Line data    Source code

       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 Computer, 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 DynamicsCompressorKernel_h
      30             : #define DynamicsCompressorKernel_h
      31             : 
      32             : #include "nsTArray.h"
      33             : #include "mozilla/MemoryReporting.h"
      34             : #include "mozilla/UniquePtr.h"
      35             : 
      36             : namespace WebCore {
      37             : 
      38           0 : class DynamicsCompressorKernel {
      39             : public:
      40             :     DynamicsCompressorKernel(float sampleRate, unsigned numberOfChannels);
      41             : 
      42             :     void setNumberOfChannels(unsigned);
      43             : 
      44             :     // Performs stereo-linked compression.
      45             :     void process(float* sourceChannels[],
      46             :                  float* destinationChannels[],
      47             :                  unsigned numberOfChannels,
      48             :                  unsigned framesToProcess,
      49             : 
      50             :                  float dbThreshold,
      51             :                  float dbKnee,
      52             :                  float ratio,
      53             :                  float attackTime,
      54             :                  float releaseTime,
      55             :                  float preDelayTime,
      56             :                  float dbPostGain,
      57             :                  float effectBlend,
      58             : 
      59             :                  float releaseZone1,
      60             :                  float releaseZone2,
      61             :                  float releaseZone3,
      62             :                  float releaseZone4
      63             :                  );
      64             : 
      65             :     void reset();
      66             : 
      67             :     unsigned latencyFrames() const { return m_lastPreDelayFrames; }
      68             : 
      69           0 :     float sampleRate() const { return m_sampleRate; }
      70             : 
      71           0 :     float meteringGain() const { return m_meteringGain; }
      72             : 
      73             :     size_t sizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
      74             : 
      75             : protected:
      76             :     float m_sampleRate;
      77             : 
      78             :     float m_detectorAverage;
      79             :     float m_compressorGain;
      80             : 
      81             :     // Metering
      82             :     float m_meteringReleaseK;
      83             :     float m_meteringGain;
      84             : 
      85             :     // Lookahead section.
      86             :     enum { MaxPreDelayFrames = 1024 };
      87             :     enum { MaxPreDelayFramesMask = MaxPreDelayFrames - 1 };
      88             :     enum { DefaultPreDelayFrames = 256 }; // setPreDelayTime() will override this initial value
      89             :     unsigned m_lastPreDelayFrames;
      90             :     void setPreDelayTime(float);
      91             : 
      92             :     nsTArray<mozilla::UniquePtr<float[]>> m_preDelayBuffers;
      93             :     int m_preDelayReadIndex;
      94             :     int m_preDelayWriteIndex;
      95             : 
      96             :     float m_maxAttackCompressionDiffDb;
      97             : 
      98             :     // Static compression curve.
      99             :     float kneeCurve(float x, float k);
     100             :     float saturate(float x, float k);
     101             :     float slopeAt(float x, float k);
     102             :     float kAtSlope(float desiredSlope);
     103             : 
     104             :     float updateStaticCurveParameters(float dbThreshold, float dbKnee, float ratio);
     105             : 
     106             :     // Amount of input change in dB required for 1 dB of output change.
     107             :     // This applies to the portion of the curve above m_kneeThresholdDb (see below).
     108             :     float m_ratio;
     109             :     float m_slope; // Inverse ratio.
     110             : 
     111             :     // The input to output change below the threshold is linear 1:1.
     112             :     float m_linearThreshold;
     113             :     float m_dbThreshold;
     114             : 
     115             :     // m_dbKnee is the number of dB above the threshold before we enter the "ratio" portion of the curve.
     116             :     // m_kneeThresholdDb = m_dbThreshold + m_dbKnee
     117             :     // The portion between m_dbThreshold and m_kneeThresholdDb is the "soft knee" portion of the curve
     118             :     // which transitions smoothly from the linear portion to the ratio portion.
     119             :     float m_dbKnee;
     120             :     float m_kneeThreshold;
     121             :     float m_kneeThresholdDb;
     122             :     float m_ykneeThresholdDb;
     123             : 
     124             :     // Internal parameter for the knee portion of the curve.
     125             :     float m_K;
     126             : };
     127             : 
     128             : } // namespace WebCore
     129             : 
     130             : #endif // DynamicsCompressorKernel_h