media / renderers / audio_renderer_impl_unittest.cc [blame]

// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/40285824): Remove this and convert code to safer constructs.
#pragma allow_unsafe_buffers
#endif

#include "media/renderers/audio_renderer_impl.h"

#include <memory>
#include <utility>
#include <vector>

#include "base/format_macros.h"
#include "base/functional/bind.h"
#include "base/functional/callback_helpers.h"
#include "base/memory/scoped_refptr.h"
#include "base/run_loop.h"
#include "base/strings/stringprintf.h"
#include "base/task/single_thread_task_runner.h"
#include "base/test/gmock_callback_support.h"
#include "base/test/scoped_feature_list.h"
#include "base/test/simple_test_tick_clock.h"
#include "base/test/task_environment.h"
#include "base/time/time.h"
#include "build/build_config.h"
#include "media/base/audio_buffer_converter.h"
#include "media/base/audio_bus.h"
#include "media/base/fake_audio_renderer_sink.h"
#include "media/base/media_client.h"
#include "media/base/media_switches.h"
#include "media/base/media_util.h"
#include "media/base/mock_audio_renderer_sink.h"
#include "media/base/mock_filters.h"
#include "media/base/mock_media_log.h"
#include "media/base/speech_recognition_client.h"
#include "media/base/test_helpers.h"
#include "testing/gmock/include/gmock/gmock.h"
#include "testing/gtest/include/gtest/gtest.h"

using ::base::TimeDelta;
using ::base::test::RunCallback;
using ::base::test::RunOnceCallback;
using ::testing::_;
using ::testing::DoAll;
using ::testing::Return;
using ::testing::SaveArg;

namespace media {

namespace {

// Since AudioBufferConverter is used due to different input/output sample
// rates, define some helper types to differentiate between the two.
struct InputFrames {
  explicit InputFrames(int value) : value(value) {}
  int value;
};

struct OutputFrames {
  explicit OutputFrames(int value) : value(value) {}
  int value;
};

}  // namespace

// Constants to specify the type of audio data used.
constexpr AudioCodec kCodec = AudioCodec::kVorbis;
constexpr SampleFormat kSampleFormat = kSampleFormatPlanarF32;
constexpr ChannelLayout kChannelLayout = CHANNEL_LAYOUT_STEREO;
constexpr int kChannels = 2;

// Use a different output sample rate so the AudioBufferConverter is invoked.
constexpr int kInputSamplesPerSecond = 5000;
constexpr int kOutputSamplesPerSecond = 10000;
constexpr double kOutputMicrosPerFrame =
    static_cast<double>(base::Time::kMicrosecondsPerSecond) /
    kOutputSamplesPerSecond;

// Arbitrarily chosen frame count for a typical input audio buffer.
// NOTE: Do not assume that N InputFrames in translates to N OutputFrames.
// Format differences between "in" vs "out" (reconciled by AudioBufferConverter)
// will cause the N InputFrames to generate M OutputFrames, such that N and M
// may be off by a significant factor.
constexpr int kInputFramesChunk = 256;

ACTION_P(EnterPendingDecoderInitStateAction, test) {
  test->EnterPendingDecoderInitState(std::move(arg2));
}

ACTION_P(AssertNotYetEnded, test) {
  ASSERT_FALSE(test->ended());
}

class AudioRendererImplTest : public ::testing::Test,
                              public RendererClient,
                              public SpeechRecognitionClient {
 public:
  std::vector<std::unique_ptr<AudioDecoder>> CreateAudioDecoderForTest() {
    auto decoder = std::make_unique<MockAudioDecoder>();
    if (!enter_pending_decoder_init_) {
      EXPECT_CALL(*decoder, Initialize_(_, _, _, _, _))
          .WillOnce(
              DoAll(SaveArg<3>(&output_cb_),
                    RunOnceCallback<2>(expected_init_result_
                                           ? DecoderStatus::Codes::kOk
                                           : DecoderStatus::Codes::kFailed)));
    } else {
      EXPECT_CALL(*decoder, Initialize_(_, _, _, _, _))
          .WillOnce(EnterPendingDecoderInitStateAction(this));
    }
    EXPECT_CALL(*decoder, Decode(_, _))
        .WillRepeatedly(Invoke(this, &AudioRendererImplTest::DecodeDecoder));
    EXPECT_CALL(*decoder, Reset_(_))
        .WillRepeatedly(Invoke(this, &AudioRendererImplTest::ResetDecoder));
    std::vector<std::unique_ptr<AudioDecoder>> decoders;
    decoders.push_back(std::move(decoder));
    return decoders;
  }

  // Give the decoder some non-garbage media properties.
  AudioRendererImplTest()
      : hardware_params_(AudioParameters::AUDIO_PCM_LOW_LATENCY,
                         ChannelLayoutConfig::FromLayout<kChannelLayout>(),
                         kOutputSamplesPerSecond,
                         512),
        main_thread_task_runner_(
            base::SingleThreadTaskRunner::GetCurrentDefault()),
        sink_(new FakeAudioRendererSink(hardware_params_)),
        demuxer_stream_(DemuxerStream::AUDIO),
        expected_init_result_(true),
        enter_pending_decoder_init_(false),
        ended_(false) {
    AudioDecoderConfig audio_config(kCodec, kSampleFormat, kChannelLayout,
                                    kInputSamplesPerSecond, EmptyExtraData(),
                                    EncryptionScheme::kUnencrypted);
    demuxer_stream_.set_audio_decoder_config(audio_config);

    ConfigureDemuxerStream(true);

    AudioParameters out_params(
        AudioParameters::AUDIO_PCM_LOW_LATENCY,
        ChannelLayoutConfig::FromLayout<kChannelLayout>(),
        kOutputSamplesPerSecond, 512);
    renderer_ = std::make_unique<AudioRendererImpl>(
        main_thread_task_runner_, sink_.get(),
        base::BindRepeating(&AudioRendererImplTest::CreateAudioDecoderForTest,
                            base::Unretained(this)),
        &media_log_, 0, this);
    renderer_->tick_clock_ = &tick_clock_;
    tick_clock_.Advance(base::Seconds(1));
  }

  AudioRendererImplTest(const AudioRendererImplTest&) = delete;
  AudioRendererImplTest& operator=(const AudioRendererImplTest&) = delete;

  ~AudioRendererImplTest() override {
    SCOPED_TRACE("~AudioRendererImplTest()");
  }

  // Mock out demuxer reads.
  void ConfigureDemuxerStream(bool supports_config_changes) {
    EXPECT_CALL(demuxer_stream_, OnRead(_))
        .WillRepeatedly(Invoke(this, &AudioRendererImplTest::OnDemuxerRead));
    EXPECT_CALL(demuxer_stream_, SupportsConfigChanges())
        .WillRepeatedly(Return(supports_config_changes));
  }

  void OnDemuxerRead(DemuxerStream::ReadCB& read_cb) {
    if (simulate_demuxer_stall_) {
      simulate_demuxer_stall_ = false;
      stalled_demixer_read_cb_ = std::move(read_cb);
      return;
    }
    scoped_refptr<DecoderBuffer> decoder_buffer(new DecoderBuffer(0));
    std::move(read_cb).Run(DemuxerStream::kOk, {std::move(decoder_buffer)});
  }

  bool IsDemuxerStalled() { return !!stalled_demixer_read_cb_; }

  void UnstallDemuxer() {
    EXPECT_TRUE(IsDemuxerStalled());
    OnDemuxerRead(stalled_demixer_read_cb_);
  }

  // Reconfigures a renderer without config change support using given params.
  void ConfigureBasicRenderer(const AudioParameters& params) {
    hardware_params_ = params;
    sink_ = base::MakeRefCounted<FakeAudioRendererSink>(hardware_params_);
    renderer_ = std::make_unique<AudioRendererImpl>(
        main_thread_task_runner_, sink_.get(),
        base::BindRepeating(&AudioRendererImplTest::CreateAudioDecoderForTest,
                            base::Unretained(this)),
        &media_log_, 0, nullptr);
    testing::Mock::VerifyAndClearExpectations(&demuxer_stream_);
    ConfigureDemuxerStream(false);
  }

  // Reconfigures a renderer with config change support using given params.
  void ConfigureConfigChangeRenderer(const AudioParameters& params,
                                     const AudioParameters& hardware_params) {
    hardware_params_ = hardware_params;
    sink_ = base::MakeRefCounted<FakeAudioRendererSink>(hardware_params_);
    renderer_ = std::make_unique<AudioRendererImpl>(
        main_thread_task_runner_, sink_.get(),
        base::BindRepeating(&AudioRendererImplTest::CreateAudioDecoderForTest,
                            base::Unretained(this)),
        &media_log_, 0, nullptr);
    testing::Mock::VerifyAndClearExpectations(&demuxer_stream_);
    ConfigureDemuxerStream(true);
  }

  void ConfigureWithMockSink(const AudioParameters& params) {
    mock_sink_ = base::MakeRefCounted<MockAudioRendererSink>();
    renderer_ = std::make_unique<AudioRendererImpl>(
        main_thread_task_runner_, mock_sink_.get(),
        base::BindRepeating(&AudioRendererImplTest::CreateAudioDecoderForTest,
                            base::Unretained(this)),
        &media_log_, 0, nullptr);
    testing::Mock::VerifyAndClearExpectations(&demuxer_stream_);
    ConfigureDemuxerStream(true);
  }

  void ConfigureWithMockMediaLog() {
    sink_ = base::MakeRefCounted<FakeAudioRendererSink>(hardware_params_);
    renderer_ = std::make_unique<AudioRendererImpl>(
        main_thread_task_runner_, sink_.get(),
        base::BindRepeating(&AudioRendererImplTest::CreateAudioDecoderForTest,
                            base::Unretained(this)),
        &mock_media_log_, 0, nullptr);
    testing::Mock::VerifyAndClearExpectations(&demuxer_stream_);
    ConfigureDemuxerStream(true);
  }

  void EnableSpeechRecognition() { renderer_->EnableSpeechRecognition(); }

  // RendererClient implementation.
  MOCK_METHOD1(OnError, void(PipelineStatus));
  void OnFallback(PipelineStatus status) override { NOTREACHED(); }
  void OnEnded() override {
    CHECK(!ended_);
    ended_ = true;
  }
  void OnStatisticsUpdate(const PipelineStatistics& stats) override {
    last_statistics_.audio_memory_usage += stats.audio_memory_usage;
  }
  MOCK_METHOD2(OnBufferingStateChange,
               void(BufferingState, BufferingStateChangeReason));
  MOCK_METHOD1(OnWaiting, void(WaitingReason));
  MOCK_METHOD1(OnAudioConfigChange, void(const AudioDecoderConfig&));
  MOCK_METHOD1(OnVideoConfigChange, void(const VideoDecoderConfig&));
  MOCK_METHOD1(OnVideoNaturalSizeChange, void(const gfx::Size&));
  MOCK_METHOD1(OnVideoOpacityChange, void(bool));
  MOCK_METHOD1(OnVideoFrameRateChange, void(std::optional<int>));
  MOCK_METHOD1(OnDurationChange, void(base::TimeDelta));
  MOCK_METHOD1(OnRemotePlayStateChange, void(MediaStatus::State state));
  MOCK_METHOD1(TranscribeAudio, void(scoped_refptr<AudioBuffer>));

