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 "Reverb.h" 34 35 #include "AudioBus.h" 36 #include "AudioFileReader.h" 37 #include "ReverbConvolver.h" 38 #include <math.h> 39 #include <wtf/MathExtras.h> 40 #include <wtf/OwnPtr.h> 41 #include <wtf/PassOwnPtr.h> 42 43 #if OS(DARWIN) 44 using namespace std; 45 #endif 46 47 namespace WebCore { 48 49 // Empirical gain calibration tested across many impulse responses to ensure perceived volume is same as dry (unprocessed) signal 50 const double GainCalibration = -58.0; 51 52 // A minimum power value to when normalizing a silent (or very quiet) impulse response 53 const double MinPower = 0.000125; 54 55 static double calculateNormalizationScale(AudioBus* response) 56 { 57 // Normalize by RMS power 58 size_t numberOfChannels = response->numberOfChannels(); 59 size_t length = response->length(); 60 61 double power = 0.0; 62 63 for (size_t i = 0; i < numberOfChannels; ++i) { 64 int n = length; 65 float* p = response->channel(i)->data(); 66 67 while (n--) { 68 float sample = *p++; 69 power += sample * sample; 70 } 71 } 72 73 power = sqrt(power / (numberOfChannels * length)); 74 75 // Protect against accidental overload 76 if (isinf(power) || isnan(power) || power < MinPower) 77 power = MinPower; 78 79 double scale = 1.0 / power; 80 81 scale *= pow(10.0, GainCalibration * 0.05); // calibrate to make perceived volume same as unprocessed 82 83 // True-stereo compensation 84 if (response->numberOfChannels() == 4) 85 scale *= 0.5; 86 87 return scale; 88 } 89 90 Reverb::Reverb(AudioBus* impulseResponse, size_t renderSliceSize, size_t maxFFTSize, size_t numberOfChannels, bool useBackgroundThreads) 91 { 92 double scale = calculateNormalizationScale(impulseResponse); 93 if (scale) 94 impulseResponse->scale(scale); 95 96 initialize(impulseResponse, renderSliceSize, maxFFTSize, numberOfChannels, useBackgroundThreads); 97 98 // Undo scaling since this shouldn't be a destructive operation on impulseResponse 99 if (scale) 100 impulseResponse->scale(1.0 / scale); 101 } 102 103 void Reverb::initialize(AudioBus* impulseResponseBuffer, size_t renderSliceSize, size_t maxFFTSize, size_t numberOfChannels, bool useBackgroundThreads) 104 { 105 m_impulseResponseLength = impulseResponseBuffer->length(); 106 107 // The reverb can handle a mono impulse response and still do stereo processing 108 size_t numResponseChannels = impulseResponseBuffer->numberOfChannels(); 109 m_convolvers.reserveCapacity(numberOfChannels); 110 111 int convolverRenderPhase = 0; 112 for (size_t i = 0; i < numResponseChannels; ++i) { 113 AudioChannel* channel = impulseResponseBuffer->channel(i); 114 115 OwnPtr<ReverbConvolver> convolver = adoptPtr(new ReverbConvolver(channel, renderSliceSize, maxFFTSize, convolverRenderPhase, useBackgroundThreads)); 116 m_convolvers.append(convolver.release()); 117 118 convolverRenderPhase += renderSliceSize; 119 } 120 121 // For "True" stereo processing we allocate a temporary buffer to avoid repeatedly allocating it in the process() method. 122 // It can be bad to allocate memory in a real-time thread. 123 if (numResponseChannels == 4) 124 m_tempBuffer = new AudioBus(2, MaxFrameSize); 125 } 126 127 void Reverb::process(AudioBus* sourceBus, AudioBus* destinationBus, size_t framesToProcess) 128 { 129 // Do a fairly comprehensive sanity check. 130 // If these conditions are satisfied, all of the source and destination pointers will be valid for the various matrixing cases. 131 bool isSafeToProcess = sourceBus && destinationBus && sourceBus->numberOfChannels() > 0 && destinationBus->numberOfChannels() > 0 132 && framesToProcess <= MaxFrameSize && framesToProcess <= sourceBus->length() && framesToProcess <= destinationBus->length(); 133 134 ASSERT(isSafeToProcess); 135 if (!isSafeToProcess) 136 return; 137 138 // For now only handle mono or stereo output 139 if (destinationBus->numberOfChannels() > 2) { 140 destinationBus->zero(); 141 return; 142 } 143 144 AudioChannel* destinationChannelL = destinationBus->channel(0); 145 AudioChannel* sourceChannelL = sourceBus->channel(0); 146 147 // Handle input -> output matrixing... 