Adding upstream version 124.0.1.upstream/124.0.1

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

1 files changed, 629 insertions, 0 deletions

diff --git a/third_party/libwebrtc/pc/peer_connection_simulcast_unittest.cc b/third_party/libwebrtc/pc/peer_connection_simulcast_unittest.cc
new file mode 100644
index 0000000000..6b6a96c473
--- /dev/null
+++ b/third_party/libwebrtc/pc/peer_connection_simulcast_unittest.cc
@@ -0,0 +1,629 @@
+/*
+ *  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 <algorithm>
+#include <iterator>
+#include <map>
+#include <memory>
+#include <ostream>  // no-presubmit-check TODO(webrtc:8982)
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "absl/algorithm/container.h"
+#include "absl/strings/match.h"
+#include "absl/strings/string_view.h"
+#include "api/audio/audio_mixer.h"
+#include "api/audio_codecs/builtin_audio_decoder_factory.h"
+#include "api/audio_codecs/builtin_audio_encoder_factory.h"
+#include "api/audio_codecs/opus_audio_decoder_factory.h"
+#include "api/audio_codecs/opus_audio_encoder_factory.h"
+#include "api/create_peerconnection_factory.h"
+#include "api/jsep.h"
+#include "api/media_types.h"
+#include "api/peer_connection_interface.h"
+#include "api/rtc_error.h"
+#include "api/rtp_parameters.h"
+#include "api/rtp_sender_interface.h"
+#include "api/rtp_transceiver_direction.h"
+#include "api/rtp_transceiver_interface.h"
+#include "api/scoped_refptr.h"
+#include "api/uma_metrics.h"
+#include "api/video/video_codec_constants.h"
+#include "api/video_codecs/video_decoder_factory_template.h"
+#include "api/video_codecs/video_decoder_factory_template_dav1d_adapter.h"
+#include "api/video_codecs/video_decoder_factory_template_libvpx_vp8_adapter.h"
+#include "api/video_codecs/video_decoder_factory_template_libvpx_vp9_adapter.h"
+#include "api/video_codecs/video_decoder_factory_template_open_h264_adapter.h"
+#include "api/video_codecs/video_encoder_factory_template.h"
+#include "api/video_codecs/video_encoder_factory_template_libaom_av1_adapter.h"
+#include "api/video_codecs/video_encoder_factory_template_libvpx_vp8_adapter.h"
+#include "api/video_codecs/video_encoder_factory_template_libvpx_vp9_adapter.h"
+#include "api/video_codecs/video_encoder_factory_template_open_h264_adapter.h"
+#include "media/base/media_constants.h"
+#include "media/base/rid_description.h"
+#include "media/base/stream_params.h"
+#include "modules/audio_device/include/audio_device.h"
+#include "modules/audio_processing/include/audio_processing.h"
+#include "pc/channel_interface.h"
+#include "pc/peer_connection_wrapper.h"
+#include "pc/sdp_utils.h"
+#include "pc/session_description.h"
+#include "pc/simulcast_description.h"
+#include "pc/test/fake_audio_capture_module.h"
+#include "pc/test/mock_peer_connection_observers.h"
+#include "pc/test/simulcast_layer_util.h"
+#include "rtc_base/checks.h"
+#include "rtc_base/gunit.h"
+#include "rtc_base/strings/string_builder.h"
+#include "rtc_base/thread.h"
+#include "rtc_base/unique_id_generator.h"
+#include "system_wrappers/include/metrics.h"
+#include "test/gmock.h"
+#include "test/gtest.h"
+
+using ::testing::Contains;
+using ::testing::Each;
+using ::testing::ElementsAre;
+using ::testing::ElementsAreArray;
+using ::testing::Eq;
+using ::testing::Field;
+using ::testing::IsEmpty;
+using ::testing::Le;
+using ::testing::Ne;
+using ::testing::Pair;
+using ::testing::Property;
+using ::testing::SizeIs;
+using ::testing::StartsWith;