  // SpeechRecognitionClient implementation.
  MOCK_METHOD1(AddAudio, void(scoped_refptr<AudioBuffer>));
  MOCK_METHOD3(AddAudioBusOnMainSequence,
               void(std::unique_ptr<AudioBus>, int, ChannelLayout));
  MOCK_METHOD0(IsSpeechRecognitionAvailable, bool());
  MOCK_METHOD1(SetOnReadyCallback, void(OnReadyCallback));
  MOCK_METHOD1(AddAudio, void(const media::AudioBus&));
  MOCK_METHOD1(Reconfigure, void(const media::AudioParameters&));

  void InitializeRenderer(DemuxerStream* demuxer_stream,
                          PipelineStatusCallback pipeline_status_cb) {
    EXPECT_CALL(*this, OnWaiting(_)).Times(0);
    EXPECT_CALL(*this, OnVideoNaturalSizeChange(_)).Times(0);
    EXPECT_CALL(*this, OnVideoOpacityChange(_)).Times(0);
    EXPECT_CALL(*this, OnVideoConfigChange(_)).Times(0);
    renderer_->Initialize(demuxer_stream, nullptr, this,
                          std::move(pipeline_status_cb));
  }

  void Initialize() {
    InitializeWithStatus(PIPELINE_OK);
    next_timestamp_ =
        std::make_unique<AudioTimestampHelper>(kInputSamplesPerSecond);
  }

  void InitializeBitstreamFormat() {
    EXPECT_CALL(media_client_, IsSupportedBitstreamAudioCodec(_))
        .WillRepeatedly(Return(true));
    SetMediaClient(&media_client_);

    hardware_params_.Reset(AudioParameters::AUDIO_BITSTREAM_EAC3,
                           ChannelLayoutConfig::FromLayout<kChannelLayout>(),
                           kOutputSamplesPerSecond, 512);
    sink_ = base::MakeRefCounted<FakeAudioRendererSink>(hardware_params_);
    AudioDecoderConfig audio_config(AudioCodec::kAC3, kSampleFormatEac3,
                                    kChannelLayout, kInputSamplesPerSecond,
                                    EmptyExtraData(),
                                    EncryptionScheme::kUnencrypted);
    demuxer_stream_.set_audio_decoder_config(audio_config);

    ConfigureDemuxerStream(true);

    renderer_ = std::make_unique<AudioRendererImpl>(
        main_thread_task_runner_, sink_.get(),
        base::BindRepeating(&AudioRendererImplTest::CreateAudioDecoderForTest,
                            base::Unretained(this)),
        &media_log_, 0, this);

    Initialize();
  }

  void InitializeWithStatus(PipelineStatus expected) {
    SCOPED_TRACE(
        base::StringPrintf("InitializeWithStatus(%d)", expected.code()));

    WaitableMessageLoopEvent event;
    InitializeRenderer(&demuxer_stream_, event.GetPipelineStatusCB());
    event.RunAndWaitForStatus(expected);

    // We should have no reads.
    EXPECT_TRUE(!decode_cb_);
  }

  void InitializeAndDestroy() {
    WaitableMessageLoopEvent event;
    InitializeRenderer(&demuxer_stream_, event.GetPipelineStatusCB());

    // Destroy the |renderer_| before we let the MessageLoop run, this simulates
    // an interleaving in which we end up destroying the |renderer_| while the
    // OnDecoderSelected callback is in flight.
    renderer_.reset();
    event.RunAndWaitForStatus(PIPELINE_ERROR_ABORT);
  }

  void InitializeAndDestroyDuringDecoderInit() {
    enter_pending_decoder_init_ = true;

    WaitableMessageLoopEvent event;
    InitializeRenderer(&demuxer_stream_, event.GetPipelineStatusCB());
    base::RunLoop().RunUntilIdle();
    DCHECK(init_decoder_cb_);

    renderer_.reset();
    event.RunAndWaitForStatus(PIPELINE_ERROR_ABORT);
  }

  void EnterPendingDecoderInitState(AudioDecoder::InitCB cb) {
    init_decoder_cb_ = std::move(cb);
  }

  void FlushDuringPendingRead() {
    SCOPED_TRACE("FlushDuringPendingRead()");
    WaitableMessageLoopEvent flush_event;
    renderer_->Flush(flush_event.GetClosure());
    SatisfyPendingRead(InputFrames(kInputFramesChunk));
    flush_event.RunAndWait();

    EXPECT_FALSE(IsDecodePending());
  }

  void Preroll() { Preroll(base::TimeDelta(), base::TimeDelta(), PIPELINE_OK); }

  void Preroll(base::TimeDelta start_timestamp,
               base::TimeDelta first_timestamp,
               PipelineStatus expected) {
    SCOPED_TRACE(base::StringPrintf("Preroll(%" PRId64 ", %d)",
                                    first_timestamp.InMilliseconds(),
                                    expected.code()));
    next_timestamp_->SetBaseTimestamp(first_timestamp);

    // Fill entire buffer to complete prerolling.
    renderer_->SetMediaTime(start_timestamp);
    renderer_->StartPlaying();
    WaitForPendingRead();
    EXPECT_CALL(*this, OnBufferingStateChange(BUFFERING_HAVE_ENOUGH,
                                              BUFFERING_CHANGE_REASON_UNKNOWN));
    DeliverRemainingAudio();
  }

  void StartTicking() {
    renderer_->StartTicking();
    renderer_->SetPlaybackRate(1.0);
  }

  void StopTicking() { renderer_->StopTicking(); }

  bool IsDecodePending() const { return !!decode_cb_; }

  void WaitForPendingRead() {
    SCOPED_TRACE("WaitForPendingRead()");
    if (decode_cb_)
      return;

    DCHECK(!wait_for_pending_decode_cb_);

    WaitableMessageLoopEvent event;
    wait_for_pending_decode_cb_ = event.GetClosure();
    event.RunAndWait();

    DCHECK(decode_cb_);
    DCHECK(!wait_for_pending_decode_cb_);
  }

  // Delivers decoded frames to |renderer_|.
  void SatisfyPendingRead(InputFrames frames) {
    CHECK_GT(frames.value, 0);
    CHECK(decode_cb_);

    scoped_refptr<AudioBuffer> buffer;
    if (hardware_params_.IsBitstreamFormat()) {
      buffer = MakeBitstreamAudioBuffer(kSampleFormatEac3, kChannelLayout,
                                        kChannels, kInputSamplesPerSecond, 1, 0,
                                        frames.value, frames.value / 2,
                                        next_timestamp_->GetTimestamp());
    } else {
      buffer = MakeAudioBuffer<float>(
          kSampleFormat, kChannelLayout, kChannels, kInputSamplesPerSecond,
          1.0f, 0.0f, frames.value, next_timestamp_->GetTimestamp());
    }
    next_timestamp_->AddFrames(frames.value);

    DeliverBuffer(DecoderStatus::Codes::kOk, std::move(buffer));
  }

  void DeliverEndOfStream() {
    DCHECK(decode_cb_);

    // Return EOS buffer to trigger EOS frame.
    DemuxerStream::DecoderBufferVector buffers;
    buffers.emplace_back(DecoderBuffer::CreateEOSBuffer());
    EXPECT_CALL(demuxer_stream_, OnRead(_))
        .WillOnce(RunOnceCallback<0>(DemuxerStream::kOk, buffers));

    // Satisfy pending |decode_cb_| to trigger a new DemuxerStream::Read().
    main_thread_task_runner_->PostTask(
        FROM_HERE,
        base::BindOnce(std::move(decode_cb_), DecoderStatus::Codes::kOk));

    WaitForPendingRead();

    main_thread_task_runner_->PostTask(
        FROM_HERE,
        base::BindOnce(std::move(decode_cb_), DecoderStatus::Codes::kOk));

    base::RunLoop().RunUntilIdle();
    EXPECT_EQ(last_statistics_.audio_memory_usage,
              renderer_->algorithm_->GetMemoryUsage());
  }

  // Delivers frames until |renderer_|'s internal buffer is full and no longer
  // has pending reads.
  void DeliverRemainingAudio() {
    // NOTE: !IsDecodePending() -> frames_remaining_in_buffer() == 0... but the
    // arrow is unidirectional! DecoderStream does its own buffering of decoded
    // output such that it generally triggers reads even after the renderer's
    // buffer is full. Hence, the loop below must check both of the conditions
    // to ensure no pending reads exist after the function returns.
    while (frames_remaining_in_buffer().value > 0 || IsDecodePending()) {
      SatisfyPendingRead(InputFrames(kInputFramesChunk));
    }
  }

  // Consumes data from the buffer until what remains drops below the buffer's
  // capacity. Note that the buffer is often over-filled, such that consuming
  // a fixed amount of data cannot guarantee we fall below the full line.
  // Precondition: the buffer must be full when called.
  bool ConsumeBufferedDataUntilNotFull() {
    int buffered = frames_buffered().value;
    int capacity = buffer_capacity().value;
    DCHECK(buffered >= capacity);

    int overfill = buffered > capacity ? buffered - capacity : 0;
    int quarter_buffer = capacity / 4;

    // Leaves the buffer 3/4 full.
    return ConsumeBufferedData(OutputFrames(overfill + quarter_buffer));
  }

