webrtc/modules/video_coding/utility/quality_scaler_unittest.cc - platform/external/webrtc - Git at Google

 /*
  *  Copyright (c) 2014 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 "webrtc/modules/video_coding/utility/include/quality_scaler.h"

 #include "testing/gtest/include/gtest/gtest.h"

 namespace webrtc {
 namespace {
 static const int kNumSeconds = 10;
 static const int kWidth = 1920;
 static const int kHalfWidth = kWidth / 2;
 static const int kHeight = 1080;
 static const int kFramerate = 30;
 static const int kLowQp = 15;
 static const int kNormalQp = 30;
 static const int kMaxQp = 56;
 }  // namespace

 class QualityScalerTest : public ::testing::Test {
  public:
   // Temporal and spatial resolution.
   struct Resolution {
     int framerate;
     int width;
     int height;
   };
  protected:
   enum ScaleDirection { kScaleDown, kScaleUp };
   enum BadQualityMetric { kDropFrame, kReportLowQP };

   QualityScalerTest() {
     input_frame_.CreateEmptyFrame(
         kWidth, kHeight, kWidth, kHalfWidth, kHalfWidth);
     qs_.Init(kMaxQp / QualityScaler::kDefaultLowQpDenominator, false);
     qs_.ReportFramerate(kFramerate);
     qs_.OnEncodeFrame(input_frame_);
   }

   bool TriggerScale(ScaleDirection scale_direction) {
     qs_.OnEncodeFrame(input_frame_);
     int initial_width = qs_.GetScaledResolution().width;
     for (int i = 0; i < kFramerate * kNumSeconds; ++i) {
       switch (scale_direction) {
         case kScaleUp:
           qs_.ReportQP(kLowQp);
           break;
         case kScaleDown:
           qs_.ReportDroppedFrame();
           break;
       }
       qs_.OnEncodeFrame(input_frame_);
       if (qs_.GetScaledResolution().width != initial_width)
         return true;
     }

     return false;
   }

   void ExpectOriginalFrame() {
     EXPECT_EQ(&input_frame_, &qs_.GetScaledFrame(input_frame_))
         << "Using scaled frame instead of original input.";
   }

   void ExpectScaleUsingReportedResolution() {
     qs_.OnEncodeFrame(input_frame_);
     QualityScaler::Resolution res = qs_.GetScaledResolution();
     const VideoFrame& scaled_frame = qs_.GetScaledFrame(input_frame_);
     EXPECT_EQ(res.width, scaled_frame.width());
     EXPECT_EQ(res.height, scaled_frame.height());
   }

   void ContinuouslyDownscalesByHalfDimensionsAndBackUp();

   void DoesNotDownscaleFrameDimensions(int width, int height);

   Resolution TriggerResolutionChange(BadQualityMetric dropframe_lowqp,
                                      int num_second,
                                      int initial_framerate);

   void VerifyQualityAdaptation(int initial_framerate, int seconds,
                                bool expect_spatial_resize,
                                bool expect_framerate_reduction);

   void DownscaleEndsAt(int input_width,
                        int input_height,
                        int end_width,
                        int end_height);

   QualityScaler qs_;
   VideoFrame input_frame_;
 };

 TEST_F(QualityScalerTest, UsesOriginalFrameInitially) {
   ExpectOriginalFrame();
 }

 TEST_F(QualityScalerTest, ReportsOriginalResolutionInitially) {
   qs_.OnEncodeFrame(input_frame_);
   QualityScaler::Resolution res = qs_.GetScaledResolution();
   EXPECT_EQ(input_frame_.width(), res.width);
   EXPECT_EQ(input_frame_.height(), res.height);
 }

 TEST_F(QualityScalerTest, DownscalesAfterContinuousFramedrop) {
   EXPECT_TRUE(TriggerScale(kScaleDown)) << "No downscale within " << kNumSeconds
                                         << " seconds.";
   QualityScaler::Resolution res = qs_.GetScaledResolution();
   EXPECT_LT(res.width, input_frame_.width());
   EXPECT_LT(res.height, input_frame_.height());
 }

