1 /*
2 * Copyright (C) 2010 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 *
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
14 * its contributors may be used to endorse or promote products derived
15 * from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
18 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
21 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
22 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
23 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
24 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 #include "config.h"
30
31 #if ENABLE(WEB_AUDIO)
32
33 #include "modules/webaudio/ChannelMergerNode.h"
34
35 #include "modules/webaudio/AudioContext.h"
36 #include "modules/webaudio/AudioNodeInput.h"
37 #include "modules/webaudio/AudioNodeOutput.h"
38
39 const unsigned DefaultNumberOfOutputChannels = 1;
40
41 namespace WebCore {
42
create(AudioContext * context,float sampleRate,unsigned numberOfInputs)43 PassRefPtr<ChannelMergerNode> ChannelMergerNode::create(AudioContext* context, float sampleRate, unsigned numberOfInputs)
44 {
45 if (!numberOfInputs || numberOfInputs > AudioContext::maxNumberOfChannels())
46 return 0;
47
48 return adoptRef(new ChannelMergerNode(context, sampleRate, numberOfInputs));
49 }
50
ChannelMergerNode(AudioContext * context,float sampleRate,unsigned numberOfInputs)51 ChannelMergerNode::ChannelMergerNode(AudioContext* context, float sampleRate, unsigned numberOfInputs)
52 : AudioNode(context, sampleRate)
53 , m_desiredNumberOfOutputChannels(DefaultNumberOfOutputChannels)
54 {
55 ScriptWrappable::init(this);
56 // Create the requested number of inputs.
57 for (unsigned i = 0; i < numberOfInputs; ++i)
58 addInput(adoptPtr(new AudioNodeInput(this)));
59
60 addOutput(adoptPtr(new AudioNodeOutput(this, 1)));
61 setNodeType(NodeTypeChannelMerger);
62 initialize();
63 }
64
process(size_t framesToProcess)65 void ChannelMergerNode::process(size_t framesToProcess)
66 {
67 AudioNodeOutput* output = this->output(0);
68 ASSERT(output);
69 ASSERT_UNUSED(framesToProcess, framesToProcess == output->bus()->length());
70
71 // Output bus not updated yet, so just output silence.
72 if (m_desiredNumberOfOutputChannels != output->numberOfChannels()) {
73 output->bus()->zero();
74 return;
75 }
76
77 // Merge all the channels from all the inputs into one output.
78 unsigned outputChannelIndex = 0;
79 for (unsigned i = 0; i < numberOfInputs(); ++i) {
80 AudioNodeInput* input = this->input(i);
81 if (input->isConnected()) {
82 unsigned numberOfInputChannels = input->bus()->numberOfChannels();
83
84 // Merge channels from this particular input.
85 for (unsigned j = 0; j < numberOfInputChannels; ++j) {
86 AudioChannel* inputChannel = input->bus()->channel(j);
87 AudioChannel* outputChannel = output->bus()->channel(outputChannelIndex);
88 outputChannel->copyFrom(inputChannel);
89
90 ++outputChannelIndex;
91 }
92 }
93 }
94
95 ASSERT(outputChannelIndex == output->numberOfChannels());
96 }
97
reset()98 void ChannelMergerNode::reset()
99 {
100 }
101
102 // Any time a connection or disconnection happens on any of our inputs, we potentially need to change the
103 // number of channels of our output.
checkNumberOfChannelsForInput(AudioNodeInput * input)104 void ChannelMergerNode::checkNumberOfChannelsForInput(AudioNodeInput* input)
105 {
106 ASSERT(context()->isAudioThread() && context()->isGraphOwner());
107
108 // Count how many channels we have all together from all of the inputs.
109 unsigned numberOfOutputChannels = 0;
110 for (unsigned i = 0; i < numberOfInputs(); ++i) {
111 AudioNodeInput* input = this->input(i);
112 if (input->isConnected())
113 numberOfOutputChannels += input->numberOfChannels();
114 }
115
116 // Set the correct number of channels on the output
117 AudioNodeOutput* output = this->output(0);
118 ASSERT(output);
119 output->setNumberOfChannels(numberOfOutputChannels);
120 // There can in rare cases be a slight delay before the output bus is updated to the new number of
121 // channels because of tryLocks() in the context's updating system. So record the new number of
122 // output channels here.
123 m_desiredNumberOfOutputChannels = numberOfOutputChannels;
124
125 AudioNode::checkNumberOfChannelsForInput(input);
126 }
127
128 } // namespace WebCore
129
130 #endif // ENABLE(WEB_AUDIO)
131