Home | History | Annotate | Download | only in audio 
      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 
     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 
     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 
    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 
    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