 TEST_F(QualityScalerTest, DownscalesAfterTwoThirdsFramedrop) {
   for (int i = 0; i < kFramerate * kNumSeconds / 3; ++i) {
     qs_.ReportQP(kNormalQp);
     qs_.ReportDroppedFrame();
     qs_.ReportDroppedFrame();
     qs_.OnEncodeFrame(input_frame_);
     if (qs_.GetScaledResolution().width < input_frame_.width())
       return;
   }

   FAIL() << "No downscale within " << kNumSeconds << " seconds.";
 }

 TEST_F(QualityScalerTest, DoesNotDownscaleOnNormalQp) {
   for (int i = 0; i < kFramerate * kNumSeconds; ++i) {
     qs_.ReportQP(kNormalQp);
     qs_.OnEncodeFrame(input_frame_);
     ASSERT_EQ(input_frame_.width(), qs_.GetScaledResolution().width)
         << "Unexpected scale on half framedrop.";
   }
 }

 TEST_F(QualityScalerTest, DoesNotDownscaleAfterHalfFramedrop) {
   for (int i = 0; i < kFramerate * kNumSeconds / 2; ++i) {
     qs_.ReportQP(kNormalQp);
     qs_.OnEncodeFrame(input_frame_);
     ASSERT_EQ(input_frame_.width(), qs_.GetScaledResolution().width)
         << "Unexpected scale on half framedrop.";

     qs_.ReportDroppedFrame();
     qs_.OnEncodeFrame(input_frame_);
     ASSERT_EQ(input_frame_.width(), qs_.GetScaledResolution().width)
         << "Unexpected scale on half framedrop.";
   }
 }

 void QualityScalerTest::ContinuouslyDownscalesByHalfDimensionsAndBackUp() {
   const int initial_min_dimension = input_frame_.width() < input_frame_.height()
                                   ? input_frame_.width()
                                   : input_frame_.height();
   int min_dimension = initial_min_dimension;
   int current_shift = 0;
   // Drop all frames to force-trigger downscaling.
   while (min_dimension >= 2 * QualityScaler::kDefaultMinDownscaleDimension) {
     EXPECT_TRUE(TriggerScale(kScaleDown)) << "No downscale within "
                                           << kNumSeconds << " seconds.";
     qs_.OnEncodeFrame(input_frame_);
     QualityScaler::Resolution res = qs_.GetScaledResolution();
     min_dimension = res.width < res.height ? res.width : res.height;
     ++current_shift;
     ASSERT_EQ(input_frame_.width() >> current_shift, res.width);
     ASSERT_EQ(input_frame_.height() >> current_shift, res.height);
     ExpectScaleUsingReportedResolution();
   }

   // Make sure we can scale back with good-quality frames.
   while (min_dimension < initial_min_dimension) {
     EXPECT_TRUE(TriggerScale(kScaleUp)) << "No upscale within " << kNumSeconds
                                         << " seconds.";
     qs_.OnEncodeFrame(input_frame_);
     QualityScaler::Resolution res = qs_.GetScaledResolution();
     min_dimension = res.width < res.height ? res.width : res.height;
     --current_shift;
     ASSERT_EQ(input_frame_.width() >> current_shift, res.width);
     ASSERT_EQ(input_frame_.height() >> current_shift, res.height);
     ExpectScaleUsingReportedResolution();
   }

   // Verify we don't start upscaling after further low use.
   for (int i = 0; i < kFramerate * kNumSeconds; ++i) {
     qs_.ReportQP(kLowQp);
     ExpectOriginalFrame();
   }
 }

 TEST_F(QualityScalerTest, ContinuouslyDownscalesByHalfDimensionsAndBackUp) {
   ContinuouslyDownscalesByHalfDimensionsAndBackUp();
 }

