+  encoded_image_2.SetSpatialIndex(1);
+  EXPECT_EQ(EncodedImageCallback::Result::OK,
+            test.router()->OnEncodedImage(encoded_image_2, &codec_info).error);
+
+  // Inactive.
+  test.Stop();
+  EXPECT_NE(EncodedImageCallback::Result::OK,
+            test.router()->OnEncodedImage(encoded_image_1, &codec_info).error);
+  EXPECT_NE(EncodedImageCallback::Result::OK,
+            test.router()->OnEncodedImage(encoded_image_2, &codec_info).error);
+}
+
+// Tests how setting individual rtp modules to active affects the overall
+// behavior of the payload router. First sets one module to active and checks
+// that outgoing data can be sent on this module, and checks that no data can
+// be sent if both modules are inactive.
+TEST(RtpVideoSenderTest, SendSimulcastSetActiveModules) {
+  constexpr uint8_t kPayload = 'a';
+  EncodedImage encoded_image_1;
+  encoded_image_1.SetTimestamp(1);
+  encoded_image_1.capture_time_ms_ = 2;
+  encoded_image_1._frameType = VideoFrameType::kVideoFrameKey;
+  encoded_image_1.SetEncodedData(EncodedImageBuffer::Create(&kPayload, 1));
+
+  EncodedImage encoded_image_2(encoded_image_1);
+  encoded_image_2.SetSpatialIndex(1);
+
+  RtpVideoSenderTestFixture test({kSsrc1, kSsrc2}, {kRtxSsrc1, kRtxSsrc2},
+                                 kPayloadType, {});
+  CodecSpecificInfo codec_info;
+  codec_info.codecType = kVideoCodecVP8;
+
+  // Only setting one stream to active will still set the payload router to
+  // active and allow sending data on the active stream.
+  std::vector<bool> active_modules({true, false});
+  test.SetActiveModules(active_modules);
+  EXPECT_EQ(EncodedImageCallback::Result::OK,
+            test.router()->OnEncodedImage(encoded_image_1, &codec_info).error);
+
+  // Setting both streams to inactive will turn the payload router to
+  // inactive.
+  active_modules = {false, false};
+  test.SetActiveModules(active_modules);
+  // An incoming encoded image will not ask the module to send outgoing data
+  // because the payload router is inactive.
+  EXPECT_NE(EncodedImageCallback::Result::OK,
+            test.router()->OnEncodedImage(encoded_image_1, &codec_info).error);
+  EXPECT_NE(EncodedImageCallback::Result::OK,
+            test.router()->OnEncodedImage(encoded_image_1, &codec_info).error);
+}
+
+TEST(
+    RtpVideoSenderTest,
+    DiscardsHigherSpatialVideoFramesAfterLayerDisabledInVideoLayersAllocation) {
+  constexpr uint8_t kPayload = 'a';
+  EncodedImage encoded_image_1;
+  encoded_image_1.SetTimestamp(1);
+  encoded_image_1.capture_time_ms_ = 2;
+  encoded_image_1._frameType = VideoFrameType::kVideoFrameKey;
+  encoded_image_1.SetEncodedData(EncodedImageBuffer::Create(&kPayload, 1));
+  EncodedImage encoded_image_2(encoded_image_1);
+  encoded_image_2.SetSpatialIndex(1);
+  CodecSpecificInfo codec_info;
+  codec_info.codecType = kVideoCodecVP8;
+  RtpVideoSenderTestFixture test({kSsrc1, kSsrc2}, {kRtxSsrc1, kRtxSsrc2},
+                                 kPayloadType, {});
+  test.SetActiveModules({true, true});
+  // A layer is sent on both rtp streams.
+  test.router()->OnVideoLayersAllocationUpdated(
+      {.active_spatial_layers = {{.rtp_stream_index = 0},
+                                 {.rtp_stream_index = 1}}});
+
+  EXPECT_EQ(EncodedImageCallback::Result::OK,
+            test.router()->OnEncodedImage(encoded_image_1, &codec_info).error);
+  EXPECT_EQ(EncodedImageCallback::Result::OK,
+            test.router()->OnEncodedImage(encoded_image_2, &codec_info).error);
+
+  // Only rtp stream index 0 is configured to send a stream.
+  test.router()->OnVideoLayersAllocationUpdated(
+      {.active_spatial_layers = {{.rtp_stream_index = 0}}});
+  EXPECT_EQ(EncodedImageCallback::Result::OK,
+            test.router()->OnEncodedImage(encoded_image_1, &codec_info).error);
+  EXPECT_NE(EncodedImageCallback::Result::OK,
+            test.router()->OnEncodedImage(encoded_image_2, &codec_info).error);
+}
+
+TEST(RtpVideoSenderTest, CreateWithNoPreviousStates) {
+  RtpVideoSenderTestFixture test({kSsrc1, kSsrc2}, {kRtxSsrc1, kRtxSsrc2},
+                                 kPayloadType, {});
+  test.SetActiveModules({true, true});
+
+  std::map<uint32_t, RtpPayloadState> initial_states =
+      test.router()->GetRtpPayloadStates();
+  EXPECT_EQ(2u, initial_states.size());
+  EXPECT_NE(initial_states.find(kSsrc1), initial_states.end());
+  EXPECT_NE(initial_states.find(kSsrc2), initial_states.end());
+}
+
+TEST(RtpVideoSenderTest, CreateWithPreviousStates) {
+  const int64_t kState1SharedFrameId = 123;
+  const int64_t kState2SharedFrameId = 234;
+  RtpPayloadState state1;
+  state1.picture_id = kInitialPictureId1;
+  state1.tl0_pic_idx = kInitialTl0PicIdx1;
+  state1.shared_frame_id = kState1SharedFrameId;
+  RtpPayloadState state2;
+  state2.picture_id = kInitialPictureId2;
+  state2.tl0_pic_idx = kInitialTl0PicIdx2;
+  state2.shared_frame_id = kState2SharedFrameId;
+  std::map<uint32_t, RtpPayloadState> states = {{kSsrc1, state1},
+                                                {kSsrc2, state2}};
+
+  RtpVideoSenderTestFixture test({kSsrc1, kSsrc2}, {kRtxSsrc1, kRtxSsrc2},
+                                 kPayloadType, states);
+  test.SetActiveModules({true, true});
+
+  std::map<uint32_t, RtpPayloadState> initial_states =
+      test.router()->GetRtpPayloadStates();
+  EXPECT_EQ(2u, initial_states.size());
+  EXPECT_EQ(kInitialPictureId1, initial_states[kSsrc1].picture_id);
+  EXPECT_EQ(kInitialTl0PicIdx1, initial_states[kSsrc1].tl0_pic_idx);
+  EXPECT_EQ(kInitialPictureId2, initial_states[kSsrc2].picture_id);
+  EXPECT_EQ(kInitialTl0PicIdx2, initial_states[kSsrc2].tl0_pic_idx);
+  EXPECT_EQ(kState2SharedFrameId, initial_states[kSsrc1].shared_frame_id);
+  EXPECT_EQ(kState2SharedFrameId, initial_states[kSsrc2].shared_frame_id);
+}
+
+TEST(RtpVideoSenderTest, FrameCountCallbacks) {
+  class MockFrameCountObserver : public FrameCountObserver {
+   public:
+    MOCK_METHOD(void,
+                FrameCountUpdated,
+                (const FrameCounts& frame_counts, uint32_t ssrc),
+                (override));
+  } callback;
+
+  RtpVideoSenderTestFixture test({kSsrc1}, {kRtxSsrc1}, kPayloadType, {},
+                                 &callback);
+
+  constexpr uint8_t kPayload = 'a';
+  EncodedImage encoded_image;
+  encoded_image.SetTimestamp(1);
+  encoded_image.capture_time_ms_ = 2;
+  encoded_image._frameType = VideoFrameType::kVideoFrameKey;
+  encoded_image.SetEncodedData(EncodedImageBuffer::Create(&kPayload, 1));
+
+  encoded_image._frameType = VideoFrameType::kVideoFrameKey;
+
+  // No callbacks when not active.
+  EXPECT_CALL(callback, FrameCountUpdated).Times(0);
+  EXPECT_NE(EncodedImageCallback::Result::OK,
+            test.router()->OnEncodedImage(encoded_image, nullptr).error);
+  ::testing::Mock::VerifyAndClearExpectations(&callback);
+
+  test.SetActiveModules({true});
+
+  FrameCounts frame_counts;
+  EXPECT_CALL(callback, FrameCountUpdated(_, kSsrc1))
+      .WillOnce(SaveArg<0>(&frame_counts));
+  EXPECT_EQ(EncodedImageCallback::Result::OK,
+            test.router()->OnEncodedImage(encoded_image, nullptr).error);
+
+  EXPECT_EQ(1, frame_counts.key_frames);
+  EXPECT_EQ(0, frame_counts.delta_frames);
+
+  ::testing::Mock::VerifyAndClearExpectations(&callback);
+
+  encoded_image._frameType = VideoFrameType::kVideoFrameDelta;
+  EXPECT_CALL(callback, FrameCountUpdated(_, kSsrc1))
+      .WillOnce(SaveArg<0>(&frame_counts));
+  EXPECT_EQ(EncodedImageCallback::Result::OK,
+            test.router()->OnEncodedImage(encoded_image, nullptr).error);
+
+  EXPECT_EQ(1, frame_counts.key_frames);
+  EXPECT_EQ(1, frame_counts.delta_frames);
+}
+
+// Integration test verifying that ack of packet via TransportFeedback means
+// that the packet is removed from RtpPacketHistory and won't be retransmitted
+// again.
+TEST(RtpVideoSenderTest, DoesNotRetrasmitAckedPackets) {
+  RtpVideoSenderTestFixture test({kSsrc1, kSsrc2}, {kRtxSsrc1, kRtxSsrc2},
+                                 kPayloadType, {});
+  test.SetActiveModules({true, true});
+
+  constexpr uint8_t kPayload = 'a';
+  EncodedImage encoded_image;
+  encoded_image.SetTimestamp(1);
+  encoded_image.capture_time_ms_ = 2;
+  encoded_image._frameType = VideoFrameType::kVideoFrameKey;
+  encoded_image.SetEncodedData(EncodedImageBuffer::Create(&kPayload, 1));
+
+  // Send two tiny images, mapping to two RTP packets. Capture sequence numbers.
+  std::vector<uint16_t> rtp_sequence_numbers;
+  std::vector<uint16_t> transport_sequence_numbers;
+  EXPECT_CALL(test.transport(), SendRtp)
+      .Times(2)
+      .WillRepeatedly([&rtp_sequence_numbers, &transport_sequence_numbers](
+                          const uint8_t* packet, size_t length,
+                          const PacketOptions& options) {
+        RtpPacket rtp_packet;
+        EXPECT_TRUE(rtp_packet.Parse(packet, length));
+        rtp_sequence_numbers.push_back(rtp_packet.SequenceNumber());
+        transport_sequence_numbers.push_back(options.packet_id);
+        return true;
+      });
+  EXPECT_EQ(EncodedImageCallback::Result::OK,
+            test.router()->OnEncodedImage(encoded_image, nullptr).error);
+  encoded_image.SetTimestamp(2);
+  encoded_image.capture_time_ms_ = 3;
+  EXPECT_EQ(EncodedImageCallback::Result::OK,
+            test.router()->OnEncodedImage(encoded_image, nullptr).error);
+
+  test.AdvanceTime(TimeDelta::Millis(33));
+
+  // Construct a NACK message for requesting retransmission of both packet.
+  rtcp::Nack nack;
+  nack.SetMediaSsrc(kSsrc1);
+  nack.SetPacketIds(rtp_sequence_numbers);
+  rtc::Buffer nack_buffer = nack.Build();
+
+  std::vector<uint16_t> retransmitted_rtp_sequence_numbers;
+  EXPECT_CALL(test.transport(), SendRtp)
+      .Times(2)
+      .WillRepeatedly([&retransmitted_rtp_sequence_numbers](
+                          const uint8_t* packet, size_t length,
+                          const PacketOptions& options) {
+        RtpPacket rtp_packet;
+        EXPECT_TRUE(rtp_packet.Parse(packet, length));
+        EXPECT_EQ(rtp_packet.Ssrc(), kRtxSsrc1);
+        // Capture the retransmitted sequence number from the RTX header.
+        rtc::ArrayView<const uint8_t> payload = rtp_packet.payload();
+        retransmitted_rtp_sequence_numbers.push_back(
+            ByteReader<uint16_t>::ReadBigEndian(payload.data()));
+        return true;
+      });
+  test.router()->DeliverRtcp(nack_buffer.data(), nack_buffer.size());
+  test.AdvanceTime(TimeDelta::Millis(33));
+
+  // Verify that both packets were retransmitted.
+  EXPECT_EQ(retransmitted_rtp_sequence_numbers, rtp_sequence_numbers);
+
+  // Simulate transport feedback indicating fist packet received, next packet
+  // lost (not other way around as that would trigger early retransmit).
+  StreamFeedbackObserver::StreamPacketInfo lost_packet_feedback;
+  lost_packet_feedback.rtp_sequence_number = rtp_sequence_numbers[0];
+  lost_packet_feedback.ssrc = kSsrc1;
+  lost_packet_feedback.received = false;
+  lost_packet_feedback.is_retransmission = false;
+
+  StreamFeedbackObserver::StreamPacketInfo received_packet_feedback;
+  received_packet_feedback.rtp_sequence_number = rtp_sequence_numbers[1];
+  received_packet_feedback.ssrc = kSsrc1;
+  received_packet_feedback.received = true;
+  lost_packet_feedback.is_retransmission = false;
+
+  test.router()->OnPacketFeedbackVector(
+      {lost_packet_feedback, received_packet_feedback});
+
+  // Advance time to make sure retransmission would be allowed and try again.
+  // This time the retransmission should not happen for the first packet since
+  // the history has been notified of the ack and removed the packet. The
+  // second packet, included in the feedback but not marked as received, should
+  // still be retransmitted.
+  test.AdvanceTime(TimeDelta::Millis(33));
+  EXPECT_CALL(test.transport(), SendRtp)
+      .WillOnce([&lost_packet_feedback](const uint8_t* packet, size_t length,
+                                        const PacketOptions& options) {
+        RtpPacket rtp_packet;
+        EXPECT_TRUE(rtp_packet.Parse(packet, length));
+        EXPECT_EQ(rtp_packet.Ssrc(), kRtxSsrc1);
+        // Capture the retransmitted sequence number from the RTX header.
+        rtc::ArrayView<const uint8_t> payload = rtp_packet.payload();
+        EXPECT_EQ(lost_packet_feedback.rtp_sequence_number,
+                  ByteReader<uint16_t>::ReadBigEndian(payload.data()));
+        return true;
+      });
+  test.router()->DeliverRtcp(nack_buffer.data(), nack_buffer.size());
+  test.AdvanceTime(TimeDelta::Millis(33));
+}
+
+// This tests that we utilize transport wide feedback to retransmit lost
+// packets. This is tested by dropping all ordinary packets from a "lossy"
+// stream sent along with a secondary untouched stream. The transport wide
+// feedback packets from the secondary stream allows the sending side to
+// detect and retreansmit the lost packets from the lossy stream.
+TEST(RtpVideoSenderTest, RetransmitsOnTransportWideLossInfo) {
+  int rtx_packets;
+  test::Scenario s(test_info_);
+  test::CallClientConfig call_conf;
+  // Keeping the bitrate fixed to avoid RTX due to probing.
+  call_conf.transport.rates.max_rate = DataRate::KilobitsPerSec(300);
+  call_conf.transport.rates.start_rate = DataRate::KilobitsPerSec(300);
+  test::NetworkSimulationConfig net_conf;
+  net_conf.bandwidth = DataRate::KilobitsPerSec(300);
+  auto send_node = s.CreateSimulationNode(net_conf);
+  auto* callee = s.CreateClient("return", call_conf);
+  auto* route = s.CreateRoutes(s.CreateClient("send", call_conf), {send_node},
+                               callee, {s.CreateSimulationNode(net_conf)});
+
+  test::VideoStreamConfig lossy_config;
+  lossy_config.source.framerate = 5;
+  auto* lossy = s.CreateVideoStream(route->forward(), lossy_config);
+  // The secondary stream acts a driver for transport feedback messages,
+  // ensuring that lost packets on the lossy stream are retransmitted.
+  s.CreateVideoStream(route->forward(), test::VideoStreamConfig());
+
+  send_node->router()->SetFilter([&](const EmulatedIpPacket& packet) {
+    RtpPacket rtp;
+    if (rtp.Parse(packet.data)) {
+      // Drops all regular packets for the lossy stream and counts all RTX
+      // packets. Since no packets are let trough, NACKs can't be triggered
+      // by the receiving side.
+      if (lossy->send()->UsingSsrc(rtp.Ssrc())) {
+        return false;
+      } else if (lossy->send()->UsingRtxSsrc(rtp.Ssrc())) {
+        ++rtx_packets;
+      }
+    }
+    return true;
+  });
+
+  // Run for a short duration and reset counters to avoid counting RTX packets
+  // from initial probing.
+  s.RunFor(TimeDelta::Seconds(1));
+  rtx_packets = 0;
+  int decoded_baseline = 0;
+  callee->SendTask([&decoded_baseline, &lossy]() {
+    decoded_baseline = lossy->receive()->GetStats().frames_decoded;
+  });
+  s.RunFor(TimeDelta::Seconds(1));
+  // We expect both that RTX packets were sent and that an appropriate number of
+  // frames were received. This is somewhat redundant but reduces the risk of
+  // false positives in future regressions (e.g. RTX is send due to probing).
+  EXPECT_GE(rtx_packets, 1);
+  int frames_decoded = 0;
+  callee->SendTask([&decoded_baseline, &frames_decoded, &lossy]() {
+    frames_decoded =
+        lossy->receive()->GetStats().frames_decoded - decoded_baseline;
+  });
+  EXPECT_EQ(frames_decoded, 5);
+}
+
+// Integration test verifying that retransmissions are sent for packets which
+// can be detected as lost early, using transport wide feedback.
+TEST(RtpVideoSenderTest, EarlyRetransmits) {
+  RtpVideoSenderTestFixture test({kSsrc1, kSsrc2}, {kRtxSsrc1, kRtxSsrc2},
+                                 kPayloadType, {});
+  test.SetActiveModules({true, true});
+
+  const uint8_t kPayload[1] = {'a'};
+  EncodedImage encoded_image;
+  encoded_image.SetTimestamp(1);
+  encoded_image.capture_time_ms_ = 2;
+  encoded_image._frameType = VideoFrameType::kVideoFrameKey;
+  encoded_image.SetEncodedData(
+      EncodedImageBuffer::Create(kPayload, sizeof(kPayload)));
+  encoded_image.SetSpatialIndex(0);
+
+  CodecSpecificInfo codec_specific;
+  codec_specific.codecType = VideoCodecType::kVideoCodecGeneric;
+
+  // Send two tiny images, mapping to single RTP packets. Capture sequence
+  // numbers.
+  uint16_t frame1_rtp_sequence_number = 0;
+  uint16_t frame1_transport_sequence_number = 0;
+  EXPECT_CALL(test.transport(), SendRtp)
+      .WillOnce(
+          [&frame1_rtp_sequence_number, &frame1_transport_sequence_number](
+              const uint8_t* packet, size_t length,
+              const PacketOptions& options) {
+            RtpPacket rtp_packet;
+            EXPECT_TRUE(rtp_packet.Parse(packet, length));
+            frame1_rtp_sequence_number = rtp_packet.SequenceNumber();
+            frame1_transport_sequence_number = options.packet_id;
+            EXPECT_EQ(rtp_packet.Ssrc(), kSsrc1);
+            return true;
+          });
+  EXPECT_EQ(test.router()->OnEncodedImage(encoded_image, &codec_specific).error,
+            EncodedImageCallback::Result::OK);
+
+  test.AdvanceTime(TimeDelta::Millis(33));
+
+  uint16_t frame2_rtp_sequence_number = 0;
+  uint16_t frame2_transport_sequence_number = 0;
+  encoded_image.SetSpatialIndex(1);
+  EXPECT_CALL(test.transport(), SendRtp)
+      .WillOnce(
+          [&frame2_rtp_sequence_number, &frame2_transport_sequence_number](
+              const uint8_t* packet, size_t length,
+              const PacketOptions& options) {
+            RtpPacket rtp_packet;
+            EXPECT_TRUE(rtp_packet.Parse(packet, length));
+            frame2_rtp_sequence_number = rtp_packet.SequenceNumber();
+            frame2_transport_sequence_number = options.packet_id;
+            EXPECT_EQ(rtp_packet.Ssrc(), kSsrc2);
+            return true;
+          });
+  EXPECT_EQ(test.router()->OnEncodedImage(encoded_image, &codec_specific).error,
+            EncodedImageCallback::Result::OK);
+  test.AdvanceTime(TimeDelta::Millis(33));
+
+  EXPECT_NE(frame1_transport_sequence_number, frame2_transport_sequence_number);
+
+  // Inject a transport feedback where the packet for the first frame is lost,
+  // expect a retransmission for it.
+  EXPECT_CALL(test.transport(), SendRtp)
+      .WillOnce([&frame1_rtp_sequence_number](const uint8_t* packet,
+                                              size_t length,
+                                              const PacketOptions& options) {
+        RtpPacket rtp_packet;
+        EXPECT_TRUE(rtp_packet.Parse(packet, length));
+        EXPECT_EQ(rtp_packet.Ssrc(), kRtxSsrc1);
+
+        // Retransmitted sequence number from the RTX header should match
+        // the lost packet.
