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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/fake_audio_input_stream.h"
#include "base/bind.h"
#include "base/lazy_instance.h"
#include "media/audio/audio_manager_base.h"
using base::Time;
using base::TimeDelta;
namespace media {
namespace {
// These values are based on experiments for local-to-local
// PeerConnection to demonstrate audio/video synchronization.
const int kBeepDurationMilliseconds = 20;
const int kBeepFrequency = 400;
struct BeepContext {
BeepContext() : beep_once(false) {}
base::Lock beep_lock;
bool beep_once;
};
static base::LazyInstance<BeepContext> g_beep_context =
LAZY_INSTANCE_INITIALIZER;
} // namespace
AudioInputStream* FakeAudioInputStream::MakeFakeStream(
AudioManagerBase* manager,
const AudioParameters& params) {
return new FakeAudioInputStream(manager, params);
}
FakeAudioInputStream::FakeAudioInputStream(AudioManagerBase* manager,
const AudioParameters& params)
: audio_manager_(manager),
callback_(NULL),
buffer_size_((params.channels() * params.bits_per_sample() *
params.frames_per_buffer()) / 8),
params_(params),
thread_("FakeAudioRecordingThread"),
callback_interval_(base::TimeDelta::FromMilliseconds(
(params.frames_per_buffer() * 1000) / params.sample_rate())),
beep_duration_in_buffers_(
kBeepDurationMilliseconds * params.sample_rate() /
params.frames_per_buffer() / 1000),
beep_generated_in_buffers_(0),
beep_period_in_frames_(params.sample_rate() / kBeepFrequency),
frames_elapsed_(0) {
}
FakeAudioInputStream::~FakeAudioInputStream() {}
bool FakeAudioInputStream::Open() {
buffer_.reset(new uint8[buffer_size_]);
memset(buffer_.get(), 0, buffer_size_);
return true;
}
void FakeAudioInputStream::Start(AudioInputCallback* callback) {
DCHECK(!thread_.IsRunning());
callback_ = callback;
last_callback_time_ = Time::Now();
thread_.Start();
thread_.message_loop()->PostDelayedTask(
FROM_HERE,
base::Bind(&FakeAudioInputStream::DoCallback, base::Unretained(this)),
callback_interval_);
}
void FakeAudioInputStream::DoCallback() {
DCHECK(callback_);
memset(buffer_.get(), 0, buffer_size_);
bool should_beep = false;
{
BeepContext* beep_context = g_beep_context.Pointer();
base::AutoLock auto_lock(beep_context->beep_lock);
should_beep = beep_context->beep_once;
beep_context->beep_once = false;
}
// If this object was instructed to generate a beep or has started to
// generate a beep sound.
if (should_beep || beep_generated_in_buffers_) {
// Compute the number of frames to output high value. Then compute the
// number of bytes based on channels and bits per channel.
int high_frames = beep_period_in_frames_ / 2;
int high_bytes = high_frames * params_.bits_per_sample() *
params_.channels() / 8;
// Separate high and low with the same number of bytes to generate a
// square wave.
int position = 0;
while (position + high_bytes <= buffer_size_) {
// Write high values first.
memset(buffer_.get() + position, 128, high_bytes);
// Then leave low values in the buffer with |high_bytes|.
position += high_bytes * 2;
}
++beep_generated_in_buffers_;
if (beep_generated_in_buffers_ >= beep_duration_in_buffers_)
beep_generated_in_buffers_ = 0;
}
callback_->OnData(this, buffer_.get(), buffer_size_, buffer_size_, 1.0);
frames_elapsed_ += params_.frames_per_buffer();
Time now = Time::Now();
base::TimeDelta next_callback_time =
last_callback_time_ + callback_interval_ * 2 - now;
// If we are falling behind, try to catch up as much as we can in the next
// callback.
if (next_callback_time < base::TimeDelta())
next_callback_time = base::TimeDelta();
last_callback_time_ = now;
thread_.message_loop()->PostDelayedTask(
FROM_HERE,
base::Bind(&FakeAudioInputStream::DoCallback, base::Unretained(this)),
next_callback_time);
}
void FakeAudioInputStream::Stop() {
thread_.Stop();
}
void FakeAudioInputStream::Close() {
if (callback_) {
callback_->OnClose(this);
callback_ = NULL;
}
audio_manager_->ReleaseInputStream(this);
}
double FakeAudioInputStream::GetMaxVolume() {
return 1.0;
}
void FakeAudioInputStream::SetVolume(double volume) {
}
double FakeAudioInputStream::GetVolume() {
return 1.0;
}
void FakeAudioInputStream::SetAutomaticGainControl(bool enabled) {}
bool FakeAudioInputStream::GetAutomaticGainControl() {
return true;
}
// static
void FakeAudioInputStream::BeepOnce() {
BeepContext* beep_context = g_beep_context.Pointer();
base::AutoLock auto_lock(beep_context->beep_lock);
beep_context->beep_once = true;
}
} // namespace media
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