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