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 "modules/webaudio/ConvolverNode.h" 30 31#include "platform/audio/Reverb.h" 32#include "modules/webaudio/AudioBuffer.h" 33#include "modules/webaudio/AudioContext.h" 34#include "modules/webaudio/AudioNodeInput.h" 35#include "modules/webaudio/AudioNodeOutput.h" 36#include "wtf/MainThread.h" 37 38// Note about empirical tuning: 39// The maximum FFT size affects reverb performance and accuracy. 40// If the reverb is single-threaded and processes entirely in the real-time audio thread, 41// it's important not to make this too high. In this case 8192 is a good value. 42// But, the Reverb object is multi-threaded, so we want this as high as possible without losing too much accuracy. 43// Very large FFTs will have worse phase errors. Given these constraints 32768 is a good compromise. 44const size_t MaxFFTSize = 32768; 45 46namespace WebCore { 47 48ConvolverNode::ConvolverNode(AudioContext* context, float sampleRate) 49 : AudioNode(context, sampleRate) 50 , m_normalize(true) 51{ 52 ScriptWrappable::init(this); 53 addInput(adoptPtr(new AudioNodeInput(this))); 54 addOutput(adoptPtr(new AudioNodeOutput(this, 2))); 55 56 // Node-specific default mixing rules. 57 m_channelCount = 2; 58 m_channelCountMode = ClampedMax; 59 m_channelInterpretation = AudioBus::Speakers; 60 61 setNodeType(NodeTypeConvolver); 62 initialize(); 63} 64 65ConvolverNode::~ConvolverNode() 66{ 67 uninitialize(); 68} 69 70void ConvolverNode::process(size_t framesToProcess) 71{ 72 AudioBus* outputBus = output(0)->bus(); 73 ASSERT(outputBus); 74 75 // Synchronize with possible dynamic changes to the impulse response. 76 MutexTryLocker tryLocker(m_processLock); 77 if (tryLocker.locked()) { 78 if (!isInitialized() || !m_reverb.get()) 79 outputBus->zero(); 80 else { 81 // Process using the convolution engine. 82 // Note that we can handle the case where nothing is connected to the input, in which case we'll just feed silence into the convolver. 83 // FIXME: If we wanted to get fancy we could try to factor in the 'tail time' and stop processing once the tail dies down if 84 // we keep getting fed silence. 85 m_reverb->process(input(0)->bus(), outputBus, framesToProcess); 86 } 87 } else { 88 // Too bad - the tryLock() failed. We must be in the middle of setting a new impulse response. 89 outputBus->zero(); 90 } 91} 92 93void ConvolverNode::reset() 94{ 95 MutexLocker locker(m_processLock); 96 if (m_reverb.get()) 97 m_reverb->reset(); 98} 99 100void ConvolverNode::initialize() 101{ 102 if (isInitialized()) 103 return; 104 105 AudioNode::initialize(); 106} 107 108void ConvolverNode::uninitialize() 109{ 110 if (!isInitialized()) 111 return; 112 113 m_reverb.clear(); 114 AudioNode::uninitialize(); 115} 116 117void ConvolverNode::setBuffer(AudioBuffer* buffer) 118{ 119 ASSERT(isMainThread()); 120 121 if (!buffer) 122 return; 123 124 unsigned numberOfChannels = buffer->numberOfChannels(); 125 size_t bufferLength = buffer->length(); 126 127 // The current implementation supports up to four channel impulse responses, which are interpreted as true-stereo (see Reverb class). 128 bool isBufferGood = numberOfChannels > 0 && numberOfChannels <= 4 && bufferLength; 129 ASSERT(isBufferGood); 130 if (!isBufferGood) 131 return; 132 133 // Wrap the AudioBuffer by an AudioBus. It's an efficient pointer set and not a memcpy(). 134 // This memory is simply used in the Reverb constructor and no reference to it is kept for later use in that class. 135 RefPtr<AudioBus> bufferBus = AudioBus::create(numberOfChannels, bufferLength, false); 136 for (unsigned i = 0; i < numberOfChannels; ++i) 137 bufferBus->setChannelMemory(i, buffer->getChannelData(i)->data(), bufferLength); 138 139 bufferBus->setSampleRate(buffer->sampleRate()); 140 141 // Create the reverb with the given impulse response. 142 bool useBackgroundThreads = !context()->isOfflineContext(); 143 OwnPtr<Reverb> reverb = adoptPtr(new Reverb(bufferBus.get(), AudioNode::ProcessingSizeInFrames, MaxFFTSize, 2, useBackgroundThreads, m_normalize)); 144 145 { 146 // Synchronize with process(). 147 MutexLocker locker(m_processLock); 148 m_reverb = reverb.release(); 149 m_buffer = buffer; 150 } 151} 152 153AudioBuffer* ConvolverNode::buffer() 154{ 155 ASSERT(isMainThread()); 156 return m_buffer.get(); 157} 158 159double ConvolverNode::tailTime() const 160{ 161 MutexTryLocker tryLocker(m_processLock); 162 if (tryLocker.locked()) 163 return m_reverb ? m_reverb->impulseResponseLength() / static_cast<double>(sampleRate()) : 0; 164 // Since we don't want to block the Audio Device thread, we return a large value 165 // instead of trying to acquire the lock. 166 return std::numeric_limits<double>::infinity(); 167} 168 169double ConvolverNode::latencyTime() const 170{ 171 MutexTryLocker tryLocker(m_processLock); 172 if (tryLocker.locked()) 173 return m_reverb ? m_reverb->latencyFrames() / static_cast<double>(sampleRate()) : 0; 174 // Since we don't want to block the Audio Device thread, we return a large value 175 // instead of trying to acquire the lock. 176 return std::numeric_limits<double>::infinity(); 177} 178 179} // namespace WebCore 180 181#endif // ENABLE(WEB_AUDIO) 182