  // Attempts to consume |requested_frames| frames from |renderer_|'s internal
  // buffer. Returns true if and only if all of |requested_frames| were able
  // to be consumed.
  bool ConsumeBufferedData(OutputFrames requested_frames,
                           base::TimeDelta delay) {
    std::unique_ptr<AudioBus> bus =
        AudioBus::Create(kChannels, requested_frames.value);
    int frames_read = 0;
    EXPECT_TRUE(sink_->Render(bus.get(), delay, &frames_read));
    return frames_read == requested_frames.value;
  }

  bool ConsumeBufferedData(OutputFrames requested_frames) {
    return ConsumeBufferedData(requested_frames, base::TimeDelta());
  }

  bool ConsumeBitstreamBufferedData(OutputFrames requested_frames,
                                    base::TimeDelta delay = base::TimeDelta()) {
    std::unique_ptr<AudioBus> bus =
        AudioBus::Create(kChannels, requested_frames.value);
    int total_frames_read = 0;
    while (total_frames_read != requested_frames.value) {
      int frames_read = 0;
      EXPECT_TRUE(sink_->Render(bus.get(), delay, &frames_read));

      if (frames_read <= 0)
        break;
      total_frames_read += frames_read;
    }

    return total_frames_read == requested_frames.value;
  }

  base::TimeTicks ConvertMediaTime(base::TimeDelta timestamp,
                                   bool* is_time_moving) {
    std::vector<base::TimeTicks> wall_clock_times;
    *is_time_moving = renderer_->GetWallClockTimes(
        std::vector<base::TimeDelta>(1, timestamp), &wall_clock_times);
    return wall_clock_times[0];
  }

  base::TimeTicks CurrentMediaWallClockTime(bool* is_time_moving) {
    std::vector<base::TimeTicks> wall_clock_times;
    *is_time_moving = renderer_->GetWallClockTimes(
        std::vector<base::TimeDelta>(), &wall_clock_times);
    return wall_clock_times[0];
  }

  OutputFrames frames_buffered() {
    return OutputFrames(renderer_->algorithm_->BufferedFrames());
  }

  OutputFrames buffer_playback_threshold() {
    return OutputFrames(renderer_->algorithm_->QueuePlaybackThreshold());
  }

  OutputFrames buffer_capacity() {
    return OutputFrames(renderer_->algorithm_->QueueCapacity());
  }

  OutputFrames frames_remaining_in_buffer() {
    // This can happen if too much data was delivered, in which case the buffer
    // will accept the data but not increase capacity.
    if (frames_buffered().value > buffer_capacity().value) {
      return OutputFrames(0);
    }
    return OutputFrames(buffer_capacity().value - frames_buffered().value);
  }

  bool is_buffer_full() { return renderer_->algorithm_->IsQueueFull(); }

  void force_config_change(const AudioDecoderConfig& config) {
    renderer_->OnConfigChange(config);
  }

  InputFrames converter_input_frames_left() const {
    return InputFrames(
        renderer_->buffer_converter_->input_frames_left_for_testing());
  }

  base::TimeDelta CurrentMediaTime() { return renderer_->CurrentMediaTime(); }

  std::vector<bool> channel_mask() const {
    CHECK(renderer_->algorithm_);
    return renderer_->algorithm_->channel_mask_for_testing();
  }

  bool ended() const { return ended_; }

  void DecodeDecoder(scoped_refptr<DecoderBuffer> buffer,
                     AudioDecoder::DecodeCB decode_cb) {
    // TODO(scherkus): Make this a DCHECK after threading semantics are fixed.
    if (!main_thread_task_runner_->BelongsToCurrentThread()) {
      main_thread_task_runner_->PostTask(
          FROM_HERE,
          base::BindOnce(&AudioRendererImplTest::DecodeDecoder,
                         base::Unretained(this), buffer, std::move(decode_cb)));
      return;
    }

    CHECK(!decode_cb_) << "Overlapping decodes are not permitted";
    decode_cb_ = std::move(decode_cb);

    // Wake up WaitForPendingRead() if needed.
    if (wait_for_pending_decode_cb_)
      std::move(wait_for_pending_decode_cb_).Run();
  }

  void ResetDecoder(base::OnceClosure& reset_cb) {
    if (decode_cb_) {
      // |reset_cb| will be called in DeliverBuffer(), after the decoder is
      // flushed.
      reset_cb_ = std::move(reset_cb);
      return;
    }

    main_thread_task_runner_->PostTask(FROM_HERE, std::move(reset_cb));
  }

  void DeliverBuffer(DecoderStatus status, scoped_refptr<AudioBuffer> buffer) {
    CHECK(decode_cb_);

    if (buffer.get() && !buffer->end_of_stream())
      output_cb_.Run(std::move(buffer));
    std::move(decode_cb_).Run(status);

    if (reset_cb_)
      std::move(reset_cb_).Run();

    base::RunLoop().RunUntilIdle();
  }

  base::TimeDelta CalculateClockAndAlgorithmDrift() {
    return renderer_->CalculateClockAndAlgorithmDrift();
  }

  // Fixture members.
  AudioParameters hardware_params_;
  base::test::TaskEnvironment task_environment_;
  const scoped_refptr<base::SingleThreadTaskRunner> main_thread_task_runner_;
  NullMediaLog media_log_;
  MockMediaLog mock_media_log_;
  std::unique_ptr<AudioRendererImpl> renderer_;
  scoped_refptr<FakeAudioRendererSink> sink_;
  scoped_refptr<MockAudioRendererSink> mock_sink_;
  base::SimpleTestTickClock tick_clock_;
  PipelineStatistics last_statistics_;

  MockDemuxerStream demuxer_stream_;
  MockMediaClient media_client_;

  // When |simulate_demuxer_stall_| is set OnDemuxerRead() will put the callback
  // in  |stalled_demixer_read_cb_| instead of calling it.
  bool simulate_demuxer_stall_ = false;
  DemuxerStream::ReadCB stalled_demixer_read_cb_;

  // Used for satisfying reads.
  AudioDecoder::OutputCB output_cb_;
  AudioDecoder::DecodeCB decode_cb_;
  base::OnceClosure reset_cb_;
  std::unique_ptr<AudioTimestampHelper> next_timestamp_;

  // Run during DecodeDecoder() to unblock WaitForPendingRead().
  base::OnceClosure wait_for_pending_decode_cb_;

  AudioDecoder::InitCB init_decoder_cb_;
  bool expected_init_result_;
  bool enter_pending_decoder_init_;
  bool ended_;
};

TEST_F(AudioRendererImplTest, Initialize_Successful) {
  Initialize();
}

TEST_F(AudioRendererImplTest, Initialize_DecoderInitFailure) {
  expected_init_result_ = false;
  InitializeWithStatus(DECODER_ERROR_NOT_SUPPORTED);
}

TEST_F(AudioRendererImplTest, ReinitializeForDifferentStream) {
  // Initialize and start playback
  Initialize();
  Preroll();
  StartTicking();
  EXPECT_TRUE(ConsumeBufferedDataUntilNotFull());
  WaitForPendingRead();

  // Stop playback and flush
  StopTicking();
  EXPECT_TRUE(IsDecodePending());
  // Flush and expect to be notified that we have nothing.
  EXPECT_CALL(*this, OnBufferingStateChange(BUFFERING_HAVE_NOTHING, _));
  FlushDuringPendingRead();

  // Prepare a new demuxer stream.
  MockDemuxerStream new_stream(DemuxerStream::AUDIO);
  EXPECT_CALL(new_stream, SupportsConfigChanges()).WillOnce(Return(false));
  AudioDecoderConfig audio_config(kCodec, kSampleFormat, kChannelLayout,
                                  kInputSamplesPerSecond, EmptyExtraData(),
                                  EncryptionScheme::kUnencrypted);
  new_stream.set_audio_decoder_config(audio_config);

  // The renderer is now in the flushed state and can be reinitialized.
  WaitableMessageLoopEvent event;
  InitializeRenderer(&new_stream, event.GetPipelineStatusCB());
  event.RunAndWaitForStatus(PIPELINE_OK);
}

TEST_F(AudioRendererImplTest, SignalConfigChange) {
  // Initialize and start playback.
  Initialize();
  Preroll();
  StartTicking();
  EXPECT_TRUE(ConsumeBufferedData(OutputFrames(256)));
  // Note: no need to WaitForPendingRead() here or below. Historically this test
  // seemed to wait, but really the read was already pending because preroll
  // didn't satisfy the final read from decoder stream.

  // Force config change to simulate detected change from decoder stream. Expect
  // that RendererClient to be signaled with the new config.
  const AudioDecoderConfig kValidAudioConfig(
      AudioCodec::kVorbis, kSampleFormatPlanarF32, CHANNEL_LAYOUT_STEREO, 44100,
      EmptyExtraData(), EncryptionScheme::kUnencrypted);
  EXPECT_TRUE(kValidAudioConfig.IsValidConfig());
  EXPECT_CALL(*this, OnAudioConfigChange(DecoderConfigEq(kValidAudioConfig)));
  force_config_change(kValidAudioConfig);

  // Verify rendering can continue after config change.
  EXPECT_TRUE(ConsumeBufferedData(OutputFrames(256)));

  // Force a config change with an invalid dummy config. This is occasionally
  // done to reset internal state and should not bubble to the RendererClient.
  EXPECT_CALL(*this, OnAudioConfigChange(_)).Times(0);
  const AudioDecoderConfig kInvalidConfig;
  EXPECT_FALSE(kInvalidConfig.IsValidConfig());
  force_config_change(kInvalidConfig);
}

TEST_F(AudioRendererImplTest, Preroll) {
  Initialize();
  Preroll();
}

TEST_F(AudioRendererImplTest, StartTicking) {
  Initialize();
  Preroll();
  StartTicking();

  // Drain internal buffer, we should have a pending read.
  EXPECT_TRUE(ConsumeBufferedData(frames_buffered()));
  WaitForPendingRead();
}

TEST_F(AudioRendererImplTest, EndOfStream) {
  Initialize();
  Preroll();
  StartTicking();

  // Drain internal buffer, we should have a pending read.
  EXPECT_TRUE(ConsumeBufferedData(frames_buffered()));
  WaitForPendingRead();

  // Forcefully trigger underflow.
  EXPECT_FALSE(ConsumeBufferedData(OutputFrames(1)));
  EXPECT_CALL(*this, OnBufferingStateChange(BUFFERING_HAVE_NOTHING, _));

  // Fulfill the read with an end-of-stream buffer. Doing so should change our
  // buffering state so playback resumes.
  EXPECT_CALL(*this, OnBufferingStateChange(BUFFERING_HAVE_ENOUGH,
                                            BUFFERING_CHANGE_REASON_UNKNOWN));
  DeliverEndOfStream();

  // Consume all remaining data. We shouldn't have signal ended yet.
  EXPECT_TRUE(ConsumeBufferedData(frames_buffered()));
  base::RunLoop().RunUntilIdle();
  EXPECT_FALSE(ended());