 TEST_F(QualityScalerTest,
        ContinuouslyDownscalesOddResolutionsByHalfDimensionsAndBackUp) {
   const int kOddWidth = 517;
   const int kHalfOddWidth = (kOddWidth + 1) / 2;
   const int kOddHeight = 1239;
   input_frame_.CreateEmptyFrame(
       kOddWidth, kOddHeight, kOddWidth, kHalfOddWidth, kHalfOddWidth);
   ContinuouslyDownscalesByHalfDimensionsAndBackUp();
 }

 void QualityScalerTest::DoesNotDownscaleFrameDimensions(int width, int height) {
   input_frame_.CreateEmptyFrame(
       width, height, width, (width + 1) / 2, (width + 1) / 2);

   for (int i = 0; i < kFramerate * kNumSeconds; ++i) {
     qs_.ReportDroppedFrame();
     qs_.OnEncodeFrame(input_frame_);
     ASSERT_EQ(input_frame_.width(), qs_.GetScaledResolution().width)
         << "Unexpected scale of minimal-size frame.";
   }
 }

 TEST_F(QualityScalerTest, DoesNotDownscaleFrom1PxWidth) {
   DoesNotDownscaleFrameDimensions(1, kHeight);
 }

 TEST_F(QualityScalerTest, DoesNotDownscaleFrom1PxHeight) {
   DoesNotDownscaleFrameDimensions(kWidth, 1);
 }

 TEST_F(QualityScalerTest, DoesNotDownscaleFrom1Px) {
   DoesNotDownscaleFrameDimensions(1, 1);
 }

 QualityScalerTest::Resolution QualityScalerTest::TriggerResolutionChange(
     BadQualityMetric dropframe_lowqp, int num_second, int initial_framerate) {
   QualityScalerTest::Resolution res;
   res.framerate = initial_framerate;
   qs_.OnEncodeFrame(input_frame_);
   res.width = qs_.GetScaledResolution().width;
   res.height = qs_.GetScaledResolution().height;
   for (int i = 0; i < kFramerate * num_second; ++i) {
     switch (dropframe_lowqp) {
       case kReportLowQP:
         qs_.ReportQP(kLowQp);
         break;
       case kDropFrame:
         qs_.ReportDroppedFrame();
         break;
     }
     qs_.OnEncodeFrame(input_frame_);
     // Simulate the case when SetRates is called right after reducing
     // framerate.
     qs_.ReportFramerate(initial_framerate);
     res.framerate = qs_.GetTargetFramerate();
     if (res.framerate != -1)
       qs_.ReportFramerate(res.framerate);
     res.width = qs_.GetScaledResolution().width;
     res.height = qs_.GetScaledResolution().height;
   }
   return res;
 }

 void QualityScalerTest::VerifyQualityAdaptation(
     int initial_framerate, int seconds, bool expect_spatial_resize,
     bool expect_framerate_reduction) {
   qs_.Init(kMaxQp / QualityScaler::kDefaultLowQpDenominator, true);
   qs_.OnEncodeFrame(input_frame_);
   int init_width = qs_.GetScaledResolution().width;
   int init_height = qs_.GetScaledResolution().height;

   // Test reducing framerate by dropping frame continuously.
   QualityScalerTest::Resolution res = TriggerResolutionChange(
       kDropFrame, seconds, initial_framerate);

   if (expect_framerate_reduction) {
     EXPECT_LT(res.framerate, initial_framerate);
   } else {
     // No framerate reduction, video decimator should be disabled.
     EXPECT_EQ(-1, res.framerate);
   }

   if (expect_spatial_resize) {
     EXPECT_LT(res.width, init_width);
     EXPECT_LT(res.height, init_height);
   } else {
     EXPECT_EQ(init_width, res.width);
     EXPECT_EQ(init_height, res.height);
   }

