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 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 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 96 void AudioChannelMerger::reset() 97 { 98 } 99 100 } // namespace WebCore 101 102 #endif // ENABLE(WEB_AUDIO) 103