  // Ended should trigger on next render call.
  EXPECT_FALSE(ConsumeBufferedData(OutputFrames(1)));
  base::RunLoop().RunUntilIdle();
  EXPECT_TRUE(ended());
}

TEST_F(AudioRendererImplTest, DecoderUnderflow) {
  Initialize();
  Preroll();
  StartTicking();

  // Drain internal buffer, we should have a pending read.
  EXPECT_TRUE(ConsumeBufferedData(frames_buffered()));
  WaitForPendingRead();

  // Verify the next FillBuffer() call triggers a buffering state change
  // update. Expect a decoder underflow flag because demuxer is not blocked on a
  // pending read.
  EXPECT_CALL(
      *this, OnBufferingStateChange(BUFFERING_HAVE_NOTHING, DECODER_UNDERFLOW));
  EXPECT_FALSE(ConsumeBufferedData(OutputFrames(1)));

  // Verify we're still not getting audio data.
  EXPECT_EQ(0, frames_buffered().value);
  EXPECT_FALSE(ConsumeBufferedData(OutputFrames(1)));

  // Deliver enough data to have enough for buffering.
  EXPECT_CALL(*this, OnBufferingStateChange(BUFFERING_HAVE_ENOUGH,
                                            BUFFERING_CHANGE_REASON_UNKNOWN));
  DeliverRemainingAudio();

  // Verify we're getting audio data.
  EXPECT_TRUE(ConsumeBufferedData(OutputFrames(1)));
}

TEST_F(AudioRendererImplTest, DemuxerUnderflow) {
  Initialize();
  Preroll();
  StartTicking();

  // Drain internal buffer, we should have a pending read.
  EXPECT_TRUE(ConsumeBufferedData(frames_buffered()));
  WaitForPendingRead();

  // Verify the next FillBuffer() call triggers a buffering state change
  // update. Expect a demuxer underflow flag because demuxer is blocked on a
  // pending read.
  EXPECT_CALL(
      *this, OnBufferingStateChange(BUFFERING_HAVE_NOTHING, DEMUXER_UNDERFLOW));
  EXPECT_FALSE(ConsumeBufferedData(OutputFrames(1)));

  // Verify we're still not getting audio data.
  EXPECT_EQ(0, frames_buffered().value);
  EXPECT_FALSE(ConsumeBufferedData(OutputFrames(1)));

  // Deliver enough data to have enough for buffering.
  EXPECT_CALL(*this, OnBufferingStateChange(BUFFERING_HAVE_ENOUGH,
                                            BUFFERING_CHANGE_REASON_UNKNOWN));

  // Stall the demuxer to trigger underflow.
  simulate_demuxer_stall_ = true;
  SatisfyPendingRead(InputFrames(kInputFramesChunk));
  UnstallDemuxer();

  DeliverRemainingAudio();

  // Verify we're getting audio data.
  EXPECT_TRUE(ConsumeBufferedData(OutputFrames(1)));
}

TEST_F(AudioRendererImplTest, Underflow_CapacityResetsAfterFlush) {
  Initialize();
  Preroll();
  StartTicking();

  // Drain internal buffer, we should have a pending read.
  EXPECT_TRUE(ConsumeBufferedData(frames_buffered()));
  WaitForPendingRead();

  // Verify the next FillBuffer() call triggers the underflow callback
  // since the decoder hasn't delivered any data after it was drained.
  OutputFrames initial_capacity = buffer_capacity();
  EXPECT_CALL(*this, OnBufferingStateChange(BUFFERING_HAVE_NOTHING, _));
  EXPECT_FALSE(ConsumeBufferedData(OutputFrames(1)));

  // Verify that the buffer capacity increased as a result of underflowing.
  EXPECT_GT(buffer_capacity().value, initial_capacity.value);

  // Verify that the buffer capacity is restored to the |initial_capacity|.
  StopTicking();
  FlushDuringPendingRead();
  EXPECT_EQ(buffer_capacity().value, initial_capacity.value);
}

TEST_F(AudioRendererImplTest, Underflow_CapacityIncreasesBeforeHaveNothing) {
  Initialize();
  Preroll();
  StartTicking();

  // Verify the next FillBuffer() call triggers the underflow callback
  // since the decoder hasn't delivered any data after it was drained.
  OutputFrames initial_capacity = buffer_capacity();

  // Drain internal buffer.
  EXPECT_FALSE(ConsumeBufferedData(OutputFrames(frames_buffered().value + 1)));

  // Verify that the buffer capacity increased despite not sending have nothing.
  EXPECT_GT(buffer_capacity().value, initial_capacity.value);
}

TEST_F(AudioRendererImplTest, Underflow_OneCapacityIncreasePerUnderflow) {
  Initialize();
  Preroll();
  StartTicking();

  OutputFrames prev_capacity = buffer_capacity();

  // Consume more than is available (partial read) to trigger underflow.
  EXPECT_CALL(*this, OnBufferingStateChange(BUFFERING_HAVE_NOTHING, _));
  EXPECT_FALSE(ConsumeBufferedData(OutputFrames(frames_buffered().value + 1)));

  // Verify first underflow triggers an increase to buffer capacity and
  // signals HAVE_NOTHING.
  EXPECT_GT(buffer_capacity().value, prev_capacity.value);
  prev_capacity = buffer_capacity();
  // Give HAVE_NOTHING a chance to post.
  base::RunLoop().RunUntilIdle();
  testing::Mock::VerifyAndClearExpectations(this);

  // Try reading again, this time with the queue totally empty. We should expect
  // NO additional HAVE_NOTHING and NO increase to capacity because we still
  // haven't refilled the queue since the previous underflow.
  EXPECT_EQ(0, frames_buffered().value);
  EXPECT_CALL(*this, OnBufferingStateChange(BUFFERING_HAVE_NOTHING, _))
      .Times(0);
  EXPECT_FALSE(ConsumeBufferedData(OutputFrames(1)));
  EXPECT_EQ(buffer_capacity().value, prev_capacity.value);
  // Give HAVE_NOTHING a chance to NOT post.
  base::RunLoop().RunUntilIdle();
  testing::Mock::VerifyAndClearExpectations(this);

  // Fill the buffer back up.
  WaitForPendingRead();
  DeliverRemainingAudio();
  EXPECT_GT(frames_buffered().value, 0);

  // Consume all available data without underflowing. Expect no buffer state
  // change and no change to capacity.
  EXPECT_CALL(*this, OnBufferingStateChange(BUFFERING_HAVE_NOTHING, _))
      .Times(0);
  EXPECT_TRUE(ConsumeBufferedData(OutputFrames(frames_buffered().value)));
  EXPECT_EQ(buffer_capacity().value, prev_capacity.value);
  // Give HAVE_NOTHING a chance to NOT post.
  base::RunLoop().RunUntilIdle();
  testing::Mock::VerifyAndClearExpectations(this);

  // Now empty, trigger underflow attempting to read one frame. This should
  // signal buffering state change and increase capacity.
  EXPECT_CALL(*this, OnBufferingStateChange(BUFFERING_HAVE_NOTHING, _));
  EXPECT_FALSE(ConsumeBufferedData(OutputFrames(1)));
  EXPECT_GT(buffer_capacity().value, prev_capacity.value);
  // Give HAVE_NOTHING a chance to NOT post.
  base::RunLoop().RunUntilIdle();
  testing::Mock::VerifyAndClearExpectations(this);
}

// Verify that the proper reduced search space is configured for playback rate
// changes when upmixing is applied to the input.
TEST_F(AudioRendererImplTest, ChannelMask) {
  AudioParameters hw_params(
      AudioParameters::AUDIO_PCM_LOW_LATENCY,
      ChannelLayoutConfig::FromLayout<CHANNEL_LAYOUT_7_1>(),
      kOutputSamplesPerSecond, 1024);
  ConfigureConfigChangeRenderer(
      AudioParameters(AudioParameters::AUDIO_PCM_LOW_LATENCY,
                      ChannelLayoutConfig::Stereo(), kOutputSamplesPerSecond,
                      1024),
      hw_params);
  Initialize();
  std::vector<bool> mask = channel_mask();
  EXPECT_FALSE(mask.empty());
  ASSERT_EQ(mask.size(), static_cast<size_t>(hw_params.channels()));
  for (int ch = 0; ch < hw_params.channels(); ++ch) {
    if (ch > 1)
      ASSERT_FALSE(mask[ch]);
    else
      ASSERT_TRUE(mask[ch]);
  }

  renderer_->SetMediaTime(base::TimeDelta());
  renderer_->StartPlaying();
  WaitForPendingRead();

  // Force a channel configuration change.
  scoped_refptr<AudioBuffer> buffer = MakeAudioBuffer<float>(
      kSampleFormat, hw_params.channel_layout(), hw_params.channels(),
      kInputSamplesPerSecond, 1.0f, 0.0f, kInputFramesChunk, base::TimeDelta());
  DeliverBuffer(DecoderStatus::Codes::kOk, std::move(buffer));

  // All channels should now be enabled.
  mask = channel_mask();
  EXPECT_FALSE(mask.empty());
  ASSERT_EQ(mask.size(), static_cast<size_t>(hw_params.channels()));
  for (int ch = 0; ch < hw_params.channels(); ++ch)
    ASSERT_TRUE(mask[ch]);
}

// Verify that the proper channel mask is configured when downmixing is applied
// to the input with discrete layout. The default hardware layout is stereo.
TEST_F(AudioRendererImplTest, ChannelMask_DownmixDiscreteLayout) {
  int audio_channels = 9;

  AudioDecoderConfig audio_config(
      AudioCodec::kOpus, kSampleFormat, CHANNEL_LAYOUT_DISCRETE,
      kInputSamplesPerSecond, EmptyExtraData(), EncryptionScheme::kUnencrypted);
  audio_config.SetChannelsForDiscrete(audio_channels);
  demuxer_stream_.set_audio_decoder_config(audio_config);
  ConfigureDemuxerStream(true);

  // Fake an attached webaudio client.
  sink_->SetIsOptimizedForHardwareParameters(false);

  Initialize();
  std::vector<bool> mask = channel_mask();
  EXPECT_FALSE(mask.empty());
  ASSERT_EQ(mask.size(), static_cast<size_t>(audio_channels));
  for (int ch = 0; ch < audio_channels; ++ch)
    ASSERT_TRUE(mask[ch]);
}

TEST_F(AudioRendererImplTest, Underflow_Flush) {
  Initialize();
  Preroll();
  StartTicking();