+
+using cricket::MediaContentDescription;
+using cricket::RidDescription;
+using cricket::SimulcastDescription;
+using cricket::SimulcastLayer;
+using cricket::StreamParams;
+
+namespace cricket {
+
+std::ostream& operator<<(  // no-presubmit-check TODO(webrtc:8982)
+    std::ostream& os,      // no-presubmit-check TODO(webrtc:8982)
+    const SimulcastLayer& layer) {
+  if (layer.is_paused) {
+    os << "~";
+  }
+  return os << layer.rid;
+}
+
+}  // namespace cricket
+
+namespace {
+
+#if RTC_METRICS_ENABLED
+std::vector<SimulcastLayer> CreateLayers(int num_layers, bool active) {
+  rtc::UniqueStringGenerator rid_generator;
+  std::vector<std::string> rids;
+  for (int i = 0; i < num_layers; ++i) {
+    rids.push_back(rid_generator.GenerateString());
+  }
+  return webrtc::CreateLayers(rids, active);
+}
+#endif
+
+}  // namespace
+
+namespace webrtc {
+
+class PeerConnectionSimulcastTests : public ::testing::Test {
+ public:
+  PeerConnectionSimulcastTests()
+      : pc_factory_(CreatePeerConnectionFactory(
+            rtc::Thread::Current(),
+            rtc::Thread::Current(),
+            rtc::Thread::Current(),
+            FakeAudioCaptureModule::Create(),
+            CreateBuiltinAudioEncoderFactory(),
+            CreateBuiltinAudioDecoderFactory(),
+            std::make_unique<
+                VideoEncoderFactoryTemplate<LibvpxVp8EncoderTemplateAdapter,
+                                            LibvpxVp9EncoderTemplateAdapter,
+                                            OpenH264EncoderTemplateAdapter,
+                                            LibaomAv1EncoderTemplateAdapter>>(),
+            std::make_unique<
+                VideoDecoderFactoryTemplate<LibvpxVp8DecoderTemplateAdapter,
+                                            LibvpxVp9DecoderTemplateAdapter,
+                                            OpenH264DecoderTemplateAdapter,
+                                            Dav1dDecoderTemplateAdapter>>(),
+            nullptr,
+            nullptr)) {}
+
+  rtc::scoped_refptr<PeerConnectionInterface> CreatePeerConnection(
+      MockPeerConnectionObserver* observer) {
+    PeerConnectionInterface::RTCConfiguration config;
+    config.sdp_semantics = SdpSemantics::kUnifiedPlan;
+    PeerConnectionDependencies pcd(observer);
+    auto result =
+        pc_factory_->CreatePeerConnectionOrError(config, std::move(pcd));
+    EXPECT_TRUE(result.ok());
+    observer->SetPeerConnectionInterface(result.value().get());
+    return result.MoveValue();
+  }
+
+  std::unique_ptr<PeerConnectionWrapper> CreatePeerConnectionWrapper() {
+    auto observer = std::make_unique<MockPeerConnectionObserver>();
+    auto pc = CreatePeerConnection(observer.get());
+    return std::make_unique<PeerConnectionWrapper>(pc_factory_, pc,
+                                                   std::move(observer));
+  }
+
+  void ExchangeOfferAnswer(PeerConnectionWrapper* local,
+                           PeerConnectionWrapper* remote,
+                           const std::vector<SimulcastLayer>& answer_layers) {
+    auto offer = local->CreateOfferAndSetAsLocal();
+    // Remove simulcast as the second peer connection won't support it.
+    RemoveSimulcast(offer.get());
+    std::string err;
+    EXPECT_TRUE(remote->SetRemoteDescription(std::move(offer), &err)) << err;
+    auto answer = remote->CreateAnswerAndSetAsLocal();
+    // Setup the answer to look like a server response.
