The Tor Browser: content/media/webaudio/blink/DynamicsCompressorKernel.h@6474c204b198

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

     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  */

    29 #ifndef DynamicsCompressorKernel_h

    30 #define DynamicsCompressorKernel_h

    32 #include "nsTArray.h"

    33 #include "nsAutoPtr.h"

    34 #include "mozilla/MemoryReporting.h"

    36 namespace WebCore {

    38 class DynamicsCompressorKernel {

    39 public:

    40     DynamicsCompressorKernel(float sampleRate, unsigned numberOfChannels);

    42     void setNumberOfChannels(unsigned);

    44     // Performs stereo-linked compression.

    45     void process(float* sourceChannels[],

    46                  float* destinationChannels[],

    47                  unsigned numberOfChannels,

    48                  unsigned framesToProcess,

    50                  float dbThreshold,

    51                  float dbKnee,

    52                  float ratio,

    53                  float attackTime,

    54                  float releaseTime,

    55                  float preDelayTime,

    56                  float dbPostGain,

    57                  float effectBlend,

    59                  float releaseZone1,

    60                  float releaseZone2,

    61                  float releaseZone3,

    62                  float releaseZone4

    63                  );

    65     void reset();

    67     unsigned latencyFrames() const { return m_lastPreDelayFrames; }

    69     float sampleRate() const { return m_sampleRate; }

    71     float meteringGain() const { return m_meteringGain; }

    73     size_t sizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;

    75 protected:

    76     float m_sampleRate;

    78     float m_detectorAverage;

    79     float m_compressorGain;

    81     // Metering

    82     float m_meteringReleaseK;

    83     float m_meteringGain;

    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);

    92     nsTArray<nsAutoArrayPtr<float> > m_preDelayBuffers;

    93     int m_preDelayReadIndex;

    94     int m_preDelayWriteIndex;

    96     float m_maxAttackCompressionDiffDb;

    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);

   104     float updateStaticCurveParameters(float dbThreshold, float dbKnee, float ratio);

   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.

   111     // The input to output change below the threshold is linear 1:1.

   112     float m_linearThreshold;

   113     float m_dbThreshold;

   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;

   124     // Internal parameter for the knee portion of the curve.

   125     float m_K;

   126 };

   128 } // namespace WebCore

   130 #endif // DynamicsCompressorKernel_h

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