/*
* 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
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* 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
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#ifndef DynamicsCompressor_h
#define DynamicsCompressor_h
#include "platform/audio/AudioArray.h"
#include "platform/audio/DynamicsCompressorKernel.h"
#include "platform/audio/ZeroPole.h"
#include "wtf/Noncopyable.h"
#include "wtf/OwnPtr.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 PLATFORM_EXPORT DynamicsCompressor {
WTF_MAKE_NONCOPYABLE(DynamicsCompressor);
public:
enum {
ParamThreshold,
ParamKnee,
ParamRatio,
ParamAttack,
ParamRelease,
ParamPreDelay,
ParamReleaseZone1,
ParamReleaseZone2,
ParamReleaseZone3,
ParamReleaseZone4,
ParamPostGain,
ParamFilterStageGain,
ParamFilterStageRatio,
ParamFilterAnchor,
ParamEffectBlend,
ParamReduction,
ParamLast
};
DynamicsCompressor(float sampleRate, unsigned numberOfChannels);
void process(const AudioBus* sourceBus, AudioBus* destinationBus, unsigned framesToProcess);
void reset();
void setNumberOfChannels(unsigned);
void setParameterValue(unsigned parameterID, float value);
float parameterValue(unsigned parameterID);
float sampleRate() const { return m_sampleRate; }
float nyquist() const { return m_sampleRate / 2; }
double tailTime() const { return 0; }
double latencyTime() const { return m_compressor.latencyFrames() / static_cast<double>(sampleRate()); }
protected:
unsigned m_numberOfChannels;
// m_parameters holds the tweakable compressor parameters.
float m_parameters[ParamLast];
void initializeParameters();
float m_sampleRate;
// Emphasis filter controls.
float m_lastFilterStageRatio;
float m_lastAnchor;
float m_lastFilterStageGain;
OwnPtr<const float*[]> m_sourceChannels;
OwnPtr<float*[]> m_destinationChannels;
// The core compressor.
DynamicsCompressorKernel m_compressor;
};
} // namespace WebCore
#endif // DynamicsCompressor_h