+    auto mcd_answer = answer->description()->contents()[0].media_description();
+    auto& receive_layers = mcd_answer->simulcast_description().receive_layers();
+    for (const SimulcastLayer& layer : answer_layers) {
+      receive_layers.AddLayer(layer);
+    }
+    EXPECT_TRUE(local->SetRemoteDescription(std::move(answer), &err)) << err;
+  }
+
+  rtc::scoped_refptr<RtpTransceiverInterface> AddTransceiver(
+      PeerConnectionWrapper* pc,
+      const std::vector<SimulcastLayer>& layers,
+      cricket::MediaType media_type = cricket::MEDIA_TYPE_VIDEO) {
+    auto init = CreateTransceiverInit(layers);
+    return pc->AddTransceiver(media_type, init);
+  }
+
+  void AddRequestToReceiveSimulcast(const std::vector<SimulcastLayer>& layers,
+                                    SessionDescriptionInterface* sd) {
+    auto mcd = sd->description()->contents()[0].media_description();
+    SimulcastDescription simulcast;
+    auto& receive_layers = simulcast.receive_layers();
+    for (const SimulcastLayer& layer : layers) {
+      receive_layers.AddLayer(layer);
+    }
+    mcd->set_simulcast_description(simulcast);
+  }
+
+  void ValidateTransceiverParameters(
+      rtc::scoped_refptr<RtpTransceiverInterface> transceiver,
+      const std::vector<SimulcastLayer>& layers) {
+    auto parameters = transceiver->sender()->GetParameters();
+    std::vector<SimulcastLayer> result_layers;
+    absl::c_transform(parameters.encodings, std::back_inserter(result_layers),
+                      [](const RtpEncodingParameters& encoding) {
+                        return SimulcastLayer(encoding.rid, !encoding.active);
+                      });
+    EXPECT_THAT(result_layers, ElementsAreArray(layers));
+  }
+
+ private:
+  rtc::scoped_refptr<PeerConnectionFactoryInterface> pc_factory_;
+};
+
+#if RTC_METRICS_ENABLED
+// This class is used to test the metrics emitted for simulcast.
+class PeerConnectionSimulcastMetricsTests
+    : public PeerConnectionSimulcastTests,
+      public ::testing::WithParamInterface<int> {
+ protected:
+  PeerConnectionSimulcastMetricsTests() { webrtc::metrics::Reset(); }
+};
+#endif
+
+// Validates that RIDs are supported arguments when adding a transceiver.
+TEST_F(PeerConnectionSimulcastTests, CanCreateTransceiverWithRid) {
+  auto pc = CreatePeerConnectionWrapper();
+  auto layers = CreateLayers({"f"}, true);
+  auto transceiver = AddTransceiver(pc.get(), layers);
+  ASSERT_TRUE(transceiver);
+  auto parameters = transceiver->sender()->GetParameters();
+  // Single RID should be removed.
+  EXPECT_THAT(parameters.encodings,
+              ElementsAre(Field("rid", &RtpEncodingParameters::rid, Eq(""))));
+}
+
+TEST_F(PeerConnectionSimulcastTests, CanCreateTransceiverWithSimulcast) {
+  auto pc = CreatePeerConnectionWrapper();
+  auto layers = CreateLayers({"f", "h", "q"}, true);
+  auto transceiver = AddTransceiver(pc.get(), layers);
+  ASSERT_TRUE(transceiver);
+  ValidateTransceiverParameters(transceiver, layers);
+}
+
+TEST_F(PeerConnectionSimulcastTests, RidsAreAutogeneratedIfNotProvided) {
+  auto pc = CreatePeerConnectionWrapper();
+  auto init = CreateTransceiverInit(CreateLayers({"f", "h", "q"}, true));
+  for (RtpEncodingParameters& parameters : init.send_encodings) {
+    parameters.rid = "";
+  }
+  auto transceiver = pc->AddTransceiver(cricket::MEDIA_TYPE_VIDEO, init);
+  auto parameters = transceiver->sender()->GetParameters();
+  ASSERT_EQ(3u, parameters.encodings.size());
+  EXPECT_THAT(parameters.encodings,
+              Each(Field("rid", &RtpEncodingParameters::rid, Ne(""))));
+}
+
+// Validates that an error is returned when there is a mix of supplied and not
+// supplied RIDs in a call to AddTransceiver.
