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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 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

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  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

  */

 #ifndef DynamicsCompressor_h

 #define DynamicsCompressor_h

 #include "DynamicsCompressorKernel.h"

 #include "ZeroPole.h"

 #include "nsTArray.h"

 #include "nsAutoPtr.h"

 #include "mozilla/MemoryReporting.h"

 namespace mozilla {

 struct AudioChunk;

 }

 namespace WebCore {

 using mozilla::AudioChunk;

 // 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,

         ParamKnee,

         ParamRatio,

         ParamAttack,

         ParamRelease,

         ParamPreDelay,

         ParamReleaseZone1,

         ParamReleaseZone2,

         ParamReleaseZone3,

         ParamReleaseZone4,

         ParamPostGain,

         ParamFilterStageGain,

         ParamFilterStageRatio,

         ParamFilterAnchor,

         ParamEffectBlend,

         ParamReduction,

         ParamLast

     };

     DynamicsCompressor(float sampleRate, unsigned numberOfChannels);

     void process(const AudioChunk* sourceChunk, AudioChunk* destinationChunk, unsigned framesToProcess);

     void reset();

     void setNumberOfChannels(unsigned);

     unsigned numberOfChannels() const { return m_numberOfChannels; }

     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()); }

     size_t sizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;

 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;

     typedef struct {

         ZeroPole filters[4];

         size_t sizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const

         {

             return aMallocSizeOf(this);

         }

     } ZeroPoleFilterPack4;

     // Per-channel emphasis filters.

     nsTArray<nsAutoPtr<ZeroPoleFilterPack4> > m_preFilterPacks;

     nsTArray<nsAutoPtr<ZeroPoleFilterPack4> > m_postFilterPacks;

     nsAutoArrayPtr<const float*> m_sourceChannels;

     nsAutoArrayPtr<float*> m_destinationChannels;

     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