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)
28
29 #include "modules/webaudio/AudioScheduledSourceNode.h"
30
31 #include "bindings/v8/ExceptionState.h"
32 #include "core/dom/ExceptionCode.h"
33 #include "modules/EventModules.h"
34 #include "modules/webaudio/AudioContext.h"
35 #include "platform/audio/AudioUtilities.h"
36 #include <algorithm>
37 #include "wtf/MathExtras.h"
38
39 using namespace std;
40
41 namespace WebCore {
42
43 const double AudioScheduledSourceNode::UnknownTime = -1;
44
AudioScheduledSourceNode(AudioContext * context,float sampleRate)45 AudioScheduledSourceNode::AudioScheduledSourceNode(AudioContext* context, float sampleRate)
46 : AudioSourceNode(context, sampleRate)
47 , m_playbackState(UNSCHEDULED_STATE)
48 , m_startTime(0)
49 , m_endTime(UnknownTime)
50 , m_hasEndedListener(false)
51 {
52 }
53
updateSchedulingInfo(size_t quantumFrameSize,AudioBus * outputBus,size_t & quantumFrameOffset,size_t & nonSilentFramesToProcess)54 void AudioScheduledSourceNode::updateSchedulingInfo(size_t quantumFrameSize,
55 AudioBus* outputBus,
56 size_t& quantumFrameOffset,
57 size_t& nonSilentFramesToProcess)
58 {
59 ASSERT(outputBus);
60 if (!outputBus)
61 return;
62
63 ASSERT(quantumFrameSize == AudioNode::ProcessingSizeInFrames);
64 if (quantumFrameSize != AudioNode::ProcessingSizeInFrames)
65 return;
66
67 double sampleRate = this->sampleRate();
68
69 // quantumStartFrame : Start frame of the current time quantum.
70 // quantumEndFrame : End frame of the current time quantum.
71 // startFrame : Start frame for this source.
72 // endFrame : End frame for this source.
73 size_t quantumStartFrame = context()->currentSampleFrame();
74 size_t quantumEndFrame = quantumStartFrame + quantumFrameSize;
75 size_t startFrame = AudioUtilities::timeToSampleFrame(m_startTime, sampleRate);
76 size_t endFrame = m_endTime == UnknownTime ? 0 : AudioUtilities::timeToSampleFrame(m_endTime, sampleRate);
77
78 // If we know the end time and it's already passed, then don't bother doing any more rendering this cycle.
79 if (m_endTime != UnknownTime && endFrame <= quantumStartFrame)
80 finish();
81
82 if (m_playbackState == UNSCHEDULED_STATE || m_playbackState == FINISHED_STATE || startFrame >= quantumEndFrame) {
83 // Output silence.
84 outputBus->zero();
85 nonSilentFramesToProcess = 0;
86 return;
87 }
88
89 // Check if it's time to start playing.
90 if (m_playbackState == SCHEDULED_STATE) {
91 // Increment the active source count only if we're transitioning from SCHEDULED_STATE to PLAYING_STATE.
92 m_playbackState = PLAYING_STATE;
93 }
94
95 quantumFrameOffset = startFrame > quantumStartFrame ? startFrame - quantumStartFrame : 0;
96 quantumFrameOffset = min(quantumFrameOffset, quantumFrameSize); // clamp to valid range
97 nonSilentFramesToProcess = quantumFrameSize - quantumFrameOffset;
98
99 if (!nonSilentFramesToProcess) {
100 // Output silence.
101 outputBus->zero();
102 return;
103 }
104
105 // Handle silence before we start playing.
106 // Zero any initial frames representing silence leading up to a rendering start time in the middle of the quantum.
107 if (quantumFrameOffset) {
108 for (unsigned i = 0; i < outputBus->numberOfChannels(); ++i)
109 memset(outputBus->channel(i)->mutableData(), 0, sizeof(float) * quantumFrameOffset);
110 }
111
112 // Handle silence after we're done playing.
113 // If the end time is somewhere in the middle of this time quantum, then zero out the
114 // frames from the end time to the very end of the quantum.
