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 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#ifndef DynamicsCompressor_h 30#define DynamicsCompressor_h 31 32#include "AudioArray.h" 33#include "DynamicsCompressorKernel.h" 34#include "ZeroPole.h" 35#include <memory> 36 37namespace WebCore { 38 39class AudioBus; 40 41// DynamicsCompressor implements a flexible audio dynamics compression effect such as 42// is commonly used in musical production and game audio. It lowers the volume 43// of the loudest parts of the signal and raises the volume of the softest parts, 44// making the sound richer, fuller, and more controlled. 45 46class DynamicsCompressor { 47public: 48 enum { 49 ParamThreshold, 50 ParamKnee, 51 ParamRatio, 52 ParamAttack, 53 ParamRelease, 54 ParamPreDelay, 55 ParamReleaseZone1, 56 ParamReleaseZone2, 57 ParamReleaseZone3, 58 ParamReleaseZone4, 59 ParamPostGain, 60 ParamFilterStageGain, 61 ParamFilterStageRatio, 62 ParamFilterAnchor, 63 ParamEffectBlend, 64 ParamReduction, 65 ParamLast 66 }; 67 68 DynamicsCompressor(float sampleRate, unsigned numberOfChannels); 69 70 void process(const AudioBus* sourceBus, AudioBus* destinationBus, unsigned framesToProcess); 71 void reset(); 72 void setNumberOfChannels(unsigned); 73 74 void setParameterValue(unsigned parameterID, float value); 75 float parameterValue(unsigned parameterID); 76 77 float sampleRate() const { return m_sampleRate; } 78 float nyquist() const { return m_sampleRate / 2; } 79 80 double tailTime() const { return 0; } 81 double latencyTime() const { return m_compressor.latencyFrames() / static_cast<double>(sampleRate()); } 82 83protected: 84 unsigned m_numberOfChannels; 85 86 // m_parameters holds the tweakable compressor parameters. 87 float m_parameters[ParamLast]; 88 void initializeParameters(); 89 90 float m_sampleRate; 91 92 // Emphasis filter controls. 93 float m_lastFilterStageRatio; 94 float m_lastAnchor; 95 float m_lastFilterStageGain; 96 97 typedef struct { 98 ZeroPole filters[4]; 99 } ZeroPoleFilterPack4; 100 101 // Per-channel emphasis filters. 102 Vector<std::unique_ptr<ZeroPoleFilterPack4>> m_preFilterPacks; 103 Vector<std::unique_ptr<ZeroPoleFilterPack4>> m_postFilterPacks; 104 105 std::unique_ptr<const float*[]> m_sourceChannels; 106 std::unique_ptr<float*[]> m_destinationChannels; 107 108 void setEmphasisStageParameters(unsigned stageIndex, float gain, float normalizedFrequency /* 0 -> 1 */); 109 void setEmphasisParameters(float gain, float anchorFreq, float filterStageRatio); 110 111 // The core compressor. 112 DynamicsCompressorKernel m_compressor; 113}; 114 115} // namespace WebCore 116 117#endif // DynamicsCompressor_h 118