Drop frames until specified bitrate is achieved.

webrtc/video/vie_encoder_unittest.cc

 /*
  *  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.
  */
 
@@ skipping 25 matching lines @@
 
 namespace webrtc {
 
 using DegredationPreference = VideoSendStream::DegradationPreference;
 using ScaleReason = ScalingObserverInterface::ScaleReason;
 using ::testing::_;
 using ::testing::Return;
 
 namespace {
 const size_t kMaxPayloadLength = 1440;
-const int kTargetBitrateBps = 100000;
+const int kTargetBitrateBps = 1000000;
+const int kLowTargetBitrateBps = kTargetBitrateBps / 10;
+const int kMaxInitialFramedrop = 4;
 
 class TestBuffer : public webrtc::I420Buffer {
  public:
   TestBuffer(rtc::Event* event, int width, int height)
       : I420Buffer(width, height), event_(event) {}
 
  private:
   friend class rtc::RefCountedObject<TestBuffer>;
   ~TestBuffer() override {
     if (event_)
@@ skipping 85 matching lines @@
 
   void ConfigureEncoder(VideoEncoderConfig video_encoder_config,
                         bool nack_enabled) {
     if (vie_encoder_)
       vie_encoder_->Stop();
     vie_encoder_.reset(new ViEEncoderUnderTest(
         stats_proxy_.get(), video_send_config_.encoder_settings));
     vie_encoder_->SetSink(&sink_, false /* rotation_applied */);
     vie_encoder_->SetSource(&video_source_,
                             VideoSendStream::DegradationPreference::kBalanced);
-    vie_encoder_->SetStartBitrate(10000);
+    vie_encoder_->SetStartBitrate(kTargetBitrateBps);
     vie_encoder_->ConfigureEncoder(std::move(video_encoder_config),
                                    kMaxPayloadLength, nack_enabled);
   }
 
   void ResetEncoder(const std::string& payload_name,
                     size_t num_streams,
                     size_t num_temporal_layers,
                     bool nack_enabled) {
     video_send_config_.encoder_settings.payload_name = payload_name;
 
     VideoEncoderConfig video_encoder_config;
     video_encoder_config.number_of_streams = num_streams;
-    video_encoder_config.max_bitrate_bps = 1000000;
+    video_encoder_config.max_bitrate_bps = kTargetBitrateBps;
     video_encoder_config.video_stream_factory =
         new rtc::RefCountedObject<VideoStreamFactory>(num_temporal_layers);
     ConfigureEncoder(std::move(video_encoder_config), nack_enabled);
   }
 
   VideoFrame CreateFrame(int64_t ntp_time_ms,
                          rtc::Event* destruction_event) const {
     VideoFrame frame(new rtc::RefCountedObject<TestBuffer>(
                          destruction_event, codec_width_, codec_height_),
                      99, 99, kVideoRotation_0);
@@ skipping 80 matching lines @@
     void WaitForEncodedFrame(int64_t expected_ntp_time) {
       uint32_t timestamp = 0;
       EXPECT_TRUE(encoded_frame_event_.Wait(kDefaultTimeoutMs));
       {
         rtc::CritScope lock(&crit_);
         timestamp = timestamp_;
       }
       test_encoder_->CheckLastTimeStampsMatch(expected_ntp_time, timestamp);
     }
 
+    void ExpectDroppedFrame() { EXPECT_FALSE(encoded_frame_event_.Wait(20)); }
+
     void SetExpectNoFrames() {
       rtc::CritScope lock(&crit_);
       expect_frames_ = false;
     }
 
     int number_of_reconfigurations() {
       rtc::CritScope lock(&crit_);
       return number_of_reconfigurations_;
     }
 
@@ skipping 396 matching lines @@
   sink_.WaitForEncodedFrame(3);
 
   stats = stats_proxy_->GetStats();
   EXPECT_FALSE(stats.cpu_limited_resolution);
   EXPECT_EQ(2, stats.number_of_cpu_adapt_changes);
 
   vie_encoder_->Stop();
 }
 
 TEST_F(ViEEncoderTest, SwitchingSourceKeepsCpuAdaptation) {
-  const int kTargetBitrateBps = 100000;
   vie_encoder_->OnBitrateUpdated(kTargetBitrateBps, 0, 0);
 
   int frame_width = 1280;
   int frame_height = 720;
   video_source_.IncomingCapturedFrame(
       CreateFrame(1, frame_width, frame_height));
   sink_.WaitForEncodedFrame(1);
 
