2 * Copyright (C) 2011, Google Inc. All rights reserved.
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
15 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
16 * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
17 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
18 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
19 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
20 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
22 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 #include "modules/webaudio/MediaElementAudioSourceNode.h"
31 #include "core/html/HTMLMediaElement.h"
32 #include "modules/webaudio/AudioContext.h"
33 #include "modules/webaudio/AudioNodeOutput.h"
34 #include "platform/Logging.h"
35 #include "platform/graphics/media/MediaPlayer.h"
36 #include "wtf/Locker.h"
38 // These are somewhat arbitrary limits, but we need to do some kind of sanity-checking.
39 const unsigned minSampleRate = 8000;
40 const unsigned maxSampleRate = 192000;
44 PassRefPtrWillBeRawPtr<MediaElementAudioSourceNode> MediaElementAudioSourceNode::create(AudioContext* context, HTMLMediaElement* mediaElement)
46 return adoptRefWillBeNoop(new MediaElementAudioSourceNode(context, mediaElement));
49 MediaElementAudioSourceNode::MediaElementAudioSourceNode(AudioContext* context, HTMLMediaElement* mediaElement)
50 : AudioSourceNode(context, context->sampleRate())
51 , m_mediaElement(mediaElement)
52 , m_sourceNumberOfChannels(0)
53 , m_sourceSampleRate(0)
55 ScriptWrappable::init(this);
56 // Default to stereo. This could change depending on what the media element .src is set to.
57 addOutput(adoptPtr(new AudioNodeOutput(this, 2)));
59 setNodeType(NodeTypeMediaElementAudioSource);
64 MediaElementAudioSourceNode::~MediaElementAudioSourceNode()
66 m_mediaElement->setAudioSourceNode(0);
70 void MediaElementAudioSourceNode::setFormat(size_t numberOfChannels, float sourceSampleRate)
72 if (numberOfChannels != m_sourceNumberOfChannels || sourceSampleRate != m_sourceSampleRate) {
73 if (!numberOfChannels || numberOfChannels > AudioContext::maxNumberOfChannels() || sourceSampleRate < minSampleRate || sourceSampleRate > maxSampleRate) {
74 // process() will generate silence for these uninitialized values.
75 WTF_LOG(Media, "MediaElementAudioSourceNode::setFormat(%u, %f) - unhandled format change", static_cast<unsigned>(numberOfChannels), sourceSampleRate);
76 m_sourceNumberOfChannels = 0;
77 m_sourceSampleRate = 0;
81 m_sourceNumberOfChannels = numberOfChannels;
82 m_sourceSampleRate = sourceSampleRate;
84 // Synchronize with process().
85 Locker<MediaElementAudioSourceNode> locker(*this);
87 if (sourceSampleRate != sampleRate()) {
88 double scaleFactor = sourceSampleRate / sampleRate();
89 m_multiChannelResampler = adoptPtr(new MultiChannelResampler(scaleFactor, numberOfChannels));
92 m_multiChannelResampler.clear();
96 // The context must be locked when changing the number of output channels.
97 AudioContext::AutoLocker contextLocker(context());
99 // Do any necesssary re-configuration to the output's number of channels.
100 output(0)->setNumberOfChannels(numberOfChannels);
105 void MediaElementAudioSourceNode::process(size_t numberOfFrames)
107 AudioBus* outputBus = output(0)->bus();
109 if (!mediaElement() || !m_sourceNumberOfChannels || !m_sourceSampleRate) {
114 // Use a tryLock() to avoid contention in the real-time audio thread.
115 // If we fail to acquire the lock then the HTMLMediaElement must be in the middle of
116 // reconfiguring its playback engine, so we output silence in this case.
117 MutexTryLocker tryLocker(m_processLock);
118 if (tryLocker.locked()) {
119 if (AudioSourceProvider* provider = mediaElement()->audioSourceProvider()) {
120 if (m_multiChannelResampler.get()) {
121 ASSERT(m_sourceSampleRate != sampleRate());
122 m_multiChannelResampler->process(provider, outputBus, numberOfFrames);
124 // Bypass the resampler completely if the source is at the context's sample-rate.
125 ASSERT(m_sourceSampleRate == sampleRate());
126 provider->provideInput(outputBus, numberOfFrames);
129 // Either this port doesn't yet support HTMLMediaElement audio stream access,
130 // or the stream is not yet available.
134 // We failed to acquire the lock.
139 void MediaElementAudioSourceNode::lock()
142 m_processLock.lock();
145 void MediaElementAudioSourceNode::unlock()
147 m_processLock.unlock();
151 } // namespace WebCore
153 #endif // ENABLE(WEB_AUDIO)