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 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 "ChannelMergerNode.h"
34
35#include "AudioContext.h"
36#include "AudioNodeInput.h"
37#include "AudioNodeOutput.h"
38#include <wtf/IsoMallocInlines.h>
39
40const unsigned DefaultNumberOfOutputChannels = 1;
41
42namespace WebCore {
43
44WTF_MAKE_ISO_ALLOCATED_IMPL(ChannelMergerNode);
45
46RefPtr<ChannelMergerNode> ChannelMergerNode::create(AudioContext& context, float sampleRate, unsigned numberOfInputs)
47{
48 if (!numberOfInputs || numberOfInputs > AudioContext::maxNumberOfChannels())
49 return nullptr;
50
51 return adoptRef(*new ChannelMergerNode(context, sampleRate, numberOfInputs));
52}
53
54ChannelMergerNode::ChannelMergerNode(AudioContext& context, float sampleRate, unsigned numberOfInputs)
55 : AudioNode(context, sampleRate)
56 , m_desiredNumberOfOutputChannels(DefaultNumberOfOutputChannels)
57{
58 setNodeType(NodeTypeChannelMerger);
59
60 // Create the requested number of inputs.
61 for (unsigned i = 0; i < numberOfInputs; ++i)
62 addInput(std::make_unique<AudioNodeInput>(this));
63
64 addOutput(std::make_unique<AudioNodeOutput>(this, 1));
65
66 initialize();
67}
68
69void ChannelMergerNode::process(size_t framesToProcess)
70{
71 AudioNodeOutput* output = this->output(0);
72 ASSERT(output);
73 ASSERT_UNUSED(framesToProcess, framesToProcess == output->bus()->length());
74
75 // Output bus not updated yet, so just output silence.
76 if (m_desiredNumberOfOutputChannels != output->numberOfChannels()) {
77 output->bus()->zero();
78 return;
79 }
80
81 // Merge all the channels from all the inputs into one output.
82 unsigned outputChannelIndex = 0;
83 for (unsigned i = 0; i < numberOfInputs(); ++i) {
84 AudioNodeInput* input = this->input(i);
85 if (input->isConnected()) {
86 unsigned numberOfInputChannels = input->bus()->numberOfChannels();
87
88 // Merge channels from this particular input.
89 for (unsigned j = 0; j < numberOfInputChannels; ++j) {
90 AudioChannel* inputChannel = input->bus()->channel(j);
91 AudioChannel* outputChannel = output->bus()->channel(outputChannelIndex);
92 outputChannel->copyFrom(inputChannel);
93
94 ++outputChannelIndex;
95 }
96 }
97 }
98
99 ASSERT(outputChannelIndex == output->numberOfChannels());
100}
101
102void ChannelMergerNode::reset()
103{
104}
105
106// Any time a connection or disconnection happens on any of our inputs, we potentially need to change the
107// number of channels of our output.
108void ChannelMergerNode::checkNumberOfChannelsForInput(AudioNodeInput* input)
109{
110 ASSERT(context().isAudioThread() && context().isGraphOwner());
111
112 // Count how many channels we have all together from all of the inputs.
113 unsigned numberOfOutputChannels = 0;
114 for (unsigned i = 0; i < numberOfInputs(); ++i) {
115 AudioNodeInput* input = this->input(i);
116 if (input->isConnected())
117 numberOfOutputChannels += input->numberOfChannels();
118 }
119
120 // Set the correct number of channels on the output
121 AudioNodeOutput* output = this->output(0);
122 ASSERT(output);
123 output->setNumberOfChannels(numberOfOutputChannels);
124 // There can in rare cases be a slight delay before the output bus is updated to the new number of
125 // channels because of tryLocks() in the context's updating system. So record the new number of
126 // output channels here.
127 m_desiredNumberOfOutputChannels = numberOfOutputChannels;
128
129 AudioNode::checkNumberOfChannelsForInput(input);
130}
131
132} // namespace WebCore
133
134#endif // ENABLE(WEB_AUDIO)
135