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/*
* Copyright (C) 2011, 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.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. 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 INC. 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) && ENABLE(VIDEO)
#include "MediaElementAudioSourceNode.h"
#include "AudioContext.h"
#include "AudioNodeOutput.h"
#include "Logging.h"
#include "MediaPlayer.h"
#include <wtf/Locker.h>
// These are somewhat arbitrary limits, but we need to do some kind of sanity-checking.
const unsigned minSampleRate = 8000;
const unsigned maxSampleRate = 192000;
namespace WebCore {
Ref<MediaElementAudioSourceNode> MediaElementAudioSourceNode::create(AudioContext& context, HTMLMediaElement* mediaElement)
{
return adoptRef(*new MediaElementAudioSourceNode(context, mediaElement));
}
MediaElementAudioSourceNode::MediaElementAudioSourceNode(AudioContext& context, HTMLMediaElement* mediaElement)
: AudioNode(context, context.sampleRate())
, m_mediaElement(mediaElement)
, m_sourceNumberOfChannels(0)
, m_sourceSampleRate(0)
{
// Default to stereo. This could change depending on what the media element .src is set to.
addOutput(std::make_unique<AudioNodeOutput>(this, 2));
setNodeType(NodeTypeMediaElementAudioSource);
initialize();
}
MediaElementAudioSourceNode::~MediaElementAudioSourceNode()
{
m_mediaElement->setAudioSourceNode(nullptr);
uninitialize();
}
void MediaElementAudioSourceNode::setFormat(size_t numberOfChannels, float sourceSampleRate)
{
if (numberOfChannels != m_sourceNumberOfChannels || sourceSampleRate != m_sourceSampleRate) {
if (!numberOfChannels || numberOfChannels > AudioContext::maxNumberOfChannels() || sourceSampleRate < minSampleRate || sourceSampleRate > maxSampleRate) {
// process() will generate silence for these uninitialized values.
LOG(Media, "MediaElementAudioSourceNode::setFormat(%u, %f) - unhandled format change", static_cast<unsigned>(numberOfChannels), sourceSampleRate);
m_sourceNumberOfChannels = 0;
m_sourceSampleRate = 0;
return;
}
m_sourceNumberOfChannels = numberOfChannels;
m_sourceSampleRate = sourceSampleRate;
// Synchronize with process().
std::lock_guard<MediaElementAudioSourceNode> lock(*this);
if (sourceSampleRate != sampleRate()) {
double scaleFactor = sourceSampleRate / sampleRate();
m_multiChannelResampler = std::make_unique<MultiChannelResampler>(scaleFactor, numberOfChannels);
} else {
// Bypass resampling.
m_multiChannelResampler = nullptr;
}
{
// The context must be locked when changing the number of output channels.
AudioContext::AutoLocker contextLocker(context());
// Do any necesssary re-configuration to the output's number of channels.
output(0)->setNumberOfChannels(numberOfChannels);
}
}
}
void MediaElementAudioSourceNode::process(size_t numberOfFrames)
{
AudioBus* outputBus = output(0)->bus();
if (!mediaElement() || !m_sourceNumberOfChannels || !m_sourceSampleRate) {
outputBus->zero();
return;
}
// Use a std::try_to_lock to avoid contention in the real-time audio thread.
// If we fail to acquire the lock then the HTMLMediaElement must be in the middle of
// reconfiguring its playback engine, so we output silence in this case.
std::unique_lock<Lock> lock(m_processMutex, std::try_to_lock);
if (!lock.owns_lock()) {
// We failed to acquire the lock.
outputBus->zero();
return;
}
if (AudioSourceProvider* provider = mediaElement()->audioSourceProvider()) {
if (m_multiChannelResampler.get()) {
ASSERT(m_sourceSampleRate != sampleRate());
m_multiChannelResampler->process(provider, outputBus, numberOfFrames);
} else {
// Bypass the resampler completely if the source is at the context's sample-rate.
ASSERT(m_sourceSampleRate == sampleRate());
provider->provideInput(outputBus, numberOfFrames);
}
} else {
// Either this port doesn't yet support HTMLMediaElement audio stream access,
// or the stream is not yet available.
outputBus->zero();
}
}
void MediaElementAudioSourceNode::reset()
{
}
void MediaElementAudioSourceNode::lock()
{
ref();
m_processMutex.lock();
}
void MediaElementAudioSourceNode::unlock()
{
m_processMutex.unlock();
deref();
}
} // namespace WebCore
#endif // ENABLE(WEB_AUDIO)
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