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 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
15 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
16 * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
17 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
18 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
19 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
20 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
22 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23 */
24
25 #include "config.h"
26
27 #if ENABLE(WEB_AUDIO)
28
29 #include "modules/webaudio/WaveShaperDSPKernel.h"
30
31 #include "wtf/MainThread.h"
32 #include "wtf/Threading.h"
33 #include <algorithm>
34
35 const unsigned RenderingQuantum = 128;
36
37 using namespace std;
38
39 namespace WebCore {
40
WaveShaperDSPKernel(WaveShaperProcessor * processor)41 WaveShaperDSPKernel::WaveShaperDSPKernel(WaveShaperProcessor* processor)
42 : AudioDSPKernel(processor)
43 {
44 if (processor->oversample() != WaveShaperProcessor::OverSampleNone)
45 lazyInitializeOversampling();
46 }
47
lazyInitializeOversampling()48 void WaveShaperDSPKernel::lazyInitializeOversampling()
49 {
50 if (!m_tempBuffer) {
51 m_tempBuffer = adoptPtr(new AudioFloatArray(RenderingQuantum * 2));
52 m_tempBuffer2 = adoptPtr(new AudioFloatArray(RenderingQuantum * 4));
53 m_upSampler = adoptPtr(new UpSampler(RenderingQuantum));
54 m_downSampler = adoptPtr(new DownSampler(RenderingQuantum * 2));
55 m_upSampler2 = adoptPtr(new UpSampler(RenderingQuantum * 2));
56 m_downSampler2 = adoptPtr(new DownSampler(RenderingQuantum * 4));
57 }
58 }
59
process(const float * source,float * destination,size_t framesToProcess)60 void WaveShaperDSPKernel::process(const float* source, float* destination, size_t framesToProcess)
61 {
62 switch (waveShaperProcessor()->oversample()) {
63 case WaveShaperProcessor::OverSampleNone:
64 processCurve(source, destination, framesToProcess);
65 break;
66 case WaveShaperProcessor::OverSample2x:
67 processCurve2x(source, destination, framesToProcess);
68 break;
69 case WaveShaperProcessor::OverSample4x:
70 processCurve4x(source, destination, framesToProcess);
71 break;
72
73 default:
74 ASSERT_NOT_REACHED();
75 }
76 }
77
processCurve(const float * source,float * destination,size_t framesToProcess)78 void WaveShaperDSPKernel::processCurve(const float* source, float* destination, size_t framesToProcess)
79 {
80 ASSERT(source && destination && waveShaperProcessor());
81
82 Float32Array* curve = waveShaperProcessor()->curve();
83 if (!curve) {
84 // Act as "straight wire" pass-through if no curve is set.
85 memcpy(destination, source, sizeof(float) * framesToProcess);
86 return;
87 }
88
89 float* curveData = curve->data();
90 int curveLength = curve->length();
91
92 ASSERT(curveData);
93
94 if (!curveData || !curveLength) {
95 memcpy(destination, source, sizeof(float) * framesToProcess);
96 return;
97 }
98
99 // Apply waveshaping curve.
100 for (unsigned i = 0; i < framesToProcess; ++i) {
101 const float input = source[i];
102
103 // Calculate a virtual index based on input -1 -> +1 with 0 being at the center of the curve data.
104 // Then linearly interpolate between the two points in the curve.
105 double virtualIndex = 0.5 * (input + 1) * curveLength;
106 int index1 = static_cast<int>(virtualIndex);
107 int index2 = index1 + 1;
108 double interpolationFactor = virtualIndex - index1;
109
110 // Clip index to the input range of the curve.
111 // This takes care of input outside of nominal range -1 -> +1
112 index1 = max(index1, 0);
113 index1 = min(index1, curveLength - 1);
114 index2 = max(index2, 0);
115 index2 = min(index2, curveLength - 1);
116
117 double value1 = curveData[index1];
118 double value2 = curveData[index2];
119
120 double output = (1.0 - interpolationFactor) * value1 + interpolationFactor * value2;
121 destination[i] = output;
122 }
123 }
124
processCurve2x(const float * source,float * destination,size_t framesToProcess)125 void WaveShaperDSPKernel::processCurve2x(const float* source, float* destination, size_t framesToProcess)
126 {
127 bool isSafe = framesToProcess == RenderingQuantum;
128 ASSERT(isSafe);
129 if (!isSafe)
130 return;
131
132 float* tempP = m_tempBuffer->data();
133
134 m_upSampler->process(source, tempP, framesToProcess);
135
136 // Process at 2x up-sampled rate.
137 processCurve(tempP, tempP, framesToProcess * 2);
138
139 m_downSampler->process(tempP, destination, framesToProcess * 2);
140 }
141
processCurve4x(const float * source,float * destination,size_t framesToProcess)142 void WaveShaperDSPKernel::processCurve4x(const float* source, float* destination, size_t framesToProcess)
143 {
144 bool isSafe = framesToProcess == RenderingQuantum;
145 ASSERT(isSafe);
146 if (!isSafe)
147 return;
148
149 float* tempP = m_tempBuffer->data();
150 float* tempP2 = m_tempBuffer2->data();
151
152 m_upSampler->process(source, tempP, framesToProcess);
153 m_upSampler2->process(tempP, tempP2, framesToProcess * 2);
154
155 // Process at 4x up-sampled rate.
156 processCurve(tempP2, tempP2, framesToProcess * 4);
157
158 m_downSampler2->process(tempP2, tempP, framesToProcess * 4);
159 m_downSampler->process(tempP, destination, framesToProcess * 2);
160 }
161
reset()162 void WaveShaperDSPKernel::reset()
163 {
164 if (m_upSampler) {
165 m_upSampler->reset();
166 m_downSampler->reset();
167 m_upSampler2->reset();
168 m_downSampler2->reset();
169 }
170 }
171
latencyTime() const172 double WaveShaperDSPKernel::latencyTime() const
173 {
174 size_t latencyFrames = 0;
175 WaveShaperDSPKernel* kernel = const_cast<WaveShaperDSPKernel*>(this);
176
177 switch (kernel->waveShaperProcessor()->oversample()) {
178 case WaveShaperProcessor::OverSampleNone:
179 break;
180 case WaveShaperProcessor::OverSample2x:
181 latencyFrames += m_upSampler->latencyFrames();
182 latencyFrames += m_downSampler->latencyFrames();
183 break;
184 case WaveShaperProcessor::OverSample4x:
185 {
186 // Account for first stage upsampling.
187 latencyFrames += m_upSampler->latencyFrames();
188 latencyFrames += m_downSampler->latencyFrames();
189
190 // Account for second stage upsampling.
191 // and divide by 2 to get back down to the regular sample-rate.
192 size_t latencyFrames2 = (m_upSampler2->latencyFrames() + m_downSampler2->latencyFrames()) / 2;
193 latencyFrames += latencyFrames2;
194 break;
195 }
196 default:
197 ASSERT_NOT_REACHED();
198 }
199
200 return static_cast<double>(latencyFrames) / sampleRate();
201 }
202
203 } // namespace WebCore
204
205 #endif // ENABLE(WEB_AUDIO)
206