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/*
* 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 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 "DynamicsCompressorKernel.h"
#include "ZeroPole.h"
#include <memory>
#include <wtf/TZoneMalloc.h>
#include <wtf/UniqueArray.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 final {
WTF_MAKE_TZONE_ALLOCATED(DynamicsCompressor);
WTF_MAKE_NONCOPYABLE(DynamicsCompressor);
public:
enum {
ParamThreshold,
ParamKnee,
ParamRatio,
ParamAttack,
ParamRelease,
ParamPreDelay,
ParamReleaseZone1,
ParamReleaseZone2,
ParamReleaseZone3,
ParamReleaseZone4,
ParamPostGain,
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 m_compressor.tailTime(); }
double latencyTime() const { return m_compressor.latencyFrames() / static_cast<double>(sampleRate()); }
bool requiresTailProcessing() const
{
// Always return true even if the tail time and latency might both be zero.
return true;
}
protected:
unsigned m_numberOfChannels;
// m_parameters holds the tweakable compressor parameters.
std::array<float, ParamLast> m_parameters;
void initializeParameters();
std::span<std::span<const float>> sourceChannels() const { return unsafeMakeSpan(m_sourceChannels.get(), m_numberOfChannels); }
std::span<std::span<float>> destinationChannels() const { return unsafeMakeSpan(m_destinationChannels.get(), m_numberOfChannels); }
float m_sampleRate;
UniqueArray<std::span<const float>> m_sourceChannels;
UniqueArray<std::span<float>> m_destinationChannels;
// The core compressor.
DynamicsCompressorKernel m_compressor;
};
} // namespace WebCore
#endif // DynamicsCompressor_h
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