  // Force underflow.
  EXPECT_TRUE(ConsumeBufferedData(frames_buffered()));
  WaitForPendingRead();
  EXPECT_CALL(*this, OnBufferingStateChange(BUFFERING_HAVE_NOTHING, _));
  EXPECT_FALSE(ConsumeBufferedData(OutputFrames(1)));
  WaitForPendingRead();
  StopTicking();

  // We shouldn't expect another buffering state change when flushing.
  FlushDuringPendingRead();
}

TEST_F(AudioRendererImplTest, PendingRead_Flush) {
  Initialize();

  Preroll();
  StartTicking();

  // Partially drain internal buffer so we get a pending read.
  EXPECT_TRUE(ConsumeBufferedDataUntilNotFull());
  WaitForPendingRead();

  StopTicking();

  EXPECT_TRUE(IsDecodePending());

  // Flush and expect to be notified that we have nothing.
  EXPECT_CALL(*this, OnBufferingStateChange(BUFFERING_HAVE_NOTHING, _));
  FlushDuringPendingRead();

  // Preroll again to a different timestamp and verify it completed normally.
  const base::TimeDelta seek_timestamp = base::Milliseconds(1000);
  Preroll(seek_timestamp, seek_timestamp, PIPELINE_OK);
}

TEST_F(AudioRendererImplTest, PendingRead_Destroy) {
  Initialize();

  Preroll();
  StartTicking();

  // Partially drain internal buffer so we get a pending read.
  EXPECT_TRUE(ConsumeBufferedDataUntilNotFull());
  WaitForPendingRead();

  StopTicking();

  EXPECT_TRUE(IsDecodePending());

  renderer_.reset();
}

TEST_F(AudioRendererImplTest, PendingFlush_Destroy) {
  Initialize();

  Preroll();
  StartTicking();

  // Partially drain internal buffer so we get a pending read.
  EXPECT_TRUE(ConsumeBufferedDataUntilNotFull());
  WaitForPendingRead();

  StopTicking();

  EXPECT_TRUE(IsDecodePending());

  // Start flushing.
  WaitableMessageLoopEvent flush_event;
  renderer_->Flush(flush_event.GetClosure());

  EXPECT_CALL(*this, OnBufferingStateChange(BUFFERING_HAVE_NOTHING, _));
  SatisfyPendingRead(InputFrames(kInputFramesChunk));

  renderer_.reset();
}

TEST_F(AudioRendererImplTest, InitializeThenDestroy) {
  InitializeAndDestroy();
}

TEST_F(AudioRendererImplTest, InitializeThenDestroyDuringDecoderInit) {
  InitializeAndDestroyDuringDecoderInit();
}

TEST_F(AudioRendererImplTest, CurrentMediaTimeBehavior) {
  Initialize();
  Preroll();
  StartTicking();

  AudioTimestampHelper timestamp_helper(kOutputSamplesPerSecond);
  timestamp_helper.SetBaseTimestamp(base::TimeDelta());

  // Time should be the starting timestamp as nothing has been consumed yet.
  EXPECT_EQ(timestamp_helper.GetTimestamp(), CurrentMediaTime());

  const OutputFrames frames_to_consume(frames_buffered().value / 3);
  const base::TimeDelta kConsumptionDuration =
      timestamp_helper.GetFrameDuration(frames_to_consume.value);

  // Render() has not be called yet, thus no data has been consumed, so
  // advancing tick clock must not change the media time.
  tick_clock_.Advance(kConsumptionDuration);
  EXPECT_EQ(timestamp_helper.GetTimestamp(), CurrentMediaTime());

  // Consume some audio data.
  EXPECT_TRUE(ConsumeBufferedData(frames_to_consume));
  // No need to wait for a pending read here. It may or may not happen depending
  // on how over-filled the buffer is. Either way, not important for this test.

  // Time shouldn't change just yet because we've only sent the initial audio
  // data to the hardware.
  EXPECT_EQ(timestamp_helper.GetTimestamp(), CurrentMediaTime());

  // Advancing the tick clock now should result in an estimated media time.
  tick_clock_.Advance(kConsumptionDuration);
  EXPECT_EQ(timestamp_helper.GetTimestamp() + kConsumptionDuration,
            CurrentMediaTime());

  // Consume some more audio data.
  EXPECT_TRUE(ConsumeBufferedData(frames_to_consume));

  // Time should change now that Render() has been called a second time.
  timestamp_helper.AddFrames(frames_to_consume.value);
  EXPECT_EQ(timestamp_helper.GetTimestamp(), CurrentMediaTime());

  // Advance current time well past all played audio to simulate an irregular or
  // delayed OS callback. The value should be clamped to what's been rendered.
  timestamp_helper.AddFrames(frames_to_consume.value);
  tick_clock_.Advance(kConsumptionDuration * 2);
  EXPECT_EQ(timestamp_helper.GetTimestamp(), CurrentMediaTime());

  // Consume some more audio data.
  EXPECT_TRUE(ConsumeBufferedData(frames_to_consume));

  // Stop ticking, the media time should be clamped to what's been rendered.
  StopTicking();
  EXPECT_EQ(timestamp_helper.GetTimestamp(), CurrentMediaTime());
  tick_clock_.Advance(kConsumptionDuration * 2);
  timestamp_helper.AddFrames(frames_to_consume.value);
  EXPECT_EQ(timestamp_helper.GetTimestamp(), CurrentMediaTime());
}

TEST_F(AudioRendererImplTest, RenderingDelayedForEarlyStartTime) {
  Initialize();

  // Choose a first timestamp a few buffers into the future, which ends halfway
  // through the desired output buffer; this allows for maximum test coverage.
  const double kBuffers = 4.5;
  const base::TimeDelta first_timestamp =
      base::Seconds(hardware_params_.frames_per_buffer() * kBuffers /
                    hardware_params_.sample_rate());

  Preroll(base::TimeDelta(), first_timestamp, PIPELINE_OK);
  StartTicking();

  // Verify the first few buffers are silent.
  std::unique_ptr<AudioBus> bus = AudioBus::Create(hardware_params_);
  int frames_read = 0;
  for (int i = 0; i < std::floor(kBuffers); ++i) {
    EXPECT_TRUE(sink_->Render(bus.get(), base::TimeDelta(), &frames_read));
    EXPECT_EQ(frames_read, bus->frames());
    for (int j = 0; j < bus->frames(); ++j)
      ASSERT_FLOAT_EQ(0.0f, bus->channel(0)[j]);

    // Buffer may have been previously over-filled. Only expect new reads when
    // we drop below "full".
    if (!is_buffer_full()) {
      WaitForPendingRead();
      DeliverRemainingAudio();
    }
  }

  // Verify the last buffer is half silence and half real data.
  EXPECT_TRUE(sink_->Render(bus.get(), base::TimeDelta(), &frames_read));
  EXPECT_EQ(frames_read, bus->frames());
  const int zero_frames =
      bus->frames() * (kBuffers - static_cast<int>(kBuffers));

  for (int i = 0; i < zero_frames; ++i)
    ASSERT_FLOAT_EQ(0.0f, bus->channel(0)[i]);
  for (int i = zero_frames; i < bus->frames(); ++i)
    ASSERT_NE(0.0f, bus->channel(0)[i]);
}

TEST_F(AudioRendererImplTest, RenderingDelayedForSuspend) {
  Initialize();
  Preroll(base::TimeDelta(), base::TimeDelta(), PIPELINE_OK);
  StartTicking();

  // Verify the first buffer is real data.
  int frames_read = 0;
  std::unique_ptr<AudioBus> bus = AudioBus::Create(hardware_params_);
  EXPECT_TRUE(sink_->Render(bus.get(), base::TimeDelta(), &frames_read));
  EXPECT_NE(0, frames_read);
  for (int i = 0; i < bus->frames(); ++i)
    ASSERT_NE(0.0f, bus->channel(0)[i]);

  // Verify after suspend we get silence.
  renderer_->OnSuspend();
  EXPECT_TRUE(sink_->Render(bus.get(), base::TimeDelta(), &frames_read));
  EXPECT_EQ(0, frames_read);

  // Verify after resume we get audio.
  bus->Zero();
  renderer_->OnResume();
  EXPECT_TRUE(sink_->Render(bus.get(), base::TimeDelta(), &frames_read));
  EXPECT_NE(0, frames_read);
  for (int i = 0; i < bus->frames(); ++i)
    ASSERT_NE(0.0f, bus->channel(0)[i]);
}

TEST_F(AudioRendererImplTest, AbsurdRenderingDelayLog) {
  ConfigureWithMockMediaLog();
  Initialize();
  Preroll(base::TimeDelta(), base::TimeDelta(), PIPELINE_OK);
  StartTicking();

  // Verify the first buffer is real data.
  int frames_read = 0;
  std::unique_ptr<AudioBus> bus = AudioBus::Create(hardware_params_);

  EXPECT_MEDIA_LOG_ON(mock_media_log_,
                      testing::HasSubstr("Large rendering delay"));
  EXPECT_TRUE(sink_->Render(bus.get(), base::Seconds(5), &frames_read));
}

TEST_F(AudioRendererImplTest, RenderingDelayDoesNotOverflow) {
  Initialize();

  // Choose a first timestamp as far into the future as possible. Without care
  // this can cause an overflow in rendering arithmetic.
  Preroll(base::TimeDelta(), base::TimeDelta::Max(), PIPELINE_OK);
  StartTicking();
  EXPECT_TRUE(ConsumeBufferedData(OutputFrames(1)));
}

TEST_F(AudioRendererImplTest, ImmediateEndOfStream) {
  Initialize();

  renderer_->SetMediaTime(base::TimeDelta());
  renderer_->StartPlaying();
  WaitForPendingRead();

  // The buffering state change must occur before the ended signal.
  EXPECT_CALL(*this, OnBufferingStateChange(BUFFERING_HAVE_ENOUGH,
                                            BUFFERING_CHANGE_REASON_UNKNOWN))
      .WillOnce(AssertNotYetEnded(this));
  DeliverEndOfStream();

  EXPECT_TRUE(ended());
}

TEST_F(AudioRendererImplTest, OnRenderErrorCausesDecodeError) {
  Initialize();
  Preroll();
  StartTicking();

  EXPECT_CALL(*this, OnError(HasStatusCode(AUDIO_RENDERER_ERROR)));
  sink_->OnRenderError();
  base::RunLoop().RunUntilIdle();
}

// Test for AudioRendererImpl calling Pause()/Play() on the sink when the
// playback rate is set to zero and non-zero.
TEST_F(AudioRendererImplTest, SetPlaybackRate) {
  Initialize();
  Preroll();