+        rtc::ArrayView<const uint8_t> payload = rtp_packet.payload();
+        EXPECT_EQ(ByteReader<uint16_t>::ReadBigEndian(payload.data()),
+                  frame1_rtp_sequence_number);
+        return true;
+      });
+
+  StreamFeedbackObserver::StreamPacketInfo first_packet_feedback;
+  first_packet_feedback.rtp_sequence_number = frame1_rtp_sequence_number;
+  first_packet_feedback.ssrc = kSsrc1;
+  first_packet_feedback.received = false;
+  first_packet_feedback.is_retransmission = false;
+
+  StreamFeedbackObserver::StreamPacketInfo second_packet_feedback;
+  second_packet_feedback.rtp_sequence_number = frame2_rtp_sequence_number;
+  second_packet_feedback.ssrc = kSsrc2;
+  second_packet_feedback.received = true;
+  first_packet_feedback.is_retransmission = false;
+
+  test.router()->OnPacketFeedbackVector(
+      {first_packet_feedback, second_packet_feedback});
+
+  // Wait for pacer to run and send the RTX packet.
+  test.AdvanceTime(TimeDelta::Millis(33));
+}
+
+TEST(RtpVideoSenderTest, SupportsDependencyDescriptor) {
+  RtpVideoSenderTestFixture test({kSsrc1}, {}, kPayloadType, {});
+  test.SetActiveModules({true});
+
+  RtpHeaderExtensionMap extensions;
+  extensions.Register<RtpDependencyDescriptorExtension>(
+      kDependencyDescriptorExtensionId);
+  std::vector<RtpPacket> sent_packets;
+  ON_CALL(test.transport(), SendRtp)
+      .WillByDefault([&](const uint8_t* packet, size_t length,
+                         const PacketOptions& options) {
+        sent_packets.emplace_back(&extensions);
+        EXPECT_TRUE(sent_packets.back().Parse(packet, length));
+        return true;
+      });
+
+  const uint8_t kPayload[1] = {'a'};
+  EncodedImage encoded_image;
+  encoded_image.SetTimestamp(1);
+  encoded_image.capture_time_ms_ = 2;
+  encoded_image.SetEncodedData(
+      EncodedImageBuffer::Create(kPayload, sizeof(kPayload)));
+
+  CodecSpecificInfo codec_specific;
+  codec_specific.codecType = VideoCodecType::kVideoCodecGeneric;
+  codec_specific.template_structure.emplace();
+  codec_specific.template_structure->num_decode_targets = 1;
+  codec_specific.template_structure->templates = {
+      FrameDependencyTemplate().T(0).Dtis("S"),
+      FrameDependencyTemplate().T(0).Dtis("S").FrameDiffs({2}),
+      FrameDependencyTemplate().T(1).Dtis("D").FrameDiffs({1}),
+  };
+
+  // Send two tiny images, mapping to single RTP packets.
+  // Send in key frame.
+  encoded_image._frameType = VideoFrameType::kVideoFrameKey;
+  codec_specific.generic_frame_info =
+      GenericFrameInfo::Builder().T(0).Dtis("S").Build();
+  codec_specific.generic_frame_info->encoder_buffers = {{0, false, true}};
+  EXPECT_EQ(test.router()->OnEncodedImage(encoded_image, &codec_specific).error,
+            EncodedImageCallback::Result::OK);
+  test.AdvanceTime(TimeDelta::Millis(33));
+  ASSERT_THAT(sent_packets, SizeIs(1));
+  EXPECT_TRUE(
+      sent_packets.back().HasExtension<RtpDependencyDescriptorExtension>());
+
+  // Send in delta frame.
+  encoded_image._frameType = VideoFrameType::kVideoFrameDelta;
+  codec_specific.template_structure = absl::nullopt;
+  codec_specific.generic_frame_info =
+      GenericFrameInfo::Builder().T(1).Dtis("D").Build();
+  codec_specific.generic_frame_info->encoder_buffers = {{0, true, false}};
+  EXPECT_EQ(test.router()->OnEncodedImage(encoded_image, &codec_specific).error,
+            EncodedImageCallback::Result::OK);
+  test.AdvanceTime(TimeDelta::Millis(33));
+  ASSERT_THAT(sent_packets, SizeIs(2));
+  EXPECT_TRUE(
+      sent_packets.back().HasExtension<RtpDependencyDescriptorExtension>());
+}
+
+TEST(RtpVideoSenderTest,
+     SupportsDependencyDescriptorForVp8NotProvidedByEncoder) {
+  constexpr uint8_t kPayload[1] = {'a'};
+  RtpVideoSenderTestFixture test({kSsrc1}, {}, kPayloadType, {});
+  RtpHeaderExtensionMap extensions;
+  extensions.Register<RtpDependencyDescriptorExtension>(
+      kDependencyDescriptorExtensionId);
+  std::vector<RtpPacket> sent_packets;
+  ON_CALL(test.transport(), SendRtp)
+      .WillByDefault(
+          [&](const uint8_t* packet, size_t length, const PacketOptions&) {
+            EXPECT_TRUE(
+                sent_packets.emplace_back(&extensions).Parse(packet, length));
+            return true;
+          });
+  test.SetActiveModules({true});
+
+  EncodedImage key_frame_image;
+  key_frame_image._frameType = VideoFrameType::kVideoFrameKey;
+  key_frame_image.SetEncodedData(
+      EncodedImageBuffer::Create(kPayload, sizeof(kPayload)));
+  CodecSpecificInfo key_frame_info;
+  key_frame_info.codecType = VideoCodecType::kVideoCodecVP8;
+  ASSERT_EQ(
+      test.router()->OnEncodedImage(key_frame_image, &key_frame_info).error,
+      EncodedImageCallback::Result::OK);
+
+  EncodedImage delta_image;
+  delta_image._frameType = VideoFrameType::kVideoFrameDelta;
+  delta_image.SetEncodedData(
+      EncodedImageBuffer::Create(kPayload, sizeof(kPayload)));
+  CodecSpecificInfo delta_info;
+  delta_info.codecType = VideoCodecType::kVideoCodecVP8;
+  ASSERT_EQ(test.router()->OnEncodedImage(delta_image, &delta_info).error,
+            EncodedImageCallback::Result::OK);
+
+  test.AdvanceTime(TimeDelta::Millis(123));
+
+  DependencyDescriptor key_frame_dd;
+  DependencyDescriptor delta_dd;
+  ASSERT_THAT(sent_packets, SizeIs(2));
+  EXPECT_TRUE(sent_packets[0].GetExtension<RtpDependencyDescriptorExtension>(
+      /*structure=*/nullptr, &key_frame_dd));
+  EXPECT_TRUE(sent_packets[1].GetExtension<RtpDependencyDescriptorExtension>(
+      key_frame_dd.attached_structure.get(), &delta_dd));
+}
+
+TEST(RtpVideoSenderTest, SupportsDependencyDescriptorForVp9) {
+  RtpVideoSenderTestFixture test({kSsrc1}, {}, kPayloadType, {});
+  test.SetActiveModules({true});
+
+  RtpHeaderExtensionMap extensions;
+  extensions.Register<RtpDependencyDescriptorExtension>(
+      kDependencyDescriptorExtensionId);
+  std::vector<RtpPacket> sent_packets;
+  ON_CALL(test.transport(), SendRtp)
+      .WillByDefault([&](const uint8_t* packet, size_t length,
+                         const PacketOptions& options) {
+        sent_packets.emplace_back(&extensions);
+        EXPECT_TRUE(sent_packets.back().Parse(packet, length));
+        return true;
+      });
+
+  const uint8_t kPayload[1] = {'a'};
+  EncodedImage encoded_image;
+  encoded_image.SetTimestamp(1);
+  encoded_image.capture_time_ms_ = 2;
+  encoded_image._frameType = VideoFrameType::kVideoFrameKey;
+  encoded_image.SetEncodedData(
+      EncodedImageBuffer::Create(kPayload, sizeof(kPayload)));
+
+  CodecSpecificInfo codec_specific;
+  codec_specific.codecType = VideoCodecType::kVideoCodecVP9;
+  codec_specific.template_structure.emplace();
+  codec_specific.template_structure->num_decode_targets = 2;
+  codec_specific.template_structure->templates = {
+      FrameDependencyTemplate().S(0).Dtis("SS"),
+      FrameDependencyTemplate().S(1).Dtis("-S").FrameDiffs({1}),
+  };
+
+  // Send two tiny images, each mapping to single RTP packet.
+  // Send in key frame for the base spatial layer.
+  codec_specific.generic_frame_info =
+      GenericFrameInfo::Builder().S(0).Dtis("SS").Build();
+  codec_specific.generic_frame_info->encoder_buffers = {{0, false, true}};
+  EXPECT_EQ(test.router()->OnEncodedImage(encoded_image, &codec_specific).error,
+            EncodedImageCallback::Result::OK);
+  // Send in 2nd spatial layer.
+  codec_specific.template_structure = absl::nullopt;
+  codec_specific.generic_frame_info =
+      GenericFrameInfo::Builder().S(1).Dtis("-S").Build();
+  codec_specific.generic_frame_info->encoder_buffers = {{0, true, false},
+                                                        {1, false, true}};
+  EXPECT_EQ(test.router()->OnEncodedImage(encoded_image, &codec_specific).error,
+            EncodedImageCallback::Result::OK);
+
+  test.AdvanceTime(TimeDelta::Millis(33));
+  ASSERT_THAT(sent_packets, SizeIs(2));
+  EXPECT_TRUE(sent_packets[0].HasExtension<RtpDependencyDescriptorExtension>());
+  EXPECT_TRUE(sent_packets[1].HasExtension<RtpDependencyDescriptorExtension>());
+}
+
+TEST(RtpVideoSenderTest,
+     SupportsDependencyDescriptorForVp9NotProvidedByEncoder) {
+  RtpVideoSenderTestFixture test({kSsrc1}, {}, kPayloadType, {});
+  test.SetActiveModules({true});
+
+  RtpHeaderExtensionMap extensions;
+  extensions.Register<RtpDependencyDescriptorExtension>(
+      kDependencyDescriptorExtensionId);
+  std::vector<RtpPacket> sent_packets;
+  ON_CALL(test.transport(), SendRtp)
+      .WillByDefault([&](const uint8_t* packet, size_t length,
+                         const PacketOptions& options) {
+        sent_packets.emplace_back(&extensions);
+        EXPECT_TRUE(sent_packets.back().Parse(packet, length));
+        return true;
+      });
+
+  const uint8_t kPayload[1] = {'a'};
+  EncodedImage encoded_image;
+  encoded_image.SetTimestamp(1);
+  encoded_image.capture_time_ms_ = 2;
+  encoded_image._frameType = VideoFrameType::kVideoFrameKey;
+  encoded_image._encodedWidth = 320;
+  encoded_image._encodedHeight = 180;
+  encoded_image.SetEncodedData(
+      EncodedImageBuffer::Create(kPayload, sizeof(kPayload)));
+
+  CodecSpecificInfo codec_specific;
+  codec_specific.codecType = VideoCodecType::kVideoCodecVP9;
+  codec_specific.codecSpecific.VP9.num_spatial_layers = 1;
+  codec_specific.codecSpecific.VP9.temporal_idx = kNoTemporalIdx;
+  codec_specific.codecSpecific.VP9.first_frame_in_picture = true;
+  codec_specific.end_of_picture = true;
+  codec_specific.codecSpecific.VP9.inter_pic_predicted = false;
+
+  // Send two tiny images, each mapping to single RTP packet.
+  EXPECT_EQ(test.router()->OnEncodedImage(encoded_image, &codec_specific).error,
+            EncodedImageCallback::Result::OK);
+
+  // Send in 2nd picture.
+  encoded_image._frameType = VideoFrameType::kVideoFrameDelta;
+  encoded_image.SetTimestamp(3000);
+  codec_specific.codecSpecific.VP9.inter_pic_predicted = true;
+  codec_specific.codecSpecific.VP9.num_ref_pics = 1;
+  codec_specific.codecSpecific.VP9.p_diff[0] = 1;
+  EXPECT_EQ(test.router()->OnEncodedImage(encoded_image, &codec_specific).error,
+            EncodedImageCallback::Result::OK);
+
+  test.AdvanceTime(TimeDelta::Millis(33));
+  ASSERT_THAT(sent_packets, SizeIs(2));
+  EXPECT_TRUE(sent_packets[0].HasExtension<RtpDependencyDescriptorExtension>());
+  EXPECT_TRUE(sent_packets[1].HasExtension<RtpDependencyDescriptorExtension>());
+}
+
+TEST(RtpVideoSenderTest, GenerateDependecyDescriptorForGenericCodecs) {
+  test::ScopedKeyValueConfig field_trials(
+      "WebRTC-GenericCodecDependencyDescriptor/Enabled/");
+  RtpVideoSenderTestFixture test({kSsrc1}, {}, kPayloadType, {}, &field_trials);
+  test.SetActiveModules({true});
+
+  RtpHeaderExtensionMap extensions;
+  extensions.Register<RtpDependencyDescriptorExtension>(
+      kDependencyDescriptorExtensionId);
+  std::vector<RtpPacket> sent_packets;
+  ON_CALL(test.transport(), SendRtp)
+      .WillByDefault([&](const uint8_t* packet, size_t length,
+                         const PacketOptions& options) {
+        sent_packets.emplace_back(&extensions);
+        EXPECT_TRUE(sent_packets.back().Parse(packet, length));
+        return true;
+      });
+
+  const uint8_t kPayload[1] = {'a'};
+  EncodedImage encoded_image;
+  encoded_image.SetTimestamp(1);
+  encoded_image.capture_time_ms_ = 2;
+  encoded_image._frameType = VideoFrameType::kVideoFrameKey;
+  encoded_image._encodedWidth = 320;
+  encoded_image._encodedHeight = 180;
+  encoded_image.SetEncodedData(
+      EncodedImageBuffer::Create(kPayload, sizeof(kPayload)));
+
+  CodecSpecificInfo codec_specific;
+  codec_specific.codecType = VideoCodecType::kVideoCodecGeneric;
+  codec_specific.end_of_picture = true;
+
+  // Send two tiny images, each mapping to single RTP packet.
+  EXPECT_EQ(test.router()->OnEncodedImage(encoded_image, &codec_specific).error,
+            EncodedImageCallback::Result::OK);
+
+  // Send in 2nd picture.
+  encoded_image._frameType = VideoFrameType::kVideoFrameDelta;
+  encoded_image.SetTimestamp(3000);
+  EXPECT_EQ(test.router()->OnEncodedImage(encoded_image, &codec_specific).error,
+            EncodedImageCallback::Result::OK);
+
+  test.AdvanceTime(TimeDelta::Millis(33));
+  ASSERT_THAT(sent_packets, SizeIs(2));
+  EXPECT_TRUE(sent_packets[0].HasExtension<RtpDependencyDescriptorExtension>());
+  EXPECT_TRUE(sent_packets[1].HasExtension<RtpDependencyDescriptorExtension>());
+}
+
+TEST(RtpVideoSenderTest, SupportsStoppingUsingDependencyDescriptor) {
+  RtpVideoSenderTestFixture test({kSsrc1}, {}, kPayloadType, {});
+  test.SetActiveModules({true});
+
+  RtpHeaderExtensionMap extensions;
+  extensions.Register<RtpDependencyDescriptorExtension>(
+      kDependencyDescriptorExtensionId);
+  std::vector<RtpPacket> sent_packets;
+  ON_CALL(test.transport(), SendRtp)
+      .WillByDefault([&](const uint8_t* packet, size_t length,
+                         const PacketOptions& options) {
+        sent_packets.emplace_back(&extensions);
+        EXPECT_TRUE(sent_packets.back().Parse(packet, length));
+        return true;
+      });
+
+  const uint8_t kPayload[1] = {'a'};
+  EncodedImage encoded_image;
+  encoded_image.SetTimestamp(1);
+  encoded_image.capture_time_ms_ = 2;
+  encoded_image.SetEncodedData(
+      EncodedImageBuffer::Create(kPayload, sizeof(kPayload)));
+
+  CodecSpecificInfo codec_specific;
+  codec_specific.codecType = VideoCodecType::kVideoCodecGeneric;
+  codec_specific.template_structure.emplace();
+  codec_specific.template_structure->num_decode_targets = 1;
+  codec_specific.template_structure->templates = {
+      FrameDependencyTemplate().T(0).Dtis("S"),
+      FrameDependencyTemplate().T(0).Dtis("S").FrameDiffs({2}),
+      FrameDependencyTemplate().T(1).Dtis("D").FrameDiffs({1}),
+  };
+
+  // Send two tiny images, mapping to single RTP packets.
+  // Send in a key frame.
+  encoded_image._frameType = VideoFrameType::kVideoFrameKey;
+  codec_specific.generic_frame_info =
+      GenericFrameInfo::Builder().T(0).Dtis("S").Build();
+  codec_specific.generic_frame_info->encoder_buffers = {{0, false, true}};
+  EXPECT_EQ(test.router()->OnEncodedImage(encoded_image, &codec_specific).error,
+            EncodedImageCallback::Result::OK);
+  test.AdvanceTime(TimeDelta::Millis(33));
+  ASSERT_THAT(sent_packets, SizeIs(1));
+  EXPECT_TRUE(
+      sent_packets.back().HasExtension<RtpDependencyDescriptorExtension>());
+
+  // Send in a new key frame without the support for the dependency descriptor.
+  encoded_image._frameType = VideoFrameType::kVideoFrameKey;
+  codec_specific.template_structure = absl::nullopt;
+  EXPECT_EQ(test.router()->OnEncodedImage(encoded_image, &codec_specific).error,
+            EncodedImageCallback::Result::OK);
+  test.AdvanceTime(TimeDelta::Millis(33));
+  ASSERT_THAT(sent_packets, SizeIs(2));
+  EXPECT_FALSE(
+      sent_packets.back().HasExtension<RtpDependencyDescriptorExtension>());
+}
+
+TEST(RtpVideoSenderTest, CanSetZeroBitrate) {
+  RtpVideoSenderTestFixture test({kSsrc1}, {kRtxSsrc1}, kPayloadType, {});
+  test.router()->OnBitrateUpdated(CreateBitrateAllocationUpdate(0),
+                                  /*framerate*/ 0);
+}
+
+TEST(RtpVideoSenderTest, SimulcastSenderRegistersFrameTransformers) {
+  rtc::scoped_refptr<MockFrameTransformer> transformer =
+      rtc::make_ref_counted<MockFrameTransformer>();
+
+  EXPECT_CALL(*transformer, RegisterTransformedFrameSinkCallback(_, kSsrc1));
+  EXPECT_CALL(*transformer, RegisterTransformedFrameSinkCallback(_, kSsrc2));
+  RtpVideoSenderTestFixture test({kSsrc1, kSsrc2}, {kRtxSsrc1, kRtxSsrc2},
+                                 kPayloadType, {}, nullptr, transformer);
+
+  EXPECT_CALL(*transformer, UnregisterTransformedFrameSinkCallback(kSsrc1));
+  EXPECT_CALL(*transformer, UnregisterTransformedFrameSinkCallback(kSsrc2));
+}
+
+TEST(RtpVideoSenderTest, OverheadIsSubtractedFromTargetBitrate) {
+  test::ScopedKeyValueConfig field_trials(
+      "WebRTC-Video-UseFrameRateForOverhead/Enabled/");
+
+  // TODO(jakobi): RTP header size should not be hard coded.
+  constexpr uint32_t kRtpHeaderSizeBytes = 20;
+  constexpr uint32_t kTransportPacketOverheadBytes = 40;
+  constexpr uint32_t kOverheadPerPacketBytes =
+      kRtpHeaderSizeBytes + kTransportPacketOverheadBytes;
+  RtpVideoSenderTestFixture test({kSsrc1}, {}, kPayloadType, {}, &field_trials);
+  test.router()->OnTransportOverheadChanged(kTransportPacketOverheadBytes);
+  test.SetActiveModules({true});
+
+  {
+    test.router()->OnBitrateUpdated(CreateBitrateAllocationUpdate(300000),
+                                    /*framerate*/ 15);
+    // 1 packet per frame.
+    EXPECT_EQ(test.router()->GetPayloadBitrateBps(),
+              300000 - kOverheadPerPacketBytes * 8 * 30);
+  }
+  {
+    test.router()->OnBitrateUpdated(CreateBitrateAllocationUpdate(150000),
+                                    /*framerate*/ 15);
+    // 1 packet per frame.
+    EXPECT_EQ(test.router()->GetPayloadBitrateBps(),
+              150000 - kOverheadPerPacketBytes * 8 * 15);
+  }
+  {
+    test.router()->OnBitrateUpdated(CreateBitrateAllocationUpdate(1000000),
+                                    /*framerate*/ 30);
+    // 3 packets per frame.
+    EXPECT_EQ(test.router()->GetPayloadBitrateBps(),
+              1000000 - kOverheadPerPacketBytes * 8 * 30 * 3);
+  }
+}
+
+TEST(RtpVideoSenderTest, ClearsPendingPacketsOnInactivation) {
+  RtpVideoSenderTestFixture test({kSsrc1}, {kRtxSsrc1}, kPayloadType, {});
+  test.SetActiveModules({true});
+
+  RtpHeaderExtensionMap extensions;
+  extensions.Register<RtpDependencyDescriptorExtension>(
+      kDependencyDescriptorExtensionId);
+  std::vector<RtpPacket> sent_packets;
+  ON_CALL(test.transport(), SendRtp)
+      .WillByDefault([&](const uint8_t* packet, size_t length,
+                         const PacketOptions& options) {
+        sent_packets.emplace_back(&extensions);
+        EXPECT_TRUE(sent_packets.back().Parse(packet, length));
+        return true;
+      });
+
+  // Set a very low bitrate.
+  test.router()->OnBitrateUpdated(
+      CreateBitrateAllocationUpdate(/*rate_bps=*/30'000),
+      /*framerate=*/30);
+
+  // Create and send a large keyframe.
+  const size_t kImageSizeBytes = 10000;
+  constexpr uint8_t kPayload[kImageSizeBytes] = {'a'};
+  EncodedImage encoded_image;
+  encoded_image.SetTimestamp(1);
+  encoded_image.capture_time_ms_ = 2;
+  encoded_image._frameType = VideoFrameType::kVideoFrameKey;
+  encoded_image.SetEncodedData(
+      EncodedImageBuffer::Create(kPayload, sizeof(kPayload)));
+  EXPECT_EQ(test.router()
+                ->OnEncodedImage(encoded_image, /*codec_specific=*/nullptr)
+                .error,
+            EncodedImageCallback::Result::OK);
+
+  // Advance time a small amount, check that sent data is only part of the
+  // image.