+TEST_F(PeerConnectionSimulcastTests, MustSupplyAllOrNoRidsInSimulcast) {
+  auto pc_wrapper = CreatePeerConnectionWrapper();
+  auto pc = pc_wrapper->pc();
+  // Cannot create a layer with empty RID. Remove the RID after init is created.
+  auto layers = CreateLayers({"f", "h", "remove"}, true);
+  auto init = CreateTransceiverInit(layers);
+  init.send_encodings[2].rid = "";
+  auto error = pc->AddTransceiver(cricket::MEDIA_TYPE_VIDEO, init);
+  EXPECT_EQ(RTCErrorType::INVALID_PARAMETER, error.error().type());
+}
+
+// Validates that an error is returned when illegal RIDs are supplied.
+TEST_F(PeerConnectionSimulcastTests, ChecksForIllegalRidValues) {
+  auto pc_wrapper = CreatePeerConnectionWrapper();
+  auto pc = pc_wrapper->pc();
+  auto layers = CreateLayers({"f", "h", "~q"}, true);
+  auto init = CreateTransceiverInit(layers);
+  auto error = pc->AddTransceiver(cricket::MEDIA_TYPE_VIDEO, init);
+  EXPECT_EQ(RTCErrorType::INVALID_PARAMETER, error.error().type());
+}
+
+// Validates that a single RID is removed from the encoding layer.
+TEST_F(PeerConnectionSimulcastTests, SingleRidIsRemovedFromSessionDescription) {
+  auto pc = CreatePeerConnectionWrapper();
+  auto transceiver = AddTransceiver(pc.get(), CreateLayers({"1"}, true));
+  auto offer = pc->CreateOfferAndSetAsLocal();
+  ASSERT_TRUE(offer);
+  auto contents = offer->description()->contents();
+  ASSERT_EQ(1u, contents.size());
+  EXPECT_THAT(contents[0].media_description()->streams(),
+              ElementsAre(Property(&StreamParams::has_rids, false)));
+}
+
+TEST_F(PeerConnectionSimulcastTests, SimulcastLayersRemovedFromTail) {
+  static_assert(
+      kMaxSimulcastStreams < 8,
+      "Test assumes that the platform does not allow 8 simulcast layers");
+  auto pc = CreatePeerConnectionWrapper();
+  auto layers = CreateLayers({"1", "2", "3", "4", "5", "6", "7", "8"}, true);
+  std::vector<SimulcastLayer> expected_layers;
+  std::copy_n(layers.begin(), kMaxSimulcastStreams,
+              std::back_inserter(expected_layers));
+  auto transceiver = AddTransceiver(pc.get(), layers);
+  ValidateTransceiverParameters(transceiver, expected_layers);
+}
+
+// Checks that an offfer to send simulcast contains a SimulcastDescription.
+TEST_F(PeerConnectionSimulcastTests, SimulcastAppearsInSessionDescription) {
+  auto pc = CreatePeerConnectionWrapper();
+  std::vector<std::string> rids({"f", "h", "q"});
+  auto layers = CreateLayers(rids, true);
+  auto transceiver = AddTransceiver(pc.get(), layers);
+  auto offer = pc->CreateOffer();
+  ASSERT_TRUE(offer);
+  auto contents = offer->description()->contents();
+  ASSERT_EQ(1u, contents.size());
+  auto content = contents[0];
+  auto mcd = content.media_description();
+  ASSERT_TRUE(mcd->HasSimulcast());
+  auto simulcast = mcd->simulcast_description();
+  EXPECT_THAT(simulcast.receive_layers(), IsEmpty());
+  // The size is validated separately because GetAllLayers() flattens the list.
