video/config/simulcast_unittest.cc

/*
 *  Copyright 2018 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/config/simulcast.h"

#include "media/base/media_constants.h"
#include "test/explicit_key_value_config.h"
#include "test/gmock.h"
#include "test/gtest.h"

namespace webrtc {
namespace {
using test::ExplicitKeyValueConfig;
using ::testing::SizeIs;

constexpr bool kScreenshare = true;
constexpr int kDefaultTemporalLayers = 3;  // Value from simulcast.cc.

// Values from kSimulcastConfigs in simulcast.cc.
const std::vector<VideoStream> GetSimulcastBitrates720p() {
  std::vector<VideoStream> streams(3);
  streams[0].min_bitrate_bps = 30000;
  streams[0].target_bitrate_bps = 150000;
  streams[0].max_bitrate_bps = 200000;
  streams[1].min_bitrate_bps = 150000;
  streams[1].target_bitrate_bps = 500000;
  streams[1].max_bitrate_bps = 700000;
  streams[2].min_bitrate_bps = 600000;
  streams[2].target_bitrate_bps = 2500000;
  streams[2].max_bitrate_bps = 2500000;
  return streams;
}

// Creates a vector of resolutions scaled down with 1/2 factor ordered from low
// to high.
std::vector<Resolution> CreateResolutions(int max_width,
                                          int max_height,
                                          int num_streams) {
  std::vector<webrtc::Resolution> resolutions(num_streams);
  for (int i = 0; i < num_streams; ++i) {
    resolutions[i].width = max_width >> (num_streams - i - 1);
    resolutions[i].height = max_height >> (num_streams - i - 1);
  }
  return resolutions;
}
}  // namespace

TEST(SimulcastTest, TotalMaxBitrateIsZeroForNoStreams) {
  std::vector<VideoStream> streams;
  EXPECT_EQ(0, cricket::GetTotalMaxBitrate(streams).bps());
}

TEST(SimulcastTest, GetTotalMaxBitrateForSingleStream) {
  std::vector<VideoStream> streams(1);
  streams[0].max_bitrate_bps = 100000;
  EXPECT_EQ(100000, cricket::GetTotalMaxBitrate(streams).bps());
}

TEST(SimulcastTest, GetTotalMaxBitrateForMultipleStreams) {
  std::vector<VideoStream> streams(3);
  streams[0].target_bitrate_bps = 100000;
  streams[1].target_bitrate_bps = 200000;
  streams[2].max_bitrate_bps = 400000;
  EXPECT_EQ(700000, cricket::GetTotalMaxBitrate(streams).bps());
}

TEST(SimulcastTest, BandwidthAboveTotalMaxBitrateGivenToHighestStream) {
  std::vector<VideoStream> streams(3);
  streams[0].target_bitrate_bps = 100000;
  streams[1].target_bitrate_bps = 200000;
  streams[2].max_bitrate_bps = 400000;

  const webrtc::DataRate one_bps = webrtc::DataRate::BitsPerSec(1);

  // No bitrate above the total max to give to the highest stream.
  const webrtc::DataRate max_total_bitrate =
      cricket::GetTotalMaxBitrate(streams);
  cricket::BoostMaxSimulcastLayer(max_total_bitrate, &streams);
  EXPECT_EQ(400000, streams[2].max_bitrate_bps);
  EXPECT_EQ(max_total_bitrate, cricket::GetTotalMaxBitrate(streams));

  // The bitrate above the total max should be given to the highest stream.
  cricket::BoostMaxSimulcastLayer(max_total_bitrate + one_bps, &streams);
  EXPECT_EQ(400000 + 1, streams[2].max_bitrate_bps);
  EXPECT_EQ(max_total_bitrate + one_bps, cricket::GetTotalMaxBitrate(streams));
}

TEST(SimulcastTest, GetConfig) {
  const ExplicitKeyValueConfig trials("");

  const std::vector<VideoStream> kExpected = GetSimulcastBitrates720p();

  const size_t kMaxLayers = 3;
  std::vector<VideoStream> streams = cricket::GetSimulcastConfig(
      CreateResolutions(1280, 720, kMaxLayers), !kScreenshare, true, trials,
      webrtc::kVideoCodecVP8);