   // The "seconds * 1.5" is to ensure spatial resolution to recover.
   // For example, in 10 seconds test, framerate reduction happens in the first
   // 5 seconds from 30fps to 15fps and causes the buffer size to be half of the
   // original one. Then it will take only 75 samples to downscale (twice in 150
   // samples). So to recover the resolution changes, we need more than 10
   // seconds (i.e, seconds * 1.5). This is because the framerate increases
   // before spatial size recovers, so it will take 150 samples to recover
   // spatial size (300 for twice).
   res = TriggerResolutionChange(kReportLowQP, seconds * 1.5, initial_framerate);
   EXPECT_EQ(-1, res.framerate);
   EXPECT_EQ(init_width, res.width);
   EXPECT_EQ(init_height, res.height);
 }

 // In 5 seconds test, only framerate adjusting should happen.
 TEST_F(QualityScalerTest, ChangeFramerateOnly) {
   VerifyQualityAdaptation(kFramerate, 5, false, true);
 }

 // In 10 seconds test, framerate adjusting and scaling are both
 // triggered, it shows that scaling would happen after framerate
 // adjusting.
 TEST_F(QualityScalerTest, ChangeFramerateAndSpatialSize) {
   VerifyQualityAdaptation(kFramerate, 10, true, true);
 }

 // When starting from a low framerate, only spatial size will be changed.
 TEST_F(QualityScalerTest, ChangeSpatialSizeOnly) {
   qs_.ReportFramerate(kFramerate >> 1);
   VerifyQualityAdaptation(kFramerate >> 1, 10, true, false);
 }

 TEST_F(QualityScalerTest, DoesNotDownscaleBelow2xDefaultMinDimensionsWidth) {
   DoesNotDownscaleFrameDimensions(
       2 * QualityScaler::kDefaultMinDownscaleDimension - 1, 1000);
 }

 TEST_F(QualityScalerTest, DoesNotDownscaleBelow2xDefaultMinDimensionsHeight) {
   DoesNotDownscaleFrameDimensions(
       1000, 2 * QualityScaler::kDefaultMinDownscaleDimension - 1);
 }

 void QualityScalerTest::DownscaleEndsAt(int input_width,
                                         int input_height,
                                         int end_width,
                                         int end_height) {
   // Create a frame with 2x expected end width/height to verify that we can
   // scale down to expected end width/height.
   input_frame_.CreateEmptyFrame(input_width, input_height, input_width,
                                 (input_width + 1) / 2, (input_width + 1) / 2);

   int last_width = input_width;
   int last_height = input_height;
   // Drop all frames to force-trigger downscaling.
   while (true) {
     TriggerScale(kScaleDown);
     QualityScaler::Resolution res = qs_.GetScaledResolution();
     if (last_width == res.width) {
       EXPECT_EQ(last_height, res.height);
       EXPECT_EQ(end_width, res.width);
       EXPECT_EQ(end_height, res.height);
       break;
     }
     last_width = res.width;
     last_height = res.height;
   }
 }

 TEST_F(QualityScalerTest, DefaultDownscalesTo160x90) {
   DownscaleEndsAt(320, 180, 160, 90);
 }

 TEST_F(QualityScalerTest, DefaultDownscalesTo90x160) {
   DownscaleEndsAt(180, 320, 90, 160);
 }

 TEST_F(QualityScalerTest, DefaultDownscalesFrom1280x720To160x90) {
   DownscaleEndsAt(1280, 720, 160, 90);
 }

 TEST_F(QualityScalerTest, DefaultDoesntDownscaleBelow160x90) {
   DownscaleEndsAt(320 - 1, 180 - 1, 320 - 1, 180 - 1);
 }

 TEST_F(QualityScalerTest, DefaultDoesntDownscaleBelow90x160) {
   DownscaleEndsAt(180 - 1, 320 - 1, 180 - 1, 320 - 1);
 }

 TEST_F(QualityScalerTest, RespectsMinResolutionWidth) {
   // Should end at 200x100, as width can't go lower.
   qs_.SetMinResolution(200, 10);
   DownscaleEndsAt(1600, 800, 200, 100);
 }

 TEST_F(QualityScalerTest, RespectsMinResolutionHeight) {
   // Should end at 100x200, as height can't go lower.
   qs_.SetMinResolution(10, 200);
   DownscaleEndsAt(800, 1600, 100, 200);
 }

