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/*
* Copyright (C) 2010 Google Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#if ENABLE(WEB_AUDIO)
#include "AudioDestinationChromium.h"
#include "AudioSourceProvider.h"
#include "WebKit.h"
#include "WebKitClient.h"
using namespace WebKit;
namespace WebCore {
// Buffer size that the Chromium audio system will call us back with.
#if OS(DARWIN)
// For Mac OS X the chromium audio backend uses a low-latency CoreAudio API, so a low buffer size is possible.
const unsigned callbackBufferSize = 128;
#else
// This value may need to be tuned based on the OS.
// FIXME: It may be possible to reduce this value once real-time threads
// and other Chromium audio improvements are made.
const unsigned callbackBufferSize = 2048;
#endif
// Buffer size at which the web audio engine will render.
const unsigned renderBufferSize = 128;
const unsigned renderCountPerCallback = callbackBufferSize / renderBufferSize;
// FIXME: add support for multi-channel.
const unsigned numberOfChannels = 2;
// Factory method: Chromium-implementation
PassOwnPtr<AudioDestination> AudioDestination::create(AudioSourceProvider& provider, double sampleRate)
{
return adoptPtr(new AudioDestinationChromium(provider, sampleRate));
}
AudioDestinationChromium::AudioDestinationChromium(AudioSourceProvider& provider, double sampleRate)
: m_provider(provider)
, m_renderBus(numberOfChannels, renderBufferSize, false)
, m_sampleRate(sampleRate)
, m_isPlaying(false)
{
m_audioDevice = adoptPtr(webKitClient()->createAudioDevice(callbackBufferSize, numberOfChannels, sampleRate, this));
ASSERT(m_audioDevice.get());
}
AudioDestinationChromium::~AudioDestinationChromium()
{
stop();
}
void AudioDestinationChromium::start()
{
if (!m_isPlaying && m_audioDevice.get()) {
m_audioDevice->start();
m_isPlaying = true;
}
}
void AudioDestinationChromium::stop()
{
if (m_isPlaying && m_audioDevice.get()) {
m_audioDevice->stop();
m_isPlaying = false;
}
}
double AudioDestination::hardwareSampleRate()
{
return webKitClient()->audioHardwareSampleRate();
}
// Pulls on our provider to get the rendered audio stream.
void AudioDestinationChromium::render(const WebVector<float*>& audioData, size_t numberOfFrames)
{
bool isNumberOfChannelsGood = audioData.size() == numberOfChannels;
if (!isNumberOfChannelsGood) {
ASSERT_NOT_REACHED();
return;
}
bool isBufferSizeGood = numberOfFrames == callbackBufferSize;
if (!isBufferSizeGood) {
ASSERT_NOT_REACHED();
return;
}
// Split up the callback buffer into smaller chunks which we'll render one after the other.
for (unsigned i = 0; i < renderCountPerCallback; ++i) {
m_renderBus.setChannelMemory(0, audioData[0] + i * renderBufferSize, renderBufferSize);
m_renderBus.setChannelMemory(1, audioData[1] + i * renderBufferSize, renderBufferSize);
m_provider.provideInput(&m_renderBus, renderBufferSize);
}
}
} // namespace WebCore
#endif // ENABLE(WEB_AUDIO)
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