/* * Copyright (C) 2011 Google Inc. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of * its contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #ifndef DynamicsCompressor_h #define DynamicsCompressor_h #include "AudioArray.h" #include "DynamicsCompressorKernel.h" #include "ZeroPole.h" namespace WebCore { class AudioBus; // DynamicsCompressor implements a flexible audio dynamics compression effect such as // is commonly used in musical production and game audio. It lowers the volume // of the loudest parts of the signal and raises the volume of the softest parts, // making the sound richer, fuller, and more controlled. class DynamicsCompressor { public: enum { ParamThreshold, ParamHeadroom, ParamAttack, ParamRelease, ParamPreDelay, ParamReleaseZone1, ParamReleaseZone2, ParamReleaseZone3, ParamReleaseZone4, ParamPostGain, ParamFilterStageGain, ParamFilterStageRatio, ParamFilterAnchor, ParamEffectBlend, ParamLast }; DynamicsCompressor(bool isStereo, double sampleRate); void process(AudioBus* sourceBus, AudioBus* destinationBus, unsigned framesToProcess); void reset(); double parameterValue(unsigned parameterID); bool isStereo() const { return m_isStereo; } double sampleRate() const { return m_sampleRate; } double nyquist() const { return 0.5 * m_sampleRate; } protected: // m_parameters holds the tweakable compressor parameters. // FIXME: expose some of the most important ones (such as threshold, attack, release) // as DynamicsCompressorNode attributes. double m_parameters[ParamLast]; void initializeParameters(); bool m_isStereo; double m_sampleRate; // Emphasis filter controls. float m_lastFilterStageRatio; float m_lastAnchor; float m_lastFilterStageGain; // Emphasis filters. ZeroPole m_preFilter[4]; ZeroPole m_preFilterR[4]; ZeroPole m_postFilter[4]; ZeroPole m_postFilterR[4]; void setEmphasisStageParameters(unsigned stageIndex, float gain, float normalizedFrequency /* 0 -> 1 */); void setEmphasisParameters(float gain, float anchorFreq, float filterStageRatio); // The core compressor. DynamicsCompressorKernel m_compressor; }; } // namespace WebCore #endif // DynamicsCompressor_h