src/cobalt/media/base/audio_buffer_converter_unittest.cc

// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "cobalt/media/base/audio_buffer_converter.h"

#include <memory>

#include "cobalt/media/base/audio_buffer.h"
#include "cobalt/media/base/sinc_resampler.h"
#include "cobalt/media/base/test_helpers.h"
#include "starboard/types.h"
#include "testing/gmock/include/gmock/gmock.h"
#include "testing/gtest/include/gtest/gtest.h"

namespace cobalt {
namespace media {

// Important: Use an odd buffer size here so SIMD issues are caught.
const int kOutFrameSize = 441;
const int kOutSampleRate = 44100;
const ChannelLayout kOutChannelLayout = CHANNEL_LAYOUT_STEREO;
const int kOutChannelCount = 2;

static scoped_refptr<AudioBuffer> MakeTestBuffer(int sample_rate,
                                                 ChannelLayout channel_layout,
                                                 int channel_count,
                                                 int frames) {
  return MakeAudioBuffer<uint8_t>(kSampleFormatU8, channel_layout,
                                  channel_count, sample_rate, 0, 1, frames,
                                  base::TimeDelta::FromSeconds(0));
}

class AudioBufferConverterTest : public ::testing::Test {
 public:
  AudioBufferConverterTest()
      : input_frames_(0),
        expected_output_frames_(0.0),
        output_frames_(0),
        output_params_(AudioParameters::AUDIO_PCM_LOW_LATENCY,
                       kOutChannelLayout, kOutSampleRate, 16, kOutFrameSize) {
    audio_buffer_converter_.reset(new AudioBufferConverter(output_params_));
  }

  void Reset() {
    audio_buffer_converter_->Reset();
    output_frames_ = expected_output_frames_ = input_frames_ = 0;
  }

  void AddInput(const scoped_refptr<AudioBuffer>& in) {
    if (!in->end_of_stream()) {
      input_frames_ += in->frame_count();
      expected_output_frames_ +=
          in->frame_count() *
          (static_cast<double>(output_params_.sample_rate()) /
           in->sample_rate());
    }
    audio_buffer_converter_->AddInput(in);
  }

  void ConsumeOutput() {
    ASSERT_TRUE(audio_buffer_converter_->HasNextBuffer());
    scoped_refptr<AudioBuffer> out = audio_buffer_converter_->GetNextBuffer();
    if (!out->end_of_stream()) {
      output_frames_ += out->frame_count();
      EXPECT_EQ(out->sample_rate(), output_params_.sample_rate());
      EXPECT_EQ(out->channel_layout(), output_params_.channel_layout());
      EXPECT_EQ(out->channel_count(), output_params_.channels());
    } else {
      EXPECT_FALSE(audio_buffer_converter_->HasNextBuffer());
    }
  }

  void ConsumeAllOutput() {
    AddInput(AudioBuffer::CreateEOSBuffer());
    while (audio_buffer_converter_->HasNextBuffer()) ConsumeOutput();
    EXPECT_EQ(output_frames_, ceil(expected_output_frames_));
  }

 protected:
  std::unique_ptr<AudioBufferConverter> audio_buffer_converter_;

  int input_frames_;
  double expected_output_frames_;
  int output_frames_;
  int input_buffers_;
  AudioParameters output_params_;
};

TEST_F(AudioBufferConverterTest, PassThrough) {
  scoped_refptr<AudioBuffer> in =
      MakeTestBuffer(kOutSampleRate, kOutChannelLayout, kOutChannelCount, 512);
  AddInput(in);
  ConsumeAllOutput();
}

TEST_F(AudioBufferConverterTest, Downsample) {
  scoped_refptr<AudioBuffer> in =
      MakeTestBuffer(48000, kOutChannelLayout, kOutChannelCount, 512);
  AddInput(in);
  ConsumeAllOutput();
}

TEST_F(AudioBufferConverterTest, Upsample) {
  scoped_refptr<AudioBuffer> in =
      MakeTestBuffer(8000, kOutChannelLayout, kOutChannelCount, 512);
  AddInput(in);
  ConsumeAllOutput();
}

// Test resampling a buffer smaller than the SincResampler's kernel size.
TEST_F(AudioBufferConverterTest, Resample_TinyBuffer) {
  AddInput(MakeTestBuffer(48000, CHANNEL_LAYOUT_STEREO, 2,
                          SincResampler::kKernelSize - 1));
  ConsumeAllOutput();
}

TEST_F(AudioBufferConverterTest, Resample_DifferingBufferSizes) {
  const int input_sample_rate = 48000;
  AddInput(MakeTestBuffer(input_sample_rate, kOutChannelLayout,
                          kOutChannelCount, 100));
  AddInput(MakeTestBuffer(input_sample_rate, kOutChannelLayout,
                          kOutChannelCount, 200));
  AddInput(MakeTestBuffer(input_sample_rate, kOutChannelLayout,
                          kOutChannelCount, 300));
  AddInput(MakeTestBuffer(input_sample_rate, kOutChannelLayout,
                          kOutChannelCount, 400));
  AddInput(MakeTestBuffer(input_sample_rate, kOutChannelLayout,
                          kOutChannelCount, 500));
  ConsumeAllOutput();
}