  ASSERT_THAT(streams, SizeIs(kMaxLayers));
  EXPECT_EQ(320u, streams[0].width);
  EXPECT_EQ(180u, streams[0].height);
  EXPECT_EQ(640u, streams[1].width);
  EXPECT_EQ(360u, streams[1].height);
  EXPECT_EQ(1280u, streams[2].width);
  EXPECT_EQ(720u, streams[2].height);

  for (size_t i = 0; i < streams.size(); ++i) {
    EXPECT_EQ(size_t{kDefaultTemporalLayers}, streams[i].num_temporal_layers);
    EXPECT_EQ(cricket::kDefaultVideoMaxFramerate, streams[i].max_framerate);
    EXPECT_EQ(-1, streams[i].max_qp);
    EXPECT_EQ(kExpected[i].min_bitrate_bps, streams[i].min_bitrate_bps);
    EXPECT_EQ(kExpected[i].target_bitrate_bps, streams[i].target_bitrate_bps);
    EXPECT_EQ(kExpected[i].max_bitrate_bps, streams[i].max_bitrate_bps);
    EXPECT_TRUE(streams[i].active);
  }
}

TEST(SimulcastTest, GetConfigWithBaseHeavyVP8TL3RateAllocation) {
  ExplicitKeyValueConfig trials(
      "WebRTC-UseBaseHeavyVP8TL3RateAllocation/Enabled/");

  const std::vector<VideoStream> kExpected = GetSimulcastBitrates720p();

  const size_t kMaxLayers = 3;
  std::vector<VideoStream> streams = cricket::GetSimulcastConfig(
      CreateResolutions(1280, 720, kMaxLayers), !kScreenshare, true, trials,
      webrtc::kVideoCodecVP8);

  ASSERT_THAT(streams, SizeIs(kMaxLayers));
  EXPECT_EQ(kExpected[0].min_bitrate_bps, streams[0].min_bitrate_bps);
  EXPECT_EQ(static_cast<int>(0.4 * kExpected[0].target_bitrate_bps / 0.6),
            streams[0].target_bitrate_bps);
  EXPECT_EQ(static_cast<int>(0.4 * kExpected[0].max_bitrate_bps / 0.6),
            streams[0].max_bitrate_bps);
  for (size_t i = 1; i < streams.size(); ++i) {
    EXPECT_EQ(kExpected[i].min_bitrate_bps, streams[i].min_bitrate_bps);
    EXPECT_EQ(kExpected[i].target_bitrate_bps, streams[i].target_bitrate_bps);
    EXPECT_EQ(kExpected[i].max_bitrate_bps, streams[i].max_bitrate_bps);
  }
}

TEST(SimulcastTest, GetConfigWithLimitedMaxLayers) {
  ExplicitKeyValueConfig trials("");

  const size_t kMaxLayers = 2;
  std::vector<VideoStream> streams = cricket::GetSimulcastConfig(
      CreateResolutions(1280, 720, kMaxLayers), !kScreenshare, true, trials,
      webrtc::kVideoCodecVP8);

  ASSERT_THAT(streams, SizeIs(kMaxLayers));
  EXPECT_EQ(640u, streams[0].width);
  EXPECT_EQ(360u, streams[0].height);
  EXPECT_EQ(1280u, streams[1].width);
  EXPECT_EQ(720u, streams[1].height);
}

TEST(SimulcastTest, GetConfigForScreenshareSimulcast) {
  ExplicitKeyValueConfig trials("");
  std::vector<VideoStream> streams = cricket::GetSimulcastConfig(
      std::vector<Resolution>{{.width = 1400, .height = 800},
                              {.width = 1400, .height = 800},
                              {.width = 1400, .height = 800}},
      kScreenshare, true, trials, webrtc::kVideoCodecVP8);

  EXPECT_THAT(streams, SizeIs(2));
  for (size_t i = 0; i < streams.size(); ++i) {
    EXPECT_EQ(1400u, streams[i].width) << "Screen content never scaled.";
    EXPECT_EQ(800u, streams[i].height) << "Screen content never scaled.";
    EXPECT_EQ(-1, streams[i].max_qp);
    EXPECT_TRUE(streams[i].active);
    EXPECT_GT(streams[i].num_temporal_layers, size_t{1});
    EXPECT_GT(streams[i].max_framerate, 0);
    EXPECT_GT(streams[i].min_bitrate_bps, 0);
    EXPECT_GT(streams[i].target_bitrate_bps, streams[i].min_bitrate_bps);
    EXPECT_GE(streams[i].max_bitrate_bps, streams[i].target_bitrate_bps);
  }
}