   VideoSendStream::Stats stats = stats_proxy_->GetStats();
   EXPECT_FALSE(stats.cpu_limited_resolution);
@@ skipping 49 matching lines @@
       CreateFrame(6, frame_width, frame_height));
   sink_.WaitForEncodedFrame(6);
   stats = stats_proxy_->GetStats();
   EXPECT_FALSE(stats.cpu_limited_resolution);
   EXPECT_EQ(2, stats.number_of_cpu_adapt_changes);
 
   vie_encoder_->Stop();
 }
 
 TEST_F(ViEEncoderTest, SwitchingSourceKeepsQualityAdaptation) {
-  const int kTargetBitrateBps = 100000;
   vie_encoder_->OnBitrateUpdated(kTargetBitrateBps, 0, 0);
 
   int frame_width = 1280;
   int frame_height = 720;
   video_source_.IncomingCapturedFrame(
       CreateFrame(1, frame_width, frame_height));
   sink_.WaitForEncodedFrame(1);
 
   VideoSendStream::Stats stats = stats_proxy_->GetStats();
   EXPECT_FALSE(stats.cpu_limited_resolution);
@@ skipping 115 matching lines @@
   sink_.WaitForEncodedFrame(1);
 
   VideoSendStream::Stats stats = stats_proxy_->GetStats();
   EXPECT_EQ(video_encoder_config_.max_bitrate_bps,
             stats.preferred_media_bitrate_bps);
 
   vie_encoder_->Stop();
 }
 
 TEST_F(ViEEncoderTest, ScalingUpAndDownDoesNothingWithMaintainResolution) {
-  const int kTargetBitrateBps = 100000;
   int frame_width = 1280;
   int frame_height = 720;
   vie_encoder_->OnBitrateUpdated(kTargetBitrateBps, 0, 0);
 
   // Expect no scaling to begin with
   EXPECT_FALSE(video_source_.sink_wants().max_pixel_count);
   EXPECT_FALSE(video_source_.sink_wants().max_pixel_count_step_up);
 
   video_source_.IncomingCapturedFrame(
       CreateFrame(1, frame_width, frame_height));
@@ skipping 32 matching lines @@
       CreateFrame(4, frame_width, frame_height));
   sink_.WaitForEncodedFrame(4);
 
   // Expect nothing to change, still no scaling
   EXPECT_FALSE(new_video_source.sink_wants().max_pixel_count);
 
   vie_encoder_->Stop();
 }
 
 TEST_F(ViEEncoderTest, DoesNotScaleBelowSetLimit) {
-  const int kTargetBitrateBps = 100000;
   int frame_width = 1280;
   int frame_height = 720;
   vie_encoder_->OnBitrateUpdated(kTargetBitrateBps, 0, 0);
 
   for (size_t i = 1; i <= 10; i++) {
     video_source_.IncomingCapturedFrame(
         CreateFrame(i, frame_width, frame_height));
     sink_.WaitForEncodedFrame(i);
     // Trigger scale down
     vie_encoder_->TriggerQualityLow();
@@ skipping 36 matching lines @@
 TEST_F(ViEEncoderTest, CallsBitrateObserver) {
   class MockBitrateObserver : public VideoBitrateAllocationObserver {
    public:
     MOCK_METHOD1(OnBitrateAllocationUpdated, void(const BitrateAllocation&));
   } bitrate_observer;
   vie_encoder_->SetBitrateObserver(&bitrate_observer);
 
   const int kDefaultFps = 30;
   const BitrateAllocation expected_bitrate =
       DefaultVideoBitrateAllocator(fake_encoder_.codec_config())
-          .GetAllocation(kTargetBitrateBps, kDefaultFps);
+          .GetAllocation(kLowTargetBitrateBps, kDefaultFps);
 
   // First called on bitrate updated, then again on first frame.
   EXPECT_CALL(bitrate_observer, OnBitrateAllocationUpdated(expected_bitrate))
       .Times(2);
-  vie_encoder_->OnBitrateUpdated(kTargetBitrateBps, 0, 0);
+  vie_encoder_->OnBitrateUpdated(kLowTargetBitrateBps, 0, 0);
 
   const int64_t kStartTimeMs = 1;
   video_source_.IncomingCapturedFrame(
       CreateFrame(kStartTimeMs, codec_width_, codec_height_));
   sink_.WaitForEncodedFrame(kStartTimeMs);
 