  // Rendering hasn't started. Sink should always be paused.
  EXPECT_EQ(FakeAudioRendererSink::kPaused, sink_->state());
  renderer_->SetPlaybackRate(0.0);
  EXPECT_EQ(FakeAudioRendererSink::kPaused, sink_->state());
  renderer_->SetPlaybackRate(1.0);
  EXPECT_EQ(FakeAudioRendererSink::kPaused, sink_->state());

  // Rendering has started with non-zero rate. Rate changes will affect sink
  // state.
  renderer_->StartTicking();
  EXPECT_EQ(FakeAudioRendererSink::kPlaying, sink_->state());
  renderer_->SetPlaybackRate(0.0);
  EXPECT_EQ(FakeAudioRendererSink::kPaused, sink_->state());
  renderer_->SetPlaybackRate(1.0);
  EXPECT_EQ(FakeAudioRendererSink::kPlaying, sink_->state());

  // Rendering has stopped. Sink should be paused.
  renderer_->StopTicking();
  EXPECT_EQ(FakeAudioRendererSink::kPaused, sink_->state());

  // Start rendering with zero playback rate. Sink should be paused until
  // non-zero rate is set.
  renderer_->SetPlaybackRate(0.0);
  renderer_->StartTicking();
  EXPECT_EQ(FakeAudioRendererSink::kPaused, sink_->state());
  renderer_->SetPlaybackRate(1.0);
  EXPECT_EQ(FakeAudioRendererSink::kPlaying, sink_->state());
}

TEST_F(AudioRendererImplTest, TimeSourceBehavior) {
  Initialize();
  Preroll();

  AudioTimestampHelper timestamp_helper(kOutputSamplesPerSecond);
  timestamp_helper.SetBaseTimestamp(base::TimeDelta());

  // Prior to start, time should be shown as not moving.
  bool is_time_moving = false;
  EXPECT_EQ(base::TimeTicks(),
            ConvertMediaTime(base::TimeDelta(), &is_time_moving));
  EXPECT_FALSE(is_time_moving);

  EXPECT_EQ(base::TimeTicks(), CurrentMediaWallClockTime(&is_time_moving));
  EXPECT_FALSE(is_time_moving);

  // Start ticking, but use a zero playback rate, time should still be stopped
  // until a positive playback rate is set and the first Render() is called.
  renderer_->SetPlaybackRate(0.0);
  StartTicking();
  EXPECT_EQ(base::TimeTicks(), CurrentMediaWallClockTime(&is_time_moving));
  EXPECT_FALSE(is_time_moving);
  renderer_->SetPlaybackRate(1.0);
  EXPECT_EQ(base::TimeTicks(), CurrentMediaWallClockTime(&is_time_moving));
  EXPECT_FALSE(is_time_moving);
  renderer_->SetPlaybackRate(1.0);

  // Issue the first render call to start time moving.
  OutputFrames frames_to_consume(frames_buffered().value / 2);
  EXPECT_TRUE(ConsumeBufferedData(frames_to_consume));
  WaitForPendingRead();

  // Time shouldn't change just yet because we've only sent the initial audio
  // data to the hardware.
  EXPECT_EQ(tick_clock_.NowTicks(),
            ConvertMediaTime(base::TimeDelta(), &is_time_moving));
  EXPECT_TRUE(is_time_moving);

  // A system suspend should freeze the time state and resume restart it.
  renderer_->OnSuspend();
  EXPECT_EQ(tick_clock_.NowTicks(),
            ConvertMediaTime(base::TimeDelta(), &is_time_moving));
  EXPECT_FALSE(is_time_moving);
  renderer_->OnResume();
  EXPECT_EQ(tick_clock_.NowTicks(),
            ConvertMediaTime(base::TimeDelta(), &is_time_moving));
  EXPECT_TRUE(is_time_moving);

  // Consume some more audio data.
  frames_to_consume = frames_buffered();
  tick_clock_.Advance(base::Seconds(1.0 / kOutputSamplesPerSecond));
  EXPECT_TRUE(ConsumeBufferedData(frames_to_consume));

  // Time should change now that the audio hardware has called back.
  const base::TimeTicks wall_clock_time_zero =
      tick_clock_.NowTicks() -
      timestamp_helper.GetFrameDuration(frames_to_consume.value);
  EXPECT_EQ(wall_clock_time_zero,
            ConvertMediaTime(base::TimeDelta(), &is_time_moving));
  EXPECT_TRUE(is_time_moving);

  // Store current media time before advancing the tick clock since the call is
  // compensated based on TimeTicks::Now().
  const base::TimeDelta current_media_time = renderer_->CurrentMediaTime();

  // The current wall clock time should change as our tick clock advances, up
  // until we've reached the end of played out frames.
  const int kSteps = 4;
  const base::TimeDelta kAdvanceDelta =
      timestamp_helper.GetFrameDuration(frames_to_consume.value) / kSteps;

  for (int i = 0; i < kSteps; ++i) {
    tick_clock_.Advance(kAdvanceDelta);
    EXPECT_EQ(tick_clock_.NowTicks(),
              CurrentMediaWallClockTime(&is_time_moving));
    EXPECT_TRUE(is_time_moving);
  }

  // Converting the current media time should be relative to wall clock zero.
  EXPECT_EQ(wall_clock_time_zero + kSteps * kAdvanceDelta,
            ConvertMediaTime(current_media_time, &is_time_moving));
  EXPECT_TRUE(is_time_moving);

  // Advancing once more will exceed the amount of played out frames finally.
  const base::TimeDelta kOneSample =
      base::Seconds(1.0 / kOutputSamplesPerSecond);
  base::TimeTicks current_time = tick_clock_.NowTicks();
  tick_clock_.Advance(kOneSample);
  EXPECT_EQ(current_time, CurrentMediaWallClockTime(&is_time_moving));
  EXPECT_TRUE(is_time_moving);

  StopTicking();
  DeliverRemainingAudio();

  // Elapse a lot of time between StopTicking() and the next Render() call.
  const base::TimeDelta kOneSecond = base::Seconds(1);
  tick_clock_.Advance(kOneSecond);
  StartTicking();

  // Time should be stopped until the next render call.
  EXPECT_EQ(current_time, CurrentMediaWallClockTime(&is_time_moving));
  EXPECT_FALSE(is_time_moving);

  // Consume some buffered data with a small delay.
  uint32_t delay_frames = 500;
  base::TimeDelta delay_time =
      base::Microseconds(std::round(delay_frames * kOutputMicrosPerFrame));

  frames_to_consume.value = frames_buffered().value / 16;
  EXPECT_TRUE(ConsumeBufferedData(frames_to_consume, delay_time));

  // Verify time is adjusted for the current delay.
  current_time = tick_clock_.NowTicks() + delay_time;
  EXPECT_EQ(current_time, CurrentMediaWallClockTime(&is_time_moving));
  EXPECT_TRUE(is_time_moving);
  EXPECT_EQ(current_time,
            ConvertMediaTime(renderer_->CurrentMediaTime(), &is_time_moving));
  EXPECT_TRUE(is_time_moving);

  tick_clock_.Advance(kOneSample);
  renderer_->SetPlaybackRate(2);
  EXPECT_EQ(current_time, CurrentMediaWallClockTime(&is_time_moving));
  EXPECT_TRUE(is_time_moving);
  EXPECT_EQ(current_time + kOneSample * 2,
            ConvertMediaTime(renderer_->CurrentMediaTime(), &is_time_moving));
  EXPECT_TRUE(is_time_moving);

  // Advance far enough that we shouldn't be clamped to current time (tested
  // already above).
  tick_clock_.Advance(kOneSecond);
  EXPECT_EQ(
      current_time + timestamp_helper.GetFrameDuration(frames_to_consume.value),
      CurrentMediaWallClockTime(&is_time_moving));
  EXPECT_TRUE(is_time_moving);
}

TEST_F(AudioRendererImplTest, MultipleRateChangesKeepSync) {
  Initialize();
  Preroll();

  AudioTimestampHelper timestamp_helper(kOutputSamplesPerSecond);
  timestamp_helper.SetBaseTimestamp(base::TimeDelta());

  // Start ticking, but use a zero playback rate, time should still be stopped
  // until a positive playback rate is set and the first Render() is called.
  renderer_->SetPlaybackRate(1.0);
  StartTicking();

  // Issue the first render call to start time moving.
  OutputFrames frames_to_consume(frames_buffered().value / 10);
  EXPECT_TRUE(ConsumeBufferedData(frames_to_consume));

  // Time shouldn't change just yet because we've only sent the initial audio
  // data to the hardware.
  bool is_time_moving;
  EXPECT_EQ(tick_clock_.NowTicks(),
            ConvertMediaTime(base::TimeDelta(), &is_time_moving));
  EXPECT_TRUE(is_time_moving);

  // Issue reads w/ multiple playback rate changes from above to below and back.
  // The drift should remain zero throughout.
  renderer_->SetPlaybackRate(2.0);
  EXPECT_TRUE(ConsumeBufferedData(frames_to_consume));
  EXPECT_EQ(CalculateClockAndAlgorithmDrift(), base::TimeDelta());

  EXPECT_TRUE(ConsumeBufferedData(frames_to_consume));
  EXPECT_EQ(CalculateClockAndAlgorithmDrift(), base::TimeDelta());

  renderer_->SetPlaybackRate(3.0);
  EXPECT_TRUE(ConsumeBufferedData(frames_to_consume));
  EXPECT_EQ(CalculateClockAndAlgorithmDrift(), base::TimeDelta());

  WaitForPendingRead();
  DeliverRemainingAudio();

  EXPECT_TRUE(ConsumeBufferedData(frames_to_consume));
  EXPECT_EQ(CalculateClockAndAlgorithmDrift(), base::TimeDelta());

  renderer_->SetPlaybackRate(0.5);
  EXPECT_TRUE(ConsumeBufferedData(frames_to_consume));
  EXPECT_EQ(CalculateClockAndAlgorithmDrift(), base::TimeDelta());

  EXPECT_TRUE(ConsumeBufferedData(frames_to_consume));
  EXPECT_EQ(CalculateClockAndAlgorithmDrift(), base::TimeDelta());

  renderer_->SetPlaybackRate(1.0);
  EXPECT_TRUE(ConsumeBufferedData(frames_to_consume));
  EXPECT_EQ(CalculateClockAndAlgorithmDrift(), base::TimeDelta());

  renderer_->SetPlaybackRate(1.5);
  EXPECT_TRUE(ConsumeBufferedData(frames_to_consume));
  EXPECT_EQ(CalculateClockAndAlgorithmDrift(), base::TimeDelta());
}

