1 /*
2 * Copyright (C) 2011, Google Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
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.
12 *
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.
23 */
24
25 #include "config.h"
26
27 #if ENABLE(WEB_AUDIO)
28
29 #include "modules/webaudio/MediaElementAudioSourceNode.h"
30
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/audio/AudioUtilities.h"
36 #include "platform/graphics/media/MediaPlayer.h"
37 #include "wtf/Locker.h"
38
39 namespace blink {
40
create(AudioContext * context,HTMLMediaElement * mediaElement)41 MediaElementAudioSourceNode* MediaElementAudioSourceNode::create(AudioContext* context, HTMLMediaElement* mediaElement)
42 {
43 return adoptRefCountedGarbageCollectedWillBeNoop(new MediaElementAudioSourceNode(context, mediaElement));
44 }
45
MediaElementAudioSourceNode(AudioContext * context,HTMLMediaElement * mediaElement)46 MediaElementAudioSourceNode::MediaElementAudioSourceNode(AudioContext* context, HTMLMediaElement* mediaElement)
47 : AudioSourceNode(context, context->sampleRate())
48 , m_mediaElement(mediaElement)
49 , m_sourceNumberOfChannels(0)
50 , m_sourceSampleRate(0)
51 {
52 // Default to stereo. This could change depending on what the media element
53 // .src is set to.
54 addOutput(AudioNodeOutput::create(this, 2));
55
56 setNodeType(NodeTypeMediaElementAudioSource);
57
58 initialize();
59 }
60
~MediaElementAudioSourceNode()61 MediaElementAudioSourceNode::~MediaElementAudioSourceNode()
62 {
63 ASSERT(!isInitialized());
64 }
65
dispose()66 void MediaElementAudioSourceNode::dispose()
67 {
68 m_mediaElement->setAudioSourceNode(0);
69 uninitialize();
70 AudioSourceNode::dispose();
71 }
72
setFormat(size_t numberOfChannels,float sourceSampleRate)73 void MediaElementAudioSourceNode::setFormat(size_t numberOfChannels, float sourceSampleRate)
74 {
75 if (numberOfChannels != m_sourceNumberOfChannels || sourceSampleRate != m_sourceSampleRate) {
76 if (!numberOfChannels || numberOfChannels > AudioContext::maxNumberOfChannels() || !AudioUtilities::isValidAudioBufferSampleRate(sourceSampleRate)) {
77 // process() will generate silence for these uninitialized values.
78 WTF_LOG(Media, "MediaElementAudioSourceNode::setFormat(%u, %f) - unhandled format change", static_cast<unsigned>(numberOfChannels), sourceSampleRate);
79 m_sourceNumberOfChannels = 0;
80 m_sourceSampleRate = 0;
81 return;
82 }
83
84 m_sourceNumberOfChannels = numberOfChannels;
85 m_sourceSampleRate = sourceSampleRate;
86
87 // Synchronize with process().
88 Locker<MediaElementAudioSourceNode> locker(*this);
89
90 if (sourceSampleRate != sampleRate()) {
91 double scaleFactor = sourceSampleRate / sampleRate();
92 m_multiChannelResampler = adoptPtr(new MultiChannelResampler(scaleFactor, numberOfChannels));
93 } else {
94 // Bypass resampling.
95 m_multiChannelResampler.clear();
96 }
97
98 {
99 // The context must be locked when changing the number of output channels.
100 AudioContext::AutoLocker contextLocker(context());
101
102 // Do any necesssary re-configuration to the output's number of channels.
103 output(0)->setNumberOfChannels(numberOfChannels);
104 }
105 }
106 }
107
process(size_t numberOfFrames)108 void MediaElementAudioSourceNode::process(size_t numberOfFrames)
109 {
110 AudioBus* outputBus = output(0)->bus();
111
112 if (!mediaElement() || !m_sourceNumberOfChannels || !m_sourceSampleRate) {
113 outputBus->zero();
114 return;
115 }
116
117 // Use a tryLock() to avoid contention in the real-time audio thread.
118 // If we fail to acquire the lock then the HTMLMediaElement must be in the middle of
119 // reconfiguring its playback engine, so we output silence in this case.
120 MutexTryLocker tryLocker(m_processLock);
121 if (tryLocker.locked()) {
122 if (AudioSourceProvider* provider = mediaElement()->audioSourceProvider()) {
123 if (m_multiChannelResampler.get()) {
124 ASSERT(m_sourceSampleRate != sampleRate());
125 m_multiChannelResampler->process(provider, outputBus, numberOfFrames);
126 } else {
127 // Bypass the resampler completely if the source is at the context's sample-rate.
128 ASSERT(m_sourceSampleRate == sampleRate());
129 provider->provideInput(outputBus, numberOfFrames);
130 }
131 } else {
132 // Either this port doesn't yet support HTMLMediaElement audio stream access,
133 // or the stream is not yet available.
134 outputBus->zero();
135 }
136 } else {
137 // We failed to acquire the lock.
138 outputBus->zero();
139 }
140 }
141
lock()142 void MediaElementAudioSourceNode::lock()
143 {
144 m_processLock.lock();
145 }
146
unlock()147 void MediaElementAudioSourceNode::unlock()
148 {
149 m_processLock.unlock();
150 }
151
trace(Visitor * visitor)152 void MediaElementAudioSourceNode::trace(Visitor* visitor)
153 {
154 visitor->trace(m_mediaElement);
155 AudioSourceNode::trace(visitor);
156 AudioSourceProviderClient::trace(visitor);
157 }
158
159 } // namespace blink
160
161 #endif // ENABLE(WEB_AUDIO)
162