+  EXPECT_THAT(simulcast.send_layers(), SizeIs(3));
+  std::vector<SimulcastLayer> result = simulcast.send_layers().GetAllLayers();
+  EXPECT_THAT(result, ElementsAreArray(layers));
+  auto streams = mcd->streams();
+  ASSERT_EQ(1u, streams.size());
+  auto stream = streams[0];
+  EXPECT_FALSE(stream.has_ssrcs());
+  EXPECT_TRUE(stream.has_rids());
+  std::vector<std::string> result_rids;
+  absl::c_transform(stream.rids(), std::back_inserter(result_rids),
+                    [](const RidDescription& rid) { return rid.rid; });
+  EXPECT_THAT(result_rids, ElementsAreArray(rids));
+}
+
+// Checks that Simulcast layers propagate to the sender parameters.
+TEST_F(PeerConnectionSimulcastTests, SimulcastLayersAreSetInSender) {
+  auto local = CreatePeerConnectionWrapper();
+  auto remote = CreatePeerConnectionWrapper();
+  auto layers = CreateLayers({"f", "h", "q"}, true);
+  auto transceiver = AddTransceiver(local.get(), layers);
+  auto offer = local->CreateOfferAndSetAsLocal();
+  {
+    SCOPED_TRACE("after create offer");
+    ValidateTransceiverParameters(transceiver, layers);
+  }
+  // Remove simulcast as the second peer connection won't support it.
+  auto simulcast = RemoveSimulcast(offer.get());
+  std::string error;
+  EXPECT_TRUE(remote->SetRemoteDescription(std::move(offer), &error)) << error;
+  auto answer = remote->CreateAnswerAndSetAsLocal();
+
+  // Setup an answer that mimics a server accepting simulcast.
+  auto mcd_answer = answer->description()->contents()[0].media_description();
+  mcd_answer->mutable_streams().clear();
+  auto simulcast_layers = simulcast.send_layers().GetAllLayers();
+  auto& receive_layers = mcd_answer->simulcast_description().receive_layers();
+  for (const auto& layer : simulcast_layers) {
+    receive_layers.AddLayer(layer);
+  }
+  EXPECT_TRUE(local->SetRemoteDescription(std::move(answer), &error)) << error;
+  {
+    SCOPED_TRACE("after set remote");
+    ValidateTransceiverParameters(transceiver, layers);
+  }
+}
+
+// Checks that paused Simulcast layers propagate to the sender parameters.
+TEST_F(PeerConnectionSimulcastTests, PausedSimulcastLayersAreDisabledInSender) {
+  auto local = CreatePeerConnectionWrapper();
+  auto remote = CreatePeerConnectionWrapper();
+  auto layers = CreateLayers({"f", "h", "q"}, {true, false, true});
+  auto server_layers = CreateLayers({"f", "h", "q"}, {true, false, false});
+  RTC_DCHECK_EQ(layers.size(), server_layers.size());
+  auto transceiver = AddTransceiver(local.get(), layers);
+  auto offer = local->CreateOfferAndSetAsLocal();
+  {
+    SCOPED_TRACE("after create offer");
+    ValidateTransceiverParameters(transceiver, layers);
+  }
+
+  // Remove simulcast as the second peer connection won't support it.
+  RemoveSimulcast(offer.get());
+  std::string error;
+  EXPECT_TRUE(remote->SetRemoteDescription(std::move(offer), &error)) << error;
+  auto answer = remote->CreateAnswerAndSetAsLocal();
+
+  // Setup an answer that mimics a server accepting simulcast.
+  auto mcd_answer = answer->description()->contents()[0].media_description();
+  mcd_answer->mutable_streams().clear();
+  auto& receive_layers = mcd_answer->simulcast_description().receive_layers();
+  for (const SimulcastLayer& layer : server_layers) {
+    receive_layers.AddLayer(layer);
+  }
+  EXPECT_TRUE(local->SetRemoteDescription(std::move(answer), &error)) << error;
+  {
+    SCOPED_TRACE("after set remote");
+    ValidateTransceiverParameters(transceiver, server_layers);
+  }
+}
+
+// Checks that when Simulcast is not supported by the remote party, then all
+// the layers (except the first) are removed.