 }  // namespace webrtc
	/*
	* Copyright (c) 2014 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 "webrtc/modules/video_coding/utility/include/quality_scaler.h"

	#include "testing/gtest/include/gtest/gtest.h"

	namespace webrtc {
	namespace {
	static const int kNumSeconds = 10;
	static const int kWidth = 1920;
	static const int kHalfWidth = kWidth / 2;
	static const int kHeight = 1080;
	static const int kFramerate = 30;
	static const int kLowQp = 15;
	static const int kNormalQp = 30;
	static const int kMaxQp = 56;
	} // namespace

	class QualityScalerTest : public ::testing::Test {
	public:
	// Temporal and spatial resolution.
	struct Resolution {
	int framerate;
	int width;
	int height;
	};
	protected:
	enum ScaleDirection { kScaleDown, kScaleUp };
	enum BadQualityMetric { kDropFrame, kReportLowQP };

	QualityScalerTest() {
	input_frame_.CreateEmptyFrame(
	kWidth, kHeight, kWidth, kHalfWidth, kHalfWidth);
	qs_.Init(kMaxQp / QualityScaler::kDefaultLowQpDenominator, false);
	qs_.ReportFramerate(kFramerate);
	qs_.OnEncodeFrame(input_frame_);
	}

	bool TriggerScale(ScaleDirection scale_direction) {
	qs_.OnEncodeFrame(input_frame_);
	int initial_width = qs_.GetScaledResolution().width;
	for (int i = 0; i < kFramerate * kNumSeconds; ++i) {
	switch (scale_direction) {
	case kScaleUp:
	qs_.ReportQP(kLowQp);
	break;
	case kScaleDown:
	qs_.ReportDroppedFrame();
	break;
	}
	qs_.OnEncodeFrame(input_frame_);
	if (qs_.GetScaledResolution().width != initial_width)
	return true;
	}

	return false;
	}

	void ExpectOriginalFrame() {
	EXPECT_EQ(&input_frame_, &qs_.GetScaledFrame(input_frame_))
	<< "Using scaled frame instead of original input.";
	}

	void ExpectScaleUsingReportedResolution() {
	qs_.OnEncodeFrame(input_frame_);
	QualityScaler::Resolution res = qs_.GetScaledResolution();
	const VideoFrame& scaled_frame = qs_.GetScaledFrame(input_frame_);
	EXPECT_EQ(res.width, scaled_frame.width());
	EXPECT_EQ(res.height, scaled_frame.height());
	}

	void ContinuouslyDownscalesByHalfDimensionsAndBackUp();

	void DoesNotDownscaleFrameDimensions(int width, int height);

	Resolution TriggerResolutionChange(BadQualityMetric dropframe_lowqp,
	int num_second,
	int initial_framerate);

	void VerifyQualityAdaptation(int initial_framerate, int seconds,
	bool expect_spatial_resize,
	bool expect_framerate_reduction);

	void DownscaleEndsAt(int input_width,
	int input_height,
	int end_width,
	int end_height);

	QualityScaler qs_;
	VideoFrame input_frame_;
	};

	TEST_F(QualityScalerTest, UsesOriginalFrameInitially) {
	ExpectOriginalFrame();
	}

	TEST_F(QualityScalerTest, ReportsOriginalResolutionInitially) {
	qs_.OnEncodeFrame(input_frame_);
	QualityScaler::Resolution res = qs_.GetScaledResolution();
	EXPECT_EQ(input_frame_.width(), res.width);
	EXPECT_EQ(input_frame_.height(), res.height);
	}

	TEST_F(QualityScalerTest, DownscalesAfterContinuousFramedrop) {
	EXPECT_TRUE(TriggerScale(kScaleDown)) << "No downscale within " << kNumSeconds
	<< " seconds.";
	QualityScaler::Resolution res = qs_.GetScaledResolution();
	EXPECT_LT(res.width, input_frame_.width());
	EXPECT_LT(res.height, input_frame_.height());
	}