+  test.AdvanceTime(TimeDelta::Millis(5));
+  DataSize transmittedPayload = DataSize::Zero();
+  for (const RtpPacket& packet : sent_packets) {
+    transmittedPayload += DataSize::Bytes(packet.payload_size());
+    // Make sure we don't see the end of the frame.
+    EXPECT_FALSE(packet.Marker());
+  }
+  EXPECT_GT(transmittedPayload, DataSize::Zero());
+  EXPECT_LT(transmittedPayload, DataSize::Bytes(kImageSizeBytes / 4));
+
+  // Record the RTP timestamp of the first frame.
+  const uint32_t first_frame_timestamp = sent_packets[0].Timestamp();
+  sent_packets.clear();
+
+  // Disable the sending module and advance time slightly. No packets should be
+  // sent.
+  test.SetActiveModules({false});
+  test.AdvanceTime(TimeDelta::Millis(20));
+  EXPECT_TRUE(sent_packets.empty());
+
+  // Reactive the send module - any packets should have been removed, so nothing
+  // should be transmitted.
+  test.SetActiveModules({true});
+  test.AdvanceTime(TimeDelta::Millis(33));
+  EXPECT_TRUE(sent_packets.empty());
+
+  // Send a new frame.
+  encoded_image.SetTimestamp(3);
+  encoded_image.capture_time_ms_ = 4;
+  EXPECT_EQ(test.router()
+                ->OnEncodedImage(encoded_image, /*codec_specific=*/nullptr)
+                .error,
+            EncodedImageCallback::Result::OK);
+  test.AdvanceTime(TimeDelta::Millis(33));
+
+  // Advance time, check we get new packets - but only for the second frame.
+  EXPECT_FALSE(sent_packets.empty());
+  EXPECT_NE(sent_packets[0].Timestamp(), first_frame_timestamp);
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/rtx_receive_stream.cc b/third_party/libwebrtc/call/rtx_receive_stream.cc
new file mode 100644
index 0000000000..6c5fa3f859
--- /dev/null
+++ b/third_party/libwebrtc/call/rtx_receive_stream.cc
@@ -0,0 +1,88 @@
+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/rtx_receive_stream.h"
+
+#include <string.h>
+
+#include <utility>
+
+#include "api/array_view.h"
+#include "modules/rtp_rtcp/include/receive_statistics.h"
+#include "modules/rtp_rtcp/include/rtp_rtcp_defines.h"
+#include "modules/rtp_rtcp/source/rtp_packet_received.h"
+#include "rtc_base/checks.h"
+#include "rtc_base/logging.h"
+
+namespace webrtc {
+
+RtxReceiveStream::RtxReceiveStream(
+    RtpPacketSinkInterface* media_sink,
+    std::map<int, int> associated_payload_types,
+    uint32_t media_ssrc,
+    ReceiveStatistics* rtp_receive_statistics /* = nullptr */)
+    : media_sink_(media_sink),
+      associated_payload_types_(std::move(associated_payload_types)),
+      media_ssrc_(media_ssrc),
+      rtp_receive_statistics_(rtp_receive_statistics) {
+  packet_checker_.Detach();
+  if (associated_payload_types_.empty()) {
+    RTC_LOG(LS_WARNING)
+        << "RtxReceiveStream created with empty payload type mapping.";
+  }
+}
+
+RtxReceiveStream::~RtxReceiveStream() = default;
+
+void RtxReceiveStream::SetAssociatedPayloadTypes(
+    std::map<int, int> associated_payload_types) {
+  RTC_DCHECK_RUN_ON(&packet_checker_);
+  associated_payload_types_ = std::move(associated_payload_types);
+}
+
+void RtxReceiveStream::OnRtpPacket(const RtpPacketReceived& rtx_packet) {
+  RTC_DCHECK_RUN_ON(&packet_checker_);
+  if (rtp_receive_statistics_) {
+    rtp_receive_statistics_->OnRtpPacket(rtx_packet);
+  }
+  rtc::ArrayView<const uint8_t> payload = rtx_packet.payload();
+
+  if (payload.size() < kRtxHeaderSize) {
+    return;
+  }
+
+  auto it = associated_payload_types_.find(rtx_packet.PayloadType());
+  if (it == associated_payload_types_.end()) {
+    RTC_DLOG(LS_VERBOSE) << "Unknown payload type "
+                         << static_cast<int>(rtx_packet.PayloadType())
+                         << " on rtx ssrc " << rtx_packet.Ssrc();
+    return;
+  }
+  RtpPacketReceived media_packet;
+  media_packet.CopyHeaderFrom(rtx_packet);
+
+  media_packet.SetSsrc(media_ssrc_);
+  media_packet.SetSequenceNumber((payload[0] << 8) + payload[1]);
+  media_packet.SetPayloadType(it->second);
+  media_packet.set_recovered(true);
+  media_packet.set_arrival_time(rtx_packet.arrival_time());
+
+  // Skip the RTX header.
+  rtc::ArrayView<const uint8_t> rtx_payload = payload.subview(kRtxHeaderSize);
+
+  uint8_t* media_payload = media_packet.AllocatePayload(rtx_payload.size());
+  RTC_DCHECK(media_payload != nullptr);
+
+  memcpy(media_payload, rtx_payload.data(), rtx_payload.size());
+
+  media_sink_->OnRtpPacket(media_packet);
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/rtx_receive_stream.h b/third_party/libwebrtc/call/rtx_receive_stream.h
new file mode 100644
index 0000000000..79b03d306b
--- /dev/null
+++ b/third_party/libwebrtc/call/rtx_receive_stream.h
@@ -0,0 +1,59 @@
+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_RTX_RECEIVE_STREAM_H_
+#define CALL_RTX_RECEIVE_STREAM_H_
+
+#include <cstdint>
+#include <map>
+
+#include "api/sequence_checker.h"
+#include "call/rtp_packet_sink_interface.h"
+#include "rtc_base/system/no_unique_address.h"
+
+namespace webrtc {
+
+class ReceiveStatistics;
+
+// This class is responsible for RTX decapsulation. The resulting media packets
+// are passed on to a sink representing the associated media stream.
+class RtxReceiveStream : public RtpPacketSinkInterface {
+ public:
+  RtxReceiveStream(RtpPacketSinkInterface* media_sink,
+                   std::map<int, int> associated_payload_types,
+                   uint32_t media_ssrc,
+                   // TODO(nisse): Delete this argument, and
+                   // corresponding member variable, by moving the
+                   // responsibility for rtcp feedback to
+                   // RtpStreamReceiverController.
+                   ReceiveStatistics* rtp_receive_statistics = nullptr);
+  ~RtxReceiveStream() override;
+
+  // Update payload types post construction. Must be called from the same
+  // calling context as `OnRtpPacket` is called on.
+  void SetAssociatedPayloadTypes(std::map<int, int> associated_payload_types);
+
+  // RtpPacketSinkInterface.
+  void OnRtpPacket(const RtpPacketReceived& packet) override;
+
+ private:
+  RTC_NO_UNIQUE_ADDRESS SequenceChecker packet_checker_;
+  RtpPacketSinkInterface* const media_sink_;
+  // Map from rtx payload type -> media payload type.
+  std::map<int, int> associated_payload_types_ RTC_GUARDED_BY(&packet_checker_);
+  // TODO(nisse): Ultimately, the media receive stream shouldn't care about the
+  // ssrc, and we should delete this.
+  const uint32_t media_ssrc_;
+  ReceiveStatistics* const rtp_receive_statistics_;
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_RTX_RECEIVE_STREAM_H_
diff --git a/third_party/libwebrtc/call/rtx_receive_stream_unittest.cc b/third_party/libwebrtc/call/rtx_receive_stream_unittest.cc
new file mode 100644
index 0000000000..b06990820f
--- /dev/null
+++ b/third_party/libwebrtc/call/rtx_receive_stream_unittest.cc
@@ -0,0 +1,271 @@
+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/rtx_receive_stream.h"
+
+#include "call/test/mock_rtp_packet_sink_interface.h"
+#include "modules/rtp_rtcp/include/rtp_header_extension_map.h"
+#include "modules/rtp_rtcp/source/rtp_header_extensions.h"
+#include "modules/rtp_rtcp/source/rtp_packet_received.h"
+#include "test/gmock.h"
+#include "test/gtest.h"
+
+namespace webrtc {
+
+namespace {
+
+using ::testing::_;
+using ::testing::Property;
+using ::testing::StrictMock;
+
+constexpr int kMediaPayloadType = 100;
+constexpr int kRtxPayloadType = 98;
+constexpr int kUnknownPayloadType = 90;
+constexpr uint32_t kMediaSSRC = 0x3333333;
+constexpr uint16_t kMediaSeqno = 0x5657;
+
+constexpr uint8_t kRtxPacket[] = {
+    0x80,  // Version 2.
+    98,    // Payload type.
+    0x12,
+    0x34,  // Seqno.
+    0x11,
+    0x11,
+    0x11,
+    0x11,  // Timestamp.
+    0x22,
+    0x22,
+    0x22,
+    0x22,  // SSRC.
+    // RTX header.
+    0x56,
+    0x57,  // Orig seqno.
+    // Payload.
+    0xee,
+};
+
+constexpr uint8_t kRtxPacketWithPadding[] = {
+    0xa0,  // Version 2, P set
+    98,    // Payload type.
+    0x12,
+    0x34,  // Seqno.
+    0x11,
+    0x11,
+    0x11,
+    0x11,  // Timestamp.
+    0x22,
+    0x22,
+    0x22,
+    0x22,  // SSRC.
+    // RTX header.
+    0x56,
+    0x57,  // Orig seqno.
+    // Padding
+    0x1,
+};
+
+constexpr uint8_t kRtxPacketWithCVO[] = {
+    0x90,  // Version 2, X set.
+    98,    // Payload type.
+    0x12,
+    0x34,  // Seqno.
+    0x11,
+    0x11,
+    0x11,
+    0x11,  // Timestamp.
+    0x22,
+    0x22,
+    0x22,
+    0x22,  // SSRC.
+    0xbe,
+    0xde,
+    0x00,
+    0x01,  // Extension header.
+    0x30,
+    0x01,
+    0x00,
+    0x00,  // 90 degree rotation.
+    // RTX header.
+    0x56,
+    0x57,  // Orig seqno.
+    // Payload.
+    0xee,
+};
+
+std::map<int, int> PayloadTypeMapping() {
+  const std::map<int, int> m = {{kRtxPayloadType, kMediaPayloadType}};
+  return m;
+}
+
+template <typename T>
+rtc::ArrayView<T> Truncate(rtc::ArrayView<T> a, size_t drop) {
+  return a.subview(0, a.size() - drop);
+}
+
+}  // namespace
+
+TEST(RtxReceiveStreamTest, RestoresPacketPayload) {
+  StrictMock<MockRtpPacketSink> media_sink;
+  RtxReceiveStream rtx_sink(&media_sink, PayloadTypeMapping(), kMediaSSRC);
+  RtpPacketReceived rtx_packet;
+  EXPECT_TRUE(rtx_packet.Parse(rtc::ArrayView<const uint8_t>(kRtxPacket)));
+
+  EXPECT_CALL(media_sink, OnRtpPacket)
+      .WillOnce([](const RtpPacketReceived& packet) {
+        EXPECT_EQ(packet.SequenceNumber(), kMediaSeqno);
+        EXPECT_EQ(packet.Ssrc(), kMediaSSRC);
+        EXPECT_EQ(packet.PayloadType(), kMediaPayloadType);
+        EXPECT_THAT(packet.payload(), ::testing::ElementsAre(0xee));
+      });
+
+  rtx_sink.OnRtpPacket(rtx_packet);
+}
+
+TEST(RtxReceiveStreamTest, SetsRecoveredFlag) {
+  StrictMock<MockRtpPacketSink> media_sink;
+  RtxReceiveStream rtx_sink(&media_sink, PayloadTypeMapping(), kMediaSSRC);
+  RtpPacketReceived rtx_packet;
+  EXPECT_TRUE(rtx_packet.Parse(rtc::ArrayView<const uint8_t>(kRtxPacket)));
+  EXPECT_FALSE(rtx_packet.recovered());
+  EXPECT_CALL(media_sink, OnRtpPacket)
+      .WillOnce([](const RtpPacketReceived& packet) {
+        EXPECT_TRUE(packet.recovered());
+      });
+
+  rtx_sink.OnRtpPacket(rtx_packet);
+}
+
+TEST(RtxReceiveStreamTest, IgnoresUnknownPayloadType) {
+  StrictMock<MockRtpPacketSink> media_sink;
+  const std::map<int, int> payload_type_mapping = {
+      {kUnknownPayloadType, kMediaPayloadType}};
+
+  RtxReceiveStream rtx_sink(&media_sink, payload_type_mapping, kMediaSSRC);
+  RtpPacketReceived rtx_packet;
+  EXPECT_TRUE(rtx_packet.Parse(rtc::ArrayView<const uint8_t>(kRtxPacket)));
+  rtx_sink.OnRtpPacket(rtx_packet);
+}
+
+TEST(RtxReceiveStreamTest, IgnoresTruncatedPacket) {
+  StrictMock<MockRtpPacketSink> media_sink;
+  RtxReceiveStream rtx_sink(&media_sink, PayloadTypeMapping(), kMediaSSRC);
+  RtpPacketReceived rtx_packet;
+  EXPECT_TRUE(
+      rtx_packet.Parse(Truncate(rtc::ArrayView<const uint8_t>(kRtxPacket), 2)));
+  rtx_sink.OnRtpPacket(rtx_packet);
+}
+
+TEST(RtxReceiveStreamTest, CopiesRtpHeaderExtensions) {
+  StrictMock<MockRtpPacketSink> media_sink;
+  RtxReceiveStream rtx_sink(&media_sink, PayloadTypeMapping(), kMediaSSRC);
+  RtpHeaderExtensionMap extension_map;
+  extension_map.RegisterByType(3, kRtpExtensionVideoRotation);
+  RtpPacketReceived rtx_packet(&extension_map);
+  EXPECT_TRUE(
+      rtx_packet.Parse(rtc::ArrayView<const uint8_t>(kRtxPacketWithCVO)));
+
+  VideoRotation rotation = kVideoRotation_0;
+  EXPECT_TRUE(rtx_packet.GetExtension<VideoOrientation>(&rotation));
+  EXPECT_EQ(kVideoRotation_90, rotation);
+
+  EXPECT_CALL(media_sink, OnRtpPacket)
+      .WillOnce([](const RtpPacketReceived& packet) {
+        EXPECT_EQ(packet.SequenceNumber(), kMediaSeqno);
+        EXPECT_EQ(packet.Ssrc(), kMediaSSRC);
+        EXPECT_EQ(packet.PayloadType(), kMediaPayloadType);
+        EXPECT_THAT(packet.payload(), ::testing::ElementsAre(0xee));
+        VideoRotation rotation = kVideoRotation_0;
+        EXPECT_TRUE(packet.GetExtension<VideoOrientation>(&rotation));
+        EXPECT_EQ(rotation, kVideoRotation_90);
+      });
+
+  rtx_sink.OnRtpPacket(rtx_packet);
+}
+
+TEST(RtxReceiveStreamTest, PropagatesArrivalTime) {
+  StrictMock<MockRtpPacketSink> media_sink;
+  RtxReceiveStream rtx_sink(&media_sink, PayloadTypeMapping(), kMediaSSRC);
+  RtpPacketReceived rtx_packet(nullptr);
+  EXPECT_TRUE(rtx_packet.Parse(rtc::ArrayView<const uint8_t>(kRtxPacket)));
+  rtx_packet.set_arrival_time(Timestamp::Millis(123));
+  EXPECT_CALL(media_sink, OnRtpPacket(Property(&RtpPacketReceived::arrival_time,
+                                               Timestamp::Millis(123))));
+  rtx_sink.OnRtpPacket(rtx_packet);
+}
+
+TEST(RtxReceiveStreamTest, SupportsLargePacket) {
+  StrictMock<MockRtpPacketSink> media_sink;
+  RtxReceiveStream rtx_sink(&media_sink, PayloadTypeMapping(), kMediaSSRC);
+  RtpPacketReceived rtx_packet;
+  constexpr int kRtxPacketSize = 2000;
+  constexpr int kRtxPayloadOffset = 14;
+  uint8_t large_rtx_packet[kRtxPacketSize];
+  memcpy(large_rtx_packet, kRtxPacket, sizeof(kRtxPacket));
+  rtc::ArrayView<uint8_t> payload(large_rtx_packet + kRtxPayloadOffset,
+                                  kRtxPacketSize - kRtxPayloadOffset);
+
+  // Fill payload.
+  for (size_t i = 0; i < payload.size(); i++) {
+    payload[i] = i;
+  }
+  EXPECT_TRUE(
+      rtx_packet.Parse(rtc::ArrayView<const uint8_t>(large_rtx_packet)));
+
+  EXPECT_CALL(media_sink, OnRtpPacket)
+      .WillOnce([&](const RtpPacketReceived& packet) {
+        EXPECT_EQ(packet.SequenceNumber(), kMediaSeqno);
+        EXPECT_EQ(packet.Ssrc(), kMediaSSRC);
+        EXPECT_EQ(packet.PayloadType(), kMediaPayloadType);
+        EXPECT_THAT(packet.payload(), ::testing::ElementsAreArray(payload));
+      });
+
+  rtx_sink.OnRtpPacket(rtx_packet);
+}
+
+TEST(RtxReceiveStreamTest, SupportsLargePacketWithPadding) {
+  StrictMock<MockRtpPacketSink> media_sink;
+  RtxReceiveStream rtx_sink(&media_sink, PayloadTypeMapping(), kMediaSSRC);
+  RtpPacketReceived rtx_packet;
+  constexpr int kRtxPacketSize = 2000;
+  constexpr int kRtxPayloadOffset = 14;
+  constexpr int kRtxPaddingSize = 50;
+  uint8_t large_rtx_packet[kRtxPacketSize];
+  memcpy(large_rtx_packet, kRtxPacketWithPadding,
+         sizeof(kRtxPacketWithPadding));
+  rtc::ArrayView<uint8_t> payload(
+      large_rtx_packet + kRtxPayloadOffset,
+      kRtxPacketSize - kRtxPayloadOffset - kRtxPaddingSize);
+  rtc::ArrayView<uint8_t> padding(
+      large_rtx_packet + kRtxPacketSize - kRtxPaddingSize, kRtxPaddingSize);
+
+  // Fill payload.
+  for (size_t i = 0; i < payload.size(); i++) {
+    payload[i] = i;
+  }
+  // Fill padding. Only value of last padding byte matters.
+  for (size_t i = 0; i < padding.size(); i++) {
+    padding[i] = kRtxPaddingSize;
+  }
+
+  EXPECT_TRUE(
+      rtx_packet.Parse(rtc::ArrayView<const uint8_t>(large_rtx_packet)));
+
+  EXPECT_CALL(media_sink, OnRtpPacket)
+      .WillOnce([&](const RtpPacketReceived& packet) {
+        EXPECT_EQ(packet.SequenceNumber(), kMediaSeqno);
+        EXPECT_EQ(packet.Ssrc(), kMediaSSRC);
+        EXPECT_EQ(packet.PayloadType(), kMediaPayloadType);
+        EXPECT_THAT(packet.payload(), ::testing::ElementsAreArray(payload));
+      });
+
+  rtx_sink.OnRtpPacket(rtx_packet);
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/simulated_network.cc b/third_party/libwebrtc/call/simulated_network.cc
new file mode 100644
index 0000000000..8f9d76dfe3
--- /dev/null
+++ b/third_party/libwebrtc/call/simulated_network.cc
@@ -0,0 +1,276 @@
+/*
+ *  Copyright 2018 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/simulated_network.h"
+
+#include <algorithm>
+#include <cmath>
+#include <cstdint>
+#include <utility>
+
+#include "api/units/data_rate.h"
+#include "api/units/data_size.h"
+#include "api/units/time_delta.h"
+#include "rtc_base/checks.h"
+
+namespace webrtc {
+namespace {
+
+// Calculate the time (in microseconds) that takes to send N `bits` on a
+// network with link capacity equal to `capacity_kbps` starting at time
+// `start_time_us`.
+int64_t CalculateArrivalTimeUs(int64_t start_time_us,
+                               int64_t bits,
+                               int capacity_kbps) {
+  // If capacity is 0, the link capacity is assumed to be infinite.
+  if (capacity_kbps == 0) {
+    return start_time_us;
+  }
+  // Adding `capacity - 1` to the numerator rounds the extra delay caused by
+  // capacity constraints up to an integral microsecond. Sending 0 bits takes 0
+  // extra time, while sending 1 bit gets rounded up to 1 (the multiplication by
+  // 1000 is because capacity is in kbps).
+  // The factor 1000 comes from 10^6 / 10^3, where 10^6 is due to the time unit
+  // being us and 10^3 is due to the rate unit being kbps.
+  return start_time_us + ((1000 * bits + capacity_kbps - 1) / capacity_kbps);
+}
+
+}  // namespace
+
+SimulatedNetwork::SimulatedNetwork(Config config, uint64_t random_seed)
+    : random_(random_seed),
+      bursting_(false),
+      last_enqueue_time_us_(0),
+      last_capacity_link_exit_time_(0) {
+  SetConfig(config);
+}
+
+SimulatedNetwork::~SimulatedNetwork() = default;
+
+void SimulatedNetwork::SetConfig(const Config& config) {
+  MutexLock lock(&config_lock_);
+  config_state_.config = config;  // Shallow copy of the struct.
