[Adaptation] Move TriggerAdaptationDueToFrameDroppedDueToSize

It has no relevance in ResourceAdaptationProcessorInterface.
The logic moves to an interaction directly on the VideoStreamAdapter.

Bug: webrtc:11700
Change-Id: I4c7b3e1e1361722a69b71e8f9bde33f5909c011a
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/178380
Commit-Queue: Evan Shrubsole <eshr@google.com>
Reviewed-by: Henrik Boström <hbos@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#31634}

call/adaptation/resource_adaptation_processor.cc

@@ -390,26 +390,6 @@ ResourceAdaptationProcessor::OnResourceOveruse(
                                        message.Release());
 }
 
-void ResourceAdaptationProcessor::TriggerAdaptationDueToFrameDroppedDueToSize(
-    rtc::scoped_refptr<Resource> reason_resource) {
-  RTC_DCHECK_RUN_ON(resource_adaptation_queue_);
-  RTC_LOG(INFO) << "TriggerAdaptationDueToFrameDroppedDueToSize called";
-  VideoAdaptationCounters counters_before =
-      stream_adapter_->adaptation_counters();
-  OnResourceOveruse(reason_resource);
-  if (effective_degradation_preference_ == DegradationPreference::BALANCED &&
-      stream_adapter_->adaptation_counters().fps_adaptations >
-          counters_before.fps_adaptations) {
-    // Oops, we adapted frame rate. Adapt again, maybe it will adapt resolution!
-    // Though this is not guaranteed...
-    OnResourceOveruse(reason_resource);
-  }
-  if (stream_adapter_->adaptation_counters().resolution_adaptations >
-      counters_before.resolution_adaptations) {
-    encoder_stats_observer_->OnInitialQualityResolutionAdaptDown();
-  }
-}
-
 std::pair<std::vector<rtc::scoped_refptr<Resource>>,
           VideoStreamAdapter::RestrictionsWithCounters>
 ResourceAdaptationProcessor::FindMostLimitedResources() const {

call/adaptation/resource_adaptation_processor.h

@@ -96,12 +96,6 @@ class ResourceAdaptationProcessor : public ResourceAdaptationProcessorInterface,
   void OnDegradationPreferenceUpdated(
       DegradationPreference degradation_preference) override;
 
-  // May trigger 1-2 adaptations. It is meant to reduce resolution but this is
-  // not guaranteed. It may adapt frame rate, which does not address the issue.
-  // TODO(hbos): Can we get rid of this?
-  void TriggerAdaptationDueToFrameDroppedDueToSize(
-      rtc::scoped_refptr<Resource> reason_resource) 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

call/adaptation/resource_adaptation_processor_interface.h

@@ -72,15 +72,6 @@ class ResourceAdaptationProcessorInterface {
       AdaptationListener* adaptation_listener) = 0;
   virtual void RemoveAdaptationListener(
       AdaptationListener* adaptation_listener) = 0;
-
-  // May trigger one or more adaptations. It is meant to reduce resolution -
-  // useful if a frame was dropped due to its size - however, the implementation
-  // may not guarantee this (see resource_adaptation_processor.h).
-  // TODO(hbos): This is only part of the interface for backwards-compatiblity
-  // reasons. Can we replace this by something which actually satisfies the
-  // resolution constraints or get rid of it altogether?
-  virtual void TriggerAdaptationDueToFrameDroppedDueToSize(
-      rtc::scoped_refptr<Resource> reason_resource) = 0;
 };
 
 }  // namespace webrtc

call/adaptation/video_stream_adapter.cc

@@ -521,6 +521,49 @@ VideoStreamAdapter::RestrictionsOrState VideoStreamAdapter::IncreaseFramerate(
   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:
+    case DegradationPreference::MAINTAIN_RESOLUTION: {
+      return Adaptation(adaptation_validation_id_,
+                        Adaptation::Status::kLimitReached, input_state, false);
+    }
+    case DegradationPreference::MAINTAIN_FRAMERATE:
+      return GetAdaptationDown();
+    case DegradationPreference::BALANCED: {
+      return RestrictionsOrStateToAdaptation(
+          GetAdaptDownResolutionStepForBalanced(input_state), input_state);
+    }
+    default:
+      RTC_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);
+  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) {

call/adaptation/video_stream_adapter.h

@@ -145,6 +145,11 @@ class VideoStreamAdapter {
   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,
@@ -170,6 +175,9 @@ class VideoStreamAdapter {
   RestrictionsOrState GetAdaptationDownStep(
       const VideoStreamInputState& input_state) const
       RTC_RUN_ON(&sequence_checker_);
+  RestrictionsOrState GetAdaptDownResolutionStepForBalanced(
+      const VideoStreamInputState& input_state) const
+      RTC_RUN_ON(&sequence_checker_);
 
   Adaptation GetAdaptationUp(const VideoStreamInputState& input_state) const
       RTC_RUN_ON(&sequence_checker_);

call/adaptation/video_stream_adapter_unittest.cc

@@ -782,6 +782,82 @@ TEST_F(VideoStreamAdapterTest,
   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,
+    GetAdaptDownResolutionReturnsLimitReachedInDisabledAndMaintainResolution) {
+  adapter_.SetDegradationPreference(DegradationPreference::DISABLED);
+  input_state_provider_.SetInputState(1280 * 720, 30,
+                                      kDefaultMinPixelsPerFrame);
+  EXPECT_EQ(Adaptation::Status::kLimitReached,
+            adapter_.GetAdaptDownResolution().status());
+  adapter_.SetDegradationPreference(DegradationPreference::DISABLED);
+  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);
+}
+
 // Death tests.
 // Disabled on Android because death tests misbehave on Android, see
 // base/test/gtest_util.h.

video/adaptation/video_stream_encoder_resource_manager.cc

@@ -445,8 +445,11 @@ void VideoStreamEncoderResourceManager::OnFrameDroppedDueToSize() {
       // happens if the processor is destroyed. No action needed.
       return;
     }
-    adaptation_processor_->TriggerAdaptationDueToFrameDroppedDueToSize(
+    Adaptation reduce_resolution = stream_adapter_->GetAdaptDownResolution();
+    if (reduce_resolution.status() == Adaptation::Status::kValid) {
+      stream_adapter_->ApplyAdaptation(reduce_resolution,
                                        quality_scaler_resource_);
+    }
   });
   initial_frame_dropper_->OnFrameDroppedDueToSize();
 }