   // Not called on second frame.
   EXPECT_CALL(bitrate_observer, OnBitrateAllocationUpdated(expected_bitrate))
       .Times(0);
   video_source_.IncomingCapturedFrame(
       CreateFrame(kStartTimeMs + 1, codec_width_, codec_height_));
   sink_.WaitForEncodedFrame(kStartTimeMs + 1);
 
   // Called after a process interval.
   const int64_t kProcessIntervalMs =
       vcm::VCMProcessTimer::kDefaultProcessIntervalMs;
   // TODO(sprang): ViEEncoder should die and/or get injectable clock.
   // Sleep for one processing interval plus one frame to avoid flakiness.
   SleepMs(kProcessIntervalMs + 1000 / kDefaultFps);
   EXPECT_CALL(bitrate_observer, OnBitrateAllocationUpdated(expected_bitrate))
       .Times(1);
   video_source_.IncomingCapturedFrame(CreateFrame(
       kStartTimeMs + kProcessIntervalMs, codec_width_, codec_height_));
   sink_.WaitForEncodedFrame(kStartTimeMs + kProcessIntervalMs);
 
   vie_encoder_->Stop();
 }
 
+TEST_F(ViEEncoderTest, DropsFramesAndScalesWhenBitrateIsTooLow) {
+  vie_encoder_->OnBitrateUpdated(kLowTargetBitrateBps, 0, 0);
+  int frame_width = 640;
+  int frame_height = 360;
+
+  video_source_.IncomingCapturedFrame(
+      CreateFrame(1, frame_width, frame_height));
+
+  // Expect to drop this frame, the wait should time out.
+  sink_.ExpectDroppedFrame();
+
+  // Expect the sink_wants to specify a scaled frame.
+  EXPECT_TRUE(video_source_.sink_wants().max_pixel_count);
+  EXPECT_LT(*video_source_.sink_wants().max_pixel_count, 1000 * 1000);
+
+  int last_pixel_count = *video_source_.sink_wants().max_pixel_count;
+
+  // Next frame is scaled
+  video_source_.IncomingCapturedFrame(
+      CreateFrame(2, frame_width * 3 / 4, frame_height * 3 / 4));
+
+  // Expect to drop this frame, the wait should time out.
+  sink_.ExpectDroppedFrame();
+
+  EXPECT_LT(*video_source_.sink_wants().max_pixel_count, last_pixel_count);
+
+  vie_encoder_->Stop();
+}
+
+TEST_F(ViEEncoderTest, NrOfDroppedFramesLimited) {
+  // 1kbps. This can never be achieved.
+  vie_encoder_->OnBitrateUpdated(1000, 0, 0);
+  int frame_width = 640;
+  int frame_height = 360;
+
+  // We expect the n initial frames to get dropped.
+  int i;
+  for (i = 1; i <= kMaxInitialFramedrop; ++i) {
+    video_source_.IncomingCapturedFrame(
+        CreateFrame(i, frame_width, frame_height));
+    sink_.ExpectDroppedFrame();
+  }
+  // The n+1th frame should not be dropped, even though it's size is too large.
+  video_source_.IncomingCapturedFrame(
+      CreateFrame(i, frame_width, frame_height));
+  sink_.WaitForEncodedFrame(i);
+
+  // Expect the sink_wants to specify a scaled frame.
+  EXPECT_TRUE(video_source_.sink_wants().max_pixel_count);
+  EXPECT_LT(*video_source_.sink_wants().max_pixel_count, 1000 * 1000);
+
+  vie_encoder_->Stop();
+}
+
+TEST_F(ViEEncoderTest, InitialFrameDropOffWithMaintainResolutionPreference) {
+  int frame_width = 640;
+  int frame_height = 360;
+  vie_encoder_->OnBitrateUpdated(kLowTargetBitrateBps, 0, 0);
+
+  // Set degradation preference.
+  vie_encoder_->SetSource(
+      &video_source_,
+      VideoSendStream::DegradationPreference::kMaintainResolution);
+
+  video_source_.IncomingCapturedFrame(
+      CreateFrame(1, frame_width, frame_height));
+  // Frame should not be dropped, even if it's too large.
+  sink_.WaitForEncodedFrame(1);
+
+  vie_encoder_->Stop();
+}
+
 }  // namespace webrtc