+  double prob_loss = config.loss_percent / 100.0;
+  if (config_state_.config.avg_burst_loss_length == -1) {
+    // Uniform loss
+    config_state_.prob_loss_bursting = prob_loss;
+    config_state_.prob_start_bursting = prob_loss;
+  } else {
+    // Lose packets according to a gilbert-elliot model.
+    int avg_burst_loss_length = config.avg_burst_loss_length;
+    int min_avg_burst_loss_length = std::ceil(prob_loss / (1 - prob_loss));
+
+    RTC_CHECK_GT(avg_burst_loss_length, min_avg_burst_loss_length)
+        << "For a total packet loss of " << config.loss_percent
+        << "%% then"
+           " avg_burst_loss_length must be "
+        << min_avg_burst_loss_length + 1 << " or higher.";
+
+    config_state_.prob_loss_bursting = (1.0 - 1.0 / avg_burst_loss_length);
+    config_state_.prob_start_bursting =
+        prob_loss / (1 - prob_loss) / avg_burst_loss_length;
+  }
+}
+
+void SimulatedNetwork::UpdateConfig(
+    std::function<void(BuiltInNetworkBehaviorConfig*)> config_modifier) {
+  MutexLock lock(&config_lock_);
+  config_modifier(&config_state_.config);
+}
+
+void SimulatedNetwork::PauseTransmissionUntil(int64_t until_us) {
+  MutexLock lock(&config_lock_);
+  config_state_.pause_transmission_until_us = until_us;
+}
+
+bool SimulatedNetwork::EnqueuePacket(PacketInFlightInfo packet) {
+  RTC_DCHECK_RUNS_SERIALIZED(&process_checker_);
+
+  // Check that old packets don't get enqueued, the SimulatedNetwork expect that
+  // the packets' send time is monotonically increasing. The tolerance for
+  // non-monotonic enqueue events is 0.5 ms because on multi core systems
+  // clock_gettime(CLOCK_MONOTONIC) can show non-monotonic behaviour between
+  // theads running on different cores.
+  // TODO(bugs.webrtc.org/14525): Open a bug on this with the goal to re-enable
+  // the DCHECK.
+  // At the moment, we see more than 130ms between non-monotonic events, which
+  // is more than expected.
+  // RTC_DCHECK_GE(packet.send_time_us - last_enqueue_time_us_, -2000);
+
+  ConfigState state = GetConfigState();
+
+  // If the network config requires packet overhead, let's apply it as early as
+  // possible.
+  packet.size += state.config.packet_overhead;
+
+  // If `queue_length_packets` is 0, the queue size is infinite.
+  if (state.config.queue_length_packets > 0 &&
+      capacity_link_.size() >= state.config.queue_length_packets) {
+    // Too many packet on the link, drop this one.
+    return false;
+  }
+
+  // If the packet has been sent before the previous packet in the network left
+  // the capacity queue, let's ensure the new packet will start its trip in the
+  // network after the last bit of the previous packet has left it.
+  int64_t packet_send_time_us = packet.send_time_us;
+  if (!capacity_link_.empty()) {
+    packet_send_time_us =
+        std::max(packet_send_time_us, capacity_link_.back().arrival_time_us);
+  }
+  capacity_link_.push({.packet = packet,
+                       .arrival_time_us = CalculateArrivalTimeUs(
+                           packet_send_time_us, packet.size * 8,
+                           state.config.link_capacity_kbps)});
+
+  // Only update `next_process_time_us_` if not already set (if set, there is no
+  // way that a new packet will make the `next_process_time_us_` change).
+  if (!next_process_time_us_) {
+    RTC_DCHECK_EQ(capacity_link_.size(), 1);
+    next_process_time_us_ = capacity_link_.front().arrival_time_us;
+  }
+
+  last_enqueue_time_us_ = packet.send_time_us;
+  return true;
+}
+
+absl::optional<int64_t> SimulatedNetwork::NextDeliveryTimeUs() const {
+  RTC_DCHECK_RUNS_SERIALIZED(&process_checker_);
+  return next_process_time_us_;
+}
+
+void SimulatedNetwork::UpdateCapacityQueue(ConfigState state,
+                                           int64_t time_now_us) {
+  // If there is at least one packet in the `capacity_link_`, let's update its
+  // arrival time to take into account changes in the network configuration
+  // since the last call to UpdateCapacityQueue.
+  if (!capacity_link_.empty()) {
+    capacity_link_.front().arrival_time_us = CalculateArrivalTimeUs(
+        std::max(capacity_link_.front().packet.send_time_us,
+                 last_capacity_link_exit_time_),
+        capacity_link_.front().packet.size * 8,
+        state.config.link_capacity_kbps);
+  }
+
+  // The capacity link is empty or the first packet is not expected to exit yet.
+  if (capacity_link_.empty() ||
+      time_now_us < capacity_link_.front().arrival_time_us) {
+    return;
+  }
+  bool reorder_packets = false;
+
+  do {
+    // Time to get this packet (the original or just updated arrival_time_us is
+    // smaller or equal to time_now_us).
+    PacketInfo packet = capacity_link_.front();
+    capacity_link_.pop();
+
+    // If the network is paused, the pause will be implemented as an extra delay
+    // to be spent in the `delay_link_` queue.
+    if (state.pause_transmission_until_us > packet.arrival_time_us) {
+      packet.arrival_time_us = state.pause_transmission_until_us;
+    }
+
+    // Store the original arrival time, before applying packet loss or extra
+    // delay. This is needed to know when it is the first available time the
+    // next packet in the `capacity_link_` queue can start transmitting.
+    last_capacity_link_exit_time_ = packet.arrival_time_us;
+
+    // Drop packets at an average rate of `state.config.loss_percent` with
+    // and average loss burst length of `state.config.avg_burst_loss_length`.
+    if ((bursting_ && random_.Rand<double>() < state.prob_loss_bursting) ||
+        (!bursting_ && random_.Rand<double>() < state.prob_start_bursting)) {
+      bursting_ = true;
+      packet.arrival_time_us = PacketDeliveryInfo::kNotReceived;
+    } else {
+      // If packets are not dropped, apply extra delay as configured.
+      bursting_ = false;
+      int64_t arrival_time_jitter_us = std::max(
+          random_.Gaussian(state.config.queue_delay_ms * 1000,
+                           state.config.delay_standard_deviation_ms * 1000),
+          0.0);
+
+      // If reordering is not allowed then adjust arrival_time_jitter
+      // to make sure all packets are sent in order.
+      int64_t last_arrival_time_us =
+          delay_link_.empty() ? -1 : delay_link_.back().arrival_time_us;
+      if (!state.config.allow_reordering && !delay_link_.empty() &&
+          packet.arrival_time_us + arrival_time_jitter_us <
+              last_arrival_time_us) {
+        arrival_time_jitter_us = last_arrival_time_us - packet.arrival_time_us;
+      }
+      packet.arrival_time_us += arrival_time_jitter_us;
+
+      // Optimization: Schedule a reorder only when a packet will exit before
+      // the one in front.
+      if (last_arrival_time_us > packet.arrival_time_us) {
+        reorder_packets = true;
+      }
+    }
+    delay_link_.emplace_back(packet);
+
+    // If there are no packets in the queue, there is nothing else to do.
+    if (capacity_link_.empty()) {
+      break;
+    }
+    // If instead there is another packet in the `capacity_link_` queue, let's
+    // calculate its arrival_time_us based on the latest config (which might
+    // have been changed since it was enqueued).
+    int64_t next_start = std::max(last_capacity_link_exit_time_,
+                                  capacity_link_.front().packet.send_time_us);
+    capacity_link_.front().arrival_time_us = CalculateArrivalTimeUs(
+        next_start, capacity_link_.front().packet.size * 8,
+        state.config.link_capacity_kbps);
+    // And if the next packet in the queue needs to exit, let's dequeue it.
+  } while (capacity_link_.front().arrival_time_us <= time_now_us);
+
+  if (state.config.allow_reordering && reorder_packets) {
+    // Packets arrived out of order and since the network config allows
+    // reordering, let's sort them per arrival_time_us to make so they will also
+    // be delivered out of order.
+    std::stable_sort(delay_link_.begin(), delay_link_.end(),
+                     [](const PacketInfo& p1, const PacketInfo& p2) {
+                       return p1.arrival_time_us < p2.arrival_time_us;
+                     });
+  }
+}
+
+SimulatedNetwork::ConfigState SimulatedNetwork::GetConfigState() const {
+  MutexLock lock(&config_lock_);
+  return config_state_;
+}
+
+std::vector<PacketDeliveryInfo> SimulatedNetwork::DequeueDeliverablePackets(
+    int64_t receive_time_us) {
+  RTC_DCHECK_RUNS_SERIALIZED(&process_checker_);
+
+  UpdateCapacityQueue(GetConfigState(), receive_time_us);
+  std::vector<PacketDeliveryInfo> packets_to_deliver;
+
+  // Check the extra delay queue.
+  while (!delay_link_.empty() &&
+         receive_time_us >= delay_link_.front().arrival_time_us) {
+    PacketInfo packet_info = delay_link_.front();
+    packets_to_deliver.emplace_back(
+        PacketDeliveryInfo(packet_info.packet, packet_info.arrival_time_us));
+    delay_link_.pop_front();
+  }
+
+  if (!delay_link_.empty()) {
+    next_process_time_us_ = delay_link_.front().arrival_time_us;
+  } else if (!capacity_link_.empty()) {
+    next_process_time_us_ = capacity_link_.front().arrival_time_us;
+  } else {
+    next_process_time_us_.reset();
+  }
+  return packets_to_deliver;
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/simulated_network.h b/third_party/libwebrtc/call/simulated_network.h
new file mode 100644
index 0000000000..8597367add
--- /dev/null
+++ b/third_party/libwebrtc/call/simulated_network.h
@@ -0,0 +1,134 @@
+/*
+ *  Copyright 2018 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+#ifndef CALL_SIMULATED_NETWORK_H_
+#define CALL_SIMULATED_NETWORK_H_
+
+#include <stdint.h>
+
+#include <deque>
+#include <queue>
+#include <vector>
+
+#include "absl/types/optional.h"
+#include "api/sequence_checker.h"
+#include "api/test/simulated_network.h"
+#include "api/units/data_size.h"
+#include "api/units/timestamp.h"
+#include "rtc_base/race_checker.h"
+#include "rtc_base/random.h"
+#include "rtc_base/synchronization/mutex.h"
+#include "rtc_base/thread_annotations.h"
+
+namespace webrtc {
+
+// Class simulating a network link.
+//
+// This is a basic implementation of NetworkBehaviorInterface that supports:
+// - Packet loss
+// - Capacity delay
+// - Extra delay with or without packets reorder
+// - Packet overhead
+// - Queue max capacity
+class SimulatedNetwork : public SimulatedNetworkInterface {
+ public:
+  using Config = BuiltInNetworkBehaviorConfig;
+  explicit SimulatedNetwork(Config config, uint64_t random_seed = 1);
+  ~SimulatedNetwork() override;
+
+  // Sets a new configuration. This will affect packets that will be sent with
+  // EnqueuePacket but also packets in the network that have not left the
+  // network emulation. Packets that are ready to be retrieved by
+  // DequeueDeliverablePackets are not affected by the new configuration.
+  // TODO(bugs.webrtc.org/14525): Fix SetConfig and make it apply only to the
+  // part of the packet that is currently being sent (instead of applying to
+  // all of it).
+  void SetConfig(const Config& config) override;
+  void UpdateConfig(std::function<void(BuiltInNetworkBehaviorConfig*)>
+                        config_modifier) override;
+  void PauseTransmissionUntil(int64_t until_us) override;
+
+  // NetworkBehaviorInterface
+  bool EnqueuePacket(PacketInFlightInfo packet) override;
+  std::vector<PacketDeliveryInfo> DequeueDeliverablePackets(
+      int64_t receive_time_us) override;
+
+  absl::optional<int64_t> NextDeliveryTimeUs() const override;
+
+ private:
+  struct PacketInfo {
+    PacketInFlightInfo packet;
+    // Time when the packet has left (or will leave) the network.
+    int64_t arrival_time_us;
+  };
+  // Contains current configuration state.
+  struct ConfigState {
+    // Static link configuration.
+    Config config;
+    // The probability to drop the packet if we are currently dropping a
+    // burst of packet
+    double prob_loss_bursting;
+    // The probability to drop a burst of packets.
+    double prob_start_bursting;
+    // Used for temporary delay spikes.
+    int64_t pause_transmission_until_us = 0;
+  };
+
+  // Moves packets from capacity- to delay link.
+  void UpdateCapacityQueue(ConfigState state, int64_t time_now_us)
+      RTC_RUN_ON(&process_checker_);
+  ConfigState GetConfigState() const;
+
+  mutable Mutex config_lock_;
+
+  // Guards the data structures involved in delay and loss processing, such as
+  // the packet queues.
+  rtc::RaceChecker process_checker_;
+  // Models the capacity of the network by rejecting packets if the queue is
+  // full and keeping them in the queue until they are ready to exit (according
+  // to the link capacity, which cannot be violated, e.g. a 1 kbps link will
+  // only be able to deliver 1000 bits per second).
+  //
+  // Invariant:
+  // The head of the `capacity_link_` has arrival_time_us correctly set to the
+  // time when the packet is supposed to be delivered (without accounting
+  // potential packet loss or potential extra delay and without accounting for a
+  // new configuration of the network, which requires a re-computation of the
+  // arrival_time_us).
+  std::queue<PacketInfo> capacity_link_ RTC_GUARDED_BY(process_checker_);
+  // Models the extra delay of the network (see `queue_delay_ms`
+  // and `delay_standard_deviation_ms` in BuiltInNetworkBehaviorConfig), packets
+  // in the `delay_link_` have technically already left the network and don't
+  // use its capacity but they are not delivered yet.
+  std::deque<PacketInfo> delay_link_ RTC_GUARDED_BY(process_checker_);
+  // Represents the next moment in time when the network is supposed to deliver
+  // packets to the client (either by pulling them from `delay_link_` or
+  // `capacity_link_` or both).
+  absl::optional<int64_t> next_process_time_us_
+      RTC_GUARDED_BY(process_checker_);
+
+  ConfigState config_state_ RTC_GUARDED_BY(config_lock_);
+
+  Random random_ RTC_GUARDED_BY(process_checker_);
+  // Are we currently dropping a burst of packets?
+  bool bursting_;
+
+  // The send time of the last enqueued packet, this is only used to check that
+  // the send time of enqueued packets is monotonically increasing.
+  int64_t last_enqueue_time_us_;
+
+  // The last time a packet left the capacity_link_ (used to enforce
+  // the capacity of the link and avoid packets starts to get sent before
+  // the link it free).
+  int64_t last_capacity_link_exit_time_;
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_SIMULATED_NETWORK_H_
diff --git a/third_party/libwebrtc/call/simulated_network_unittest.cc b/third_party/libwebrtc/call/simulated_network_unittest.cc
new file mode 100644
index 0000000000..825dd6d065
--- /dev/null
+++ b/third_party/libwebrtc/call/simulated_network_unittest.cc
@@ -0,0 +1,513 @@
+/*
+ *  Copyright 2022 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+#include "call/simulated_network.h"
+
+#include <algorithm>
+#include <map>
+#include <optional>
+#include <set>
+#include <vector>
+
+#include "absl/algorithm/container.h"
+#include "api/test/simulated_network.h"
+#include "api/units/data_rate.h"
+#include "api/units/time_delta.h"
+#include "test/gmock.h"
+#include "test/gtest.h"
+
+namespace webrtc {
+namespace {
+
+using ::testing::ElementsAre;
+
+PacketInFlightInfo PacketWithSize(size_t size) {
+  return PacketInFlightInfo(/*size=*/size, /*send_time_us=*/0, /*packet_id=*/1);
+}
+
+TEST(SimulatedNetworkTest, NextDeliveryTimeIsUnknownOnEmptyNetwork) {
+  SimulatedNetwork network = SimulatedNetwork({});
+  EXPECT_EQ(network.NextDeliveryTimeUs(), absl::nullopt);
+}
+
+TEST(SimulatedNetworkTest, EnqueueFirstPacketOnNetworkWithInfiniteCapacity) {
+  // A packet of 1 kB that gets enqueued on a network with infinite capacity
+  // should be ready to exit the network immediately.
+  SimulatedNetwork network = SimulatedNetwork({});
+  ASSERT_TRUE(network.EnqueuePacket(PacketWithSize(1'000)));
+
+  EXPECT_EQ(network.NextDeliveryTimeUs(), 0);
+}
+
+TEST(SimulatedNetworkTest, EnqueueFirstPacketOnNetworkWithLimitedCapacity) {
+  // A packet of 125 bytes that gets enqueued on a network with 1 kbps capacity
+  // should be ready to exit the network in 1 second.
+  SimulatedNetwork network = SimulatedNetwork({.link_capacity_kbps = 1});
+  ASSERT_TRUE(network.EnqueuePacket(PacketWithSize(125)));
+
+  EXPECT_EQ(network.NextDeliveryTimeUs(), TimeDelta::Seconds(1).us());
+}
+
+TEST(SimulatedNetworkTest,
+     EnqueuePacketsButNextDeliveryIsBasedOnFirstEnqueuedPacket) {
+  // A packet of 125 bytes that gets enqueued on a network with 1 kbps capacity
+  // should be ready to exit the network in 1 second.
+  SimulatedNetwork network = SimulatedNetwork({.link_capacity_kbps = 1});
+  ASSERT_TRUE(network.EnqueuePacket(
+      PacketInFlightInfo(/*size=*/125, /*send_time_us=*/0, /*packet_id=*/1)));
+  EXPECT_EQ(network.NextDeliveryTimeUs(), TimeDelta::Seconds(1).us());
+
+  // Enqueuing another packet after 100 us doesn't change the next delivery
+  // time.
+  ASSERT_TRUE(network.EnqueuePacket(
+      PacketInFlightInfo(/*size=*/125, /*send_time_us=*/100, /*packet_id=*/2)));
+  EXPECT_EQ(network.NextDeliveryTimeUs(), TimeDelta::Seconds(1).us());
+
+  // Enqueuing another packet after 2 seconds doesn't change the next delivery
+  // time since the first packet has not left the network yet.
+  ASSERT_TRUE(network.EnqueuePacket(PacketInFlightInfo(
+      /*size=*/125, /*send_time_us=*/TimeDelta::Seconds(2).us(),
+      /*packet_id=*/3)));
+  EXPECT_EQ(network.NextDeliveryTimeUs(), TimeDelta::Seconds(1).us());
+}
+
+TEST(SimulatedNetworkTest, EnqueueFailsWhenQueueLengthIsReached) {
+  SimulatedNetwork network =
+      SimulatedNetwork({.queue_length_packets = 1, .link_capacity_kbps = 1});
+  ASSERT_TRUE(network.EnqueuePacket(
+      PacketInFlightInfo(/*size=*/125, /*send_time_us=*/0, /*packet_id=*/1)));
+
+  // Until there is 1 packet in the queue, no other packets can be enqueued,
+  // the only way to make space for new packets is calling
+  // DequeueDeliverablePackets at a time greater than or equal to
+  // NextDeliveryTimeUs.
+  EXPECT_FALSE(network.EnqueuePacket(
+      PacketInFlightInfo(/*size=*/125,
+                         /*send_time_us=*/TimeDelta::Seconds(0.5).us(),
+                         /*packet_id=*/2)));
+
+  // Even if the send_time_us is after NextDeliveryTimeUs, it is still not
+  // possible to enqueue a new packet since the client didn't deque any packet
+  // from the queue (in this case the client is introducing unbounded delay but
+  // the network cannot do anything about it).
+  EXPECT_FALSE(network.EnqueuePacket(
+      PacketInFlightInfo(/*size=*/125,
+                         /*send_time_us=*/TimeDelta::Seconds(2).us(),
+                         /*packet_id=*/3)));
+}
+
+TEST(SimulatedNetworkTest, PacketOverhead) {
+  // A packet of 125 bytes that gets enqueued on a network with 1 kbps capacity
+  // should be ready to exit the network in 1 second, but since there is an
+  // overhead per packet of 125 bytes, it will exit the network after 2 seconds.
+  SimulatedNetwork network =
+      SimulatedNetwork({.link_capacity_kbps = 1, .packet_overhead = 125});
+  ASSERT_TRUE(network.EnqueuePacket(PacketWithSize(125)));
+
+  EXPECT_EQ(network.NextDeliveryTimeUs(), TimeDelta::Seconds(2).us());
+}
+
+TEST(SimulatedNetworkTest,
+     DequeueDeliverablePacketsLeavesPacketsInCapacityLink) {
+  // A packet of 125 bytes that gets enqueued on a network with 1 kbps capacity
+  // should be ready to exit the network in 1 second.
+  SimulatedNetwork network = SimulatedNetwork({.link_capacity_kbps = 1});
+  ASSERT_TRUE(network.EnqueuePacket(
+      PacketInFlightInfo(/*size=*/125, /*send_time_us=*/0, /*packet_id=*/1)));
+  // Enqueue another packet of 125 bytes (this one should exit after 2 seconds).
+  ASSERT_TRUE(network.EnqueuePacket(
+      PacketInFlightInfo(/*size=*/125,
+                         /*send_time_us=*/TimeDelta::Seconds(1).us(),
+                         /*packet_id=*/2)));
+
+  // The first packet will exit after 1 second, so that is the next delivery
+  // time.
+  EXPECT_EQ(network.NextDeliveryTimeUs(), TimeDelta::Seconds(1).us());
+
+  // After 1 seconds, we collect the delivered packets...
+  std::vector<PacketDeliveryInfo> delivered_packets =
+      network.DequeueDeliverablePackets(
+          /*receive_time_us=*/TimeDelta::Seconds(1).us());
+  ASSERT_EQ(delivered_packets.size(), 1ul);
+  EXPECT_EQ(delivered_packets[0].packet_id, 1ul);
+  EXPECT_EQ(delivered_packets[0].receive_time_us, TimeDelta::Seconds(1).us());
+
+  // ... And after the first enqueued packet has left the network, the next
+  // delivery time reflects the delivery time of the next packet.