	TEST_F(QualityScalerTest, DownscalesAfterTwoThirdsFramedrop) {
	for (int i = 0; i < kFramerate * kNumSeconds / 3; ++i) {
	qs_.ReportQP(kNormalQp);
	qs_.ReportDroppedFrame();
	qs_.ReportDroppedFrame();
	qs_.OnEncodeFrame(input_frame_);
	if (qs_.GetScaledResolution().width < input_frame_.width())
	return;
	}

	FAIL() << "No downscale within " << kNumSeconds << " seconds.";
	}

	TEST_F(QualityScalerTest, DoesNotDownscaleOnNormalQp) {
	for (int i = 0; i < kFramerate * kNumSeconds; ++i) {
	qs_.ReportQP(kNormalQp);
	qs_.OnEncodeFrame(input_frame_);
	ASSERT_EQ(input_frame_.width(), qs_.GetScaledResolution().width)
	<< "Unexpected scale on half framedrop.";
	}
	}

	TEST_F(QualityScalerTest, DoesNotDownscaleAfterHalfFramedrop) {
	for (int i = 0; i < kFramerate * kNumSeconds / 2; ++i) {
	qs_.ReportQP(kNormalQp);
	qs_.OnEncodeFrame(input_frame_);
	ASSERT_EQ(input_frame_.width(), qs_.GetScaledResolution().width)
	<< "Unexpected scale on half framedrop.";

	qs_.ReportDroppedFrame();
	qs_.OnEncodeFrame(input_frame_);
	ASSERT_EQ(input_frame_.width(), qs_.GetScaledResolution().width)
	<< "Unexpected scale on half framedrop.";
	}
	}

	void QualityScalerTest::ContinuouslyDownscalesByHalfDimensionsAndBackUp() {
	const int initial_min_dimension = input_frame_.width() < input_frame_.height()
	? input_frame_.width()
	: input_frame_.height();
	int min_dimension = initial_min_dimension;
	int current_shift = 0;
	// Drop all frames to force-trigger downscaling.
	while (min_dimension >= 2 * QualityScaler::kDefaultMinDownscaleDimension) {
	EXPECT_TRUE(TriggerScale(kScaleDown)) << "No downscale within "
	<< kNumSeconds << " seconds.";
	qs_.OnEncodeFrame(input_frame_);
	QualityScaler::Resolution res = qs_.GetScaledResolution();
	min_dimension = res.width < res.height ? res.width : res.height;
	++current_shift;
	ASSERT_EQ(input_frame_.width() >> current_shift, res.width);
	ASSERT_EQ(input_frame_.height() >> current_shift, res.height);
	ExpectScaleUsingReportedResolution();
	}

	// Make sure we can scale back with good-quality frames.
	while (min_dimension < initial_min_dimension) {
	EXPECT_TRUE(TriggerScale(kScaleUp)) << "No upscale within " << kNumSeconds
	<< " seconds.";
	qs_.OnEncodeFrame(input_frame_);
	QualityScaler::Resolution res = qs_.GetScaledResolution();
	min_dimension = res.width < res.height ? res.width : res.height;
	--current_shift;
	ASSERT_EQ(input_frame_.width() >> current_shift, res.width);
	ASSERT_EQ(input_frame_.height() >> current_shift, res.height);
	ExpectScaleUsingReportedResolution();
	}

	// Verify we don't start upscaling after further low use.
	for (int i = 0; i < kFramerate * kNumSeconds; ++i) {
	qs_.ReportQP(kLowQp);
	ExpectOriginalFrame();
	}
	}

	TEST_F(QualityScalerTest, ContinuouslyDownscalesByHalfDimensionsAndBackUp) {
	ContinuouslyDownscalesByHalfDimensionsAndBackUp();
	}

