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 DynamicsCompressor_h
30#define DynamicsCompressor_h
31
32#include "platform/audio/AudioArray.h"
33#include "platform/audio/DynamicsCompressorKernel.h"
34#include "platform/audio/ZeroPole.h"
35#include "wtf/Noncopyable.h"
36#include "wtf/OwnPtr.h"
37
38namespace blink {
39
40class AudioBus;
41
42// DynamicsCompressor implements a flexible audio dynamics compression effect such as
43// is commonly used in musical production and game audio. It lowers the volume
44// of the loudest parts of the signal and raises the volume of the softest parts,
45// making the sound richer, fuller, and more controlled.
46
47class PLATFORM_EXPORT DynamicsCompressor {
48    WTF_MAKE_NONCOPYABLE(DynamicsCompressor);
49public:
50    enum {
51        ParamThreshold,
52        ParamKnee,
53        ParamRatio,
54        ParamAttack,
55        ParamRelease,
56        ParamPreDelay,
57        ParamReleaseZone1,
58        ParamReleaseZone2,
59        ParamReleaseZone3,
60        ParamReleaseZone4,
61        ParamPostGain,
62        ParamFilterStageGain,
63        ParamFilterStageRatio,
64        ParamFilterAnchor,
65        ParamEffectBlend,
66        ParamReduction,
67        ParamLast
68    };
69
70    DynamicsCompressor(float sampleRate, unsigned numberOfChannels);
71
72    void process(const AudioBus* sourceBus, AudioBus* destinationBus, unsigned framesToProcess);
73    void reset();
74    void setNumberOfChannels(unsigned);
75
76    void setParameterValue(unsigned parameterID, float value);
77    float parameterValue(unsigned parameterID);
78
79    float sampleRate() const { return m_sampleRate; }
80    float nyquist() const { return m_sampleRate / 2; }
81
82    double tailTime() const { return 0; }
83    double latencyTime() const { return m_compressor.latencyFrames() / static_cast<double>(sampleRate()); }
84
85protected:
86    unsigned m_numberOfChannels;
87
88    // m_parameters holds the tweakable compressor parameters.
89    float m_parameters[ParamLast];
90    void initializeParameters();
91
92    float m_sampleRate;
93
94    // Emphasis filter controls.
95    float m_lastFilterStageRatio;
96    float m_lastAnchor;
97    float m_lastFilterStageGain;
98
99    OwnPtr<const float*[]> m_sourceChannels;
100    OwnPtr<float*[]> m_destinationChannels;
101
102    // The core compressor.
103    DynamicsCompressorKernel m_compressor;
104};
105
106} // namespace blink
107
108#endif // DynamicsCompressor_h
109