115 if (m_endTime != UnknownTime && endFrame >= quantumStartFrame && endFrame < quantumEndFrame) {
116 size_t zeroStartFrame = endFrame - quantumStartFrame;
117 size_t framesToZero = quantumFrameSize - zeroStartFrame;
118
119 bool isSafe = zeroStartFrame < quantumFrameSize && framesToZero <= quantumFrameSize && zeroStartFrame + framesToZero <= quantumFrameSize;
120 ASSERT(isSafe);
121
122 if (isSafe) {
123 if (framesToZero > nonSilentFramesToProcess)
124 nonSilentFramesToProcess = 0;
125 else
126 nonSilentFramesToProcess -= framesToZero;
127
128 for (unsigned i = 0; i < outputBus->numberOfChannels(); ++i)
129 memset(outputBus->channel(i)->mutableData() + zeroStartFrame, 0, sizeof(float) * framesToZero);
130 }
131
132 finish();
133 }
134
135 return;
136 }
137
start(double when,ExceptionState & exceptionState)138 void AudioScheduledSourceNode::start(double when, ExceptionState& exceptionState)
139 {
140 ASSERT(isMainThread());
141
142 if (m_playbackState != UNSCHEDULED_STATE) {
143 exceptionState.throwDOMException(
144 InvalidStateError,
145 "cannot call start more than once.");
146 return;
147 }
148
149 m_startTime = when;
150 m_playbackState = SCHEDULED_STATE;
151 }
152
stop(double when,ExceptionState & exceptionState)153 void AudioScheduledSourceNode::stop(double when, ExceptionState& exceptionState)
154 {
155 ASSERT(isMainThread());
156
157 if (m_playbackState == UNSCHEDULED_STATE) {
158 exceptionState.throwDOMException(
159 InvalidStateError,
160 "cannot call stop without calling start first.");
161 } else {
162 // stop() can be called more than once, with the last call to stop taking effect, unless the
163 // source has already stopped due to earlier calls to stop. No exceptions are thrown in any
164 // case.
165 when = max(0.0, when);
166 m_endTime = when;
167 }
168 }
169
setOnended(PassRefPtr<EventListener> listener)170 void AudioScheduledSourceNode::setOnended(PassRefPtr<EventListener> listener)
171 {
172 m_hasEndedListener = listener;
173 setAttributeEventListener(EventTypeNames::ended, listener);
174 }
175
finish()176 void AudioScheduledSourceNode::finish()
177 {
178 if (m_playbackState != FINISHED_STATE) {
179 // Let the context dereference this AudioNode.
180 context()->notifyNodeFinishedProcessing(this);
181 m_playbackState = FINISHED_STATE;
182 }
183
184 if (m_hasEndedListener) {
185 // |task| will keep the AudioScheduledSourceNode alive until the listener has been handled.
186 OwnPtr<NotifyEndedTask> task = adoptPtr(new NotifyEndedTask(this));
187 callOnMainThread(&AudioScheduledSourceNode::notifyEndedDispatch, task.leakPtr());
188 }
189 }
190
notifyEndedDispatch(void * userData)191 void AudioScheduledSourceNode::notifyEndedDispatch(void* userData)
192 {
193 OwnPtr<NotifyEndedTask> task = adoptPtr(static_cast<NotifyEndedTask*>(userData));
194
195 task->notifyEnded();
196 }
197
NotifyEndedTask(PassRefPtr<AudioScheduledSourceNode> sourceNode)198 AudioScheduledSourceNode::NotifyEndedTask::NotifyEndedTask(PassRefPtr<AudioScheduledSourceNode> sourceNode)
199 : m_scheduledNode(sourceNode)
200 {
201 }
202
notifyEnded()203 void AudioScheduledSourceNode::NotifyEndedTask::notifyEnded()
204 {
205 RefPtrWillBeRawPtr<Event> event = Event::create(EventTypeNames::ended);
206 event->setTarget(m_scheduledNode.get());
207 m_scheduledNode->dispatchEvent(event.get());
208 }
209
210 } // namespace WebCore
211
212 #endif // ENABLE(WEB_AUDIO)
213