media/base/audio_bus.cc

// Copyright (c) 2012 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 "media/base/audio_bus.h"

#include "base/logging.h"
#include "base/numerics/safe_conversions.h"
#include "media/audio/audio_parameters.h"
#include "media/base/limits.h"
#include "media/base/vector_math.h"

namespace media {

static const uint8 kUint8Bias = 128;

static bool IsAligned(void* ptr) {
  return (reinterpret_cast<uintptr_t>(ptr) &
          (AudioBus::kChannelAlignment - 1)) == 0U;
}

// Calculates the required size for an AudioBus with the given params, sets
// |aligned_frames| to the actual frame length of each channel array.
static int CalculateMemorySizeInternal(int channels, int frames,
                                       int* out_aligned_frames) {
  // Choose a size such that each channel will be aligned by
  // kChannelAlignment when stored in a contiguous block.
  int aligned_frames =
      ((frames * sizeof(float) + AudioBus::kChannelAlignment - 1) &
       ~(AudioBus::kChannelAlignment - 1)) / sizeof(float);

  if (out_aligned_frames)
    *out_aligned_frames = aligned_frames;

  return sizeof(float) * channels * aligned_frames;
}

// |Format| is the destination type.  If a bias is present, |Fixed| must be a
// type larger than |Format| such that operations can be made without
// overflowing.  Without a bias |Fixed| must be the same as |Format|.
template<class Format, class Fixed, Format Bias>
static void FromInterleavedInternal(const void* src, int start_frame,
                                    int frames, AudioBus* dest,
                                    float min, float max) {
  COMPILE_ASSERT((Bias == 0 && sizeof(Fixed) == sizeof(Format)) ||
                 sizeof(Fixed) > sizeof(Format), invalid_deinterleave_types);
  const Format* source = static_cast<const Format*>(src);
  const int channels = dest->channels();
  for (int ch = 0; ch < channels; ++ch) {
    float* channel_data = dest->channel(ch);
    for (int i = start_frame, offset = ch; i < start_frame + frames;
         ++i, offset += channels) {
      const Fixed v = static_cast<Fixed>(source[offset]) - Bias;
      channel_data[i] = v * (v < 0 ? -min : max);
    }
  }
}

// |Format| is the destination type.  If a bias is present, |Fixed| must be a
// type larger than |Format| such that operations can be made without
// overflowing.  Without a bias |Fixed| must be the same as |Format|.
template<class Format, class Fixed, Format Bias>
static void ToInterleavedInternal(const AudioBus* source, int start_frame,
                                  int frames, void* dst, Fixed min, Fixed max) {
  COMPILE_ASSERT((Bias == 0 && sizeof(Fixed) == sizeof(Format)) ||
                 sizeof(Fixed) > sizeof(Format), invalid_interleave_types);
  Format* dest = static_cast<Format*>(dst);
  const int channels = source->channels();
  for (int ch = 0; ch < channels; ++ch) {
    const float* channel_data = source->channel(ch);
    for (int i = start_frame, offset = ch; i < start_frame + frames;
         ++i, offset += channels) {
      const float v = channel_data[i];

      Fixed sample;
      if (v < 0)
        sample = v <= -1 ? min : static_cast<Fixed>(-v * min);
      else
        sample = v >= 1 ? max : static_cast<Fixed>(v * max);

      dest[offset] = static_cast<Format>(sample) + Bias;
    }
  }
}

static void ValidateConfig(int channels, int frames) {
  CHECK_GT(frames, 0);
  CHECK_GT(channels, 0);
  CHECK_LE(channels, static_cast<int>(limits::kMaxChannels));
}

static void CheckOverflow(int start_frame, int frames, int total_frames) {
  CHECK_GE(start_frame, 0);
  CHECK_GE(frames, 0);
  CHECK_GT(total_frames, 0);
  int sum = start_frame + frames;
  CHECK_LE(sum, total_frames);
  CHECK_GE(sum, 0);
}

AudioBus::AudioBus(int channels, int frames)
    : frames_(frames),
      can_set_channel_data_(false) {
  ValidateConfig(channels, frames_);

  int aligned_frames = 0;
  int size = CalculateMemorySizeInternal(channels, frames, &aligned_frames);

  data_.reset(static_cast<float*>(base::AlignedAlloc(
      size, AudioBus::kChannelAlignment)));