TEST_F(AudioRendererImplTest, BitstreamEndOfStream) {
  // NOTE: bitstream formats are pass-through to sink, so input size == output
  // NOTE: bitstream audio buffers must always consume a whole number of
  // buffers (i.e. N*kOutputFramesChunk).
  const int kOutputFramesChunk = kInputFramesChunk;

  InitializeBitstreamFormat();
  Preroll();
  StartTicking();

  // Drain past the internal buffer, triggering underflow and a pending read.
  EXPECT_FALSE(ConsumeBitstreamBufferedData(
      OutputFrames(frames_buffered().value + kOutputFramesChunk)));
  EXPECT_CALL(*this, OnBufferingStateChange(BUFFERING_HAVE_NOTHING, _));
  WaitForPendingRead();

  // Fulfill the read with an end-of-stream buffer. Doing so should change our
  // buffering state so playback resumes.
  EXPECT_CALL(*this, OnBufferingStateChange(BUFFERING_HAVE_ENOUGH,
                                            BUFFERING_CHANGE_REASON_UNKNOWN));
  DeliverEndOfStream();

  // Consume all remaining data. We shouldn't have signal ended yet.
  if (frames_buffered().value != 0)
    EXPECT_TRUE(ConsumeBitstreamBufferedData(frames_buffered()));
  base::RunLoop().RunUntilIdle();
  EXPECT_FALSE(ended());

  // Ended should trigger on next render call.
  EXPECT_FALSE(ConsumeBitstreamBufferedData(OutputFrames(1)));
  base::RunLoop().RunUntilIdle();
  EXPECT_TRUE(ended());

  // Clear the use of |media_client_|, which was set in
  // InitializeBitstreamFormat().
  SetMediaClient(nullptr);
}

TEST_F(AudioRendererImplTest, MutedPlaybackBadDeviceInfo) {
  base::test::ScopedFeatureList scoped_feature_list_;
  scoped_feature_list_.InitAndEnableFeature(kSuspendMutedAudio);

  mock_sink_ = base::MakeRefCounted<MockAudioRendererSink>(
      std::string(), OUTPUT_DEVICE_STATUS_ERROR_NOT_AUTHORIZED,
      AudioParameters());
  renderer_ = std::make_unique<AudioRendererImpl>(
      main_thread_task_runner_, mock_sink_.get(),
      base::BindRepeating(&AudioRendererImplTest::CreateAudioDecoderForTest,
                          base::Unretained(this)),
      &media_log_, 0, nullptr);
  testing::Mock::VerifyAndClearExpectations(&demuxer_stream_);
  ConfigureDemuxerStream(true);

  EXPECT_CALL(*mock_sink_, SetVolume(0)).Times(0);
  renderer_->SetVolume(0);

  // Playback startup should use never touch our passed in sink, since an
  // internal NullAudioSink is always used for bad device info.
  EXPECT_CALL(*mock_sink_, Start()).Times(0);
  Initialize();
  Preroll();
  StartTicking();

  EXPECT_CALL(*mock_sink_, Pause()).Times(0);
  StopTicking();
  EXPECT_CALL(*mock_sink_, Play()).Times(0);
  StartTicking();
  testing::Mock::VerifyAndClearExpectations(mock_sink_.get());

  EXPECT_CALL(*mock_sink_, SetVolume(1)).Times(0);
  EXPECT_CALL(*mock_sink_, Start()).Times(0);
  EXPECT_CALL(*mock_sink_, Play()).Times(0);
  renderer_->SetVolume(1);

  EXPECT_CALL(*mock_sink_, Pause()).Times(0);
  StopTicking();
  EXPECT_CALL(*mock_sink_, Stop()).Times(0);
}

TEST_F(AudioRendererImplTest, BasicMutedPlayback) {
  base::test::ScopedFeatureList scoped_feature_list_;
  scoped_feature_list_.InitAndEnableFeature(kSuspendMutedAudio);
  ConfigureWithMockSink(hardware_params_);

  EXPECT_CALL(*mock_sink_, SetVolume(0));
  renderer_->SetVolume(0);

  // Playback startup shouldn't start the real sink.
  EXPECT_CALL(*mock_sink_, Start()).Times(0);
  Initialize();
  Preroll();
  StartTicking();

  // Play pause should all function as normal on the muted sink.
  EXPECT_CALL(*mock_sink_, Pause()).Times(0);
  StopTicking();
  EXPECT_CALL(*mock_sink_, Play()).Times(0);
  StartTicking();
  testing::Mock::VerifyAndClearExpectations(mock_sink_.get());

  // First unmute should start and play the real sink.
  EXPECT_CALL(*mock_sink_, SetVolume(1));
  EXPECT_CALL(*mock_sink_, Start());
  EXPECT_CALL(*mock_sink_, Play());
  renderer_->SetVolume(1);

  // Play pause should all function as normal on the normal sink.
  EXPECT_CALL(*mock_sink_, Pause());
  StopTicking();
  EXPECT_CALL(*mock_sink_, Play());
  StartTicking();
  testing::Mock::VerifyAndClearExpectations(mock_sink_.get());

  // Muting again should pause the real sink.
  EXPECT_CALL(*mock_sink_, SetVolume(0));
  EXPECT_CALL(*mock_sink_, Pause());
  renderer_->SetVolume(0);
  testing::Mock::VerifyAndClearExpectations(mock_sink_.get());

  // Second unmuted play shouldn't try to Start() again.
  EXPECT_CALL(*mock_sink_, SetVolume(0.5f));
  EXPECT_CALL(*mock_sink_, Play());
  renderer_->SetVolume(0.5f);
  testing::Mock::VerifyAndClearExpectations(mock_sink_.get());

  EXPECT_CALL(*mock_sink_, Pause());
  StopTicking();
  EXPECT_CALL(*mock_sink_, Stop());
}

TEST_F(AudioRendererImplTest, SinkIsFlushed) {
  ConfigureWithMockSink(
      AudioParameters(AudioParameters::AUDIO_PCM_LOW_LATENCY,
                      ChannelLayoutConfig::FromLayout<kChannelLayout>(),
                      kOutputSamplesPerSecond, 1024 * 15));
  Initialize();
  Preroll();
  StartTicking();
  StopTicking();

  // Verify renderer Flush() triggers sink Flush().
  EXPECT_CALL(*mock_sink_, Flush());
  EXPECT_CALL(*this, OnBufferingStateChange(BUFFERING_HAVE_NOTHING, _));
  WaitableMessageLoopEvent flush_event;
  renderer_->Flush(flush_event.GetClosure());
  flush_event.RunAndWait();
}

TEST_F(AudioRendererImplTest, LowLatencyHint) {
  // Frames per buffer chosen to be small enough that we will have some room to
  // decrease the algorithm buffer below its default value of 200ms.
  int kFramesPerBuffer = 100;
  // Use a basic setup that avoids buffer conversion and sample rate mismatch.
  // This simplifies passing frames to the algorithm and verification of
  // frames-to-time logic.
  ConfigureBasicRenderer(
      AudioParameters(AudioParameters::AUDIO_PCM_LOW_LATENCY,
                      ChannelLayoutConfig::FromLayout<kChannelLayout>(),
                      kInputSamplesPerSecond, kFramesPerBuffer));
  Initialize();

  // Setup renderer for playback.
  next_timestamp_->SetBaseTimestamp(base::TimeDelta());
  renderer_->SetMediaTime(base::TimeDelta());
  renderer_->StartPlaying();
  StartTicking();
  WaitForPendingRead();

  // With no latency hint set, the default playback threshold should equal
  // the buffer's total capacity.
  const int default_buffer_playback_threshold =
      buffer_playback_threshold().value;
  const int default_buffer_capacity = buffer_capacity().value;
  EXPECT_EQ(default_buffer_playback_threshold, default_buffer_capacity);

  // Fill the buffer to the playback threshold. Verify HAVE_ENOUGH is reached.
  EXPECT_CALL(*this, OnBufferingStateChange(BUFFERING_HAVE_ENOUGH,
                                            BUFFERING_CHANGE_REASON_UNKNOWN));
  SatisfyPendingRead(InputFrames(default_buffer_playback_threshold));
  EXPECT_EQ(frames_buffered().value, default_buffer_playback_threshold);
  base::RunLoop().RunUntilIdle();  // Let HAVE_ENOUGH post.
  testing::Mock::VerifyAndClearExpectations(this);

  // Force underflow by reading 1 frame past the buffered amount.
  EXPECT_CALL(*this, OnBufferingStateChange(BUFFERING_HAVE_NOTHING, _));
  ConsumeBitstreamBufferedData(OutputFrames(frames_buffered().value + 1));
  base::RunLoop().RunUntilIdle();  // Let HAVE_NOTHING post.
  testing::Mock::VerifyAndClearExpectations(this);

  // Underflow should trigger a capacity increase *when no latency hint is set*.
  // Playback threshold should also increase, still matching capacity.
  EXPECT_GT(buffer_capacity().value, default_buffer_capacity);
  EXPECT_EQ(buffer_playback_threshold().value, buffer_capacity().value);

  // Set a *LATENCY HINT* that reduces the playback buffering threshold by half.
  base::TimeDelta default_buffering_latency =
      AudioTimestampHelper::FramesToTime(default_buffer_playback_threshold,
                                         kInputSamplesPerSecond);
  base::TimeDelta low_latency = default_buffering_latency / 2;
  renderer_->SetLatencyHint(low_latency);

  // Verify playback threshold now reflects the lower latency target.
  int low_latency_playback_threshold = buffer_playback_threshold().value;
  EXPECT_EQ(AudioTimestampHelper::FramesToTime(low_latency_playback_threshold,
                                               kInputSamplesPerSecond),
            low_latency);

  // Verify total buffer capacity is unchanged, leaving it higher than the
  // playback threshold.
  EXPECT_EQ(buffer_capacity().value, default_buffer_capacity);
  EXPECT_GT(buffer_capacity().value, low_latency_playback_threshold);

  // Verify HAVE_ENOUGH is reached when filled to this lower threshold value.
  EXPECT_CALL(*this, OnBufferingStateChange(BUFFERING_HAVE_ENOUGH,
                                            BUFFERING_CHANGE_REASON_UNKNOWN));
  SatisfyPendingRead(InputFrames(low_latency_playback_threshold));
  EXPECT_EQ(frames_buffered().value, low_latency_playback_threshold);
  base::RunLoop().RunUntilIdle();  // Let HAVE_ENOUGH post.
  testing::Mock::VerifyAndClearExpectations(this);

