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 "modules/webaudio/AudioContext.h"
32 #include "modules/webaudio/AudioNodeOutput.h"
33 #include "platform/Logging.h"
34 #include "platform/graphics/media/MediaPlayer.h"
35 #include "wtf/Locker.h"
36
37 // These are somewhat arbitrary limits, but we need to do some kind of sanity-checking.
38 const unsigned minSampleRate = 8000;
39 const unsigned maxSampleRate = 192000;
40
41 namespace WebCore {
42
create(AudioContext * context,HTMLMediaElement * mediaElement)43 PassRefPtr<MediaElementAudioSourceNode> MediaElementAudioSourceNode::create(AudioContext* context, HTMLMediaElement* mediaElement)
44 {
45 return adoptRef(new MediaElementAudioSourceNode(context, mediaElement));
46 }
47
MediaElementAudioSourceNode(AudioContext * context,HTMLMediaElement * mediaElement)48 MediaElementAudioSourceNode::MediaElementAudioSourceNode(AudioContext* context, HTMLMediaElement* mediaElement)
49 : AudioSourceNode(context, context->sampleRate())
50 , m_mediaElement(mediaElement)
51 , m_sourceNumberOfChannels(0)
52 , m_sourceSampleRate(0)
53 {
54 ScriptWrappable::init(this);
55 // Default to stereo. This could change depending on what the media element .src is set to.
56 addOutput(adoptPtr(new AudioNodeOutput(this, 2)));
57
58 setNodeType(NodeTypeMediaElementAudioSource);
59
60 initialize();
61 }
62
~MediaElementAudioSourceNode()63 MediaElementAudioSourceNode::~MediaElementAudioSourceNode()
64 {
65 m_mediaElement->setAudioSourceNode(0);
66 uninitialize();
67 }
68
setFormat(size_t numberOfChannels,float sourceSampleRate)69 void MediaElementAudioSourceNode::setFormat(size_t numberOfChannels, float sourceSampleRate)
70 {
71 if (numberOfChannels != m_sourceNumberOfChannels || sourceSampleRate != m_sourceSampleRate) {
72 if (!numberOfChannels || numberOfChannels > AudioContext::maxNumberOfChannels() || sourceSampleRate < minSampleRate || sourceSampleRate > maxSampleRate) {
73 // process() will generate silence for these uninitialized values.
74 WTF_LOG(Media, "MediaElementAudioSourceNode::setFormat(%u, %f) - unhandled format change", static_cast<unsigned>(numberOfChannels), sourceSampleRate);
75 m_sourceNumberOfChannels = 0;
76 m_sourceSampleRate = 0;
77 return;
78 }
79
80 m_sourceNumberOfChannels = numberOfChannels;
81 m_sourceSampleRate = sourceSampleRate;
82
83 // Synchronize with process().
84 Locker<MediaElementAudioSourceNode> locker(*this);
85
86 if (sourceSampleRate != sampleRate()) {
87 double scaleFactor = sourceSampleRate / sampleRate();
88 m_multiChannelResampler = adoptPtr(new MultiChannelResampler(scaleFactor, numberOfChannels));
89 } else {
90 // Bypass resampling.
91 m_multiChannelResampler.clear();
92 }
93
94 {
95 // The context must be locked when changing the number of output channels.
96 AudioContext::AutoLocker contextLocker(context());
97
98 // Do any necesssary re-configuration to the output's number of channels.
99 output(0)->setNumberOfChannels(numberOfChannels);
100 }
101 }
102 }
103
process(size_t numberOfFrames)104 void MediaElementAudioSourceNode::process(size_t numberOfFrames)
105 {
106 AudioBus* outputBus = output(0)->bus();
107
108 if (!mediaElement() || !m_sourceNumberOfChannels || !m_sourceSampleRate) {
109 outputBus->zero();
110 return;
111 }
112
113 // Use a tryLock() to avoid contention in the real-time audio thread.
114 // If we fail to acquire the lock then the HTMLMediaElement must be in the middle of
115 // reconfiguring its playback engine, so we output silence in this case.
116 MutexTryLocker tryLocker(m_processLock);
117 if (tryLocker.locked()) {
118 if (AudioSourceProvider* provider = mediaElement()->audioSourceProvider()) {
119 if (m_multiChannelResampler.get()) {
120 ASSERT(m_sourceSampleRate != sampleRate());
121 m_multiChannelResampler->process(provider, outputBus, numberOfFrames);
122 } else {
123 // Bypass the resampler completely if the source is at the context's sample-rate.
124 ASSERT(m_sourceSampleRate == sampleRate());
125 provider->provideInput(outputBus, numberOfFrames);
126 }
127 } else {
128 // Either this port doesn't yet support HTMLMediaElement audio stream access,
129 // or the stream is not yet available.
130 outputBus->zero();
131 }
132 } else {
133 // We failed to acquire the lock.
134 outputBus->zero();
135 }
136 }
137
reset()138 void MediaElementAudioSourceNode::reset()
139 {
140 }
141
lock()142 void MediaElementAudioSourceNode::lock()
143 {
144 ref();
145 m_processLock.lock();
146 }
147
unlock()148 void MediaElementAudioSourceNode::unlock()
149 {
150 m_processLock.unlock();
151 deref();
152 }
153
154 } // namespace WebCore
155
156 #endif // ENABLE(WEB_AUDIO)
157