+TEST_F(PeerConnectionSimulcastTests, SimulcastRejectedRemovesExtraLayers) {
+  auto local = CreatePeerConnectionWrapper();
+  auto remote = CreatePeerConnectionWrapper();
+  auto layers = CreateLayers({"1", "2", "3", "4"}, true);
+  auto transceiver = AddTransceiver(local.get(), layers);
+  ExchangeOfferAnswer(local.get(), remote.get(), {});
+  auto parameters = transceiver->sender()->GetParameters();
+  // Should only have the first layer.
+  EXPECT_THAT(parameters.encodings,
+              ElementsAre(Field("rid", &RtpEncodingParameters::rid, Eq("1"))));
+}
+
+// Checks that if Simulcast is supported by remote party, but some layers are
+// rejected, then only rejected layers are removed from the sender.
+TEST_F(PeerConnectionSimulcastTests, RejectedSimulcastLayersAreDeactivated) {
+  auto local = CreatePeerConnectionWrapper();
+  auto remote = CreatePeerConnectionWrapper();
+  auto layers = CreateLayers({"1", "2", "3"}, true);
+  auto expected_layers = CreateLayers({"2", "3"}, true);
+  auto transceiver = AddTransceiver(local.get(), layers);
+  auto offer = local->CreateOfferAndSetAsLocal();
+  {
+    SCOPED_TRACE("after create offer");
+    ValidateTransceiverParameters(transceiver, layers);
+  }
+  // Remove simulcast as the second peer connection won't support it.
+  auto removed_simulcast = RemoveSimulcast(offer.get());
+  std::string error;
+  EXPECT_TRUE(remote->SetRemoteDescription(std::move(offer), &error)) << error;
+  auto answer = remote->CreateAnswerAndSetAsLocal();
+  auto mcd_answer = answer->description()->contents()[0].media_description();
+  // Setup the answer to look like a server response.
+  // Remove one of the layers to reject it in the answer.
+  auto simulcast_layers = removed_simulcast.send_layers().GetAllLayers();
+  simulcast_layers.erase(simulcast_layers.begin());
+  auto& receive_layers = mcd_answer->simulcast_description().receive_layers();
+  for (const auto& layer : simulcast_layers) {
+    receive_layers.AddLayer(layer);
+  }
+  ASSERT_TRUE(mcd_answer->HasSimulcast());
+  EXPECT_TRUE(local->SetRemoteDescription(std::move(answer), &error)) << error;
+  {
+    SCOPED_TRACE("after set remote");
+    ValidateTransceiverParameters(transceiver, expected_layers);
+  }
+}
+
+// Checks that simulcast is set up correctly when the server sends an offer
+// requesting to receive simulcast.
+TEST_F(PeerConnectionSimulcastTests, ServerSendsOfferToReceiveSimulcast) {
+  auto local = CreatePeerConnectionWrapper();
+  auto remote = CreatePeerConnectionWrapper();
+  auto layers = CreateLayers({"f", "h", "q"}, true);
+  AddTransceiver(local.get(), layers);
+  auto offer = local->CreateOfferAndSetAsLocal();
+  // Remove simulcast as a sender and set it up as a receiver.
+  RemoveSimulcast(offer.get());
+  AddRequestToReceiveSimulcast(layers, offer.get());
+  std::string error;
+  EXPECT_TRUE(remote->SetRemoteDescription(std::move(offer), &error)) << error;
+  auto transceiver = remote->pc()->GetTransceivers()[0];
+  transceiver->SetDirectionWithError(RtpTransceiverDirection::kSendRecv);
+  EXPECT_TRUE(remote->CreateAnswerAndSetAsLocal());
+  ValidateTransceiverParameters(transceiver, layers);
+}
+
+// Checks that SetRemoteDescription doesn't attempt to associate a transceiver
+// when simulcast is requested by the server.
+TEST_F(PeerConnectionSimulcastTests, TransceiverIsNotRecycledWithSimulcast) {
+  auto local = CreatePeerConnectionWrapper();
+  auto remote = CreatePeerConnectionWrapper();
+  auto layers = CreateLayers({"f", "h", "q"}, true);
+  AddTransceiver(local.get(), layers);
+  auto offer = local->CreateOfferAndSetAsLocal();
+  // Remove simulcast as a sender and set it up as a receiver.