  BuildChannelData(channels, aligned_frames, data_.get());
}

AudioBus::AudioBus(int channels, int frames, float* data)
    : frames_(frames),
      can_set_channel_data_(false) {
  // Since |data| may have come from an external source, ensure it's valid.
  CHECK(data);
  ValidateConfig(channels, frames_);

  int aligned_frames = 0;
  CalculateMemorySizeInternal(channels, frames, &aligned_frames);

  BuildChannelData(channels, aligned_frames, data);
}

AudioBus::AudioBus(int frames, const std::vector<float*>& channel_data)
    : channel_data_(channel_data),
      frames_(frames),
      can_set_channel_data_(false) {
  ValidateConfig(
      base::checked_cast<int>(channel_data_.size()), frames_);

  // Sanity check wrapped vector for alignment and channel count.
  for (size_t i = 0; i < channel_data_.size(); ++i)
    DCHECK(IsAligned(channel_data_[i]));
}

AudioBus::AudioBus(int channels)
    : channel_data_(channels),
      frames_(0),
      can_set_channel_data_(true) {
  CHECK_GT(channels, 0);
  for (size_t i = 0; i < channel_data_.size(); ++i)
    channel_data_[i] = NULL;
}

AudioBus::~AudioBus() {}

scoped_ptr<AudioBus> AudioBus::Create(int channels, int frames) {
  return scoped_ptr<AudioBus>(new AudioBus(channels, frames));
}

scoped_ptr<AudioBus> AudioBus::Create(const AudioParameters& params) {
  return scoped_ptr<AudioBus>(new AudioBus(
      params.channels(), params.frames_per_buffer()));
}

scoped_ptr<AudioBus> AudioBus::CreateWrapper(int channels) {
  return scoped_ptr<AudioBus>(new AudioBus(channels));
}

scoped_ptr<AudioBus> AudioBus::WrapVector(
    int frames, const std::vector<float*>& channel_data) {
  return scoped_ptr<AudioBus>(new AudioBus(frames, channel_data));
}

scoped_ptr<AudioBus> AudioBus::WrapMemory(int channels, int frames,
                                          void* data) {
  // |data| must be aligned by AudioBus::kChannelAlignment.
  CHECK(IsAligned(data));
  return scoped_ptr<AudioBus>(new AudioBus(
      channels, frames, static_cast<float*>(data)));
}

scoped_ptr<AudioBus> AudioBus::WrapMemory(const AudioParameters& params,
                                          void* data) {
  // |data| must be aligned by AudioBus::kChannelAlignment.
  CHECK(IsAligned(data));
  return scoped_ptr<AudioBus>(new AudioBus(
      params.channels(), params.frames_per_buffer(),
      static_cast<float*>(data)));
}

void AudioBus::SetChannelData(int channel, float* data) {
  CHECK(can_set_channel_data_);
  CHECK(data);
  CHECK_GE(channel, 0);
  CHECK_LT(static_cast<size_t>(channel), channel_data_.size());
  DCHECK(IsAligned(data));
  channel_data_[channel] = data;
}

void AudioBus::set_frames(int frames) {
  CHECK(can_set_channel_data_);
  ValidateConfig(static_cast<int>(channel_data_.size()), frames);
  frames_ = frames;
}

void AudioBus::ZeroFramesPartial(int start_frame, int frames) {
  CheckOverflow(start_frame, frames, frames_);

  if (frames <= 0)
    return;

  for (size_t i = 0; i < channel_data_.size(); ++i) {
    memset(channel_data_[i] + start_frame, 0,
           frames * sizeof(*channel_data_[i]));
  }
}

void AudioBus::ZeroFrames(int frames) {
  ZeroFramesPartial(0, frames);
}

void AudioBus::Zero() {
  ZeroFrames(frames_);
}

int AudioBus::CalculateMemorySize(const AudioParameters& params) {
  return CalculateMemorySizeInternal(
      params.channels(), params.frames_per_buffer(), NULL);
}

int AudioBus::CalculateMemorySize(int channels, int frames) {
  return CalculateMemorySizeInternal(channels, frames, NULL);
}

void AudioBus::BuildChannelData(int channels, int aligned_frames, float* data) {
  DCHECK(IsAligned(data));
  DCHECK_EQ(channel_data_.size(), 0U);
  // Separate audio data out into channels for easy lookup later.  Figure out
  channel_data_.reserve(channels);
  for (int i = 0; i < channels; ++i)
    channel_data_.push_back(data + i * aligned_frames);
}

