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 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 "DynamicsCompressorKernel.h"
33#include "ZeroPole.h"
34#include <memory>
35#include <wtf/UniqueArray.h>
36
37namespace WebCore {
38
39class AudioBus;
40
41// DynamicsCompressor implements a flexible audio dynamics compression effect such as
42// is commonly used in musical production and game audio. It lowers the volume
43// of the loudest parts of the signal and raises the volume of the softest parts,
44// making the sound richer, fuller, and more controlled.
45
46class DynamicsCompressor {
47 WTF_MAKE_FAST_ALLOCATED;
48public:
49 enum {
50 ParamThreshold,
51 ParamKnee,
52 ParamRatio,
53 ParamAttack,
54 ParamRelease,
55 ParamPreDelay,
56 ParamReleaseZone1,
57 ParamReleaseZone2,
58 ParamReleaseZone3,
59 ParamReleaseZone4,
60 ParamPostGain,
61 ParamFilterStageGain,
62 ParamFilterStageRatio,
63 ParamFilterAnchor,
64 ParamEffectBlend,
65 ParamReduction,
66 ParamLast
67 };
68
69 DynamicsCompressor(float sampleRate, unsigned numberOfChannels);
70
71 void process(const AudioBus* sourceBus, AudioBus* destinationBus, unsigned framesToProcess);
72 void reset();
73 void setNumberOfChannels(unsigned);
74
75 void setParameterValue(unsigned parameterID, float value);
76 float parameterValue(unsigned parameterID);
77
78 float sampleRate() const { return m_sampleRate; }
79 float nyquist() const { return m_sampleRate / 2; }
80
81 double tailTime() const { return 0; }
82 double latencyTime() const { return m_compressor.latencyFrames() / static_cast<double>(sampleRate()); }
83
84protected:
85 unsigned m_numberOfChannels;
86
87 // m_parameters holds the tweakable compressor parameters.
88 float m_parameters[ParamLast];
89 void initializeParameters();
90
91 float m_sampleRate;
92
93 // Emphasis filter controls.
94 float m_lastFilterStageRatio;
95 float m_lastAnchor;
96 float m_lastFilterStageGain;
97
98 typedef struct {
99 ZeroPole filters[4];
100 } ZeroPoleFilterPack4;
101
102 // Per-channel emphasis filters.
103 Vector<std::unique_ptr<ZeroPoleFilterPack4>> m_preFilterPacks;
104 Vector<std::unique_ptr<ZeroPoleFilterPack4>> m_postFilterPacks;
105
106 UniqueArray<const float*> m_sourceChannels;
107 UniqueArray<float*> m_destinationChannels;
108
109 void setEmphasisStageParameters(unsigned stageIndex, float gain, float normalizedFrequency /* 0 -> 1 */);
110 void setEmphasisParameters(float gain, float anchorFreq, float filterStageRatio);
111
112 // The core compressor.
113 DynamicsCompressorKernel m_compressor;
114};
115
116} // namespace WebCore
117
118#endif // DynamicsCompressor_h
119