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 * 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 "AudioChannelSplitter.h"
30
31 #include "AudioNodeInput.h"
32 #include "AudioNodeOutput.h"
33
34 namespace WebCore {
35
36 // This is considering that 5.1 (6 channels) is the largest we'll ever deal with.
37 // It can easily be increased to support more if the web audio specification is updated.
38 const unsigned NumberOfOutputs = 6;
39
AudioChannelSplitter(AudioContext * context,double sampleRate)40 AudioChannelSplitter::AudioChannelSplitter(AudioContext* context, double sampleRate)
41 : AudioNode(context, sampleRate)
42 {
43 addInput(adoptPtr(new AudioNodeInput(this)));
44
45 // Create a fixed number of outputs (able to handle the maximum number of channels fed to an input).
46 for (unsigned i = 0; i < NumberOfOutputs; ++i)
47 addOutput(adoptPtr(new AudioNodeOutput(this, 1)));
48
49 setType(NodeTypeChannelSplitter);
50
51 initialize();
52 }
53
process(size_t framesToProcess)54 void AudioChannelSplitter::process(size_t framesToProcess)
55 {
56 AudioBus* source = input(0)->bus();
57 ASSERT(source);
58 ASSERT_UNUSED(framesToProcess, framesToProcess == source->length());
59
60 unsigned numberOfSourceChannels = source->numberOfChannels();
61
62 ASSERT(numberOfOutputs() == NumberOfOutputs);
63 for (unsigned i = 0; i < NumberOfOutputs; ++i) {
64 AudioBus* destination = output(i)->bus();
65 ASSERT(destination);
66
67 if (i < numberOfSourceChannels) {
68 // Split the channel out if it exists in the source.
69 // It would be nice to avoid the copy and simply pass along pointers, but this becomes extremely difficult with fanout and fanin.
70 destination->channel(0)->copyFrom(source->channel(i));
71 } else if (output(i)->renderingFanOutCount() > 0) {
72 // Only bother zeroing out the destination if it's connected to anything
73 destination->zero();
74 }
75 }
76 }
77
reset()78 void AudioChannelSplitter::reset()
79 {
80 }
81
82 } // namespace WebCore
83
84 #endif // ENABLE(WEB_AUDIO)
85