Line data    Source code

       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 "FFTConvolver.h"
      30             : #include "mozilla/PodOperations.h"
      31             : 
      32             : using namespace mozilla;
      33             : 
      34             : namespace WebCore {
      35             : 
      36           0 : FFTConvolver::FFTConvolver(size_t fftSize, size_t renderPhase)
      37             :     : m_frame(fftSize)
      38           0 :     , m_readWriteIndex(renderPhase % (fftSize / 2))
      39             : {
      40           0 :     MOZ_ASSERT(fftSize >= 2 * WEBAUDIO_BLOCK_SIZE);
      41           0 :   m_inputBuffer.SetLength(fftSize);
      42           0 :   PodZero(m_inputBuffer.Elements(), fftSize);
      43           0 :   m_outputBuffer.SetLength(fftSize);
      44           0 :   PodZero(m_outputBuffer.Elements(), fftSize);
      45           0 :   m_lastOverlapBuffer.SetLength(fftSize / 2);
      46           0 :   PodZero(m_lastOverlapBuffer.Elements(), fftSize / 2);
      47           0 : }
      48             : 
      49           0 : size_t FFTConvolver::sizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
      50             : {
      51           0 :     size_t amount = 0;
      52           0 :     amount += m_frame.SizeOfExcludingThis(aMallocSizeOf);
      53           0 :     amount += m_inputBuffer.ShallowSizeOfExcludingThis(aMallocSizeOf);
      54           0 :     amount += m_outputBuffer.ShallowSizeOfExcludingThis(aMallocSizeOf);
      55           0 :     amount += m_lastOverlapBuffer.ShallowSizeOfExcludingThis(aMallocSizeOf);
      56           0 :     return amount;
      57             : }
      58             : 
      59           0 : size_t FFTConvolver::sizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
      60             : {
      61           0 :   return aMallocSizeOf(this) + sizeOfExcludingThis(aMallocSizeOf);
      62             : }
      63             : 
      64           0 : const float* FFTConvolver::process(FFTBlock* fftKernel, const float* sourceP)
      65             : {
      66           0 :     size_t halfSize = fftSize() / 2;
      67             : 
      68             :     // WEBAUDIO_BLOCK_SIZE must be an exact multiple of halfSize,
      69             :     // halfSize must be a multiple of WEBAUDIO_BLOCK_SIZE
      70             :     // and > WEBAUDIO_BLOCK_SIZE.
      71           0 :     MOZ_ASSERT(halfSize % WEBAUDIO_BLOCK_SIZE == 0 &&
      72             :                WEBAUDIO_BLOCK_SIZE <= halfSize);
      73             : 
      74             :     // Copy samples to input buffer (note contraint above!)
      75           0 :     float* inputP = m_inputBuffer.Elements();
      76             : 
      77           0 :     MOZ_ASSERT(sourceP && inputP && m_readWriteIndex + WEBAUDIO_BLOCK_SIZE <= m_inputBuffer.Length());
      78             : 
      79           0 :     memcpy(inputP + m_readWriteIndex, sourceP, sizeof(float) * WEBAUDIO_BLOCK_SIZE);
      80             : 
      81           0 :     float* outputP = m_outputBuffer.Elements();
      82           0 :     m_readWriteIndex += WEBAUDIO_BLOCK_SIZE;
      83             : 
      84             :     // Check if it's time to perform the next FFT
      85           0 :     if (m_readWriteIndex == halfSize) {
      86             :         // The input buffer is now filled (get frequency-domain version)
      87           0 :         m_frame.PerformFFT(m_inputBuffer.Elements());
      88           0 :         m_frame.Multiply(*fftKernel);
      89           0 :         m_frame.GetInverseWithoutScaling(m_outputBuffer.Elements());
      90             : 
      91             :         // Overlap-add 1st half from previous time
      92           0 :         AudioBufferAddWithScale(m_lastOverlapBuffer.Elements(), 1.0f,
      93           0 :                                 m_outputBuffer.Elements(), halfSize);
      94             : 
      95             :         // Finally, save 2nd half of result
      96           0 :         MOZ_ASSERT(m_outputBuffer.Length() == 2 * halfSize && m_lastOverlapBuffer.Length() == halfSize);
      97             : 
      98           0 :         memcpy(m_lastOverlapBuffer.Elements(), m_outputBuffer.Elements() + halfSize, sizeof(float) * halfSize);
      99             : 
     100             :         // Reset index back to start for next time
     101           0 :         m_readWriteIndex = 0;
     102             :     }
     103             : 
     104           0 :     return outputP + m_readWriteIndex;
     105             : }
     106             : 
     107           0 : void FFTConvolver::reset()
     108             : {
     109           0 :     PodZero(m_lastOverlapBuffer.Elements(), m_lastOverlapBuffer.Length());
     110           0 :     m_readWriteIndex = 0;
     111           0 : }
     112             : 
     113           0 : size_t FFTConvolver::latencyFrames() const
     114             : {
     115           0 :     return std::max<size_t>(fftSize()/2, WEBAUDIO_BLOCK_SIZE) -
     116           0 :         WEBAUDIO_BLOCK_SIZE;
     117             : }
     118             : 
     119             : } // namespace WebCore