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
39namespace blink {
40
41MediaElementAudioSourceNode* MediaElementAudioSourceNode::create(AudioContext* context, HTMLMediaElement* mediaElement)
42{
43    return adoptRefCountedGarbageCollectedWillBeNoop(new MediaElementAudioSourceNode(context, mediaElement));
44}
45
46MediaElementAudioSourceNode::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
61MediaElementAudioSourceNode::~MediaElementAudioSourceNode()
62{
63    ASSERT(!isInitialized());
64}
65
66void MediaElementAudioSourceNode::dispose()
67{
68    m_mediaElement->setAudioSourceNode(0);
69    uninitialize();
70    AudioSourceNode::dispose();
71}
72
73void 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
108void 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
142void MediaElementAudioSourceNode::lock()
143{
144    m_processLock.lock();
145}
146
147void MediaElementAudioSourceNode::unlock()
148{
149    m_processLock.unlock();
150}
151
152void 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