// TODO(dalecurtis): See if intrinsic optimizations help any here.
void AudioBus::FromInterleavedPartial(const void* source, int start_frame,
                                      int frames, int bytes_per_sample) {
  CheckOverflow(start_frame, frames, frames_);
  switch (bytes_per_sample) {
    case 1:
      FromInterleavedInternal<uint8, int16, kUint8Bias>(
          source, start_frame, frames, this,
          1.0f / kint8min, 1.0f / kint8max);
      break;
    case 2:
      FromInterleavedInternal<int16, int16, 0>(
          source, start_frame, frames, this,
          1.0f / kint16min, 1.0f / kint16max);
      break;
    case 4:
      FromInterleavedInternal<int32, int32, 0>(
          source, start_frame, frames, this,
          1.0f / kint32min, 1.0f / kint32max);
      break;
    default:
      NOTREACHED() << "Unsupported bytes per sample encountered.";
      ZeroFramesPartial(start_frame, frames);
      return;
  }

  // Don't clear remaining frames if this is a partial deinterleave.
  if (!start_frame) {
    // Zero any remaining frames.
    ZeroFramesPartial(frames, frames_ - frames);
  }
}

void AudioBus::FromInterleaved(const void* source, int frames,
                               int bytes_per_sample) {
  FromInterleavedPartial(source, 0, frames, bytes_per_sample);
}

void AudioBus::ToInterleaved(int frames, int bytes_per_sample,
                             void* dest) const {
  ToInterleavedPartial(0, frames, bytes_per_sample, dest);
}

// TODO(dalecurtis): See if intrinsic optimizations help any here.
void AudioBus::ToInterleavedPartial(int start_frame, int frames,
                                    int bytes_per_sample, void* dest) const {
  CheckOverflow(start_frame, frames, frames_);
  switch (bytes_per_sample) {
    case 1:
      ToInterleavedInternal<uint8, int16, kUint8Bias>(
          this, start_frame, frames, dest, kint8min, kint8max);
      break;
    case 2:
      ToInterleavedInternal<int16, int16, 0>(
          this, start_frame, frames, dest, kint16min, kint16max);
      break;
    case 4:
      ToInterleavedInternal<int32, int32, 0>(
          this, start_frame, frames, dest, kint32min, kint32max);
      break;
    default:
      NOTREACHED() << "Unsupported bytes per sample encountered.";
      memset(dest, 0, frames * bytes_per_sample);
      return;
  }
}

void AudioBus::CopyTo(AudioBus* dest) const {
  CopyPartialFramesTo(0, frames(), 0, dest);
}

void AudioBus::CopyPartialFramesTo(int source_start_frame,
                                   int frame_count,
                                   int dest_start_frame,
                                   AudioBus* dest) const {
  CHECK_EQ(channels(), dest->channels());
  CHECK_LE(source_start_frame + frame_count, frames());
  CHECK_LE(dest_start_frame + frame_count, dest->frames());

  // Since we don't know if the other AudioBus is wrapped or not (and we don't
  // want to care), just copy using the public channel() accessors.
  for (int i = 0; i < channels(); ++i) {
    memcpy(dest->channel(i) + dest_start_frame,
           channel(i) + source_start_frame,
           sizeof(*channel(i)) * frame_count);
  }
}

void AudioBus::Scale(float volume) {
  if (volume > 0 && volume != 1) {
    for (int i = 0; i < channels(); ++i)
      vector_math::FMUL(channel(i), volume, frames(), channel(i));
  } else if (volume == 0) {
    Zero();
  }
}

void AudioBus::SwapChannels(int a, int b) {
  DCHECK(a < channels() && a >= 0);
  DCHECK(b < channels() && b >= 0);
  DCHECK_NE(a, b);
  std::swap(channel_data_[a], channel_data_[b]);
}

}  // namespace media