+  EXPECT_EQ(network.NextDeliveryTimeUs(), TimeDelta::Seconds(2).us());
+}
+
+TEST(SimulatedNetworkTest,
+     DequeueDeliverablePacketsAppliesConfigChangesToCapacityLink) {
+  // A packet of 125 bytes that gets enqueued on a network with 1 kbps capacity
+  // should be ready to exit the network in 1 second.
+  SimulatedNetwork network = SimulatedNetwork({.link_capacity_kbps = 1});
+  const PacketInFlightInfo packet_1 =
+      PacketInFlightInfo(/*size=*/125, /*send_time_us=*/0, /*packet_id=*/1);
+  ASSERT_TRUE(network.EnqueuePacket(packet_1));
+
+  // Enqueue another packet of 125 bytes with send time 1 second so this should
+  // exit after 2 seconds.
+  PacketInFlightInfo packet_2 =
+      PacketInFlightInfo(/*size=*/125,
+                         /*send_time_us=*/TimeDelta::Seconds(1).us(),
+                         /*packet_id=*/2);
+  ASSERT_TRUE(network.EnqueuePacket(packet_2));
+
+  // The first packet will exit after 1 second, so that is the next delivery
+  // time.
+  EXPECT_EQ(network.NextDeliveryTimeUs(), TimeDelta::Seconds(1).us());
+
+  // Since the link capacity changes from 1 kbps to 10 kbps, packets will take
+  // 100 ms each to leave the network.
+  network.SetConfig({.link_capacity_kbps = 10});
+
+  // The next delivery time doesn't change (it will be updated, if needed at
+  // DequeueDeliverablePackets time).
+  EXPECT_EQ(network.NextDeliveryTimeUs(), TimeDelta::Seconds(1).us());
+
+  // Getting the first enqueued packet after 100 ms.
+  std::vector<PacketDeliveryInfo> delivered_packets =
+      network.DequeueDeliverablePackets(
+          /*receive_time_us=*/TimeDelta::Millis(100).us());
+  ASSERT_EQ(delivered_packets.size(), 1ul);
+  EXPECT_THAT(delivered_packets,
+              ElementsAre(PacketDeliveryInfo(
+                  /*source=*/packet_1,
+                  /*receive_time_us=*/TimeDelta::Millis(100).us())));
+
+  // Getting the second enqueued packet that cannot be delivered before its send
+  // time, hence it will be delivered after 1.1 seconds.
+  EXPECT_EQ(network.NextDeliveryTimeUs(), TimeDelta::Millis(1100).us());
+  delivered_packets = network.DequeueDeliverablePackets(
+      /*receive_time_us=*/TimeDelta::Millis(1100).us());
+  ASSERT_EQ(delivered_packets.size(), 1ul);
+  EXPECT_THAT(delivered_packets,
+              ElementsAre(PacketDeliveryInfo(
+                  /*source=*/packet_2,
+                  /*receive_time_us=*/TimeDelta::Millis(1100).us())));
+}
+
+TEST(SimulatedNetworkTest, NetworkEmptyAfterLastPacketDequeued) {
+  // A packet of 125 bytes that gets enqueued on a network with 1 kbps capacity
+  // should be ready to exit the network in 1 second.
+  SimulatedNetwork network = SimulatedNetwork({.link_capacity_kbps = 1});
+  ASSERT_TRUE(network.EnqueuePacket(PacketWithSize(125)));
+
+  // Collecting all the delivered packets ...
+  std::vector<PacketDeliveryInfo> delivered_packets =
+      network.DequeueDeliverablePackets(
+          /*receive_time_us=*/TimeDelta::Seconds(1).us());
+  EXPECT_EQ(delivered_packets.size(), 1ul);
+
+  // ... leaves the network empty.
+  EXPECT_EQ(network.NextDeliveryTimeUs(), absl::nullopt);
+}
+
+TEST(SimulatedNetworkTest, DequeueDeliverablePacketsOnLateCall) {
+  // A packet of 125 bytes that gets enqueued on a network with 1 kbps capacity
+  // should be ready to exit the network in 1 second.
+  SimulatedNetwork network = SimulatedNetwork({.link_capacity_kbps = 1});
+  ASSERT_TRUE(network.EnqueuePacket(
+      PacketInFlightInfo(/*size=*/125, /*send_time_us=*/0, /*packet_id=*/1)));
+
+  // Enqueue another packet of 125 bytes with send time 1 second so this should
+  // exit after 2 seconds.
+  ASSERT_TRUE(network.EnqueuePacket(
+      PacketInFlightInfo(/*size=*/125,
+                         /*send_time_us=*/TimeDelta::Seconds(1).us(),
+                         /*packet_id=*/2)));
+
+  // Collecting delivered packets after 3 seconds will result in the delivery of
+  // both the enqueued packets.
+  std::vector<PacketDeliveryInfo> delivered_packets =
+      network.DequeueDeliverablePackets(
+          /*receive_time_us=*/TimeDelta::Seconds(3).us());
+  EXPECT_EQ(delivered_packets.size(), 2ul);
+}
+
+TEST(SimulatedNetworkTest,
+     DequeueDeliverablePacketsOnEarlyCallReturnsNoPackets) {
+  // A packet of 125 bytes that gets enqueued on a network with 1 kbps capacity
+  // should be ready to exit the network in 1 second.
+  SimulatedNetwork network = SimulatedNetwork({.link_capacity_kbps = 1});
+  ASSERT_TRUE(network.EnqueuePacket(PacketWithSize(125)));
+
+  // Collecting delivered packets after 0.5 seconds will result in the delivery
+  // of 0 packets.
+  std::vector<PacketDeliveryInfo> delivered_packets =
+      network.DequeueDeliverablePackets(
+          /*receive_time_us=*/TimeDelta::Seconds(0.5).us());
+  EXPECT_EQ(delivered_packets.size(), 0ul);
+
+  // Since the first enqueued packet was supposed to exit after 1 second.
+  EXPECT_EQ(network.NextDeliveryTimeUs(), TimeDelta::Seconds(1).us());
+}
+
+TEST(SimulatedNetworkTest, QueueDelayMsWithoutStandardDeviation) {
+  // A packet of 125 bytes that gets enqueued on a network with 1 kbps capacity
+  // should be ready to exit the network in 1 second.
+  SimulatedNetwork network =
+      SimulatedNetwork({.queue_delay_ms = 100, .link_capacity_kbps = 1});
+  ASSERT_TRUE(network.EnqueuePacket(PacketWithSize(125)));
+  // The next delivery time is still 1 second even if there are 100 ms of
+  // extra delay but this will be applied at DequeueDeliverablePackets time.
+  ASSERT_EQ(network.NextDeliveryTimeUs(), TimeDelta::Seconds(1).us());
+
+  // Since all packets are delayed by 100 ms, after 1 second, no packets will
+  // exit the network.
+  std::vector<PacketDeliveryInfo> delivered_packets =
+      network.DequeueDeliverablePackets(
+          /*receive_time_us=*/TimeDelta::Seconds(1).us());
+  EXPECT_EQ(delivered_packets.size(), 0ul);
+
+  // And the updated next delivery time takes into account the extra delay of
+  // 100 ms so the first packet in the network will be delivered after 1.1
+  // seconds.
+  EXPECT_EQ(network.NextDeliveryTimeUs(), TimeDelta::Millis(1100).us());
+  delivered_packets = network.DequeueDeliverablePackets(
+      /*receive_time_us=*/TimeDelta::Millis(1100).us());
+  EXPECT_EQ(delivered_packets.size(), 1ul);
+}
+
+TEST(SimulatedNetworkTest,
+     QueueDelayMsWithStandardDeviationAndReorderNotAllowed) {
+  SimulatedNetwork network =
+      SimulatedNetwork({.queue_delay_ms = 100,
+                        .delay_standard_deviation_ms = 90,
+                        .link_capacity_kbps = 1,
+                        .allow_reordering = false});
+  // A packet of 125 bytes that gets enqueued on a network with 1 kbps capacity
+  // should be ready to exit the network in 1 second.
+  ASSERT_TRUE(network.EnqueuePacket(
+      PacketInFlightInfo(/*size=*/125, /*send_time_us=*/0, /*packet_id=*/1)));
+
+  // But 3 more packets of size 1 byte are enqueued at the same time.
+  ASSERT_TRUE(network.EnqueuePacket(
+      PacketInFlightInfo(/*size=*/1, /*send_time_us=*/0, /*packet_id=*/2)));
+  ASSERT_TRUE(network.EnqueuePacket(
+      PacketInFlightInfo(/*size=*/1, /*send_time_us=*/0, /*packet_id=*/3)));
+  ASSERT_TRUE(network.EnqueuePacket(
+      PacketInFlightInfo(/*size=*/1, /*send_time_us=*/0, /*packet_id=*/4)));
+
+  // After 5 seconds all of them exit the network.
+  std::vector<PacketDeliveryInfo> delivered_packets =
+      network.DequeueDeliverablePackets(
+          /*receive_time_us=*/TimeDelta::Seconds(5).us());
+  ASSERT_EQ(delivered_packets.size(), 4ul);
+
+  // And they are still in order even if the delay was applied.
+  EXPECT_EQ(delivered_packets[0].packet_id, 1ul);
+  EXPECT_EQ(delivered_packets[1].packet_id, 2ul);
+  EXPECT_GE(delivered_packets[1].receive_time_us,
+            delivered_packets[0].receive_time_us);
+  EXPECT_EQ(delivered_packets[2].packet_id, 3ul);
+  EXPECT_GE(delivered_packets[2].receive_time_us,
+            delivered_packets[1].receive_time_us);
+  EXPECT_EQ(delivered_packets[3].packet_id, 4ul);
+  EXPECT_GE(delivered_packets[3].receive_time_us,
+            delivered_packets[2].receive_time_us);
+}
+
+TEST(SimulatedNetworkTest, QueueDelayMsWithStandardDeviationAndReorderAllowed) {
+  SimulatedNetwork network =
+      SimulatedNetwork({.queue_delay_ms = 100,
+                        .delay_standard_deviation_ms = 90,
+                        .link_capacity_kbps = 1,
+                        .allow_reordering = true},
+                       /*random_seed=*/1);
+  // A packet of 125 bytes that gets enqueued on a network with 1 kbps capacity
+  // should be ready to exit the network in 1 second.
+  ASSERT_TRUE(network.EnqueuePacket(
+      PacketInFlightInfo(/*size=*/125, /*send_time_us=*/0, /*packet_id=*/1)));
+
+  // But 3 more packets of size 1 byte are enqueued at the same time.
+  ASSERT_TRUE(network.EnqueuePacket(
+      PacketInFlightInfo(/*size=*/1, /*send_time_us=*/0, /*packet_id=*/2)));
+  ASSERT_TRUE(network.EnqueuePacket(
+      PacketInFlightInfo(/*size=*/1, /*send_time_us=*/0, /*packet_id=*/3)));
+  ASSERT_TRUE(network.EnqueuePacket(
+      PacketInFlightInfo(/*size=*/1, /*send_time_us=*/0, /*packet_id=*/4)));
+
+  // After 5 seconds all of them exit the network.
+  std::vector<PacketDeliveryInfo> delivered_packets =
+      network.DequeueDeliverablePackets(
+          /*receive_time_us=*/TimeDelta::Seconds(5).us());
+  ASSERT_EQ(delivered_packets.size(), 4ul);
+
+  // And they have been reordered accorting to the applied extra delay.
+  EXPECT_EQ(delivered_packets[0].packet_id, 3ul);
+  EXPECT_EQ(delivered_packets[1].packet_id, 1ul);
+  EXPECT_GE(delivered_packets[1].receive_time_us,
+            delivered_packets[0].receive_time_us);
+  EXPECT_EQ(delivered_packets[2].packet_id, 2ul);
+  EXPECT_GE(delivered_packets[2].receive_time_us,
+            delivered_packets[1].receive_time_us);
+  EXPECT_EQ(delivered_packets[3].packet_id, 4ul);
+  EXPECT_GE(delivered_packets[3].receive_time_us,
+            delivered_packets[2].receive_time_us);
+}
+
+TEST(SimulatedNetworkTest, PacketLoss) {
+  // On a network with 50% probablility of packet loss ...
+  SimulatedNetwork network = SimulatedNetwork({.loss_percent = 50});
+
+  // Enqueueing 8 packets ...
+  for (int i = 0; i < 8; i++) {
+    ASSERT_TRUE(network.EnqueuePacket(PacketInFlightInfo(
+        /*size=*/1, /*send_time_us=*/0, /*packet_id=*/i + 1)));
+  }
+
+  std::vector<PacketDeliveryInfo> delivered_packets =
+      network.DequeueDeliverablePackets(
+          /*receive_time_us=*/TimeDelta::Seconds(5).us());
+  EXPECT_EQ(delivered_packets.size(), 8ul);
+
+  // Results in the loss of 4 of them.
+  int lost_packets = 0;
+  for (const auto& packet : delivered_packets) {
+    if (packet.receive_time_us == PacketDeliveryInfo::kNotReceived) {
+      lost_packets++;
+    }
+  }
+  EXPECT_EQ(lost_packets, 4);
+}
+
+TEST(SimulatedNetworkTest, PacketLossBurst) {
+  // On a network with 50% probablility of packet loss and an average burst loss
+  // length of 100 ...
+  SimulatedNetwork network = SimulatedNetwork(
+      {.loss_percent = 50, .avg_burst_loss_length = 100}, /*random_seed=*/1);
+
+  // Enqueueing 20 packets ...
+  for (int i = 0; i < 20; i++) {
+    ASSERT_TRUE(network.EnqueuePacket(PacketInFlightInfo(
+        /*size=*/1, /*send_time_us=*/0, /*packet_id=*/i + 1)));
+  }
+
+  std::vector<PacketDeliveryInfo> delivered_packets =
+      network.DequeueDeliverablePackets(
+          /*receive_time_us=*/TimeDelta::Seconds(5).us());
+  EXPECT_EQ(delivered_packets.size(), 20ul);
+
+  // Results in a burst of lost packets after the first packet lost.
+  // With the current random seed, the first 12 are not lost, while the
+  // last 8 are.
+  int current_packet = 0;
+  for (const auto& packet : delivered_packets) {
+    if (current_packet < 12) {
+      EXPECT_NE(packet.receive_time_us, PacketDeliveryInfo::kNotReceived);
+      current_packet++;
+    } else {
+      EXPECT_EQ(packet.receive_time_us, PacketDeliveryInfo::kNotReceived);
+      current_packet++;
+    }
+  }
+}
+
+TEST(SimulatedNetworkTest, PauseTransmissionUntil) {
+  // 3 packets of 125 bytes that gets enqueued on a network with 1 kbps capacity
+  // should be ready to exit the network after 1, 2 and 3 seconds respectively.
+  SimulatedNetwork network = SimulatedNetwork({.link_capacity_kbps = 1});
+  ASSERT_TRUE(network.EnqueuePacket(
+      PacketInFlightInfo(/*size=*/125, /*send_time_us=*/0, /*packet_id=*/1)));
+  ASSERT_TRUE(network.EnqueuePacket(
+      PacketInFlightInfo(/*size=*/125, /*send_time_us=*/0, /*packet_id=*/2)));
+  ASSERT_TRUE(network.EnqueuePacket(
+      PacketInFlightInfo(/*size=*/125, /*send_time_us=*/0, /*packet_id=*/3)));
+  ASSERT_EQ(network.NextDeliveryTimeUs(), TimeDelta::Seconds(1).us());
+
+  // The network gets paused for 5 seconds, which means that the first packet
+  // can exit after 5 seconds instead of 1 second.
+  network.PauseTransmissionUntil(TimeDelta::Seconds(5).us());
+
+  // No packets after 1 second.
+  std::vector<PacketDeliveryInfo> delivered_packets =
+      network.DequeueDeliverablePackets(
+          /*receive_time_us=*/TimeDelta::Seconds(1).us());
+  EXPECT_EQ(delivered_packets.size(), 0ul);
+  EXPECT_EQ(network.NextDeliveryTimeUs(), TimeDelta::Seconds(5).us());
+
+  // The first packet exits after 5 seconds.
+  delivered_packets = network.DequeueDeliverablePackets(
+      /*receive_time_us=*/TimeDelta::Seconds(5).us());
+  EXPECT_EQ(delivered_packets.size(), 1ul);
+
+  // After the first packet is exited, the next delivery time reflects the
+  // delivery time of the next packet which accounts for the network pause.
+  EXPECT_EQ(network.NextDeliveryTimeUs(), TimeDelta::Seconds(6).us());
+
+  // And 2 seconds after the exit of the first enqueued packet, the following 2
+  // packets are also delivered.
+  delivered_packets = network.DequeueDeliverablePackets(
+      /*receive_time_us=*/TimeDelta::Seconds(7).us());
+  EXPECT_EQ(delivered_packets.size(), 2ul);
+}
+
+TEST(SimulatedNetworkTest, CongestedNetworkRespectsLinkCapacity) {
+  SimulatedNetwork network = SimulatedNetwork({.link_capacity_kbps = 1});
+  for (size_t i = 0; i < 1'000; ++i) {
+    ASSERT_TRUE(network.EnqueuePacket(
+        PacketInFlightInfo(/*size=*/125, /*send_time_us=*/0, /*packet_id=*/i)));
+  }
+  PacketDeliveryInfo last_delivered_packet{
+      PacketInFlightInfo(/*size=*/0, /*send_time_us=*/0, /*packet_id=*/0), 0};
+  while (network.NextDeliveryTimeUs().has_value()) {
+    std::vector<PacketDeliveryInfo> delivered_packets =
+        network.DequeueDeliverablePackets(
+            /*receive_time_us=*/network.NextDeliveryTimeUs().value());
+    if (!delivered_packets.empty()) {
+      last_delivered_packet = delivered_packets.back();
+    }
+  }
+  // 1000 packets of 1000 bits each will take 1000 seconds to exit a 1 kpbs
+  // network.
+  EXPECT_EQ(last_delivered_packet.receive_time_us,
+            TimeDelta::Seconds(1000).us());
+  EXPECT_EQ(last_delivered_packet.packet_id, 999ul);
+}
+
+TEST(SimulatedNetworkTest, EnqueuePacketWithSubSecondNonMonotonicBehaviour) {
+  // On multi-core systems, different threads can experience sub-millisecond non
+  // monothonic behaviour when running on different cores. This test checks that
+  // when a non monotonic packet enqueue, the network continues to work and the
+  // out of order packet is sent anyway.
+  SimulatedNetwork network = SimulatedNetwork({.link_capacity_kbps = 1});
+  ASSERT_TRUE(network.EnqueuePacket(PacketInFlightInfo(
+      /*size=*/125, /*send_time_us=*/TimeDelta::Seconds(1).us(),
+      /*packet_id=*/0)));
+  ASSERT_TRUE(network.EnqueuePacket(PacketInFlightInfo(
+      /*size=*/125, /*send_time_us=*/TimeDelta::Seconds(1).us() - 1,
+      /*packet_id=*/1)));
+
+  std::vector<PacketDeliveryInfo> delivered_packets =
+      network.DequeueDeliverablePackets(
+          /*receive_time_us=*/TimeDelta::Seconds(2).us());
+  ASSERT_EQ(delivered_packets.size(), 1ul);
+  EXPECT_EQ(delivered_packets[0].packet_id, 0ul);
+  EXPECT_EQ(delivered_packets[0].receive_time_us, TimeDelta::Seconds(2).us());
+
+  delivered_packets = network.DequeueDeliverablePackets(
+      /*receive_time_us=*/TimeDelta::Seconds(3).us());
+  ASSERT_EQ(delivered_packets.size(), 1ul);
+  EXPECT_EQ(delivered_packets[0].packet_id, 1ul);
+  EXPECT_EQ(delivered_packets[0].receive_time_us, TimeDelta::Seconds(3).us());
+}
+
+// TODO(bugs.webrtc.org/14525): Re-enable when the DCHECK will be uncommented
+// and the non-monotonic events on real time clock tests is solved/understood.
+// TEST(SimulatedNetworkDeathTest, EnqueuePacketExpectMonotonicSendTime) {
+//   SimulatedNetwork network = SimulatedNetwork({.link_capacity_kbps = 1});
+//   ASSERT_TRUE(network.EnqueuePacket(PacketInFlightInfo(
+//       /*size=*/125, /*send_time_us=*/2'000'000, /*packet_id=*/0)));
+//   EXPECT_DEATH_IF_SUPPORTED(network.EnqueuePacket(PacketInFlightInfo(
+//       /*size=*/125, /*send_time_us=*/900'000, /*packet_id=*/1)), "");
+// }
+}  // namespace
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/simulated_packet_receiver.h b/third_party/libwebrtc/call/simulated_packet_receiver.h
new file mode 100644
index 0000000000..2db46e8c38
--- /dev/null
+++ b/third_party/libwebrtc/call/simulated_packet_receiver.h
@@ -0,0 +1,42 @@
+/*
+ *  Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_SIMULATED_PACKET_RECEIVER_H_
+#define CALL_SIMULATED_PACKET_RECEIVER_H_
+
+#include "api/test/simulated_network.h"
+#include "call/packet_receiver.h"
+
+namespace webrtc {
+
+// Private API that is fixing surface between DirectTransport and underlying
+// network conditions simulation implementation.
+class SimulatedPacketReceiverInterface : public PacketReceiver {
+ public:
+  // Must not be called in parallel with DeliverPacket or Process.
+  // Destination receiver will be injected with this method
+  virtual void SetReceiver(PacketReceiver* receiver) = 0;
+
+  // Reports average packet delay.
+  virtual int AverageDelay() = 0;
+
+  // Process any pending tasks such as timeouts.
+  // Called on a worker thread.
+  virtual void Process() = 0;
+
+  // Returns the time until next process or nullopt to indicate that the next
+  // process time is unknown. If the next process time is unknown, this should
+  // be checked again any time a packet is enqueued.