+  RemoveSimulcast(offer.get());
+  AddRequestToReceiveSimulcast(layers, offer.get());
+  // Call AddTrack so that a transceiver is created.
+  remote->AddVideoTrack("fake_track");
+  std::string error;
+  EXPECT_TRUE(remote->SetRemoteDescription(std::move(offer), &error)) << error;
+  auto transceivers = remote->pc()->GetTransceivers();
+  ASSERT_EQ(2u, transceivers.size());
+  auto transceiver = transceivers[1];
+  transceiver->SetDirectionWithError(RtpTransceiverDirection::kSendRecv);
+  EXPECT_TRUE(remote->CreateAnswerAndSetAsLocal());
+  ValidateTransceiverParameters(transceiver, layers);
+}
+
+// Checks that if the number of layers changes during negotiation, then any
+// outstanding get/set parameters transaction is invalidated.
+TEST_F(PeerConnectionSimulcastTests, ParametersAreInvalidatedWhenLayersChange) {
+  auto local = CreatePeerConnectionWrapper();
+  auto remote = CreatePeerConnectionWrapper();
+  auto layers = CreateLayers({"1", "2", "3"}, true);
+  auto transceiver = AddTransceiver(local.get(), layers);
+  auto parameters = transceiver->sender()->GetParameters();
+  ASSERT_EQ(3u, parameters.encodings.size());
+  // Response will reject simulcast altogether.
+  ExchangeOfferAnswer(local.get(), remote.get(), {});
+  auto result = transceiver->sender()->SetParameters(parameters);
+  EXPECT_EQ(RTCErrorType::INVALID_STATE, result.type());
+}
+
+// Checks that even though negotiation modifies the sender's parameters, an
+// outstanding get/set parameters transaction is not invalidated.
+// This test negotiates twice because initial parameters before negotiation
+// is missing critical information and cannot be set on the sender.
+TEST_F(PeerConnectionSimulcastTests,
+       NegotiationDoesNotInvalidateParameterTransactions) {
+  auto local = CreatePeerConnectionWrapper();
+  auto remote = CreatePeerConnectionWrapper();
+  auto layers = CreateLayers({"1", "2", "3"}, true);
+  auto expected_layers = CreateLayers({"1", "2", "3"}, false);
+  auto transceiver = AddTransceiver(local.get(), layers);
+  ExchangeOfferAnswer(local.get(), remote.get(), expected_layers);
+
+  // Verify that negotiation does not invalidate the parameters.
+  auto parameters = transceiver->sender()->GetParameters();
+  ExchangeOfferAnswer(local.get(), remote.get(), expected_layers);
+
+  auto result = transceiver->sender()->SetParameters(parameters);
+  EXPECT_TRUE(result.ok());
+  ValidateTransceiverParameters(transceiver, expected_layers);
+}
+
+// Tests that a simulcast answer is rejected if the RID extension is not
+// negotiated.
+TEST_F(PeerConnectionSimulcastTests, NegotiationDoesNotHaveRidExtensionFails) {
+  auto local = CreatePeerConnectionWrapper();
+  auto remote = CreatePeerConnectionWrapper();
+  auto layers = CreateLayers({"1", "2", "3"}, true);
+  auto expected_layers = CreateLayers({"1"}, true);
+  auto transceiver = AddTransceiver(local.get(), layers);
+  auto offer = local->CreateOfferAndSetAsLocal();
+  // Remove simulcast as the second peer connection won't support it.
+  RemoveSimulcast(offer.get());
+  std::string err;
+  EXPECT_TRUE(remote->SetRemoteDescription(std::move(offer), &err)) << err;
+  auto answer = remote->CreateAnswerAndSetAsLocal();
+  // Setup the answer to look like a server response.
+  // Drop the RID header extension.