TEST(SimulcastTest, GetConfigForScreenshareSimulcastWithLimitedMaxLayers) {
  ExplicitKeyValueConfig trials("");
  std::vector<VideoStream> streams = cricket::GetSimulcastConfig(
      std::vector<Resolution>{{.width = 1400, .height = 800}}, kScreenshare,
      true, trials, webrtc::kVideoCodecVP8);
  EXPECT_THAT(streams, SizeIs(1));
}

TEST(SimulcastTest, AveragesBitratesForNonStandardResolution) {
  ExplicitKeyValueConfig trials("");
  std::vector<VideoStream> streams = cricket::GetSimulcastConfig(
      std::vector<Resolution>{{.width = 900, .height = 800}}, !kScreenshare,
      true, trials, webrtc::kVideoCodecVP8);

  ASSERT_THAT(streams, SizeIs(1));
  EXPECT_EQ(900u, streams[0].width);
  EXPECT_EQ(800u, streams[0].height);
  EXPECT_EQ(1850000, streams[0].max_bitrate_bps);
  EXPECT_EQ(1850000, streams[0].target_bitrate_bps);
  EXPECT_EQ(475000, streams[0].min_bitrate_bps);
}

TEST(SimulcastTest, BitratesForCloseToStandardResolution) {
  ExplicitKeyValueConfig trials("");

  const size_t kMaxLayers = 3;
  // Resolution very close to 720p in number of pixels
  const size_t kWidth = 1280;
  const size_t kHeight = 716;
  const std::vector<VideoStream> kExpectedNear = GetSimulcastBitrates720p();

  std::vector<VideoStream> streams = cricket::GetSimulcastConfig(
      CreateResolutions(kWidth, kHeight, kMaxLayers), !kScreenshare, true,
      trials, webrtc::kVideoCodecVP8);

  ASSERT_THAT(streams, SizeIs(kMaxLayers));
  EXPECT_EQ(kWidth, streams[2].width);
  EXPECT_EQ(kHeight, streams[2].height);
  for (size_t i = 0; i < streams.size(); ++i) {
    EXPECT_NEAR(kExpectedNear[i].max_bitrate_bps, streams[i].max_bitrate_bps,
                20000);
    EXPECT_NEAR(kExpectedNear[i].target_bitrate_bps,
                streams[i].target_bitrate_bps, 20000);
    EXPECT_NEAR(kExpectedNear[i].min_bitrate_bps, streams[i].min_bitrate_bps,
                20000);
  }
}

TEST(SimulcastTest, MaxLayersWithRoundUpDisabled) {
  ExplicitKeyValueConfig trials(
      "WebRTC-SimulcastLayerLimitRoundUp/max_ratio:0.0/");

  const size_t kMinLayers = 1;
  const int kMaxLayers = 3;

  size_t num_layers = cricket::LimitSimulcastLayerCount(
      kMinLayers, kMaxLayers, 960, 540, trials, webrtc::kVideoCodecVP8);
  EXPECT_EQ(num_layers, 3u);
  // <960x540: 2 layers
  num_layers = cricket::LimitSimulcastLayerCount(
      kMinLayers, kMaxLayers, 960, 539, trials, webrtc::kVideoCodecVP8);
  EXPECT_EQ(num_layers, 2u);
  num_layers = cricket::LimitSimulcastLayerCount(
      kMinLayers, kMaxLayers, 480, 270, trials, webrtc::kVideoCodecVP8);
  EXPECT_EQ(num_layers, 2u);
  // <480x270: 1 layer
  num_layers = cricket::LimitSimulcastLayerCount(
      kMinLayers, kMaxLayers, 480, 269, trials, webrtc::kVideoCodecVP8);
  EXPECT_EQ(num_layers, 1u);
}