+  virtual absl::optional<int64_t> TimeUntilNextProcess() = 0;
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_SIMULATED_PACKET_RECEIVER_H_
diff --git a/third_party/libwebrtc/call/syncable.cc b/third_party/libwebrtc/call/syncable.cc
new file mode 100644
index 0000000000..a821881884
--- /dev/null
+++ b/third_party/libwebrtc/call/syncable.cc
@@ -0,0 +1,17 @@
+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/syncable.h"
+
+namespace webrtc {
+
+Syncable::~Syncable() = default;
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/syncable.h b/third_party/libwebrtc/call/syncable.h
new file mode 100644
index 0000000000..6817be9c55
--- /dev/null
+++ b/third_party/libwebrtc/call/syncable.h
@@ -0,0 +1,46 @@
+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+// Syncable is used by RtpStreamsSynchronizer in VideoReceiveStreamInterface,
+// and implemented by AudioReceiveStreamInterface.
+
+#ifndef CALL_SYNCABLE_H_
+#define CALL_SYNCABLE_H_
+
+#include <stdint.h>
+
+#include "absl/types/optional.h"
+
+namespace webrtc {
+
+class Syncable {
+ public:
+  struct Info {
+    int64_t latest_receive_time_ms = 0;
+    uint32_t latest_received_capture_timestamp = 0;
+    uint32_t capture_time_ntp_secs = 0;
+    uint32_t capture_time_ntp_frac = 0;
+    uint32_t capture_time_source_clock = 0;
+    int current_delay_ms = 0;
+  };
+
+  virtual ~Syncable();
+
+  virtual uint32_t id() const = 0;
+  virtual absl::optional<Info> GetInfo() const = 0;
+  virtual bool GetPlayoutRtpTimestamp(uint32_t* rtp_timestamp,
+                                      int64_t* time_ms) const = 0;
+  virtual bool SetMinimumPlayoutDelay(int delay_ms) = 0;
+  virtual void SetEstimatedPlayoutNtpTimestampMs(int64_t ntp_timestamp_ms,
+                                                 int64_t time_ms) = 0;
+};
+}  // namespace webrtc
+
+#endif  // CALL_SYNCABLE_H_
diff --git a/third_party/libwebrtc/call/test/mock_audio_send_stream.h b/third_party/libwebrtc/call/test/mock_audio_send_stream.h
new file mode 100644
index 0000000000..1993de8de0
--- /dev/null
+++ b/third_party/libwebrtc/call/test/mock_audio_send_stream.h
@@ -0,0 +1,51 @@
+/*
+ *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_TEST_MOCK_AUDIO_SEND_STREAM_H_
+#define CALL_TEST_MOCK_AUDIO_SEND_STREAM_H_
+
+#include <memory>
+
+#include "call/audio_send_stream.h"
+#include "test/gmock.h"
+
+namespace webrtc {
+namespace test {
+
+class MockAudioSendStream : public AudioSendStream {
+ public:
+  MOCK_METHOD(const webrtc::AudioSendStream::Config&,
+              GetConfig,
+              (),
+              (const, override));
+  MOCK_METHOD(void,
+              Reconfigure,
+              (const Config& config, SetParametersCallback callback),
+              (override));
+  MOCK_METHOD(void, Start, (), (override));
+  MOCK_METHOD(void, Stop, (), (override));
+  // GMock doesn't like move-only types, such as std::unique_ptr.
+  void SendAudioData(std::unique_ptr<webrtc::AudioFrame> audio_frame) override {
+    SendAudioDataForMock(audio_frame.get());
+  }
+  MOCK_METHOD(void, SendAudioDataForMock, (webrtc::AudioFrame*));
+  MOCK_METHOD(
+      bool,
+      SendTelephoneEvent,
+      (int payload_type, int payload_frequency, int event, int duration_ms),
+      (override));
+  MOCK_METHOD(void, SetMuted, (bool muted), (override));
+  MOCK_METHOD(Stats, GetStats, (), (const, override));
+  MOCK_METHOD(Stats, GetStats, (bool has_remote_tracks), (const, override));
+};
+}  // namespace test
+}  // namespace webrtc
+
+#endif  // CALL_TEST_MOCK_AUDIO_SEND_STREAM_H_
diff --git a/third_party/libwebrtc/call/test/mock_bitrate_allocator.h b/third_party/libwebrtc/call/test/mock_bitrate_allocator.h
new file mode 100644
index 0000000000..b08916fe4f
--- /dev/null
+++ b/third_party/libwebrtc/call/test/mock_bitrate_allocator.h
@@ -0,0 +1,32 @@
+/*
+ *  Copyright 2018 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+#ifndef CALL_TEST_MOCK_BITRATE_ALLOCATOR_H_
+#define CALL_TEST_MOCK_BITRATE_ALLOCATOR_H_
+
+#include <string>
+
+#include "call/bitrate_allocator.h"
+#include "test/gmock.h"
+
+namespace webrtc {
+class MockBitrateAllocator : public BitrateAllocatorInterface {
+ public:
+  MOCK_METHOD(void,
+              AddObserver,
+              (BitrateAllocatorObserver*, MediaStreamAllocationConfig),
+              (override));
+  MOCK_METHOD(void, RemoveObserver, (BitrateAllocatorObserver*), (override));
+  MOCK_METHOD(int,
+              GetStartBitrate,
+              (BitrateAllocatorObserver*),
+              (const, override));
+};
+}  // namespace webrtc
+#endif  // CALL_TEST_MOCK_BITRATE_ALLOCATOR_H_
diff --git a/third_party/libwebrtc/call/test/mock_rtp_packet_sink_interface.h b/third_party/libwebrtc/call/test/mock_rtp_packet_sink_interface.h
new file mode 100644
index 0000000000..e6d14f05c5
--- /dev/null
+++ b/third_party/libwebrtc/call/test/mock_rtp_packet_sink_interface.h
@@ -0,0 +1,25 @@
+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+#ifndef CALL_TEST_MOCK_RTP_PACKET_SINK_INTERFACE_H_
+#define CALL_TEST_MOCK_RTP_PACKET_SINK_INTERFACE_H_
+
+#include "call/rtp_packet_sink_interface.h"
+#include "test/gmock.h"
+
+namespace webrtc {
+
+class MockRtpPacketSink : public RtpPacketSinkInterface {
+ public:
+  MOCK_METHOD(void, OnRtpPacket, (const RtpPacketReceived&), (override));
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_TEST_MOCK_RTP_PACKET_SINK_INTERFACE_H_
diff --git a/third_party/libwebrtc/call/test/mock_rtp_transport_controller_send.h b/third_party/libwebrtc/call/test/mock_rtp_transport_controller_send.h
new file mode 100644
index 0000000000..6e78534de2
--- /dev/null
+++ b/third_party/libwebrtc/call/test/mock_rtp_transport_controller_send.h
@@ -0,0 +1,106 @@
+/*
+ *  Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_TEST_MOCK_RTP_TRANSPORT_CONTROLLER_SEND_H_
+#define CALL_TEST_MOCK_RTP_TRANSPORT_CONTROLLER_SEND_H_
+
+#include <map>
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "absl/strings/string_view.h"
+#include "api/crypto/crypto_options.h"
+#include "api/crypto/frame_encryptor_interface.h"
+#include "api/frame_transformer_interface.h"
+#include "api/transport/bitrate_settings.h"
+#include "call/rtp_transport_controller_send_interface.h"
+#include "modules/pacing/packet_router.h"
+#include "rtc_base/network/sent_packet.h"
+#include "rtc_base/network_route.h"
+#include "rtc_base/rate_limiter.h"
+#include "test/gmock.h"
+
+namespace webrtc {
+
+class MockRtpTransportControllerSend
+    : public RtpTransportControllerSendInterface {
+ public:
+  MOCK_METHOD(RtpVideoSenderInterface*,
+              CreateRtpVideoSender,
+              ((const std::map<uint32_t, RtpState>&),
+               (const std::map<uint32_t, RtpPayloadState>&),
+               const RtpConfig&,
+               int rtcp_report_interval_ms,
+               Transport*,
+               const RtpSenderObservers&,
+               RtcEventLog*,
+               std::unique_ptr<FecController>,
+               const RtpSenderFrameEncryptionConfig&,
+               rtc::scoped_refptr<FrameTransformerInterface>),
+              (override));
+  MOCK_METHOD(void,
+              DestroyRtpVideoSender,
+              (RtpVideoSenderInterface*),
+              (override));
+  MOCK_METHOD(MaybeWorkerThread*, GetWorkerQueue, (), (override));
+  MOCK_METHOD(PacketRouter*, packet_router, (), (override));
+  MOCK_METHOD(NetworkStateEstimateObserver*,
+              network_state_estimate_observer,
+              (),
+              (override));
+  MOCK_METHOD(TransportFeedbackObserver*,
+              transport_feedback_observer,
+              (),
+              (override));
+  MOCK_METHOD(RtpPacketSender*, packet_sender, (), (override));
+  MOCK_METHOD(void,
+              SetAllocatedSendBitrateLimits,
+              (BitrateAllocationLimits),
+              (override));
+  MOCK_METHOD(void, SetPacingFactor, (float), (override));
+  MOCK_METHOD(void, SetQueueTimeLimit, (int), (override));
+  MOCK_METHOD(StreamFeedbackProvider*,
+              GetStreamFeedbackProvider,
+              (),
+              (override));
+  MOCK_METHOD(void,
+              RegisterTargetTransferRateObserver,
+              (TargetTransferRateObserver*),
+              (override));
+  MOCK_METHOD(void,
+              OnNetworkRouteChanged,
+              (absl::string_view, const rtc::NetworkRoute&),
+              (override));
+  MOCK_METHOD(void, OnNetworkAvailability, (bool), (override));
+  MOCK_METHOD(RtcpBandwidthObserver*, GetBandwidthObserver, (), (override));
+  MOCK_METHOD(int64_t, GetPacerQueuingDelayMs, (), (const, override));
+  MOCK_METHOD(absl::optional<Timestamp>,
+              GetFirstPacketTime,
+              (),
+              (const, override));
+  MOCK_METHOD(void, EnablePeriodicAlrProbing, (bool), (override));
+  MOCK_METHOD(void, OnSentPacket, (const rtc::SentPacket&), (override));
+  MOCK_METHOD(void,
+              SetSdpBitrateParameters,
+              (const BitrateConstraints&),
+              (override));
+  MOCK_METHOD(void,
+              SetClientBitratePreferences,
+              (const BitrateSettings&),
+              (override));
+  MOCK_METHOD(void, OnTransportOverheadChanged, (size_t), (override));
+  MOCK_METHOD(void, AccountForAudioPacketsInPacedSender, (bool), (override));
+  MOCK_METHOD(void, IncludeOverheadInPacedSender, (), (override));
+  MOCK_METHOD(void, OnReceivedPacket, (const ReceivedPacket&), (override));
+  MOCK_METHOD(void, EnsureStarted, (), (override));
+};
+}  // namespace webrtc
+#endif  // CALL_TEST_MOCK_RTP_TRANSPORT_CONTROLLER_SEND_H_
diff --git a/third_party/libwebrtc/call/version.cc b/third_party/libwebrtc/call/version.cc
new file mode 100644
index 0000000000..70497dfc69
--- /dev/null
+++ b/third_party/libwebrtc/call/version.cc
@@ -0,0 +1,25 @@
+/*
+ *  Copyright (c) 2020 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/version.h"
+
+namespace webrtc {
+
+// The timestamp is always in UTC.
+const char* const kSourceTimestamp = "WebRTC source stamp 2023-01-26T04:01:54";
+
+void LoadWebRTCVersionInRegister() {
+  // Using volatile to instruct the compiler to not optimize `p` away even
+  // if it looks unused.
+  const char* volatile p = kSourceTimestamp;
+  static_cast<void>(p);
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/version.h b/third_party/libwebrtc/call/version.h
new file mode 100644
index 0000000000..d476e0e108
--- /dev/null
+++ b/third_party/libwebrtc/call/version.h
@@ -0,0 +1,25 @@
+/*
+ *  Copyright (c) 2020 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_VERSION_H_
+#define CALL_VERSION_H_
+
+// LoadWebRTCVersionInRegistry is a helper function that loads the pointer to
+// the WebRTC version string into a register. While this function doesn't do
+// anything useful, it is needed in order to avoid that compiler optimizations
+// remove the WebRTC version string from the final binary.
+
+namespace webrtc {
+
+void LoadWebRTCVersionInRegister();
+
+}  // namespace webrtc
+
+#endif  // CALL_VERSION_H_
diff --git a/third_party/libwebrtc/call/version_gn/moz.build b/third_party/libwebrtc/call/version_gn/moz.build
new file mode 100644
index 0000000000..d638203521
--- /dev/null
+++ b/third_party/libwebrtc/call/version_gn/moz.build
@@ -0,0 +1,217 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+  ### This moz.build was AUTOMATICALLY GENERATED from a GN config,  ###
+  ### DO NOT edit it by hand.                                       ###
+
+COMPILE_FLAGS["OS_INCLUDES"] = []
+AllowCompilerWarnings()
+
+DEFINES["ABSL_ALLOCATOR_NOTHROW"] = "1"
+DEFINES["RTC_DAV1D_IN_INTERNAL_DECODER_FACTORY"] = True
+DEFINES["RTC_ENABLE_VP9"] = True
+DEFINES["WEBRTC_ENABLE_PROTOBUF"] = "0"
+DEFINES["WEBRTC_LIBRARY_IMPL"] = True
+DEFINES["WEBRTC_MOZILLA_BUILD"] = True
+DEFINES["WEBRTC_NON_STATIC_TRACE_EVENT_HANDLERS"] = "0"
+DEFINES["WEBRTC_STRICT_FIELD_TRIALS"] = "0"
+
+FINAL_LIBRARY = "webrtc"
+
+
+LOCAL_INCLUDES += [
+    "!/ipc/ipdl/_ipdlheaders",
+    "!/third_party/libwebrtc/gen",
+    "/ipc/chromium/src",
+    "/third_party/libwebrtc/",
+    "/third_party/libwebrtc/third_party/abseil-cpp/",
+    "/tools/profiler/public"
+]
+
+UNIFIED_SOURCES += [
+    "/third_party/libwebrtc/call/version.cc"
+]
+
+if not CONFIG["MOZ_DEBUG"]:
+
+    DEFINES["DYNAMIC_ANNOTATIONS_ENABLED"] = "0"
+    DEFINES["NDEBUG"] = True
+    DEFINES["NVALGRIND"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1":
+
+    DEFINES["DYNAMIC_ANNOTATIONS_ENABLED"] = "1"
+
+if CONFIG["OS_TARGET"] == "Android":
+
+    DEFINES["ANDROID"] = True
+    DEFINES["ANDROID_NDK_VERSION_ROLL"] = "r22_1"
+    DEFINES["HAVE_SYS_UIO_H"] = True
+    DEFINES["WEBRTC_ANDROID"] = True
+    DEFINES["WEBRTC_ANDROID_OPENSLES"] = True
+    DEFINES["WEBRTC_LINUX"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_GNU_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+if CONFIG["OS_TARGET"] == "Darwin":
+
+    DEFINES["WEBRTC_MAC"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_LIBCPP_HAS_NO_ALIGNED_ALLOCATION"] = True
+    DEFINES["__ASSERT_MACROS_DEFINE_VERSIONS_WITHOUT_UNDERSCORES"] = "0"
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+if CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["USE_AURA"] = "1"
+    DEFINES["USE_GLIB"] = "1"
+    DEFINES["USE_NSS_CERTS"] = "1"
+    DEFINES["USE_OZONE"] = "1"
+    DEFINES["USE_UDEV"] = True
+    DEFINES["WEBRTC_LINUX"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_FILE_OFFSET_BITS"] = "64"
+    DEFINES["_LARGEFILE64_SOURCE"] = True
+    DEFINES["_LARGEFILE_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+if CONFIG["OS_TARGET"] == "OpenBSD":
+
+    DEFINES["USE_GLIB"] = "1"
+    DEFINES["USE_OZONE"] = "1"
+    DEFINES["USE_X11"] = "1"
+    DEFINES["WEBRTC_BSD"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_FILE_OFFSET_BITS"] = "64"
+    DEFINES["_LARGEFILE64_SOURCE"] = True
+    DEFINES["_LARGEFILE_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+if CONFIG["OS_TARGET"] == "WINNT":
+
+    DEFINES["CERT_CHAIN_PARA_HAS_EXTRA_FIELDS"] = True
+    DEFINES["NOMINMAX"] = True
+    DEFINES["NTDDI_VERSION"] = "0x0A000000"
+    DEFINES["PSAPI_VERSION"] = "2"
+    DEFINES["UNICODE"] = True
+    DEFINES["USE_AURA"] = "1"
+    DEFINES["WEBRTC_WIN"] = True
+    DEFINES["WIN32"] = True
+    DEFINES["WIN32_LEAN_AND_MEAN"] = True
+    DEFINES["WINAPI_FAMILY"] = "WINAPI_FAMILY_DESKTOP_APP"
+    DEFINES["WINVER"] = "0x0A00"
+    DEFINES["_ATL_NO_OPENGL"] = True
+    DEFINES["_CRT_RAND_S"] = True
+    DEFINES["_CRT_SECURE_NO_DEPRECATE"] = True
+    DEFINES["_ENABLE_EXTENDED_ALIGNED_STORAGE"] = True
+    DEFINES["_HAS_EXCEPTIONS"] = "0"
+    DEFINES["_HAS_NODISCARD"] = True
+    DEFINES["_SCL_SECURE_NO_DEPRECATE"] = True
+    DEFINES["_SECURE_ATL"] = True
+    DEFINES["_UNICODE"] = True
+    DEFINES["_WIN32_WINNT"] = "0x0A00"
+    DEFINES["_WINDOWS"] = True
+    DEFINES["__STD_C"] = True
+
+if CONFIG["CPU_ARCH"] == "aarch64":
+
+    DEFINES["WEBRTC_ARCH_ARM64"] = True
+    DEFINES["WEBRTC_HAS_NEON"] = True
+
+if CONFIG["CPU_ARCH"] == "arm":
+
+    CXXFLAGS += [
+        "-mfpu=neon"
+    ]
+
+    DEFINES["WEBRTC_ARCH_ARM"] = True
+    DEFINES["WEBRTC_ARCH_ARM_V7"] = True
+    DEFINES["WEBRTC_HAS_NEON"] = True
+
+if CONFIG["CPU_ARCH"] == "mips32":
+
+    DEFINES["MIPS32_LE"] = True
+    DEFINES["MIPS_FPU_LE"] = True
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "mips64":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86":
+
+    DEFINES["WEBRTC_ENABLE_AVX2"] = True
+
+if CONFIG["CPU_ARCH"] == "x86_64":
+
+    DEFINES["WEBRTC_ENABLE_AVX2"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Android":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Darwin":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "OpenBSD":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "WINNT":
+
+    DEFINES["_HAS_ITERATOR_DEBUGGING"] = "0"
+
+if CONFIG["MOZ_X11"] == "1" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["USE_X11"] = "1"
+
+if CONFIG["CPU_ARCH"] == "arm" and CONFIG["OS_TARGET"] == "Android":
+
+    OS_LIBS += [
+        "android_support",
+        "unwind"
+    ]
+
+if CONFIG["CPU_ARCH"] == "x86" and CONFIG["OS_TARGET"] == "Android":
+
+    CXXFLAGS += [
+        "-msse2"
+    ]
+
+    OS_LIBS += [
+        "android_support"
+    ]
+
+if CONFIG["CPU_ARCH"] == "aarch64" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "arm" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86" and CONFIG["OS_TARGET"] == "Linux":
+
+    CXXFLAGS += [
+        "-msse2"
+    ]
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86_64" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+Library("version_gn")
diff --git a/third_party/libwebrtc/call/video_receive_stream.cc b/third_party/libwebrtc/call/video_receive_stream.cc
new file mode 100644
index 0000000000..838dfcf135
--- /dev/null
+++ b/third_party/libwebrtc/call/video_receive_stream.cc
@@ -0,0 +1,162 @@
+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/video_receive_stream.h"
+
+#include "rtc_base/strings/string_builder.h"
+
+namespace webrtc {
+
+VideoReceiveStreamInterface::Decoder::Decoder(SdpVideoFormat video_format,
+                                              int payload_type)
+    : video_format(std::move(video_format)), payload_type(payload_type) {}
+VideoReceiveStreamInterface::Decoder::Decoder() : video_format("Unset") {}
+VideoReceiveStreamInterface::Decoder::Decoder(const Decoder&) = default;
+VideoReceiveStreamInterface::Decoder::~Decoder() = default;
+
+bool VideoReceiveStreamInterface::Decoder::operator==(
+    const Decoder& other) const {
+  return payload_type == other.payload_type &&
+         video_format == other.video_format;
+}
+
+std::string VideoReceiveStreamInterface::Decoder::ToString() const {
+  char buf[1024];
+  rtc::SimpleStringBuilder ss(buf);
+  ss << "{payload_type: " << payload_type;
+  ss << ", payload_name: " << video_format.name;
+  ss << ", codec_params: {";
+  for (auto it = video_format.parameters.begin();
+       it != video_format.parameters.end(); ++it) {
+    if (it != video_format.parameters.begin()) {
+      ss << ", ";
+    }
+    ss << it->first << ": " << it->second;
+  }
+  ss << '}';
+  ss << '}';
+
+  return ss.str();
+}
+
+VideoReceiveStreamInterface::Stats::Stats() = default;
+VideoReceiveStreamInterface::Stats::~Stats() = default;
+
+std::string VideoReceiveStreamInterface::Stats::ToString(
+    int64_t time_ms) const {
+  char buf[2048];
+  rtc::SimpleStringBuilder ss(buf);
+  ss << "VideoReceiveStreamInterface stats: " << time_ms << ", {ssrc: " << ssrc
+     << ", ";
+  ss << "total_bps: " << total_bitrate_bps << ", ";
+  ss << "width: " << width << ", ";
+  ss << "height: " << height << ", ";
+  ss << "key: " << frame_counts.key_frames << ", ";
+  ss << "delta: " << frame_counts.delta_frames << ", ";
+  ss << "frames_dropped: " << frames_dropped << ", ";
+  ss << "network_fps: " << network_frame_rate << ", ";
+  ss << "decode_fps: " << decode_frame_rate << ", ";
+  ss << "render_fps: " << render_frame_rate << ", ";
+  ss << "decode_ms: " << decode_ms << ", ";
+  ss << "max_decode_ms: " << max_decode_ms << ", ";
+  ss << "first_frame_received_to_decoded_ms: "
+     << first_frame_received_to_decoded_ms << ", ";
+  ss << "cur_delay_ms: " << current_delay_ms << ", ";
+  ss << "targ_delay_ms: " << target_delay_ms << ", ";
+  ss << "jb_delay_ms: " << jitter_buffer_ms << ", ";
+  ss << "jb_cumulative_delay_seconds: " << jitter_buffer_delay_seconds << ", ";
+  ss << "jb_emitted_count: " << jitter_buffer_emitted_count << ", ";
+  ss << "min_playout_delay_ms: " << min_playout_delay_ms << ", ";
+  ss << "sync_offset_ms: " << sync_offset_ms << ", ";
+  ss << "cum_loss: " << rtp_stats.packets_lost << ", ";
+  ss << "nack: " << rtcp_packet_type_counts.nack_packets << ", ";
+  ss << "fir: " << rtcp_packet_type_counts.fir_packets << ", ";
+  ss << "pli: " << rtcp_packet_type_counts.pli_packets;
+  ss << '}';
+  return ss.str();
+}
+
+VideoReceiveStreamInterface::Config::Config(const Config&) = default;
+VideoReceiveStreamInterface::Config::Config(Config&&) = default;
+VideoReceiveStreamInterface::Config::Config(
+    Transport* rtcp_send_transport,
+    VideoDecoderFactory* decoder_factory)
+    : decoder_factory(decoder_factory),
+      rtcp_send_transport(rtcp_send_transport) {}
+
+VideoReceiveStreamInterface::Config&
+VideoReceiveStreamInterface::Config::operator=(Config&&) = default;
+VideoReceiveStreamInterface::Config::Config::~Config() = default;
+
+std::string VideoReceiveStreamInterface::Config::ToString() const {
+  char buf[4 * 1024];
+  rtc::SimpleStringBuilder ss(buf);
+  ss << "{decoders: [";
+  for (size_t i = 0; i < decoders.size(); ++i) {
+    ss << decoders[i].ToString();
+    if (i != decoders.size() - 1)
+      ss << ", ";
+  }
+  ss << ']';
+  ss << ", rtp: " << rtp.ToString();
+  ss << ", renderer: " << (renderer ? "(renderer)" : "nullptr");
+  ss << ", render_delay_ms: " << render_delay_ms;
+  if (!sync_group.empty())
+    ss << ", sync_group: " << sync_group;
+  ss << '}';
+
+  return ss.str();
+}
+
+VideoReceiveStreamInterface::Config::Rtp::Rtp() = default;
+VideoReceiveStreamInterface::Config::Rtp::Rtp(const Rtp&) = default;
+VideoReceiveStreamInterface::Config::Rtp::~Rtp() = default;
+
+std::string VideoReceiveStreamInterface::Config::Rtp::ToString() const {
+  char buf[2 * 1024];
+  rtc::SimpleStringBuilder ss(buf);
+  ss << "{remote_ssrc: " << remote_ssrc;
+  ss << ", local_ssrc: " << local_ssrc;
+  ss << ", rtcp_mode: "
+     << (rtcp_mode == RtcpMode::kCompound ? "RtcpMode::kCompound"
+                                          : "RtcpMode::kReducedSize");
+  ss << ", rtcp_xr: ";
+  ss << "{receiver_reference_time_report: "
+     << (rtcp_xr.receiver_reference_time_report ? "on" : "off");
+  ss << '}';
+  ss << ", lntf: {enabled: " << (lntf.enabled ? "true" : "false") << '}';
+  ss << ", nack: {rtp_history_ms: " << nack.rtp_history_ms << '}';
+  ss << ", ulpfec_payload_type: " << ulpfec_payload_type;
+  ss << ", red_type: " << red_payload_type;
+  ss << ", rtx_ssrc: " << rtx_ssrc;
+  ss << ", rtx_payload_types: {";
+  for (auto& kv : rtx_associated_payload_types) {
+    ss << kv.first << " (pt) -> " << kv.second << " (apt), ";
+  }
+  ss << '}';
+  ss << ", raw_payload_types: {";
+  for (const auto& pt : raw_payload_types) {
+    ss << pt << ", ";
+  }
+  ss << '}';
+  ss << ", extensions: [";
+  for (size_t i = 0; i < extensions.size(); ++i) {
+    ss << extensions[i].ToString();
+    if (i != extensions.size() - 1)
+      ss << ", ";
+  }
+  ss << ']';
+  ss << ", rtcp_event_observer: "
+     << (rtcp_event_observer ? "(rtcp_event_observer)" : "nullptr");
+  ss << '}';
+  return ss.str();
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/video_receive_stream.h b/third_party/libwebrtc/call/video_receive_stream.h
new file mode 100644
index 0000000000..1ab4a2a85b
--- /dev/null
+++ b/third_party/libwebrtc/call/video_receive_stream.h
@@ -0,0 +1,335 @@
+/*
+ *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_VIDEO_RECEIVE_STREAM_H_
+#define CALL_VIDEO_RECEIVE_STREAM_H_
+
+#include <limits>
+#include <map>
+#include <set>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "api/call/transport.h"
+#include "modules/rtp_rtcp/include/rtp_rtcp_defines.h"
+#include "api/crypto/crypto_options.h"
+#include "api/rtp_headers.h"
+#include "api/rtp_parameters.h"
+#include "api/video/recordable_encoded_frame.h"
+#include "api/video/video_content_type.h"
+#include "api/video/video_frame.h"
+#include "api/video/video_sink_interface.h"
+#include "api/video/video_timing.h"
+#include "api/video_codecs/sdp_video_format.h"
+#include "call/receive_stream.h"
+#include "call/rtp_config.h"
+#include "common_video/frame_counts.h"
+#include "modules/rtp_rtcp/include/rtcp_statistics.h"
+#include "modules/rtp_rtcp/include/rtp_rtcp_defines.h"
+
+namespace webrtc {
+
+class RtpPacketSinkInterface;
+class VideoDecoderFactory;
+
+class VideoReceiveStreamInterface : public MediaReceiveStreamInterface {
+ public:
+  // Class for handling moving in/out recording state.