+  auto mcd_answer = answer->description()->contents()[0].media_description();
+  auto& receive_layers = mcd_answer->simulcast_description().receive_layers();
+  for (const SimulcastLayer& layer : layers) {
+    receive_layers.AddLayer(layer);
+  }
+  cricket::RtpHeaderExtensions extensions;
+  for (auto extension : mcd_answer->rtp_header_extensions()) {
+    if (extension.uri != RtpExtension::kRidUri) {
+      extensions.push_back(extension);
+    }
+  }
+  mcd_answer->set_rtp_header_extensions(extensions);
+  EXPECT_EQ(layers.size(), mcd_answer->simulcast_description()
+                               .receive_layers()
+                               .GetAllLayers()
+                               .size());
+  EXPECT_FALSE(local->SetRemoteDescription(std::move(answer), &err)) << err;
+}
+
+TEST_F(PeerConnectionSimulcastTests, SimulcastAudioRejected) {
+  auto local = CreatePeerConnectionWrapper();
+  auto remote = CreatePeerConnectionWrapper();
+  auto layers = CreateLayers({"1", "2", "3", "4"}, true);
+  auto transceiver =
+      AddTransceiver(local.get(), layers, cricket::MEDIA_TYPE_AUDIO);
+  // Should only have the first layer.
+  auto parameters = transceiver->sender()->GetParameters();
+  EXPECT_EQ(1u, parameters.encodings.size());
+  EXPECT_THAT(parameters.encodings,
+              ElementsAre(Field("rid", &RtpEncodingParameters::rid, Eq(""))));
+  ExchangeOfferAnswer(local.get(), remote.get(), {});
+  // Still have a single layer after negotiation
+  parameters = transceiver->sender()->GetParameters();
+  EXPECT_EQ(1u, parameters.encodings.size());
+  EXPECT_THAT(parameters.encodings,
+              ElementsAre(Field("rid", &RtpEncodingParameters::rid, Eq(""))));
+}
+
+// Check that modifying the offer to remove simulcast and at the same
+// time leaving in a RID line does not cause an exception.
+TEST_F(PeerConnectionSimulcastTests, SimulcastSldModificationRejected) {
+  auto local = CreatePeerConnectionWrapper();
+  auto remote = CreatePeerConnectionWrapper();
+  auto layers = CreateLayers({"1", "2", "3"}, true);
+  AddTransceiver(local.get(), layers);
+  auto offer = local->CreateOffer();
+  std::string as_string;
+  EXPECT_TRUE(offer->ToString(&as_string));
+  auto simulcast_marker = "a=rid:3 send\r\na=simulcast:send 1;2;3\r\n";
+  auto pos = as_string.find(simulcast_marker);
+  EXPECT_NE(pos, std::string::npos);
+  as_string.erase(pos, strlen(simulcast_marker));
+  SdpParseError parse_error;
+  auto modified_offer =
+      CreateSessionDescription(SdpType::kOffer, as_string, &parse_error);
+  EXPECT_TRUE(modified_offer);
+  EXPECT_TRUE(local->SetLocalDescription(std::move(modified_offer)));
+}
+
+#if RTC_METRICS_ENABLED
+
+const int kMaxLayersInMetricsTest = 8;
+
+// Checks that the number of send encodings is logged in a metric.
+TEST_P(PeerConnectionSimulcastMetricsTests, NumberOfSendEncodingsIsLogged) {
+  auto local = CreatePeerConnectionWrapper();
+  auto num_layers = GetParam();
+  auto layers = ::CreateLayers(num_layers, true);
+  AddTransceiver(local.get(), layers);
+  EXPECT_EQ(1, metrics::NumSamples(
+                   "WebRTC.PeerConnection.Simulcast.NumberOfSendEncodings"));
+  EXPECT_EQ(1, metrics::NumEvents(
+                   "WebRTC.PeerConnection.Simulcast.NumberOfSendEncodings",
+                   num_layers));
+}
+
+INSTANTIATE_TEST_SUITE_P(NumberOfSendEncodings,
+                         PeerConnectionSimulcastMetricsTests,
+                         ::testing::Range(0, kMaxLayersInMetricsTest));
+#endif
+
+}  // namespace webrtc