TEST(SimulcastTest, MaxLayersWithDefaultRoundUpRatio) {
  // Default: "WebRTC-SimulcastLayerLimitRoundUp/max_ratio:0.1/"
  ExplicitKeyValueConfig trials("");
  const size_t kMinLayers = 1;
  const int kMaxLayers = 3;

  size_t num_layers = cricket::LimitSimulcastLayerCount(
      kMinLayers, kMaxLayers, 960, 540, trials, webrtc::kVideoCodecVP8);
  EXPECT_EQ(num_layers, 3u);
  // Lowest cropped height where max layers from higher resolution is used.
  num_layers = cricket::LimitSimulcastLayerCount(
      kMinLayers, kMaxLayers, 960, 512, trials, webrtc::kVideoCodecVP8);
  EXPECT_EQ(num_layers, 3u);
  num_layers = cricket::LimitSimulcastLayerCount(
      kMinLayers, kMaxLayers, 960, 508, trials, webrtc::kVideoCodecVP8);
  EXPECT_EQ(num_layers, 2u);
  num_layers = cricket::LimitSimulcastLayerCount(
      kMinLayers, kMaxLayers, 480, 270, trials, webrtc::kVideoCodecVP8);
  EXPECT_EQ(num_layers, 2u);
  // Lowest cropped height where max layers from higher resolution is used.
  num_layers = cricket::LimitSimulcastLayerCount(
      kMinLayers, kMaxLayers, 480, 256, trials, webrtc::kVideoCodecVP8);
  EXPECT_EQ(num_layers, 2u);
  num_layers = cricket::LimitSimulcastLayerCount(
      kMinLayers, kMaxLayers, 480, 254, trials, webrtc::kVideoCodecVP8);
  EXPECT_EQ(num_layers, 1u);
}

TEST(SimulcastTest, MaxLayersWithRoundUpRatio) {
  ExplicitKeyValueConfig trials(
      "WebRTC-SimulcastLayerLimitRoundUp/max_ratio:0.13/");

  const size_t kMinLayers = 1;
  const int kMaxLayers = 3;

  size_t num_layers = cricket::LimitSimulcastLayerCount(
      kMinLayers, kMaxLayers, 480, 270, trials, webrtc::kVideoCodecVP8);
  EXPECT_EQ(num_layers, 2u);
  // Lowest cropped height where max layers from higher resolution is used.
  num_layers = cricket::LimitSimulcastLayerCount(
      kMinLayers, kMaxLayers, 480, 252, trials, webrtc::kVideoCodecVP8);
  EXPECT_EQ(num_layers, 2u);
  num_layers = cricket::LimitSimulcastLayerCount(
      kMinLayers, kMaxLayers, 480, 250, trials, webrtc::kVideoCodecVP8);
  EXPECT_EQ(num_layers, 1u);
}

TEST(SimulcastTest, BitratesInterpolatedForResBelow180p) {
  // TODO(webrtc:12415): Remove when feature launches.
  ExplicitKeyValueConfig trials(
      "WebRTC-LowresSimulcastBitrateInterpolation/Enabled/");

  const size_t kMaxLayers = 3;
  std::vector<VideoStream> streams = cricket::GetSimulcastConfig(
      CreateResolutions(/*max_width=*/960, /*max_height=*/540, kMaxLayers),
      !kScreenshare, true, trials, webrtc::kVideoCodecVP8);

  ASSERT_THAT(streams, SizeIs(kMaxLayers));
  EXPECT_EQ(240u, streams[0].width);
  EXPECT_EQ(135u, streams[0].height);
  EXPECT_EQ(streams[0].max_bitrate_bps, 112500);
  EXPECT_EQ(streams[0].target_bitrate_bps, 84375);
  EXPECT_EQ(streams[0].min_bitrate_bps, 30000);
}

TEST(SimulcastTest, BitratesConsistentForVerySmallRes) {
  // TODO(webrtc:12415): Remove when feature launches.
  ExplicitKeyValueConfig trials(
      "WebRTC-LowresSimulcastBitrateInterpolation/Enabled/");

  std::vector<VideoStream> streams = cricket::GetSimulcastConfig(
      std::vector<Resolution>{{.width = 1, .height = 1}}, !kScreenshare, true,
      trials, webrtc::kVideoCodecVP8);

  ASSERT_THAT(streams, SizeIs(1));
  EXPECT_EQ(1u, streams[0].width);
  EXPECT_EQ(1u, streams[0].height);
  EXPECT_EQ(streams[0].max_bitrate_bps, 30000);
  EXPECT_EQ(streams[0].target_bitrate_bps, 30000);
  EXPECT_EQ(streams[0].min_bitrate_bps, 30000);
}

