1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/content/media/webaudio/blink/DynamicsCompressorKernel.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,130 @@
1.4 +/*
1.5 + * Copyright (C) 2011 Google Inc. All rights reserved.
1.6 + *
1.7 + * Redistribution and use in source and binary forms, with or without
1.8 + * modification, are permitted provided that the following conditions
1.9 + * are met:
1.10 + *
1.11 + * 1. Redistributions of source code must retain the above copyright
1.12 + * notice, this list of conditions and the following disclaimer.
1.13 + * 2. Redistributions in binary form must reproduce the above copyright
1.14 + * notice, this list of conditions and the following disclaimer in the
1.15 + * documentation and/or other materials provided with the distribution.
1.16 + * 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
1.17 + * its contributors may be used to endorse or promote products derived
1.18 + * from this software without specific prior written permission.
1.19 + *
1.20 + * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
1.21 + * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
1.22 + * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
1.23 + * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
1.24 + * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
1.25 + * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
1.26 + * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
1.27 + * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
1.28 + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
1.29 + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.30 + */
1.31 +
1.32 +#ifndef DynamicsCompressorKernel_h
1.33 +#define DynamicsCompressorKernel_h
1.34 +
1.35 +#include "nsTArray.h"
1.36 +#include "nsAutoPtr.h"
1.37 +#include "mozilla/MemoryReporting.h"
1.38 +
1.39 +namespace WebCore {
1.40 +
1.41 +class DynamicsCompressorKernel {
1.42 +public:
1.43 + DynamicsCompressorKernel(float sampleRate, unsigned numberOfChannels);
1.44 +
1.45 + void setNumberOfChannels(unsigned);
1.46 +
1.47 + // Performs stereo-linked compression.
1.48 + void process(float* sourceChannels[],
1.49 + float* destinationChannels[],
1.50 + unsigned numberOfChannels,
1.51 + unsigned framesToProcess,
1.52 +
1.53 + float dbThreshold,
1.54 + float dbKnee,
1.55 + float ratio,
1.56 + float attackTime,
1.57 + float releaseTime,
1.58 + float preDelayTime,
1.59 + float dbPostGain,
1.60 + float effectBlend,
1.61 +
1.62 + float releaseZone1,
1.63 + float releaseZone2,
1.64 + float releaseZone3,
1.65 + float releaseZone4
1.66 + );
1.67 +
1.68 + void reset();
1.69 +
1.70 + unsigned latencyFrames() const { return m_lastPreDelayFrames; }
1.71 +
1.72 + float sampleRate() const { return m_sampleRate; }
1.73 +
1.74 + float meteringGain() const { return m_meteringGain; }
1.75 +
1.76 + size_t sizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
1.77 +
1.78 +protected:
1.79 + float m_sampleRate;
1.80 +
1.81 + float m_detectorAverage;
1.82 + float m_compressorGain;
1.83 +
1.84 + // Metering
1.85 + float m_meteringReleaseK;
1.86 + float m_meteringGain;
1.87 +
1.88 + // Lookahead section.
1.89 + enum { MaxPreDelayFrames = 1024 };
1.90 + enum { MaxPreDelayFramesMask = MaxPreDelayFrames - 1 };
1.91 + enum { DefaultPreDelayFrames = 256 }; // setPreDelayTime() will override this initial value
1.92 + unsigned m_lastPreDelayFrames;
1.93 + void setPreDelayTime(float);
1.94 +
1.95 + nsTArray<nsAutoArrayPtr<float> > m_preDelayBuffers;
1.96 + int m_preDelayReadIndex;
1.97 + int m_preDelayWriteIndex;
1.98 +
1.99 + float m_maxAttackCompressionDiffDb;
1.100 +
1.101 + // Static compression curve.
1.102 + float kneeCurve(float x, float k);
1.103 + float saturate(float x, float k);
1.104 + float slopeAt(float x, float k);
1.105 + float kAtSlope(float desiredSlope);
1.106 +
1.107 + float updateStaticCurveParameters(float dbThreshold, float dbKnee, float ratio);
1.108 +
1.109 + // Amount of input change in dB required for 1 dB of output change.
1.110 + // This applies to the portion of the curve above m_kneeThresholdDb (see below).
1.111 + float m_ratio;
1.112 + float m_slope; // Inverse ratio.
1.113 +
1.114 + // The input to output change below the threshold is linear 1:1.
1.115 + float m_linearThreshold;
1.116 + float m_dbThreshold;
1.117 +
1.118 + // m_dbKnee is the number of dB above the threshold before we enter the "ratio" portion of the curve.
1.119 + // m_kneeThresholdDb = m_dbThreshold + m_dbKnee
1.120 + // The portion between m_dbThreshold and m_kneeThresholdDb is the "soft knee" portion of the curve
1.121 + // which transitions smoothly from the linear portion to the ratio portion.
1.122 + float m_dbKnee;
1.123 + float m_kneeThreshold;
1.124 + float m_kneeThresholdDb;
1.125 + float m_ykneeThresholdDb;
1.126 +
1.127 + // Internal parameter for the knee portion of the curve.
1.128 + float m_K;
1.129 +};
1.130 +
1.131 +} // namespace WebCore
1.132 +
1.133 +#endif // DynamicsCompressorKernel_h