148 size_t numInputChannels = sourceBus->numberOfChannels(); 149 size_t numOutputChannels = destinationBus->numberOfChannels(); 150 size_t numReverbChannels = m_convolvers.size(); 151 152 if (numInputChannels == 2 && numReverbChannels == 2 && numOutputChannels == 2) { 153 // 2 -> 2 -> 2 154 AudioChannel* sourceChannelR = sourceBus->channel(1); 155 AudioChannel* destinationChannelR = destinationBus->channel(1); 156 m_convolvers[0]->process(sourceChannelL, destinationChannelL, framesToProcess); 157 m_convolvers[1]->process(sourceChannelR, destinationChannelR, framesToProcess); 158 } else if (numInputChannels == 1 && numOutputChannels == 2 && numReverbChannels == 2) { 159 // 1 -> 2 -> 2 160 for (int i = 0; i < 2; ++i) { 161 AudioChannel* destinationChannel = destinationBus->channel(i); 162 m_convolvers[i]->process(sourceChannelL, destinationChannel, framesToProcess); 163 } 164 } else if (numInputChannels == 1 && numReverbChannels == 1 && numOutputChannels == 2) { 165 // 1 -> 1 -> 2 166 m_convolvers[0]->process(sourceChannelL, destinationChannelL, framesToProcess); 167 168 // simply copy L -> R 169 AudioChannel* destinationChannelR = destinationBus->channel(1); 170 bool isCopySafe = destinationChannelL->data() && destinationChannelR->data() && destinationChannelL->length() >= framesToProcess && destinationChannelR->length() >= framesToProcess; 171 ASSERT(isCopySafe); 172 if (!isCopySafe) 173 return; 174 memcpy(destinationChannelR->data(), destinationChannelL->data(), sizeof(float) * framesToProcess); 175 } else if (numInputChannels == 1 && numReverbChannels == 1 && numOutputChannels == 1) { 176 // 1 -> 1 -> 1 177 m_convolvers[0]->process(sourceChannelL, destinationChannelL, framesToProcess); 178 } else if (numInputChannels == 2 && numReverbChannels == 4 && numOutputChannels == 2) { 179 // 2 -> 4 -> 2 ("True" stereo) 180 AudioChannel* sourceChannelR = sourceBus->channel(1); 181 AudioChannel* destinationChannelR = destinationBus->channel(1); 182 183 AudioChannel* tempChannelL = m_tempBuffer->channel(0); 184 AudioChannel* tempChannelR = m_tempBuffer->channel(1); 185 186 // Process left virtual source 187 m_convolvers[0]->process(sourceChannelL, destinationChannelL, framesToProcess); 188 m_convolvers[1]->process(sourceChannelL, destinationChannelR, framesToProcess); 189 190 // Process right virtual source 191 m_convolvers[2]->process(sourceChannelR, tempChannelL, framesToProcess); 192 m_convolvers[3]->process(sourceChannelR, tempChannelR, framesToProcess); 193 194 destinationBus->sumFrom(*m_tempBuffer); 195 } else if (numInputChannels == 1 && numReverbChannels == 4 && numOutputChannels == 2) { 196 // 1 -> 4 -> 2 (Processing mono with "True" stereo impulse response) 197 // This is an inefficient use of a four-channel impulse response, but we should handle the case. 198 AudioChannel* destinationChannelR = destinationBus->channel(1); 199 200 AudioChannel* tempChannelL = m_tempBuffer->channel(0); 201 AudioChannel* tempChannelR = m_tempBuffer->channel(1); 202 203 // Process left virtual source 204 m_convolvers[0]->process(sourceChannelL, destinationChannelL, framesToProcess); 205 m_convolvers[1]->process(sourceChannelL, destinationChannelR, framesToProcess); 206 207 // Process right virtual source 208 m_convolvers[2]->process(sourceChannelL, tempChannelL, framesToProcess); 209 m_convolvers[3]->process(sourceChannelL, tempChannelR, framesToProcess); 210 211 destinationBus->sumFrom(*m_tempBuffer); 212 } else { 213 // Handle gracefully any unexpected / unsupported matrixing 214 // FIXME: add code for 5.1 support... 215 destinationBus->zero(); 216 } 217 } 218 219 void Reverb::reset() 220 { 221 for (size_t i = 0; i < m_convolvers.size(); ++i) 222 m_convolvers[i]->reset(); 223 } 224 225 } // namespace WebCore 226 227 #endif // ENABLE(WEB_AUDIO) 228