	TEST_F(QualityScalerTest,
	ContinuouslyDownscalesOddResolutionsByHalfDimensionsAndBackUp) {
	const int kOddWidth = 517;
	const int kHalfOddWidth = (kOddWidth + 1) / 2;
	const int kOddHeight = 1239;
	input_frame_.CreateEmptyFrame(
	kOddWidth, kOddHeight, kOddWidth, kHalfOddWidth, kHalfOddWidth);
	ContinuouslyDownscalesByHalfDimensionsAndBackUp();
	}

	void QualityScalerTest::DoesNotDownscaleFrameDimensions(int width, int height) {
	input_frame_.CreateEmptyFrame(
	width, height, width, (width + 1) / 2, (width + 1) / 2);

	for (int i = 0; i < kFramerate * kNumSeconds; ++i) {
	qs_.ReportDroppedFrame();
	qs_.OnEncodeFrame(input_frame_);
	ASSERT_EQ(input_frame_.width(), qs_.GetScaledResolution().width)
	<< "Unexpected scale of minimal-size frame.";
	}
	}

	TEST_F(QualityScalerTest, DoesNotDownscaleFrom1PxWidth) {
	DoesNotDownscaleFrameDimensions(1, kHeight);
	}

	TEST_F(QualityScalerTest, DoesNotDownscaleFrom1PxHeight) {
	DoesNotDownscaleFrameDimensions(kWidth, 1);
	}

	TEST_F(QualityScalerTest, DoesNotDownscaleFrom1Px) {
	DoesNotDownscaleFrameDimensions(1, 1);
	}

	QualityScalerTest::Resolution QualityScalerTest::TriggerResolutionChange(
	BadQualityMetric dropframe_lowqp, int num_second, int initial_framerate) {
	QualityScalerTest::Resolution res;
	res.framerate = initial_framerate;
	qs_.OnEncodeFrame(input_frame_);
	res.width = qs_.GetScaledResolution().width;
	res.height = qs_.GetScaledResolution().height;
	for (int i = 0; i < kFramerate * num_second; ++i) {
	switch (dropframe_lowqp) {
	case kReportLowQP:
	qs_.ReportQP(kLowQp);
	break;
	case kDropFrame:
	qs_.ReportDroppedFrame();
	break;
	}
	qs_.OnEncodeFrame(input_frame_);
	// Simulate the case when SetRates is called right after reducing
	// framerate.
	qs_.ReportFramerate(initial_framerate);
	res.framerate = qs_.GetTargetFramerate();
	if (res.framerate != -1)
	qs_.ReportFramerate(res.framerate);
	res.width = qs_.GetScaledResolution().width;
	res.height = qs_.GetScaledResolution().height;
	}
	return res;
	}

	void QualityScalerTest::VerifyQualityAdaptation(
	int initial_framerate, int seconds, bool expect_spatial_resize,
	bool expect_framerate_reduction) {
	qs_.Init(kMaxQp / QualityScaler::kDefaultLowQpDenominator, true);
	qs_.OnEncodeFrame(input_frame_);
	int init_width = qs_.GetScaledResolution().width;
	int init_height = qs_.GetScaledResolution().height;

	// Test reducing framerate by dropping frame continuously.
	QualityScalerTest::Resolution res = TriggerResolutionChange(
	kDropFrame, seconds, initial_framerate);

	if (expect_framerate_reduction) {
	EXPECT_LT(res.framerate, initial_framerate);
	} else {
	// No framerate reduction, video decimator should be disabled.
	EXPECT_EQ(-1, res.framerate);
	}

	if (expect_spatial_resize) {
	EXPECT_LT(res.width, init_width);
	EXPECT_LT(res.height, init_height);
	} else {
	EXPECT_EQ(init_width, res.width);
	EXPECT_EQ(init_height, res.height);
	}

	// The "seconds * 1.5" is to ensure spatial resolution to recover.
	// For example, in 10 seconds test, framerate reduction happens in the first
	// 5 seconds from 30fps to 15fps and causes the buffer size to be half of the
	// original one. Then it will take only 75 samples to downscale (twice in 150
	// samples). So to recover the resolution changes, we need more than 10
	// seconds (i.e, seconds * 1.5). This is because the framerate increases
	// before spatial size recovers, so it will take 150 samples to recover
	// spatial size (300 for twice).
	res = TriggerResolutionChange(kReportLowQP, seconds * 1.5, initial_framerate);
	EXPECT_EQ(-1, res.framerate);
	EXPECT_EQ(init_width, res.width);
	EXPECT_EQ(init_height, res.height);
	}

