1 files changed, 101 insertions, 0 deletions
diff --git a/third_party/libwebrtc/video/adaptation/pixel_limit_resource.cc b/third_party/libwebrtc/video/adaptation/pixel_limit_resource.cc
new file mode 100644
index 0000000000..872e169879
--- /dev/null
+++ b/third_party/libwebrtc/video/adaptation/pixel_limit_resource.cc
@@ -0,0 +1,101 @@
+/*
+ *  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 "video/adaptation/pixel_limit_resource.h"
+
+#include "api/sequence_checker.h"
+#include "api/units/time_delta.h"
+#include "call/adaptation/video_stream_adapter.h"
+#include "rtc_base/checks.h"
+
+namespace webrtc {
+
+namespace {
+
+constexpr TimeDelta kResourceUsageCheckIntervalMs = TimeDelta::Seconds(5);
+
+}  // namespace
+
+// static
+rtc::scoped_refptr<PixelLimitResource> PixelLimitResource::Create(
+    TaskQueueBase* task_queue,
+    VideoStreamInputStateProvider* input_state_provider) {
+  return rtc::make_ref_counted<PixelLimitResource>(task_queue,
+                                                   input_state_provider);
+}
+
+PixelLimitResource::PixelLimitResource(
+    TaskQueueBase* task_queue,
+    VideoStreamInputStateProvider* input_state_provider)
+    : task_queue_(task_queue),
+      input_state_provider_(input_state_provider),
+      max_pixels_(absl::nullopt) {
+  RTC_DCHECK(task_queue_);
+  RTC_DCHECK(input_state_provider_);
+}
+
+PixelLimitResource::~PixelLimitResource() {
+  RTC_DCHECK(!listener_);
+  RTC_DCHECK(!repeating_task_.Running());
+}
+
+void PixelLimitResource::SetMaxPixels(int max_pixels) {
+  RTC_DCHECK_RUN_ON(task_queue_);
+  max_pixels_ = max_pixels;
+}
+
+void PixelLimitResource::SetResourceListener(ResourceListener* listener) {
+  RTC_DCHECK_RUN_ON(task_queue_);
+  listener_ = listener;
+  if (listener_) {
+    repeating_task_.Stop();
+    repeating_task_ = RepeatingTaskHandle::Start(task_queue_, [&] {
+      RTC_DCHECK_RUN_ON(task_queue_);
+      if (!listener_) {
+        // We don't have a listener so resource adaptation must not be running,
+        // try again later.
+        return kResourceUsageCheckIntervalMs;
+      }
+      if (!max_pixels_.has_value()) {
+        // No pixel limit configured yet, try again later.
+        return kResourceUsageCheckIntervalMs;
+      }
+      absl::optional<int> frame_size_pixels =
+          input_state_provider_->InputState().frame_size_pixels();
+      if (!frame_size_pixels.has_value()) {
+        // We haven't observed a frame yet so we don't know if it's going to be
+        // too big or too small, try again later.
+        return kResourceUsageCheckIntervalMs;
+      }
+      int current_pixels = frame_size_pixels.value();
+      int target_pixel_upper_bounds = max_pixels_.value();
+      // To avoid toggling, we allow any resolutions between
+      // `target_pixel_upper_bounds` and video_stream_adapter.h's
+      // GetLowerResolutionThan(). This is the pixels we end up if we adapt down
+      // from `target_pixel_upper_bounds`.
+      int target_pixels_lower_bounds =
+          GetLowerResolutionThan(target_pixel_upper_bounds);
+      if (current_pixels > target_pixel_upper_bounds) {
+        listener_->OnResourceUsageStateMeasured(
+            rtc::scoped_refptr<Resource>(this), ResourceUsageState::kOveruse);
+      } else if (current_pixels < target_pixels_lower_bounds) {
+        listener_->OnResourceUsageStateMeasured(
+            rtc::scoped_refptr<Resource>(this), ResourceUsageState::kUnderuse);
+      }
+      return kResourceUsageCheckIntervalMs;
+    });
+  } else {
+    repeating_task_.Stop();
+  }
+  // The task must be running if we have a listener.
+  RTC_DCHECK(repeating_task_.Running() || !listener_);
+}
+
+}  // namespace webrtc