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// 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/null_audio_sink.h"
#include "base/bind.h"
#include "base/threading/platform_thread.h"
namespace media {
NullAudioSink::NullAudioSink()
: initialized_(false),
playback_rate_(0.0),
playing_(false),
callback_(NULL),
thread_("NullAudioThread") {
}
void NullAudioSink::Initialize(const AudioParameters& params,
RenderCallback* callback) {
DCHECK(!initialized_);
params_ = params;
audio_data_.reserve(params.channels());
for (int i = 0; i < params.channels(); ++i) {
float* channel_data = new float[params.frames_per_buffer()];
audio_data_.push_back(channel_data);
}
callback_ = callback;
initialized_ = true;
}
void NullAudioSink::Start() {
if (!thread_.Start())
return;
thread_.message_loop()->PostTask(FROM_HERE, base::Bind(
&NullAudioSink::FillBufferTask, this));
}
void NullAudioSink::Stop() {
SetPlaying(false);
thread_.Stop();
}
void NullAudioSink::Play() {
SetPlaying(true);
}
void NullAudioSink::Pause(bool /* flush */) {
SetPlaying(false);
}
void NullAudioSink::SetPlaybackRate(float rate) {
base::AutoLock auto_lock(lock_);
playback_rate_ = rate;
}
bool NullAudioSink::SetVolume(double volume) {
// Audio is always muted.
return volume == 0.0;
}
void NullAudioSink::GetVolume(double* volume) {
// Audio is always muted.
*volume = 0.0;
}
void NullAudioSink::SetPlaying(bool is_playing) {
base::AutoLock auto_lock(lock_);
playing_ = is_playing;
}
NullAudioSink::~NullAudioSink() {
DCHECK(!thread_.IsRunning());
for (size_t i = 0; i < audio_data_.size(); ++i)
delete [] audio_data_[i];
}
void NullAudioSink::FillBufferTask() {
base::AutoLock auto_lock(lock_);
base::TimeDelta delay;
// Only consume buffers when actually playing.
if (playing_) {
DCHECK_GT(playback_rate_, 0.0f);
int requested_frames = params_.frames_per_buffer();
int frames_received = callback_->Render(audio_data_, requested_frames, 0);
int frames_per_millisecond =
params_.sample_rate() / base::Time::kMillisecondsPerSecond;
// Calculate our sleep duration, taking playback rate into consideration.
delay = base::TimeDelta::FromMilliseconds(
frames_received / (frames_per_millisecond * playback_rate_));
} else {
// If paused, sleep for 10 milliseconds before polling again.
delay = base::TimeDelta::FromMilliseconds(10);
}
// Sleep for at least one millisecond so we don't spin the CPU.
MessageLoop::current()->PostDelayedTask(
FROM_HERE,
base::Bind(&NullAudioSink::FillBufferTask, this),
std::max(delay, base::TimeDelta::FromMilliseconds(1)));
}
} // namespace media
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