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