media/audio/audio_parameters.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/audio/audio_parameters.h"

#include "base/logging.h"
#include "media/base/limits.h"

namespace media {

AudioParameters::AudioParameters()
    : format_(AUDIO_PCM_LINEAR),
      channel_layout_(CHANNEL_LAYOUT_NONE),
      sample_rate_(0),
      bits_per_sample_(0),
      frames_per_buffer_(0),
      channels_(0),
      effects_(NO_EFFECTS) {
}

AudioParameters::AudioParameters(Format format, ChannelLayout channel_layout,
                                 int sample_rate, int bits_per_sample,
                                 int frames_per_buffer)
    : format_(format),
      channel_layout_(channel_layout),
      sample_rate_(sample_rate),
      bits_per_sample_(bits_per_sample),
      frames_per_buffer_(frames_per_buffer),
      channels_(ChannelLayoutToChannelCount(channel_layout)),
      effects_(NO_EFFECTS) {
}

AudioParameters::AudioParameters(Format format, ChannelLayout channel_layout,
                                 int sample_rate, int bits_per_sample,
                                 int frames_per_buffer, int effects)
    : format_(format),
      channel_layout_(channel_layout),
      sample_rate_(sample_rate),
      bits_per_sample_(bits_per_sample),
      frames_per_buffer_(frames_per_buffer),
      channels_(ChannelLayoutToChannelCount(channel_layout)),
      effects_(effects) {
}

AudioParameters::AudioParameters(Format format, ChannelLayout channel_layout,
                                 int channels, int sample_rate,
                                 int bits_per_sample, int frames_per_buffer,
                                 int effects)
    : format_(format),
      channel_layout_(channel_layout),
      sample_rate_(sample_rate),
      bits_per_sample_(bits_per_sample),
      frames_per_buffer_(frames_per_buffer),
      channels_(channels),
      effects_(effects) {
  if (channel_layout != CHANNEL_LAYOUT_DISCRETE)
    DCHECK_EQ(channels, ChannelLayoutToChannelCount(channel_layout));
}

void AudioParameters::Reset(Format format, ChannelLayout channel_layout,
                            int channels, int sample_rate,
                            int bits_per_sample, int frames_per_buffer) {
  if (channel_layout != CHANNEL_LAYOUT_DISCRETE)
    DCHECK_EQ(channels, ChannelLayoutToChannelCount(channel_layout));

  format_ = format;
  channel_layout_ = channel_layout;
  channels_ = channels;
  sample_rate_ = sample_rate;
  bits_per_sample_ = bits_per_sample;
  frames_per_buffer_ = frames_per_buffer;
}

bool AudioParameters::IsValid() const {
  return (format_ >= AUDIO_PCM_LINEAR) &&
         (format_ < AUDIO_LAST_FORMAT) &&
         (channels_ > 0) &&
         (channels_ <= media::limits::kMaxChannels) &&
         (channel_layout_ > CHANNEL_LAYOUT_UNSUPPORTED) &&
         (channel_layout_ <= CHANNEL_LAYOUT_MAX) &&
         (sample_rate_ >= media::limits::kMinSampleRate) &&
         (sample_rate_ <= media::limits::kMaxSampleRate) &&
         (bits_per_sample_ > 0) &&
         (bits_per_sample_ <= media::limits::kMaxBitsPerSample) &&
         (frames_per_buffer_ > 0) &&
         (frames_per_buffer_ <= media::limits::kMaxSamplesPerPacket);
}

std::string AudioParameters::AsHumanReadableString() const {
  std::ostringstream s;
  s << "format: " << format()
    << " channels: " << channels()
    << " channel_layout: " << channel_layout()
    << " sample_rate: " << sample_rate()
    << " bits_per_sample: " << bits_per_sample()
    << " frames_per_buffer: " << frames_per_buffer();
  return s.str();
}

int AudioParameters::GetBytesPerBuffer() const {
  return frames_per_buffer_ * GetBytesPerFrame();
}

int AudioParameters::GetBytesPerSecond() const {
  return sample_rate_ * GetBytesPerFrame();
}

int AudioParameters::GetBytesPerFrame() const {
  return channels_ * bits_per_sample_ / 8;
}

base::TimeDelta AudioParameters::GetBufferDuration() const {
  return base::TimeDelta::FromMicroseconds(static_cast<int64>(
      frames_per_buffer_ * base::Time::kMicrosecondsPerSecond /
      static_cast<float>(sample_rate_)));
}

bool AudioParameters::Equals(const AudioParameters& other) const {
  return format_ == other.format() &&
         sample_rate_ == other.sample_rate() &&
         channel_layout_ == other.channel_layout() &&
         channels_ == other.channels() &&
         bits_per_sample_ == other.bits_per_sample() &&
         frames_per_buffer_ == other.frames_per_buffer() &&
         effects_ == other.effects();
}

}  // namespace media