1/*
2 * Copyright (C) 2012, 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) && ENABLE(MEDIA_STREAM)
28
29#include "MediaStreamAudioSourceNode.h"
30
31#include "AudioContext.h"
32#include "AudioNodeOutput.h"
33#include "Logging.h"
34#include <wtf/IsoMallocInlines.h>
35#include <wtf/Locker.h>
36
37namespace WebCore {
38
39WTF_MAKE_ISO_ALLOCATED_IMPL(MediaStreamAudioSourceNode);
40
41Ref<MediaStreamAudioSourceNode> MediaStreamAudioSourceNode::create(AudioContext& context, MediaStream& mediaStream, MediaStreamTrack& audioTrack)
42{
43 return adoptRef(*new MediaStreamAudioSourceNode(context, mediaStream, audioTrack));
44}
45
46MediaStreamAudioSourceNode::MediaStreamAudioSourceNode(AudioContext& context, MediaStream& mediaStream, MediaStreamTrack& audioTrack)
47 : AudioNode(context, context.sampleRate())
48 , m_mediaStream(mediaStream)
49 , m_audioTrack(audioTrack)
50{
51 setNodeType(NodeTypeMediaStreamAudioSource);
52
53 AudioSourceProvider* audioSourceProvider = m_audioTrack->audioSourceProvider();
54 ASSERT(audioSourceProvider);
55
56 audioSourceProvider->setClient(this);
57
58 // Default to stereo. This could change depending on the format of the MediaStream's audio track.
59 addOutput(std::make_unique<AudioNodeOutput>(this, 2));
60
61 initialize();
62}
63
64MediaStreamAudioSourceNode::~MediaStreamAudioSourceNode()
65{
66 AudioSourceProvider* audioSourceProvider = m_audioTrack->audioSourceProvider();
67 ASSERT(audioSourceProvider);
68 audioSourceProvider->setClient(nullptr);
69 uninitialize();
70}
71
72void MediaStreamAudioSourceNode::setFormat(size_t numberOfChannels, float sourceSampleRate)
73{
74 float sampleRate = this->sampleRate();
75 if (numberOfChannels == m_sourceNumberOfChannels && sourceSampleRate == sampleRate)
76 return;
77
78 // The sample-rate must be equal to the context's sample-rate.
79 if (!numberOfChannels || numberOfChannels > AudioContext::maxNumberOfChannels()) {
80 // process() will generate silence for these uninitialized values.
81 LOG(Media, "MediaStreamAudioSourceNode::setFormat(%u, %f) - unhandled format change", static_cast<unsigned>(numberOfChannels), sourceSampleRate);
82 m_sourceNumberOfChannels = 0;
83 return;
84 }
85
86 // Synchronize with process().
87 std::lock_guard<Lock> lock(m_processMutex);
88
89 m_sourceNumberOfChannels = numberOfChannels;
90 m_sourceSampleRate = sourceSampleRate;
91
92 if (sourceSampleRate == sampleRate)
93 m_multiChannelResampler = nullptr;
94 else {
95 double scaleFactor = sourceSampleRate / sampleRate;
96 m_multiChannelResampler = std::make_unique<MultiChannelResampler>(scaleFactor, numberOfChannels);
97 }
98
99 m_sourceNumberOfChannels = numberOfChannels;
100
101 {
102 // The context must be locked when changing the number of output channels.
103 AudioContext::AutoLocker contextLocker(context());
104
105 // Do any necesssary re-configuration to the output's number of channels.
106 output(0)->setNumberOfChannels(numberOfChannels);
107 }
108}
109
110void MediaStreamAudioSourceNode::process(size_t numberOfFrames)
111{
112 AudioBus* outputBus = output(0)->bus();
113 AudioSourceProvider* provider = m_audioTrack->audioSourceProvider();
114
115 if (!mediaStream() || !m_sourceNumberOfChannels || !m_sourceSampleRate || !provider) {
116 outputBus->zero();
117 return;
118 }
119
120 // Use std::try_to_lock to avoid contention in the real-time audio thread.
121 // If we fail to acquire the lock then the MediaStream must be in the middle of
122 // a format change, so we output silence in this case.
123 std::unique_lock<Lock> lock(m_processMutex, std::try_to_lock);
124 if (!lock.owns_lock()) {
125 // We failed to acquire the lock.
126 outputBus->zero();
127 return;
128 }
129
130 if (m_multiChannelResampler.get()) {
131 ASSERT(m_sourceSampleRate != sampleRate());
132 m_multiChannelResampler->process(provider, outputBus, numberOfFrames);
133 } else {
134 // Bypass the resampler completely if the source is at the context's sample-rate.
135 ASSERT(m_sourceSampleRate == sampleRate());
136 provider->provideInput(outputBus, numberOfFrames);
137 }
138}
139
140} // namespace WebCore
141
142#endif // ENABLE(WEB_AUDIO) && ENABLE(MEDIA_STREAM)
143