1 /* 2 * Copyright (C) 2011 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 "platform/audio/DynamicsCompressor.h" 34 35 #include "platform/audio/AudioBus.h" 36 #include "platform/audio/AudioUtilities.h" 37 #include "wtf/MathExtras.h" 38 39 namespace blink { 40 41 using namespace AudioUtilities; 42 43 DynamicsCompressor::DynamicsCompressor(float sampleRate, unsigned numberOfChannels) 44 : m_numberOfChannels(numberOfChannels) 45 , m_sampleRate(sampleRate) 46 , m_compressor(sampleRate, numberOfChannels) 47 { 48 // Uninitialized state - for parameter recalculation. 49 m_lastFilterStageRatio = -1; 50 m_lastAnchor = -1; 51 m_lastFilterStageGain = -1; 52 53 setNumberOfChannels(numberOfChannels); 54 initializeParameters(); 55 } 56 57 void DynamicsCompressor::setParameterValue(unsigned parameterID, float value) 58 { 59 ASSERT(parameterID < ParamLast); 60 if (parameterID < ParamLast) 61 m_parameters[parameterID] = value; 62 } 63 64 void DynamicsCompressor::initializeParameters() 65 { 66 // Initializes compressor to default values. 67 68 m_parameters[ParamThreshold] = -24; // dB 69 m_parameters[ParamKnee] = 30; // dB 70 m_parameters[ParamRatio] = 12; // unit-less 71 m_parameters[ParamAttack] = 0.003f; // seconds 72 m_parameters[ParamRelease] = 0.250f; // seconds 73 m_parameters[ParamPreDelay] = 0.006f; // seconds 74 75 // Release zone values 0 -> 1. 76 m_parameters[ParamReleaseZone1] = 0.09f; 77 m_parameters[ParamReleaseZone2] = 0.16f; 78 m_parameters[ParamReleaseZone3] = 0.42f; 79 m_parameters[ParamReleaseZone4] = 0.98f; 80 81 m_parameters[ParamFilterStageGain] = 4.4f; // dB 82 m_parameters[ParamFilterStageRatio] = 2; 83 m_parameters[ParamFilterAnchor] = 15000 / nyquist(); 84 85 m_parameters[ParamPostGain] = 0; // dB 86 m_parameters[ParamReduction] = 0; // dB 87 88 // Linear crossfade (0 -> 1). 89 m_parameters[ParamEffectBlend] = 1; 90 } 91 92 float DynamicsCompressor::parameterValue(unsigned parameterID) 93 { 94 ASSERT(parameterID < ParamLast); 95 return m_parameters[parameterID]; 96 } 97 98 void DynamicsCompressor::process(const AudioBus* sourceBus, AudioBus* destinationBus, unsigned framesToProcess) 99 { 100 // Though numberOfChannels is retrived from destinationBus, we still name it numberOfChannels instead of numberOfDestinationChannels. 101 // It's because we internally match sourceChannels's size to destinationBus by channel up/down mix. Thus we need numberOfChannels 102 // to do the loop work for both m_sourceChannels and m_destinationChannels. 103 104 unsigned numberOfChannels = destinationBus->numberOfChannels(); 105 unsigned numberOfSourceChannels = sourceBus->numberOfChannels(); 106 107 ASSERT(numberOfChannels == m_numberOfChannels && numberOfSourceChannels); 108 109 if (numberOfChannels != m_numberOfChannels || !numberOfSourceChannels) { 110 destinationBus->zero(); 111 return; 112 } 113 114 switch (numberOfChannels) { 115 case 2: // stereo 116 m_sourceChannels[0] = sourceBus->channel(0)->data(); 117 118 if (numberOfSourceChannels > 1) 119 m_sourceChannels[1] = sourceBus->channel(1)->data(); 120 else 121 // Simply duplicate mono channel input data to right channel for stereo processing. 122 m_sourceChannels[1] = m_sourceChannels[0]; 123 124 break; 125 default: 126 // FIXME : support other number of channels. 127 ASSERT_NOT_REACHED(); 128 destinationBus->zero(); 129 return; 130 } 131 132 for (unsigned i = 0; i < numberOfChannels; ++i) 133 m_destinationChannels[i] = destinationBus->channel(i)->mutableData(); 134 135 float filterStageGain = parameterValue(ParamFilterStageGain); 136 float filterStageRatio = parameterValue(ParamFilterStageRatio); 137 float anchor = parameterValue(ParamFilterAnchor); 138 139 if (filterStageGain != m_lastFilterStageGain || filterStageRatio != m_lastFilterStageRatio || anchor != m_lastAnchor) { 140 m_lastFilterStageGain = filterStageGain; 141 m_lastFilterStageRatio = filterStageRatio; 142 m_lastAnchor = anchor; 143 144 } 145 146 float dbThreshold = parameterValue(ParamThreshold); 147 float dbKnee = parameterValue(ParamKnee); 148 float ratio = parameterValue(ParamRatio); 149 float attackTime = parameterValue(ParamAttack); 150 float releaseTime = parameterValue(ParamRelease); 151 float preDelayTime = parameterValue(ParamPreDelay); 152 153 // This is effectively a master volume on the compressed signal (pre-blending). 154 float dbPostGain = parameterValue(ParamPostGain); 155 156 // Linear blending value from dry to completely processed (0 -> 1) 157 // 0 means the signal is completely unprocessed. 158 // 1 mixes in only the compressed signal. 159 float effectBlend = parameterValue(ParamEffectBlend); 160 161 float releaseZone1 = parameterValue(ParamReleaseZone1); 162 float releaseZone2 = parameterValue(ParamReleaseZone2); 163 float releaseZone3 = parameterValue(ParamReleaseZone3); 164 float releaseZone4 = parameterValue(ParamReleaseZone4); 165 166 // Apply compression to the source signal. 167 m_compressor.process(m_sourceChannels.get(), 168 m_destinationChannels.get(), 169 numberOfChannels, 170 framesToProcess, 171 172 dbThreshold, 173 dbKnee, 174 ratio, 175 attackTime, 176 releaseTime, 177 preDelayTime, 178 dbPostGain, 179 effectBlend, 180 181 releaseZone1, 182 releaseZone2, 183 releaseZone3, 184 releaseZone4 185 ); 186 187 // Update the compression amount. 188 setParameterValue(ParamReduction, m_compressor.meteringGain()); 189 190 } 191 192 void DynamicsCompressor::reset() 193 { 194 m_lastFilterStageRatio = -1; // for recalc 195 m_lastAnchor = -1; 196 m_lastFilterStageGain = -1; 197 198 m_compressor.reset(); 199 } 200 201 void DynamicsCompressor::setNumberOfChannels(unsigned numberOfChannels) 202 { 203 m_sourceChannels = adoptArrayPtr(new const float* [numberOfChannels]); 204 m_destinationChannels = adoptArrayPtr(new float* [numberOfChannels]); 205 206 m_compressor.setNumberOfChannels(numberOfChannels); 207 m_numberOfChannels = numberOfChannels; 208 } 209 210 } // namespace blink 211 212 #endif // ENABLE(WEB_AUDIO) 213