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1 /*
2  * Copyright (C) 2010 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/ReverbConvolverStage.h"
34 
35 #include "platform/audio/ReverbAccumulationBuffer.h"
36 #include "platform/audio/ReverbConvolver.h"
37 #include "platform/audio/ReverbInputBuffer.h"
38 #include "platform/audio/VectorMath.h"
39 #include "wtf/PassOwnPtr.h"
40 
41 namespace blink {
42 
43 using namespace VectorMath;
44 
ReverbConvolverStage(const float * impulseResponse,size_t,size_t reverbTotalLatency,size_t stageOffset,size_t stageLength,size_t fftSize,size_t renderPhase,size_t renderSliceSize,ReverbAccumulationBuffer * accumulationBuffer,bool directMode)45 ReverbConvolverStage::ReverbConvolverStage(const float* impulseResponse, size_t, size_t reverbTotalLatency, size_t stageOffset, size_t stageLength,
46                                            size_t fftSize, size_t renderPhase, size_t renderSliceSize, ReverbAccumulationBuffer* accumulationBuffer, bool directMode)
47     : m_accumulationBuffer(accumulationBuffer)
48     , m_accumulationReadIndex(0)
49     , m_inputReadIndex(0)
50     , m_directMode(directMode)
51 {
52     ASSERT(impulseResponse);
53     ASSERT(accumulationBuffer);
54 
55     if (!m_directMode) {
56         m_fftKernel = adoptPtr(new FFTFrame(fftSize));
57         m_fftKernel->doPaddedFFT(impulseResponse + stageOffset, stageLength);
58         m_fftConvolver = adoptPtr(new FFTConvolver(fftSize));
59     } else {
60         ASSERT(!stageOffset);
61         ASSERT(stageLength <= fftSize / 2);
62 
63         m_directKernel = adoptPtr(new AudioFloatArray(fftSize / 2));
64         m_directKernel->copyToRange(impulseResponse, 0, stageLength);
65         m_directConvolver = adoptPtr(new DirectConvolver(renderSliceSize));
66     }
67     m_temporaryBuffer.allocate(renderSliceSize);
68 
69     // The convolution stage at offset stageOffset needs to have a corresponding delay to cancel out the offset.
70     size_t totalDelay = stageOffset + reverbTotalLatency;
71 
72     // But, the FFT convolution itself incurs fftSize / 2 latency, so subtract this out...
73     size_t halfSize = fftSize / 2;
74     if (!m_directMode) {
75         ASSERT(totalDelay >= halfSize);
76         if (totalDelay >= halfSize)
77             totalDelay -= halfSize;
78     }
79 
80     // We divide up the total delay, into pre and post delay sections so that we can schedule at exactly the moment when the FFT will happen.
81     // This is coordinated with the other stages, so they don't all do their FFTs at the same time...
82     int maxPreDelayLength = std::min(halfSize, totalDelay);
83     m_preDelayLength = totalDelay > 0 ? renderPhase % maxPreDelayLength : 0;
84     if (m_preDelayLength > totalDelay)
85         m_preDelayLength = 0;
86 
87     m_postDelayLength = totalDelay - m_preDelayLength;
88     m_preReadWriteIndex = 0;
89     m_framesProcessed = 0; // total frames processed so far
90 
91     size_t delayBufferSize = m_preDelayLength < fftSize ? fftSize : m_preDelayLength;
92     delayBufferSize = delayBufferSize < renderSliceSize ? renderSliceSize : delayBufferSize;
93     m_preDelayBuffer.allocate(delayBufferSize);
94 }
95 
processInBackground(ReverbConvolver * convolver,size_t framesToProcess)96 void ReverbConvolverStage::processInBackground(ReverbConvolver* convolver, size_t framesToProcess)
97 {
98     ReverbInputBuffer* inputBuffer = convolver->inputBuffer();
99     float* source = inputBuffer->directReadFrom(&m_inputReadIndex, framesToProcess);
100     process(source, framesToProcess);
101 }
102 
process(const float * source,size_t framesToProcess)103 void ReverbConvolverStage::process(const float* source, size_t framesToProcess)
104 {
105     ASSERT(source);
106     if (!source)
107         return;
108 
109     // Deal with pre-delay stream : note special handling of zero delay.
110 
111     const float* preDelayedSource;
112     float* preDelayedDestination;
113     float* temporaryBuffer;
114     bool isTemporaryBufferSafe = false;
115     if (m_preDelayLength > 0) {
116         // Handles both the read case (call to process() ) and the write case (memcpy() )
117         bool isPreDelaySafe = m_preReadWriteIndex + framesToProcess <= m_preDelayBuffer.size();
118         ASSERT(isPreDelaySafe);
119         if (!isPreDelaySafe)
120             return;
121 
122         isTemporaryBufferSafe = framesToProcess <= m_temporaryBuffer.size();
123 
124         preDelayedDestination = m_preDelayBuffer.data() + m_preReadWriteIndex;
125         preDelayedSource = preDelayedDestination;
126         temporaryBuffer = m_temporaryBuffer.data();
127     } else {
128         // Zero delay
129         preDelayedDestination = 0;
130         preDelayedSource = source;
131         temporaryBuffer = m_preDelayBuffer.data();
132 
133         isTemporaryBufferSafe = framesToProcess <= m_preDelayBuffer.size();
134     }
135 
136     ASSERT(isTemporaryBufferSafe);
137     if (!isTemporaryBufferSafe)
138         return;
139 
140     if (m_framesProcessed < m_preDelayLength) {
141         // For the first m_preDelayLength frames don't process the convolver, instead simply buffer in the pre-delay.
142         // But while buffering the pre-delay, we still need to update our index.
143         m_accumulationBuffer->updateReadIndex(&m_accumulationReadIndex, framesToProcess);
144     } else {
145         // Now, run the convolution (into the delay buffer).
146         // An expensive FFT will happen every fftSize / 2 frames.
147         // We process in-place here...
148         if (!m_directMode)
149             m_fftConvolver->process(m_fftKernel.get(), preDelayedSource, temporaryBuffer, framesToProcess);
150         else
151             m_directConvolver->process(m_directKernel.get(), preDelayedSource, temporaryBuffer, framesToProcess);
152 
153         // Now accumulate into reverb's accumulation buffer.
154         m_accumulationBuffer->accumulate(temporaryBuffer, framesToProcess, &m_accumulationReadIndex, m_postDelayLength);
155     }
156 
157     // Finally copy input to pre-delay.
158     if (m_preDelayLength > 0) {
159         memcpy(preDelayedDestination, source, sizeof(float) * framesToProcess);
160         m_preReadWriteIndex += framesToProcess;
161 
162         ASSERT(m_preReadWriteIndex <= m_preDelayLength);
163         if (m_preReadWriteIndex >= m_preDelayLength)
164             m_preReadWriteIndex = 0;
165     }
166 
167     m_framesProcessed += framesToProcess;
168 }
169 
reset()170 void ReverbConvolverStage::reset()
171 {
172     if (!m_directMode)
173         m_fftConvolver->reset();
174     else
175         m_directConvolver->reset();
176     m_preDelayBuffer.zero();
177     m_accumulationReadIndex = 0;
178     m_inputReadIndex = 0;
179     m_framesProcessed = 0;
180 }
181 
182 } // namespace blink
183 
184 #endif // ENABLE(WEB_AUDIO)
185