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 "AudioChannelMerger.h"
34
35 #include "AudioNodeInput.h"
36 #include "AudioNodeOutput.h"
37
38 namespace WebCore {
39
40 // This is considering that 5.1 (6 channels) is the largest we'll ever deal with.
41 // It can easily be increased to support more if the web audio specification is updated.
42 const unsigned NumberOfInputs = 6;
43
AudioChannelMerger(AudioContext * context,double sampleRate)44 AudioChannelMerger::AudioChannelMerger(AudioContext* context, double sampleRate)
45 : AudioNode(context, sampleRate)
46 {
47 // Create a fixed number of inputs (able to handle the maximum number of channels we deal with).
48 for (unsigned i = 0; i < NumberOfInputs; ++i)
49 addInput(adoptPtr(new AudioNodeInput(this)));
50
51 addOutput(adoptPtr(new AudioNodeOutput(this, 1)));
52
53 setType(NodeTypeChannelMerger);
54
55 initialize();
56 }
57
process(size_t framesToProcess)58 void AudioChannelMerger::process(size_t framesToProcess)
59 {
60 AudioNodeOutput* output = this->output(0);
61 ASSERT(output);
62 ASSERT_UNUSED(framesToProcess, framesToProcess == output->bus()->length());
63
64 // Count how many channels we have all together from all of the inputs.
65 unsigned numberOfOutputChannels = 0;
66 for (unsigned i = 0; i < numberOfInputs(); ++i) {
67 AudioNodeInput* input = this->input(i);
68 if (input->isConnected())
69 numberOfOutputChannels += input->bus()->numberOfChannels();
70 }
71
72 // Set the correct number of channels on the output
73 output->setNumberOfChannels(numberOfOutputChannels);
74
75 // Now merge the channels back into one output.
76 unsigned outputChannelIndex = 0;
77 for (unsigned i = 0; i < numberOfInputs(); ++i) {
78 AudioNodeInput* input = this->input(i);
79 if (input->isConnected()) {
80 unsigned numberOfInputChannels = input->bus()->numberOfChannels();
81
82 // Merge channels from this particular input.
83 for (unsigned j = 0; j < numberOfInputChannels; ++j) {
84 AudioChannel* inputChannel = input->bus()->channel(j);
85 AudioChannel* outputChannel = output->bus()->channel(outputChannelIndex);
86 outputChannel->copyFrom(inputChannel);
87
88 ++outputChannelIndex;
89 }
90 }
91 }
92
93 ASSERT(outputChannelIndex == numberOfOutputChannels);
94 }
95
reset()96 void AudioChannelMerger::reset()
97 {
98 }
99
100 } // namespace WebCore
101
102 #endif // ENABLE(WEB_AUDIO)
103