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 #include "config.h"
30
31 #if ENABLE(WEB_AUDIO)
32
33 #include "platform/audio/DynamicsCompressor.h"
34
35 #include "platform/audio/AudioBus.h"
36 #include "platform/audio/AudioUtilities.h"
37 #include "wtf/MathExtras.h"
38
39 namespace blink {
40
41 using namespace AudioUtilities;
42
DynamicsCompressor(float sampleRate,unsigned numberOfChannels)43 DynamicsCompressor::DynamicsCompressor(float sampleRate, unsigned numberOfChannels)
44 : m_numberOfChannels(numberOfChannels)
45 , m_sampleRate(sampleRate)
46 , m_compressor(sampleRate, numberOfChannels)
47 {
48 // Uninitialized state - for parameter recalculation.
49 m_lastFilterStageRatio = -1;
50 m_lastAnchor = -1;
51 m_lastFilterStageGain = -1;
52
53 setNumberOfChannels(numberOfChannels);
54 initializeParameters();
55 }
56
setParameterValue(unsigned parameterID,float value)57 void DynamicsCompressor::setParameterValue(unsigned parameterID, float value)
58 {
59 ASSERT(parameterID < ParamLast);
60 if (parameterID < ParamLast)
61 m_parameters[parameterID] = value;
62 }
63
initializeParameters()64 void DynamicsCompressor::initializeParameters()
65 {
66 // Initializes compressor to default values.
67
68 m_parameters[ParamThreshold] = -24; // dB
69 m_parameters[ParamKnee] = 30; // dB
70 m_parameters[ParamRatio] = 12; // unit-less
71 m_parameters[ParamAttack] = 0.003f; // seconds
72 m_parameters[ParamRelease] = 0.250f; // seconds
73 m_parameters[ParamPreDelay] = 0.006f; // seconds
74
75 // Release zone values 0 -> 1.
76 m_parameters[ParamReleaseZone1] = 0.09f;
77 m_parameters[ParamReleaseZone2] = 0.16f;
78 m_parameters[ParamReleaseZone3] = 0.42f;
79 m_parameters[ParamReleaseZone4] = 0.98f;
80
81 m_parameters[ParamFilterStageGain] = 4.4f; // dB
82 m_parameters[ParamFilterStageRatio] = 2;
83 m_parameters[ParamFilterAnchor] = 15000 / nyquist();
84
85 m_parameters[ParamPostGain] = 0; // dB
86 m_parameters[ParamReduction] = 0; // dB
87
88 // Linear crossfade (0 -> 1).
89 m_parameters[ParamEffectBlend] = 1;
90 }
91
parameterValue(unsigned parameterID)92 float DynamicsCompressor::parameterValue(unsigned parameterID)
93 {
94 ASSERT(parameterID < ParamLast);
95 return m_parameters[parameterID];
96 }
97
process(const AudioBus * sourceBus,AudioBus * destinationBus,unsigned framesToProcess)98 void DynamicsCompressor::process(const AudioBus* sourceBus, AudioBus* destinationBus, unsigned framesToProcess)
99 {
100 // Though numberOfChannels is retrived from destinationBus, we still name it numberOfChannels instead of numberOfDestinationChannels.
101 // It's because we internally match sourceChannels's size to destinationBus by channel up/down mix. Thus we need numberOfChannels
102 // to do the loop work for both m_sourceChannels and m_destinationChannels.
103
104 unsigned numberOfChannels = destinationBus->numberOfChannels();
105 unsigned numberOfSourceChannels = sourceBus->numberOfChannels();
106
107 ASSERT(numberOfChannels == m_numberOfChannels && numberOfSourceChannels);
108
109 if (numberOfChannels != m_numberOfChannels || !numberOfSourceChannels) {
110 destinationBus->zero();
111 return;
112 }
113
114 switch (numberOfChannels) {
115 case 2: // stereo
116 m_sourceChannels[0] = sourceBus->channel(0)->data();
117
118 if (numberOfSourceChannels > 1)
119 m_sourceChannels[1] = sourceBus->channel(1)->data();
120 else
121 // Simply duplicate mono channel input data to right channel for stereo processing.
122 m_sourceChannels[1] = m_sourceChannels[0];
123
124 break;
125 default:
126 // FIXME : support other number of channels.
127 ASSERT_NOT_REACHED();
128 destinationBus->zero();
129 return;
130 }
131
132 for (unsigned i = 0; i < numberOfChannels; ++i)
133 m_destinationChannels[i] = destinationBus->channel(i)->mutableData();
134
135 float filterStageGain = parameterValue(ParamFilterStageGain);
136 float filterStageRatio = parameterValue(ParamFilterStageRatio);
137 float anchor = parameterValue(ParamFilterAnchor);
138
139 if (filterStageGain != m_lastFilterStageGain || filterStageRatio != m_lastFilterStageRatio || anchor != m_lastAnchor) {
140 m_lastFilterStageGain = filterStageGain;
141 m_lastFilterStageRatio = filterStageRatio;
142 m_lastAnchor = anchor;
143
144 }
145
146 float dbThreshold = parameterValue(ParamThreshold);
147 float dbKnee = parameterValue(ParamKnee);
148 float ratio = parameterValue(ParamRatio);
149 float attackTime = parameterValue(ParamAttack);
150 float releaseTime = parameterValue(ParamRelease);
151 float preDelayTime = parameterValue(ParamPreDelay);
152
153 // This is effectively a master volume on the compressed signal (pre-blending).
154 float dbPostGain = parameterValue(ParamPostGain);
155
156 // Linear blending value from dry to completely processed (0 -> 1)
157 // 0 means the signal is completely unprocessed.
158 // 1 mixes in only the compressed signal.
159 float effectBlend = parameterValue(ParamEffectBlend);
160
161 float releaseZone1 = parameterValue(ParamReleaseZone1);
162 float releaseZone2 = parameterValue(ParamReleaseZone2);
163 float releaseZone3 = parameterValue(ParamReleaseZone3);
164 float releaseZone4 = parameterValue(ParamReleaseZone4);
165
166 // Apply compression to the source signal.
167 m_compressor.process(m_sourceChannels.get(),
168 m_destinationChannels.get(),
169 numberOfChannels,
170 framesToProcess,
171
172 dbThreshold,
173 dbKnee,
174 ratio,
175 attackTime,
176 releaseTime,
177 preDelayTime,
178 dbPostGain,
179 effectBlend,
180
181 releaseZone1,
182 releaseZone2,
183 releaseZone3,
184 releaseZone4
185 );
186
187 // Update the compression amount.
188 setParameterValue(ParamReduction, m_compressor.meteringGain());
189
190 }
191
reset()192 void DynamicsCompressor::reset()
193 {
194 m_lastFilterStageRatio = -1; // for recalc
195 m_lastAnchor = -1;
196 m_lastFilterStageGain = -1;
197
198 m_compressor.reset();
199 }
200
setNumberOfChannels(unsigned numberOfChannels)201 void DynamicsCompressor::setNumberOfChannels(unsigned numberOfChannels)
202 {
203 m_sourceChannels = adoptArrayPtr(new const float* [numberOfChannels]);
204 m_destinationChannels = adoptArrayPtr(new float* [numberOfChannels]);
205
206 m_compressor.setNumberOfChannels(numberOfChannels);
207 m_numberOfChannels = numberOfChannels;
208 }
209
210 } // namespace blink
211
212 #endif // ENABLE(WEB_AUDIO)
213