+  struct RecordingState {
+    RecordingState() = default;
+    explicit RecordingState(
+        std::function<void(const RecordableEncodedFrame&)> callback)
+        : callback(std::move(callback)) {}
+
+    // Callback stored from the VideoReceiveStreamInterface. The
+    // VideoReceiveStreamInterface client should not interpret the attribute.
+    std::function<void(const RecordableEncodedFrame&)> callback;
+    // Memento of when a keyframe request was last sent. The
+    // VideoReceiveStreamInterface client should not interpret the attribute.
+    absl::optional<int64_t> last_keyframe_request_ms;
+  };
+
+  // TODO(mflodman) Move all these settings to VideoDecoder and move the
+  // declaration to common_types.h.
+  struct Decoder {
+    Decoder(SdpVideoFormat video_format, int payload_type);
+    Decoder();
+    Decoder(const Decoder&);
+    ~Decoder();
+
+    bool operator==(const Decoder& other) const;
+
+    std::string ToString() const;
+
+    SdpVideoFormat video_format;
+
+    // Received RTP packets with this payload type will be sent to this decoder
+    // instance.
+    int payload_type = 0;
+  };
+
+  struct Stats {
+    Stats();
+    ~Stats();
+    std::string ToString(int64_t time_ms) const;
+
+    int network_frame_rate = 0;
+    int decode_frame_rate = 0;
+    int render_frame_rate = 0;
+    uint32_t frames_rendered = 0;
+
+    // Decoder stats.
+    std::string decoder_implementation_name = "unknown";
+    absl::optional<bool> power_efficient_decoder;
+    FrameCounts frame_counts;
+    int decode_ms = 0;
+    int max_decode_ms = 0;
+    int current_delay_ms = 0;
+    int target_delay_ms = 0;
+    int jitter_buffer_ms = 0;
+    // https://w3c.github.io/webrtc-stats/#dom-rtcvideoreceiverstats-jitterbufferdelay
+    double jitter_buffer_delay_seconds = 0;
+    // https://w3c.github.io/webrtc-stats/#dom-rtcvideoreceiverstats-jitterbufferemittedcount
+    uint64_t jitter_buffer_emitted_count = 0;
+    int min_playout_delay_ms = 0;
+    int render_delay_ms = 10;
+    int64_t interframe_delay_max_ms = -1;
+    // Frames dropped due to decoding failures or if the system is too slow.
+    // https://www.w3.org/TR/webrtc-stats/#dom-rtcvideoreceiverstats-framesdropped
+    uint32_t frames_dropped = 0;
+    uint32_t frames_decoded = 0;
+    // https://w3c.github.io/webrtc-stats/#dom-rtcreceivedrtpstreamstats-packetsdiscarded
+    uint64_t packets_discarded = 0;
+    // https://w3c.github.io/webrtc-stats/#dom-rtcinboundrtpstreamstats-totaldecodetime
+    TimeDelta total_decode_time = TimeDelta::Zero();
+    // https://w3c.github.io/webrtc-stats/#dom-rtcinboundrtpstreamstats-totalprocessingdelay
+    TimeDelta total_processing_delay = TimeDelta::Zero();
+    // TODO(bugs.webrtc.org/13986): standardize
+    TimeDelta total_assembly_time = TimeDelta::Zero();
+    uint32_t frames_assembled_from_multiple_packets = 0;
+    // Total inter frame delay in seconds.
+    // https://w3c.github.io/webrtc-stats/#dom-rtcinboundrtpstreamstats-totalinterframedelay
+    double total_inter_frame_delay = 0;
+    // Total squared inter frame delay in seconds^2.
+    // https://w3c.github.io/webrtc-stats/#dom-rtcinboundrtpstreamstats-totalsqauredinterframedelay
+    double total_squared_inter_frame_delay = 0;
+    int64_t first_frame_received_to_decoded_ms = -1;
+    absl::optional<uint64_t> qp_sum;
+
+    int current_payload_type = -1;
+
+    int total_bitrate_bps = 0;
+
+    int width = 0;
+    int height = 0;
+
+    uint32_t freeze_count = 0;
+    uint32_t pause_count = 0;
+    uint32_t total_freezes_duration_ms = 0;
+    uint32_t total_pauses_duration_ms = 0;
+
+    VideoContentType content_type = VideoContentType::UNSPECIFIED;
+
+    // https://w3c.github.io/webrtc-stats/#dom-rtcinboundrtpstreamstats-estimatedplayouttimestamp
+    absl::optional<int64_t> estimated_playout_ntp_timestamp_ms;
+    int sync_offset_ms = std::numeric_limits<int>::max();
+
+    uint32_t ssrc = 0;
+    std::string c_name;
+    RtpReceiveStats rtp_stats;
+    RtcpPacketTypeCounter rtcp_packet_type_counts;
+
+    // Mozilla modification: Init these.
+    uint32_t rtcp_sender_packets_sent = 0;
+    uint32_t rtcp_sender_octets_sent = 0;
+    int64_t rtcp_sender_ntp_timestamp_ms = 0;
+    int64_t rtcp_sender_remote_ntp_timestamp_ms = 0;
+
+    // Timing frame info: all important timestamps for a full lifetime of a
+    // single 'timing frame'.
+    absl::optional<webrtc::TimingFrameInfo> timing_frame_info;
+  };
+
+  struct Config {
+   private:
+    // Access to the copy constructor is private to force use of the Copy()
+    // method for those exceptional cases where we do use it.
+    Config(const Config&);
+
+   public:
+    Config() = delete;
+    Config(Config&&);
+    Config(Transport* rtcp_send_transport,
+           VideoDecoderFactory* decoder_factory = nullptr);
+    Config& operator=(Config&&);
+    Config& operator=(const Config&) = delete;
+    ~Config();
+
+    // Mostly used by tests.  Avoid creating copies if you can.
+    Config Copy() const { return Config(*this); }
+
+    std::string ToString() const;
+
+    // Decoders for every payload that we can receive.
+    std::vector<Decoder> decoders;
+
+    // Ownership stays with WebrtcVideoEngine (delegated from PeerConnection).
+    VideoDecoderFactory* decoder_factory = nullptr;
+
+    // Receive-stream specific RTP settings.
+    struct Rtp : public ReceiveStreamRtpConfig {
+      Rtp();
+      Rtp(const Rtp&);
+      ~Rtp();
+      std::string ToString() const;
+
+      // See NackConfig for description.
+      NackConfig nack;
+
+      // See RtcpMode for description.
+      RtcpMode rtcp_mode = RtcpMode::kCompound;
+
+      // Extended RTCP settings.
+      struct RtcpXr {
+        // True if RTCP Receiver Reference Time Report Block extension
+        // (RFC 3611) should be enabled.
+        bool receiver_reference_time_report = false;
+      } rtcp_xr;
+
+      // How to request keyframes from a remote sender. Applies only if lntf is
+      // disabled.
+      KeyFrameReqMethod keyframe_method = KeyFrameReqMethod::kPliRtcp;
+
+      // See draft-alvestrand-rmcat-remb for information.
+      bool remb = false;
+
+      bool tmmbr = false;
+
+      // See LntfConfig for description.
+      LntfConfig lntf;
+
+      // Payload types for ULPFEC and RED, respectively.
+      int ulpfec_payload_type = -1;
+      int red_payload_type = -1;
+
+      // SSRC for retransmissions.
+      uint32_t rtx_ssrc = 0;
+
+      // Set if the stream is protected using FlexFEC.
+      bool protected_by_flexfec = false;
+
+      // Optional callback sink to support additional packet handlers such as
+      // FlexFec.
+      RtpPacketSinkInterface* packet_sink_ = nullptr;
+
+      // Map from rtx payload type -> media payload type.
+      // For RTX to be enabled, both an SSRC and this mapping are needed.
+      std::map<int, int> rtx_associated_payload_types;
+
+      // Payload types that should be depacketized using raw depacketizer
+      // (payload header will not be parsed and must not be present, additional
+      // meta data is expected to be present in generic frame descriptor
+      // RTP header extension).
+      std::set<int> raw_payload_types;
+
+      RtcpEventObserver* rtcp_event_observer = nullptr;
+    } rtp;
+
+    // Transport for outgoing packets (RTCP).
+    Transport* rtcp_send_transport = nullptr;
+
+    // Must always be set.
+    rtc::VideoSinkInterface<VideoFrame>* renderer = nullptr;
+
+    // Expected delay needed by the renderer, i.e. the frame will be delivered
+    // this many milliseconds, if possible, earlier than the ideal render time.
+    int render_delay_ms = 10;
+
+    // If false, pass frames on to the renderer as soon as they are
+    // available.
+    bool enable_prerenderer_smoothing = true;
+
+    // Identifier for an A/V synchronization group. Empty string to disable.
+    // TODO(pbos): Synchronize streams in a sync group, not just video streams
+    // to one of the audio streams.
+    std::string sync_group;
+
+    // An optional custom frame decryptor that allows the entire frame to be
+    // decrypted in whatever way the caller choses. This is not required by
+    // default.
+    rtc::scoped_refptr<webrtc::FrameDecryptorInterface> frame_decryptor;
+
+    // Per PeerConnection cryptography options.
+    CryptoOptions crypto_options;
+
+    rtc::scoped_refptr<webrtc::FrameTransformerInterface> frame_transformer;
+  };
+
+  // TODO(pbos): Add info on currently-received codec to Stats.
+  virtual Stats GetStats() const = 0;
+
+  // Sets a base minimum for the playout delay. Base minimum delay sets lower
+  // bound on minimum delay value determining lower bound on playout delay.
+  //
+  // Returns true if value was successfully set, false overwise.
+  virtual bool SetBaseMinimumPlayoutDelayMs(int delay_ms) = 0;
+
+  // Returns current value of base minimum delay in milliseconds.
+  virtual int GetBaseMinimumPlayoutDelayMs() const = 0;
+
+  // Sets and returns recording state. The old state is moved out
+  // of the video receive stream and returned to the caller, and `state`
+  // is moved in. If the state's callback is set, it will be called with
+  // recordable encoded frames as they arrive.
+  // If `generate_key_frame` is true, the method will generate a key frame.
+  // When the function returns, it's guaranteed that all old callouts
+  // to the returned callback has ceased.
+  // Note: the client should not interpret the returned state's attributes, but
+  // instead treat it as opaque data.
+  virtual RecordingState SetAndGetRecordingState(RecordingState state,
+                                                 bool generate_key_frame) = 0;
+
+  // Cause eventual generation of a key frame from the sender.
+  virtual void GenerateKeyFrame() = 0;
+
+  virtual void SetRtcpMode(RtcpMode mode) = 0;
+
+  // Sets or clears a flexfec RTP sink. This affects `rtp.packet_sink_` and
+  // `rtp.protected_by_flexfec` parts of the configuration. Must be called on
+  // the packet delivery thread.
+  // TODO(bugs.webrtc.org/11993): Packet delivery thread today means `worker
+  // thread` but will be `network thread`.
+  virtual void SetFlexFecProtection(RtpPacketSinkInterface* flexfec_sink) = 0;
+
+  // Turns on/off loss notifications. Must be called on the packet delivery
+  // thread.
+  virtual void SetLossNotificationEnabled(bool enabled) = 0;
+
+  // Modify `rtp.nack.rtp_history_ms` post construction. Setting this value
+  // to 0 disables nack.
+  // Must be called on the packet delivery thread.
+  virtual void SetNackHistory(TimeDelta history) = 0;
+
+  virtual void SetProtectionPayloadTypes(int red_payload_type,
+                                         int ulpfec_payload_type) = 0;
+
+  virtual void SetRtcpXr(Config::Rtp::RtcpXr rtcp_xr) = 0;
+
+  virtual void SetAssociatedPayloadTypes(
+      std::map<int, int> associated_payload_types) = 0;
+
+ protected:
+  virtual ~VideoReceiveStreamInterface() {}
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_VIDEO_RECEIVE_STREAM_H_
diff --git a/third_party/libwebrtc/call/video_send_stream.cc b/third_party/libwebrtc/call/video_send_stream.cc
new file mode 100644
index 0000000000..241d44a230
--- /dev/null
+++ b/third_party/libwebrtc/call/video_send_stream.cc
@@ -0,0 +1,129 @@
+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "call/video_send_stream.h"
+
+#include <utility>
+
+#include "api/crypto/frame_encryptor_interface.h"
+#include "rtc_base/strings/string_builder.h"
+#include "rtc_base/strings/string_format.h"
+
+namespace webrtc {
+
+namespace {
+
+const char* StreamTypeToString(VideoSendStream::StreamStats::StreamType type) {
+  switch (type) {
+    case VideoSendStream::StreamStats::StreamType::kMedia:
+      return "media";
+    case VideoSendStream::StreamStats::StreamType::kRtx:
+      return "rtx";
+    case VideoSendStream::StreamStats::StreamType::kFlexfec:
+      return "flexfec";
+  }
+  RTC_CHECK_NOTREACHED();
+}
+
+}  // namespace
+
+VideoSendStream::StreamStats::StreamStats() = default;
+VideoSendStream::StreamStats::~StreamStats() = default;
+
+std::string VideoSendStream::StreamStats::ToString() const {
+  char buf[1024];
+  rtc::SimpleStringBuilder ss(buf);
+  ss << "type: " << StreamTypeToString(type);
+  if (referenced_media_ssrc.has_value())
+    ss << " (for: " << referenced_media_ssrc.value() << ")";
+  ss << ", ";
+  ss << "width: " << width << ", ";
+  ss << "height: " << height << ", ";
+  ss << "key: " << frame_counts.key_frames << ", ";
+  ss << "delta: " << frame_counts.delta_frames << ", ";
+  ss << "total_bps: " << total_bitrate_bps << ", ";
+  ss << "retransmit_bps: " << retransmit_bitrate_bps << ", ";
+  ss << "avg_delay_ms: " << avg_delay_ms << ", ";
+  ss << "max_delay_ms: " << max_delay_ms << ", ";
+  if (report_block_data) {
+    ss << "cum_loss: " << report_block_data->report_block().packets_lost
+       << ", ";
+    ss << "max_ext_seq: "
+       << report_block_data->report_block().extended_highest_sequence_number
+       << ", ";
+  }
+  ss << "nack: " << rtcp_packet_type_counts.nack_packets << ", ";
+  ss << "fir: " << rtcp_packet_type_counts.fir_packets << ", ";
+  ss << "pli: " << rtcp_packet_type_counts.pli_packets;
+  return ss.str();
+}
+
+VideoSendStream::Stats::Stats() = default;
+VideoSendStream::Stats::~Stats() = default;
+
+std::string VideoSendStream::Stats::ToString(int64_t time_ms) const {
+  char buf[2048];
+  rtc::SimpleStringBuilder ss(buf);
+  ss << "VideoSendStream stats: " << time_ms << ", {";
+  ss << "input_fps: " << rtc::StringFormat("%.1f", input_frame_rate) << ", ";
+  ss << "encode_fps: " << encode_frame_rate << ", ";
+  ss << "encode_ms: " << avg_encode_time_ms << ", ";
+  ss << "encode_usage_perc: " << encode_usage_percent << ", ";
+  ss << "target_bps: " << target_media_bitrate_bps << ", ";
+  ss << "media_bps: " << media_bitrate_bps << ", ";
+  ss << "suspended: " << (suspended ? "true" : "false") << ", ";
+  ss << "bw_adapted_res: " << (bw_limited_resolution ? "true" : "false")
+     << ", ";
+  ss << "cpu_adapted_res: " << (cpu_limited_resolution ? "true" : "false")
+     << ", ";
+  ss << "bw_adapted_fps: " << (bw_limited_framerate ? "true" : "false") << ", ";
+  ss << "cpu_adapted_fps: " << (cpu_limited_framerate ? "true" : "false")
+     << ", ";
+  ss << "#cpu_adaptations: " << number_of_cpu_adapt_changes << ", ";
+  ss << "#quality_adaptations: " << number_of_quality_adapt_changes;
+  ss << '}';
+  for (const auto& substream : substreams) {
+    if (substream.second.type ==
+        VideoSendStream::StreamStats::StreamType::kMedia) {
+      ss << " {ssrc: " << substream.first << ", ";
+      ss << substream.second.ToString();
+      ss << '}';
+    }
+  }
+  return ss.str();
+}
+
+VideoSendStream::Config::Config(const Config&) = default;
+VideoSendStream::Config::Config(Config&&) = default;
+VideoSendStream::Config::Config(Transport* send_transport)
+    : rtp(),
+      encoder_settings(VideoEncoder::Capabilities(rtp.lntf.enabled)),
+      send_transport(send_transport) {}
+
+VideoSendStream::Config& VideoSendStream::Config::operator=(Config&&) = default;
+VideoSendStream::Config::Config::~Config() = default;
+
+std::string VideoSendStream::Config::ToString() const {
+  char buf[2 * 1024];
+  rtc::SimpleStringBuilder ss(buf);
+  ss << "{encoder_settings: { experiment_cpu_load_estimator: "
+     << (encoder_settings.experiment_cpu_load_estimator ? "on" : "off") << "}}";
+  ss << ", rtp: " << rtp.ToString();
+  ss << ", rtcp_report_interval_ms: " << rtcp_report_interval_ms;
+  ss << ", send_transport: " << (send_transport ? "(Transport)" : "nullptr");
+  ss << ", render_delay_ms: " << render_delay_ms;
+  ss << ", target_delay_ms: " << target_delay_ms;
+  ss << ", suspend_below_min_bitrate: "
+     << (suspend_below_min_bitrate ? "on" : "off");
+  ss << '}';
+  return ss.str();
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/call/video_send_stream.h b/third_party/libwebrtc/call/video_send_stream.h
new file mode 100644
index 0000000000..de18fc7b92
--- /dev/null
+++ b/third_party/libwebrtc/call/video_send_stream.h
@@ -0,0 +1,274 @@
+/*
+ *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef CALL_VIDEO_SEND_STREAM_H_
+#define CALL_VIDEO_SEND_STREAM_H_
+
+#include <stdint.h>
+
+#include <map>
+#include <string>
+#include <vector>
+
+#include "absl/types/optional.h"
+#include "api/adaptation/resource.h"
+#include "api/call/transport.h"
+#include "api/crypto/crypto_options.h"
+#include "api/frame_transformer_interface.h"
+#include "api/rtp_parameters.h"
+#include "api/rtp_sender_setparameters_callback.h"
+#include "api/scoped_refptr.h"
+#include "api/video/video_content_type.h"
+#include "api/video/video_frame.h"
+#include "api/video/video_sink_interface.h"
+#include "api/video/video_source_interface.h"
+#include "api/video/video_stream_encoder_settings.h"
+#include "api/video_codecs/scalability_mode.h"
+#include "call/rtp_config.h"
+#include "common_video/frame_counts.h"
+#include "common_video/include/quality_limitation_reason.h"
+#include "modules/rtp_rtcp/include/report_block_data.h"
+#include "modules/rtp_rtcp/include/rtcp_statistics.h"
+#include "modules/rtp_rtcp/include/rtp_rtcp_defines.h"
+#include "video/config/video_encoder_config.h"
+
+namespace webrtc {
+
+class FrameEncryptorInterface;
+
+class VideoSendStream {
+ public:
+  // Multiple StreamStats objects are present if simulcast is used (multiple
+  // kMedia streams) or if RTX or FlexFEC is negotiated. Multiple SVC layers, on
+  // the other hand, does not cause additional StreamStats.