	// In 5 seconds test, only framerate adjusting should happen.
	TEST_F(QualityScalerTest, ChangeFramerateOnly) {
	VerifyQualityAdaptation(kFramerate, 5, false, true);
	}

	// In 10 seconds test, framerate adjusting and scaling are both
	// triggered, it shows that scaling would happen after framerate
	// adjusting.
	TEST_F(QualityScalerTest, ChangeFramerateAndSpatialSize) {
	VerifyQualityAdaptation(kFramerate, 10, true, true);
	}

	// When starting from a low framerate, only spatial size will be changed.
	TEST_F(QualityScalerTest, ChangeSpatialSizeOnly) {
	qs_.ReportFramerate(kFramerate >> 1);
	VerifyQualityAdaptation(kFramerate >> 1, 10, true, false);
	}

	TEST_F(QualityScalerTest, DoesNotDownscaleBelow2xDefaultMinDimensionsWidth) {
	DoesNotDownscaleFrameDimensions(
	2 * QualityScaler::kDefaultMinDownscaleDimension - 1, 1000);
	}

	TEST_F(QualityScalerTest, DoesNotDownscaleBelow2xDefaultMinDimensionsHeight) {
	DoesNotDownscaleFrameDimensions(
	1000, 2 * QualityScaler::kDefaultMinDownscaleDimension - 1);
	}

	void QualityScalerTest::DownscaleEndsAt(int input_width,
	int input_height,
	int end_width,
	int end_height) {
	// Create a frame with 2x expected end width/height to verify that we can
	// scale down to expected end width/height.
	input_frame_.CreateEmptyFrame(input_width, input_height, input_width,
	(input_width + 1) / 2, (input_width + 1) / 2);

	int last_width = input_width;
	int last_height = input_height;
	// Drop all frames to force-trigger downscaling.
	while (true) {
	TriggerScale(kScaleDown);
	QualityScaler::Resolution res = qs_.GetScaledResolution();
	if (last_width == res.width) {
	EXPECT_EQ(last_height, res.height);
	EXPECT_EQ(end_width, res.width);
	EXPECT_EQ(end_height, res.height);
	break;
	}
	last_width = res.width;
	last_height = res.height;
	}
	}

	TEST_F(QualityScalerTest, DefaultDownscalesTo160x90) {
	DownscaleEndsAt(320, 180, 160, 90);
	}

	TEST_F(QualityScalerTest, DefaultDownscalesTo90x160) {
	DownscaleEndsAt(180, 320, 90, 160);
	}

	TEST_F(QualityScalerTest, DefaultDownscalesFrom1280x720To160x90) {
	DownscaleEndsAt(1280, 720, 160, 90);
	}

	TEST_F(QualityScalerTest, DefaultDoesntDownscaleBelow160x90) {
	DownscaleEndsAt(320 - 1, 180 - 1, 320 - 1, 180 - 1);
	}

	TEST_F(QualityScalerTest, DefaultDoesntDownscaleBelow90x160) {
	DownscaleEndsAt(180 - 1, 320 - 1, 180 - 1, 320 - 1);
	}

	TEST_F(QualityScalerTest, RespectsMinResolutionWidth) {
	// Should end at 200x100, as width can't go lower.
	qs_.SetMinResolution(200, 10);
	DownscaleEndsAt(1600, 800, 200, 100);
	}

	TEST_F(QualityScalerTest, RespectsMinResolutionHeight) {
	// Should end at 100x200, as height can't go lower.
	qs_.SetMinResolution(10, 200);
	DownscaleEndsAt(800, 1600, 100, 200);
	}

	} // namespace webrtc