Remove limit on how often quality scaling downscales.

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 567 matching lines @@
 TEST_F(ViEEncoderTest,
        ResolutionSinkWantsResetOnSetSourceWithDisabledResolutionScaling) {
   vie_encoder_->OnBitrateUpdated(kTargetBitrateBps, 0, 0);
 
   EXPECT_FALSE(video_source_.sink_wants().max_pixel_count);
   EXPECT_FALSE(video_source_.sink_wants().max_pixel_count_step_up);
 
   int frame_width = 1280;
   int frame_height = 720;
 
+  video_source_.IncomingCapturedFrame(
+      CreateFrame(1, frame_width, frame_height));
+  sink_.WaitForEncodedFrame(1);
   // Trigger CPU overuse.
   vie_encoder_->TriggerCpuOveruse();
 
   video_source_.IncomingCapturedFrame(
-      CreateFrame(1, frame_width, frame_height));
-  sink_.WaitForEncodedFrame(1);
+      CreateFrame(2, frame_width, frame_height));
+  sink_.WaitForEncodedFrame(2);
   EXPECT_LT(video_source_.sink_wants().max_pixel_count.value_or(
                 std::numeric_limits<int>::max()),
             frame_width * frame_height);
   EXPECT_FALSE(video_source_.sink_wants().max_pixel_count_step_up);
 
   // Set new source.
   test::FrameForwarder new_video_source;
   vie_encoder_->SetSource(
       &new_video_source,
       VideoSendStream::DegradationPreference::kMaintainResolution);
 
   EXPECT_FALSE(new_video_source.sink_wants().max_pixel_count);
   EXPECT_FALSE(new_video_source.sink_wants().max_pixel_count_step_up);
 
   new_video_source.IncomingCapturedFrame(
-      CreateFrame(2, frame_width, frame_height));
-  sink_.WaitForEncodedFrame(2);
+      CreateFrame(3, frame_width, frame_height));
+  sink_.WaitForEncodedFrame(3);
   EXPECT_FALSE(new_video_source.sink_wants().max_pixel_count);
   EXPECT_FALSE(new_video_source.sink_wants().max_pixel_count_step_up);
 
   // Calling SetSource with resolution scaling enabled apply the old SinkWants.
   vie_encoder_->SetSource(&new_video_source,
                           VideoSendStream::DegradationPreference::kBalanced);
   EXPECT_LT(new_video_source.sink_wants().max_pixel_count.value_or(
                 std::numeric_limits<int>::max()),
             frame_width * frame_height);
   EXPECT_FALSE(new_video_source.sink_wants().max_pixel_count_step_up);
@@ skipping 246 matching lines @@
 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);
 
-  // Trigger scale down
-  vie_encoder_->TriggerQualityLow();
   video_source_.IncomingCapturedFrame(
       CreateFrame(1, frame_width, frame_height));
   sink_.WaitForEncodedFrame(1);
 
+  // Trigger scale down
+  vie_encoder_->TriggerQualityLow();
+
+  video_source_.IncomingCapturedFrame(
+      CreateFrame(2, frame_width, frame_height));
+  sink_.WaitForEncodedFrame(2);
+
   // Expect a scale down.
   EXPECT_TRUE(video_source_.sink_wants().max_pixel_count);
   EXPECT_LT(*video_source_.sink_wants().max_pixel_count,
             frame_width * frame_height);
 
   // Set adaptation disabled.
   test::FrameForwarder new_video_source;
   vie_encoder_->SetSource(
       &new_video_source,
       VideoSendStream::DegradationPreference::kMaintainResolution);
 
   // Trigger scale down
   vie_encoder_->TriggerQualityLow();
   new_video_source.IncomingCapturedFrame(
-      CreateFrame(2, frame_width, frame_height));
-  sink_.WaitForEncodedFrame(2);
+      CreateFrame(3, frame_width, frame_height));
+  sink_.WaitForEncodedFrame(3);
 
   // Expect no scaling
   EXPECT_FALSE(new_video_source.sink_wants().max_pixel_count);
 
   // Trigger scale up
   vie_encoder_->TriggerQualityHigh();
   new_video_source.IncomingCapturedFrame(
-      CreateFrame(3, frame_width, frame_height));
-  sink_.WaitForEncodedFrame(3);
+      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;
+  // from vie_encoder.cc
+  const int kMinPixelsPerFrame = 120 * 90;
+  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();
+    EXPECT_GE(*video_source_.sink_wants().max_pixel_count, kMinPixelsPerFrame);
+  }
+
+  vie_encoder_->Stop();
+}
+
 TEST_F(ViEEncoderTest, UMACpuLimitedResolutionInPercent) {
   vie_encoder_->OnBitrateUpdated(kTargetBitrateBps, 0, 0);
 
   int frame_width = 640;
   int frame_height = 360;
 
   for (int i = 1; i <= SendStatisticsProxy::kMinRequiredMetricsSamples; ++i) {
     video_source_.IncomingCapturedFrame(
         CreateFrame(i, frame_width, frame_height));
     sink_.WaitForEncodedFrame(i);
@@ skipping 11 matching lines @@
   vie_encoder_->Stop();
 
   stats_proxy_.reset();
   EXPECT_EQ(1,
             metrics::NumSamples("WebRTC.Video.CpuLimitedResolutionInPercent"));
   EXPECT_EQ(
       1, metrics::NumEvents("WebRTC.Video.CpuLimitedResolutionInPercent", 50));
 }
 
 }  // namespace webrtc