+  struct StreamStats {
+    enum class StreamType {
+      // A media stream is an RTP stream for audio or video. Retransmissions and
+      // FEC is either sent over the same SSRC or negotiated to be sent over
+      // separate SSRCs, in which case separate StreamStats objects exist with
+      // references to this media stream's SSRC.
+      kMedia,
+      // RTX streams are streams dedicated to retransmissions. They have a
+      // dependency on a single kMedia stream: `referenced_media_ssrc`.
+      kRtx,
+      // FlexFEC streams are streams dedicated to FlexFEC. They have a
+      // dependency on a single kMedia stream: `referenced_media_ssrc`.
+      kFlexfec,
+    };
+
+    StreamStats();
+    ~StreamStats();
+
+    std::string ToString() const;
+
+    StreamType type = StreamType::kMedia;
+    // If `type` is kRtx or kFlexfec this value is present. The referenced SSRC
+    // is the kMedia stream that this stream is performing retransmissions or
+    // FEC for. If `type` is kMedia, this value is null.
+    absl::optional<uint32_t> referenced_media_ssrc;
+    FrameCounts frame_counts;
+    int width = 0;
+    int height = 0;
+    // TODO(holmer): Move bitrate_bps out to the webrtc::Call layer.
+    int total_bitrate_bps = 0;
+    int retransmit_bitrate_bps = 0;
+    // `avg_delay_ms` and `max_delay_ms` are only used in tests. Consider
+    // deleting.
+    int avg_delay_ms = 0;
+    int max_delay_ms = 0;
+    StreamDataCounters rtp_stats;
+    RtcpPacketTypeCounter rtcp_packet_type_counts;
+    // A snapshot of the most recent Report Block with additional data of
+    // interest to statistics. Used to implement RTCRemoteInboundRtpStreamStats.
+    absl::optional<ReportBlockData> report_block_data;
+    double encode_frame_rate = 0.0;
+    int frames_encoded = 0;
+    absl::optional<uint64_t> qp_sum;
+    uint64_t total_encode_time_ms = 0;
+    uint64_t total_encoded_bytes_target = 0;
+    uint32_t huge_frames_sent = 0;
+    absl::optional<ScalabilityMode> scalability_mode;
+  };
+
+  struct Stats {
+    Stats();
+    ~Stats();
+    std::string ToString(int64_t time_ms) const;
+    std::string encoder_implementation_name = "unknown";
+    double input_frame_rate = 0;
+    int encode_frame_rate = 0;
+    int avg_encode_time_ms = 0;
+    int encode_usage_percent = 0;
+    uint32_t frames_encoded = 0;
+    // https://w3c.github.io/webrtc-stats/#dom-rtcoutboundrtpstreamstats-totalencodetime
+    uint64_t total_encode_time_ms = 0;
+    // https://w3c.github.io/webrtc-stats/#dom-rtcoutboundrtpstreamstats-totalencodedbytestarget
+    uint64_t total_encoded_bytes_target = 0;
+    uint32_t frames = 0;
+    uint32_t frames_dropped_by_capturer = 0;
+    uint32_t frames_dropped_by_encoder_queue = 0;
+    uint32_t frames_dropped_by_rate_limiter = 0;
+    uint32_t frames_dropped_by_congestion_window = 0;
+    uint32_t frames_dropped_by_encoder = 0;
+    // Bitrate the encoder is currently configured to use due to bandwidth
+    // limitations.
+    int target_media_bitrate_bps = 0;
+    // Bitrate the encoder is actually producing.
+    int media_bitrate_bps = 0;
+    bool suspended = false;
+    bool bw_limited_resolution = false;
+    bool cpu_limited_resolution = false;
+    bool bw_limited_framerate = false;
+    bool cpu_limited_framerate = false;
+    // https://w3c.github.io/webrtc-stats/#dom-rtcoutboundrtpstreamstats-qualitylimitationreason
+    QualityLimitationReason quality_limitation_reason =
+        QualityLimitationReason::kNone;
+    // https://w3c.github.io/webrtc-stats/#dom-rtcoutboundrtpstreamstats-qualitylimitationdurations
+    std::map<QualityLimitationReason, int64_t> quality_limitation_durations_ms;
+    // https://w3c.github.io/webrtc-stats/#dom-rtcoutboundrtpstreamstats-qualitylimitationresolutionchanges
+    uint32_t quality_limitation_resolution_changes = 0;
+    // Total number of times resolution as been requested to be changed due to
+    // CPU/quality adaptation.
+    int number_of_cpu_adapt_changes = 0;
+    int number_of_quality_adapt_changes = 0;
+    bool has_entered_low_resolution = false;
+    std::map<uint32_t, StreamStats> substreams;
+    webrtc::VideoContentType content_type =
+        webrtc::VideoContentType::UNSPECIFIED;
+    uint32_t frames_sent = 0;
+    uint32_t huge_frames_sent = 0;
+    absl::optional<bool> power_efficient_encoder;
+  };
+
+  struct Config {
+   public:
+    Config() = delete;
+    Config(Config&&);
+    explicit Config(Transport* send_transport);
+
+    Config& operator=(Config&&);
+    Config& operator=(const Config&) = delete;
+
+    ~Config();
+
+    // Mostly used by tests.  Avoid creating copies if you can.
+    Config Copy() const { return Config(*this); }
+
+    std::string ToString() const;
+
+    RtpConfig rtp;
+
+    VideoStreamEncoderSettings encoder_settings;
+
+    // Time interval between RTCP report for video
+    int rtcp_report_interval_ms = 1000;
+
+    // Transport for outgoing packets.
+    Transport* send_transport = nullptr;
+
+    // Expected delay needed by the renderer, i.e. the frame will be delivered
+    // this many milliseconds, if possible, earlier than expected render time.
+    // Only valid if `local_renderer` is set.
+    int render_delay_ms = 0;
+
+    // Target delay in milliseconds. A positive value indicates this stream is
+    // used for streaming instead of a real-time call.
+    int target_delay_ms = 0;
+
+    // True if the stream should be suspended when the available bitrate fall
+    // below the minimum configured bitrate. If this variable is false, the
+    // stream may send at a rate higher than the estimated available bitrate.
+    bool suspend_below_min_bitrate = false;
+
+    // Enables periodic bandwidth probing in application-limited region.
+    bool periodic_alr_bandwidth_probing = false;
+
+    // An optional custom frame encryptor that allows the entire frame to be
+    // encrypted in whatever way the caller chooses. This is not required by
+    // default.
+    rtc::scoped_refptr<webrtc::FrameEncryptorInterface> frame_encryptor;
+
+    // An optional encoder selector provided by the user.
+    // Overrides VideoEncoderFactory::GetEncoderSelector().
+    // Owned by RtpSenderBase.
+    VideoEncoderFactory::EncoderSelectorInterface* encoder_selector = nullptr;
+
+    // Per PeerConnection cryptography options.
+    CryptoOptions crypto_options;
+
+    rtc::scoped_refptr<webrtc::FrameTransformerInterface> frame_transformer;
+
+   private:
+    // Access to the copy constructor is private to force use of the Copy()
+    // method for those exceptional cases where we do use it.
+    Config(const Config&);
+  };
+
+  // Updates the sending state for all simulcast layers that the video send
+  // stream owns. This can mean updating the activity one or for multiple
+  // layers. The ordering of active layers is the order in which the
+  // rtp modules are stored in the VideoSendStream.
+  // Note: This starts stream activity if it is inactive and one of the layers
+  // is active. This stops stream activity if it is active and all layers are
+  // inactive.
+  // `active_layers` should have the same size as the number of configured
+  // simulcast layers or one if only one rtp stream is used.
+  virtual void StartPerRtpStream(std::vector<bool> active_layers) = 0;
+
+  // Starts stream activity.
+  // When a stream is active, it can receive, process and deliver packets.
+  // Prefer to use StartPerRtpStream.
+  virtual void Start() = 0;
+
+  // Stops stream activity.
+  // When a stream is stopped, it can't receive, process or deliver packets.
+  virtual void Stop() = 0;
+
+  // Accessor for determining if the stream is active. This is an inexpensive
+  // call that must be made on the same thread as `Start()` and `Stop()` methods
+  // are called on and will return `true` iff activity has been started either
+  // via `Start()` or `StartPerRtpStream()`. If activity is either
+  // stopped or is in the process of being stopped as a result of a call to
+  // either `Stop()` or `StartPerRtpStream()` where all layers were
+  // deactivated, the return value will be `false`.
+  virtual bool started() = 0;
+
+  // If the resource is overusing, the VideoSendStream will try to reduce
+  // resolution or frame rate until no resource is overusing.
+  // TODO(https://crbug.com/webrtc/11565): When the ResourceAdaptationProcessor
+  // is moved to Call this method could be deleted altogether in favor of
+  // Call-level APIs only.
+  virtual void AddAdaptationResource(rtc::scoped_refptr<Resource> resource) = 0;
+  virtual std::vector<rtc::scoped_refptr<Resource>>
+  GetAdaptationResources() = 0;
+
+  virtual void SetSource(
+      rtc::VideoSourceInterface<webrtc::VideoFrame>* source,
+      const DegradationPreference& degradation_preference) = 0;
+
+  // Set which streams to send. Must have at least as many SSRCs as configured
+  // in the config. Encoder settings are passed on to the encoder instance along
+  // with the VideoStream settings.
+  virtual void ReconfigureVideoEncoder(VideoEncoderConfig config) = 0;
+
+  virtual void ReconfigureVideoEncoder(VideoEncoderConfig config,
+                                       SetParametersCallback callback) = 0;
+
+  virtual Stats GetStats() = 0;
+
+  virtual void GenerateKeyFrame(const std::vector<std::string>& rids) = 0;
+
+ protected:
+  virtual ~VideoSendStream() {}
+};
+
+}  // namespace webrtc
+
+#endif  // CALL_VIDEO_SEND_STREAM_H_
diff --git a/third_party/libwebrtc/call/video_stream_api_gn/moz.build b/third_party/libwebrtc/call/video_stream_api_gn/moz.build
new file mode 100644
index 0000000000..c441da8309
--- /dev/null
+++ b/third_party/libwebrtc/call/video_stream_api_gn/moz.build
@@ -0,0 +1,233 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+  ### This moz.build was AUTOMATICALLY GENERATED from a GN config,  ###
+  ### DO NOT edit it by hand.                                       ###
+
+COMPILE_FLAGS["OS_INCLUDES"] = []
+AllowCompilerWarnings()
+
+DEFINES["ABSL_ALLOCATOR_NOTHROW"] = "1"
+DEFINES["RTC_DAV1D_IN_INTERNAL_DECODER_FACTORY"] = True
+DEFINES["RTC_ENABLE_VP9"] = True
+DEFINES["WEBRTC_ENABLE_PROTOBUF"] = "0"
+DEFINES["WEBRTC_LIBRARY_IMPL"] = True
+DEFINES["WEBRTC_MOZILLA_BUILD"] = True
+DEFINES["WEBRTC_NON_STATIC_TRACE_EVENT_HANDLERS"] = "0"
+DEFINES["WEBRTC_STRICT_FIELD_TRIALS"] = "0"
+
+FINAL_LIBRARY = "webrtc"
+
+
+LOCAL_INCLUDES += [
+    "!/ipc/ipdl/_ipdlheaders",
+    "!/third_party/libwebrtc/gen",
+    "/ipc/chromium/src",
+    "/third_party/libwebrtc/",
+    "/third_party/libwebrtc/third_party/abseil-cpp/",
+    "/tools/profiler/public"
+]
+
+UNIFIED_SOURCES += [
+    "/third_party/libwebrtc/call/video_receive_stream.cc",
+    "/third_party/libwebrtc/call/video_send_stream.cc"
+]
+
+if not CONFIG["MOZ_DEBUG"]:
+
+    DEFINES["DYNAMIC_ANNOTATIONS_ENABLED"] = "0"
+    DEFINES["NDEBUG"] = True
+    DEFINES["NVALGRIND"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1":
+
+    DEFINES["DYNAMIC_ANNOTATIONS_ENABLED"] = "1"
+
+if CONFIG["OS_TARGET"] == "Android":
+
+    DEFINES["ANDROID"] = True
+    DEFINES["ANDROID_NDK_VERSION_ROLL"] = "r22_1"
+    DEFINES["HAVE_SYS_UIO_H"] = True
+    DEFINES["WEBRTC_ANDROID"] = True
+    DEFINES["WEBRTC_ANDROID_OPENSLES"] = True
+    DEFINES["WEBRTC_LINUX"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_GNU_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+    OS_LIBS += [
+        "log"
+    ]
+
+if CONFIG["OS_TARGET"] == "Darwin":
+
+    DEFINES["WEBRTC_MAC"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_LIBCPP_HAS_NO_ALIGNED_ALLOCATION"] = True
+    DEFINES["__ASSERT_MACROS_DEFINE_VERSIONS_WITHOUT_UNDERSCORES"] = "0"
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+if CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["USE_AURA"] = "1"
+    DEFINES["USE_GLIB"] = "1"
+    DEFINES["USE_NSS_CERTS"] = "1"
+    DEFINES["USE_OZONE"] = "1"
+    DEFINES["USE_UDEV"] = True
+    DEFINES["WEBRTC_LINUX"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_FILE_OFFSET_BITS"] = "64"
+    DEFINES["_LARGEFILE64_SOURCE"] = True
+    DEFINES["_LARGEFILE_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+    OS_LIBS += [
+        "rt"
+    ]
+
+if CONFIG["OS_TARGET"] == "OpenBSD":
+
+    DEFINES["USE_GLIB"] = "1"
+    DEFINES["USE_OZONE"] = "1"
+    DEFINES["USE_X11"] = "1"
+    DEFINES["WEBRTC_BSD"] = True
+    DEFINES["WEBRTC_POSIX"] = True
+    DEFINES["_FILE_OFFSET_BITS"] = "64"
+    DEFINES["_LARGEFILE64_SOURCE"] = True
+    DEFINES["_LARGEFILE_SOURCE"] = True
+    DEFINES["__STDC_CONSTANT_MACROS"] = True
+    DEFINES["__STDC_FORMAT_MACROS"] = True
+
+if CONFIG["OS_TARGET"] == "WINNT":
+
+    DEFINES["CERT_CHAIN_PARA_HAS_EXTRA_FIELDS"] = True
+    DEFINES["NOMINMAX"] = True
+    DEFINES["NTDDI_VERSION"] = "0x0A000000"
+    DEFINES["PSAPI_VERSION"] = "2"
+    DEFINES["UNICODE"] = True
+    DEFINES["USE_AURA"] = "1"
+    DEFINES["WEBRTC_WIN"] = True
+    DEFINES["WIN32"] = True
+    DEFINES["WIN32_LEAN_AND_MEAN"] = True
+    DEFINES["WINAPI_FAMILY"] = "WINAPI_FAMILY_DESKTOP_APP"
+    DEFINES["WINVER"] = "0x0A00"
+    DEFINES["_ATL_NO_OPENGL"] = True
+    DEFINES["_CRT_RAND_S"] = True
+    DEFINES["_CRT_SECURE_NO_DEPRECATE"] = True
+    DEFINES["_ENABLE_EXTENDED_ALIGNED_STORAGE"] = True
+    DEFINES["_HAS_EXCEPTIONS"] = "0"
+    DEFINES["_HAS_NODISCARD"] = True
+    DEFINES["_SCL_SECURE_NO_DEPRECATE"] = True
+    DEFINES["_SECURE_ATL"] = True
+    DEFINES["_UNICODE"] = True
+    DEFINES["_WIN32_WINNT"] = "0x0A00"
+    DEFINES["_WINDOWS"] = True
+    DEFINES["__STD_C"] = True
+
+    OS_LIBS += [
+        "crypt32",
+        "iphlpapi",
+        "secur32",
+        "winmm"
+    ]
+
+if CONFIG["CPU_ARCH"] == "aarch64":
+
+    DEFINES["WEBRTC_ARCH_ARM64"] = True
+    DEFINES["WEBRTC_HAS_NEON"] = True
+
+if CONFIG["CPU_ARCH"] == "arm":
+
+    CXXFLAGS += [
+        "-mfpu=neon"
+    ]
+
+    DEFINES["WEBRTC_ARCH_ARM"] = True
+    DEFINES["WEBRTC_ARCH_ARM_V7"] = True
+    DEFINES["WEBRTC_HAS_NEON"] = True
+
+if CONFIG["CPU_ARCH"] == "mips32":
+
+    DEFINES["MIPS32_LE"] = True
+    DEFINES["MIPS_FPU_LE"] = True
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "mips64":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86":
+
+    DEFINES["WEBRTC_ENABLE_AVX2"] = True
+
+if CONFIG["CPU_ARCH"] == "x86_64":
+
+    DEFINES["WEBRTC_ENABLE_AVX2"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Android":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Darwin":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "OpenBSD":
+
+    DEFINES["_DEBUG"] = True
+
+if CONFIG["MOZ_DEBUG"] == "1" and CONFIG["OS_TARGET"] == "WINNT":
+
+    DEFINES["_HAS_ITERATOR_DEBUGGING"] = "0"
+
+if CONFIG["MOZ_X11"] == "1" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["USE_X11"] = "1"
+
+if CONFIG["CPU_ARCH"] == "arm" and CONFIG["OS_TARGET"] == "Android":
+
+    OS_LIBS += [
+        "android_support",
+        "unwind"
+    ]
+
+if CONFIG["CPU_ARCH"] == "x86" and CONFIG["OS_TARGET"] == "Android":
+
+    CXXFLAGS += [
+        "-msse2"
+    ]
+
+    OS_LIBS += [
+        "android_support"
+    ]
+
+if CONFIG["CPU_ARCH"] == "aarch64" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "arm" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86" and CONFIG["OS_TARGET"] == "Linux":
+
+    CXXFLAGS += [
+        "-msse2"
+    ]
+
+    DEFINES["_GNU_SOURCE"] = True
+
+if CONFIG["CPU_ARCH"] == "x86_64" and CONFIG["OS_TARGET"] == "Linux":
+
+    DEFINES["_GNU_SOURCE"] = True
+
+Library("video_stream_api_gn")