TEST(SimulcastTest,
     BitratesNotInterpolatedForResBelow180pWhenDisabledTrialSet) {
  ExplicitKeyValueConfig trials(
      "WebRTC-LowresSimulcastBitrateInterpolation/Disabled/");

  const size_t kMaxLayers = 3;
  std::vector<VideoStream> streams = cricket::GetSimulcastConfig(
      CreateResolutions(/*max_width=*/960, /*max_height=*/540, kMaxLayers),
      !kScreenshare, true, trials, webrtc::kVideoCodecVP8);

  ASSERT_THAT(streams, SizeIs(kMaxLayers));
  EXPECT_EQ(240u, streams[0].width);
  EXPECT_EQ(135u, streams[0].height);
  EXPECT_EQ(streams[0].max_bitrate_bps, 200000);
  EXPECT_EQ(streams[0].target_bitrate_bps, 150000);
  EXPECT_EQ(streams[0].min_bitrate_bps, 30000);
}

TEST(SimulcastTest, BitratesBasedOnCodec) {
  ExplicitKeyValueConfig trials("");

  const size_t kMaxLayers = 3;
  std::vector<VideoStream> streams_vp8 = cricket::GetSimulcastConfig(
      CreateResolutions(/*max_width=*/1280, /*max_height=*/720, kMaxLayers),
      !kScreenshare, true, trials, webrtc::kVideoCodecVP8);

  std::vector<VideoStream> streams_vp9 = cricket::GetSimulcastConfig(
      CreateResolutions(/*max_width=*/1280, /*max_height=*/720, kMaxLayers),
      !kScreenshare, true, trials, webrtc::kVideoCodecVP9);

  ASSERT_THAT(streams_vp8, SizeIs(kMaxLayers));
  ASSERT_THAT(streams_vp9, SizeIs(kMaxLayers));

  EXPECT_EQ(streams_vp9[0].width, streams_vp8[0].width);
  EXPECT_EQ(streams_vp9[0].height, streams_vp8[0].height);

  EXPECT_NE(streams_vp9[0].max_bitrate_bps, streams_vp8[0].max_bitrate_bps);
  EXPECT_NE(streams_vp9[0].target_bitrate_bps,
            streams_vp8[0].target_bitrate_bps);

  EXPECT_NE(streams_vp9[1].max_bitrate_bps, streams_vp8[1].max_bitrate_bps);
  EXPECT_NE(streams_vp9[1].target_bitrate_bps,
            streams_vp8[1].target_bitrate_bps);
  EXPECT_NE(streams_vp9[1].min_bitrate_bps, streams_vp8[1].min_bitrate_bps);

  EXPECT_NE(streams_vp9[2].max_bitrate_bps, streams_vp8[2].max_bitrate_bps);
  EXPECT_NE(streams_vp9[2].target_bitrate_bps,
            streams_vp8[2].target_bitrate_bps);
  EXPECT_NE(streams_vp9[2].min_bitrate_bps, streams_vp8[2].min_bitrate_bps);
}

TEST(SimulcastTest, BitratesForVP9) {
  ExplicitKeyValueConfig trials("");

  const size_t kMaxLayers = 3;
  std::vector<VideoStream> streams = cricket::GetSimulcastConfig(
      CreateResolutions(/*max_width=*/1280, /*max_height=*/720, kMaxLayers),
      !kScreenshare, true, trials, webrtc::kVideoCodecVP9);

  ASSERT_THAT(streams, SizeIs(kMaxLayers));
  EXPECT_EQ(1280u, streams[2].width);
  EXPECT_EQ(720u, streams[2].height);
  EXPECT_EQ(streams[2].max_bitrate_bps, 1524000);
  EXPECT_EQ(streams[2].target_bitrate_bps, 1524000);
  EXPECT_EQ(streams[2].min_bitrate_bps, 481000);

  streams = cricket::GetSimulcastConfig(
      CreateResolutions(/*max_width=*/1276, /*max_height=*/716, kMaxLayers),
      !kScreenshare, true, trials, webrtc::kVideoCodecVP9);

  ASSERT_THAT(streams, SizeIs(kMaxLayers));
  EXPECT_EQ(1276u, streams[2].width);
  EXPECT_EQ(716u, streams[2].height);
  EXPECT_NEAR(streams[2].max_bitrate_bps, 1524000, 20000);
  EXPECT_NEAR(streams[2].target_bitrate_bps, 1524000, 20000);
  EXPECT_NEAR(streams[2].min_bitrate_bps, 481000, 20000);
}

}  // namespace webrtc