  // Verify the buffer will happily continue filling, exceeding the playback
  // threshold, until it becomes "full";
  DeliverRemainingAudio();
  EXPECT_GE(frames_buffered().value, buffer_capacity().value);

  // Again force underflow by reading 1 frame past the buffered amount.
  EXPECT_CALL(*this, OnBufferingStateChange(BUFFERING_HAVE_NOTHING, _));
  ConsumeBitstreamBufferedData(OutputFrames(frames_buffered().value + 1));
  base::RunLoop().RunUntilIdle();  // Let HAVE_NOTHING post.
  testing::Mock::VerifyAndClearExpectations(this);

  // With latency hint set, this underflow should NOT trigger a capacity
  // increase, nor a change to the playback threshold.
  EXPECT_EQ(buffer_capacity().value, default_buffer_capacity);
  EXPECT_EQ(buffer_playback_threshold().value, low_latency_playback_threshold);
}

TEST_F(AudioRendererImplTest, HighLatencyHint) {
  // Frames per buffer chosen to be small enough that we will have some room to
  // decrease the algorithm buffer below its default value of 200ms.
  int kFramesPerBuffer = 100;
  // Use a basic setup that avoids buffer conversion and sample rate mismatch.
  // This simplifies passing frames to the algorithm and verification of
  // frames-to-time logic.
  ConfigureBasicRenderer(
      AudioParameters(AudioParameters::AUDIO_PCM_LOW_LATENCY,
                      ChannelLayoutConfig::FromLayout<kChannelLayout>(),
                      kInputSamplesPerSecond, kFramesPerBuffer));
  Initialize();

  // Setup renderer for playback.
  next_timestamp_->SetBaseTimestamp(base::TimeDelta());
  renderer_->SetMediaTime(base::TimeDelta());
  renderer_->StartPlaying();
  StartTicking();
  WaitForPendingRead();

  // With no latency hint set, the default playback threshold should equal
  // the buffer's total capacity.
  const int default_buffer_playback_threshold =
      buffer_playback_threshold().value;
  const int default_buffer_capacity = buffer_capacity().value;
  EXPECT_EQ(default_buffer_playback_threshold, default_buffer_capacity);

  // Fill the buffer to the playback threshold. Verify HAVE_ENOUGH is reached.
  EXPECT_CALL(*this, OnBufferingStateChange(BUFFERING_HAVE_ENOUGH,
                                            BUFFERING_CHANGE_REASON_UNKNOWN));
  SatisfyPendingRead(InputFrames(default_buffer_playback_threshold));
  EXPECT_EQ(frames_buffered().value, default_buffer_playback_threshold);
  base::RunLoop().RunUntilIdle();  // Let HAVE_ENOUGH post.
  testing::Mock::VerifyAndClearExpectations(this);

  // Force underflow by reading 1 frame past the buffered amount.
  EXPECT_CALL(*this, OnBufferingStateChange(BUFFERING_HAVE_NOTHING, _));
  ConsumeBitstreamBufferedData(OutputFrames(frames_buffered().value + 1));
  base::RunLoop().RunUntilIdle();  // Let HAVE_NOTHING post.
  testing::Mock::VerifyAndClearExpectations(this);

  // Underflow should trigger a capacity increase *when no latency hint is set*.
  // Playback threshold should also increase, still matching capacity.
  EXPECT_GT(buffer_capacity().value, default_buffer_capacity);
  EXPECT_EQ(buffer_playback_threshold().value, buffer_capacity().value);

  // Set a *LATENCY HINT* that increases the playback buffering threshold by 2x.
  base::TimeDelta default_buffering_latency =
      AudioTimestampHelper::FramesToTime(default_buffer_playback_threshold,
                                         kInputSamplesPerSecond);
  base::TimeDelta high_latency = default_buffering_latency * 2;
  renderer_->SetLatencyHint(high_latency);

  // Verify playback threshold now reflects the higher latency target.
  int high_latency_playback_threshold = buffer_playback_threshold().value;
  EXPECT_EQ(AudioTimestampHelper::FramesToTime(high_latency_playback_threshold,
                                               kInputSamplesPerSecond),
            high_latency);

  // Verify total buffer capacity is also increased by the same amount.
  EXPECT_GT(buffer_capacity().value, default_buffer_capacity);
  EXPECT_EQ(buffer_capacity().value, high_latency_playback_threshold);

  // Verify HAVE_ENOUGH is reached when filled to this higher threshold value.
  EXPECT_CALL(*this, OnBufferingStateChange(BUFFERING_HAVE_ENOUGH,
                                            BUFFERING_CHANGE_REASON_UNKNOWN));
  SatisfyPendingRead(InputFrames(high_latency_playback_threshold));
  EXPECT_EQ(frames_buffered().value, high_latency_playback_threshold);
  base::RunLoop().RunUntilIdle();  // Let HAVE_ENOUGH post.
  testing::Mock::VerifyAndClearExpectations(this);

  // Verify the buffer is also considered "full" when saturated to this higher
  // threshold.
  EXPECT_GE(frames_buffered().value, buffer_capacity().value);

  // Again force underflow by reading 1 frame past the buffered amount.
  EXPECT_CALL(*this, OnBufferingStateChange(BUFFERING_HAVE_NOTHING, _));
  ConsumeBitstreamBufferedData(OutputFrames(frames_buffered().value + 1));
  base::RunLoop().RunUntilIdle();  // Let HAVE_NOTHING post.
  testing::Mock::VerifyAndClearExpectations(this);

  // With a latency hint set, this underflow should NOT trigger a capacity
  // increase, nor a change to the playback threshold.
  EXPECT_EQ(buffer_capacity().value, high_latency_playback_threshold);
  EXPECT_EQ(buffer_playback_threshold().value, high_latency_playback_threshold);
}

TEST_F(AudioRendererImplTest, PlayUnmuted) {
  // Setting the volume to a non-zero value does not count as unmuted until the
  // audio is played.
  EXPECT_EQ(renderer_->was_unmuted_for_testing(), 0);
  renderer_->SetVolume(1);
  EXPECT_EQ(renderer_->was_unmuted_for_testing(), 0);

  Initialize();
  Preroll();
  StartTicking();
  EXPECT_EQ(renderer_->was_unmuted_for_testing(), 1);
}

TEST_F(AudioRendererImplTest, UnmuteWhilePlaying) {
  ConfigureWithMockSink(hardware_params_);
  EXPECT_CALL(*mock_sink_, SetVolume(0));
  renderer_->SetVolume(0);
  EXPECT_EQ(renderer_->was_unmuted_for_testing(), 0);

  EXPECT_CALL(*mock_sink_, Start());
  EXPECT_CALL(*mock_sink_, Play());
  Initialize();
  Preroll();
  StartTicking();
  EXPECT_EQ(renderer_->was_unmuted_for_testing(), 0);

  EXPECT_CALL(*mock_sink_, SetVolume(1));
  renderer_->SetVolume(1);
  EXPECT_EQ(renderer_->was_unmuted_for_testing(), 1);

  // Muting should pause the sink.
  EXPECT_CALL(*mock_sink_, SetVolume(0));
  EXPECT_CALL(*mock_sink_, Pause());
  renderer_->SetVolume(0);
  EXPECT_EQ(renderer_->was_unmuted_for_testing(), 1);

  StopTicking();
  EXPECT_CALL(*mock_sink_, Stop());
}

TEST_F(AudioRendererImplTest, DecodeAudioReadyPreemptsFlush) {
  Initialize();

  Preroll();
  StartTicking();
  EXPECT_TRUE(ConsumeBufferedDataUntilNotFull());
  WaitForPendingRead();
  EXPECT_CALL(*this, OnError(HasStatusCode(PIPELINE_ERROR_DECODE)));
  StopTicking();
  EXPECT_TRUE(IsDecodePending());

  // Imitate the behavior of a pending seek as flush_cb_;
  renderer_->Flush(base::BindOnce(&AudioRendererImpl::StartPlaying,
                                  base::Unretained(renderer_.get())));

  // This shouldn't cause a deadlock.
  renderer_->decoded_audio_ready_for_testing();
}

#if !BUILDFLAG(IS_ANDROID)
TEST_F(AudioRendererImplTest,
       TranscribeAudioCallback_SpeechRecognitionDisabled) {
  EXPECT_CALL(*this, SetOnReadyCallback(_));
  Initialize();

  EXPECT_CALL(*this, AddAudio(testing::An<scoped_refptr<AudioBuffer>>()))
      .Times(0);
  Preroll();

  StartTicking();
}

TEST_F(AudioRendererImplTest,
       TranscribeAudioCallback_Muted_WithoutUserActivation) {
  EnableSpeechRecognition();
  EXPECT_CALL(*this, SetOnReadyCallback(_));
  Initialize();

  EXPECT_CALL(*this, AddAudio(testing::An<scoped_refptr<AudioBuffer>>()))
      .Times(0);
  Preroll();

  StartTicking();
}

TEST_F(AudioRendererImplTest,
       TranscribeAudioCallback_Unmuted_WithoutUserActivation) {
  EnableSpeechRecognition();

  EXPECT_CALL(*this, SetOnReadyCallback(_));
  Initialize();

  EXPECT_CALL(*this, AddAudio(testing::An<scoped_refptr<AudioBuffer>>()))
      .Times(3);
  next_timestamp_->SetBaseTimestamp(base::TimeDelta());
  renderer_->SetMediaTime(base::TimeDelta());
  renderer_->StartPlaying();
  renderer_->SetVolume(1);
  WaitForPendingRead();

  EXPECT_CALL(*this, OnBufferingStateChange(BUFFERING_HAVE_ENOUGH,
                                            BUFFERING_CHANGE_REASON_UNKNOWN));
  DeliverRemainingAudio();
  StartTicking();

  EXPECT_EQ(renderer_->was_unmuted_for_testing(), 1);
}

TEST_F(AudioRendererImplTest,
       TranscribeAudioCallback_Muted_WithUserActivation) {
  EnableSpeechRecognition();
  renderer_->SetWasPlayedWithUserActivationAndHighMediaEngagement(true);

  EXPECT_CALL(*this, SetOnReadyCallback(_));
  Initialize();

  EXPECT_CALL(*this, AddAudio(testing::An<scoped_refptr<AudioBuffer>>()))
      .Times(3);
  Preroll();

  StartTicking();
  EXPECT_EQ(renderer_->was_unmuted_for_testing(), 1);
}
#endif

}  // namespace media