TEST_F(AudioBufferConverterTest, ChannelDownmix) {
  scoped_refptr<AudioBuffer> in =
      MakeTestBuffer(kOutSampleRate, CHANNEL_LAYOUT_MONO, 1, 512);
  AddInput(in);
  ConsumeAllOutput();
}

TEST_F(AudioBufferConverterTest, ChannelUpmix) {
  scoped_refptr<AudioBuffer> in =
      MakeTestBuffer(kOutSampleRate, CHANNEL_LAYOUT_5_1, 6, 512);
  AddInput(in);
  ConsumeAllOutput();
}

TEST_F(AudioBufferConverterTest, ResampleAndRemix) {
  scoped_refptr<AudioBuffer> in =
      MakeTestBuffer(48000, CHANNEL_LAYOUT_5_1, 6, 512);
  AddInput(in);
  ConsumeAllOutput();
}

TEST_F(AudioBufferConverterTest, ConfigChange_SampleRate) {
  AddInput(MakeTestBuffer(48000, kOutChannelLayout, kOutChannelCount, 512));
  AddInput(MakeTestBuffer(44100, kOutChannelLayout, kOutChannelCount, 512));
  ConsumeAllOutput();
}

TEST_F(AudioBufferConverterTest, ConfigChange_ChannelLayout) {
  AddInput(MakeTestBuffer(kOutSampleRate, CHANNEL_LAYOUT_STEREO, 2, 512));
  AddInput(MakeTestBuffer(kOutSampleRate, CHANNEL_LAYOUT_MONO, 1, 512));
  ConsumeAllOutput();
}

TEST_F(AudioBufferConverterTest, ConfigChange_SampleRateAndChannelLayout) {
  AddInput(MakeTestBuffer(44100, CHANNEL_LAYOUT_STEREO, 2, 512));
  AddInput(MakeTestBuffer(48000, CHANNEL_LAYOUT_MONO, 1, 512));
  ConsumeAllOutput();
}

TEST_F(AudioBufferConverterTest, ConfigChange_Multiple) {
  AddInput(MakeTestBuffer(44100, CHANNEL_LAYOUT_STEREO, 2, 512));
  AddInput(MakeTestBuffer(48000, CHANNEL_LAYOUT_MONO, 1, 512));
  AddInput(MakeTestBuffer(44100, CHANNEL_LAYOUT_5_1, 6, 512));
  AddInput(MakeTestBuffer(22050, CHANNEL_LAYOUT_STEREO, 2, 512));
  ConsumeAllOutput();
}

TEST_F(AudioBufferConverterTest, Reset) {
  AddInput(MakeTestBuffer(44100, CHANNEL_LAYOUT_STEREO, 2, 512));
  Reset();
  ConsumeAllOutput();
}

TEST_F(AudioBufferConverterTest, ResampleThenReset) {
  // Resampling is likely to leave some data buffered in AudioConverter's
  // fifo or resampler, so make sure Reset() cleans that all up.
  AddInput(MakeTestBuffer(48000, CHANNEL_LAYOUT_STEREO, 2, 512));
  Reset();
  ConsumeAllOutput();
}

TEST_F(AudioBufferConverterTest, ResetThenConvert) {
  AddInput(
      MakeTestBuffer(kOutSampleRate, kOutChannelLayout, kOutChannelCount, 512));
  Reset();
  // Make sure we can keep using the AudioBufferConverter after we've Reset().
  AddInput(
      MakeTestBuffer(kOutSampleRate, kOutChannelLayout, kOutChannelCount, 512));
  ConsumeAllOutput();
}

TEST_F(AudioBufferConverterTest, DiscreteChannelLayout) {
  output_params_ =
      AudioParameters(AudioParameters::AUDIO_PCM_LOW_LATENCY,
                      CHANNEL_LAYOUT_DISCRETE, kOutSampleRate, 16, 512);
  output_params_.set_channels_for_discrete(2);
  audio_buffer_converter_.reset(new AudioBufferConverter(output_params_));
  AddInput(MakeTestBuffer(kOutSampleRate, CHANNEL_LAYOUT_STEREO, 2, 512));
  ConsumeAllOutput();
}

TEST_F(AudioBufferConverterTest, LargeBuffersResampling) {
  output_params_ = AudioParameters(AudioParameters::AUDIO_PCM_LOW_LATENCY,
                                   kOutChannelLayout, kOutSampleRate, 16, 2048);

  audio_buffer_converter_.reset(new AudioBufferConverter(output_params_));
  const int kInputSampleRate = 48000;
  const int kInputFrameSize = 8192;
  ASSERT_NE(kInputSampleRate, kOutSampleRate);

  const int kInputBuffers = 3;
  for (int i = 0; i < kInputBuffers; ++i) {
    AddInput(MakeTestBuffer(kInputSampleRate, kOutChannelLayout,
                            kOutChannelCount, kInputFrameSize));
  }

  // Do not add an EOS packet here, as it will invoke flushing.
  while (audio_buffer_converter_->HasNextBuffer()) ConsumeOutput();

  // Since the input buffer size is a multiple of the input request size there
  // should never be any frames remaining at this point.
  ASSERT_EQ(kInputFrameSize %
                audio_buffer_converter_->input_buffer_size_for_testing(),
            0);
  EXPECT_EQ(0, audio_buffer_converter_->input_frames_left_for_testing());
}

}  // namespace media
}  // namespace cobalt