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             : #ifndef FFTConvolver_h
      30             : #define FFTConvolver_h
      31             : 
      32             : #include "nsTArray.h"
      33             : #include "mozilla/FFTBlock.h"
      34             : #include "mozilla/MemoryReporting.h"
      35             : 
      36             : namespace WebCore {
      37             : 
      38             : typedef AlignedTArray<float> AlignedAudioFloatArray;
      39             : using mozilla::FFTBlock;
      40             : 
      41           0 : class FFTConvolver {
      42             : public:
      43             :     // |fftSize| must be a power of two.
      44             :     //
      45             :     // |renderPhase| is the initial offset in the initially zero input buffer.
      46             :     // It is coordinated with the other stages, so they don't all do their
      47             :     // FFTs at the same time.
      48             :     explicit FFTConvolver(size_t fftSize, size_t renderPhase = 0);
      49             : 
      50             :     // Process WEBAUDIO_BLOCK_SIZE elements of array |sourceP| and return a
      51             :     // pointer to an output array of the same size.
      52             :     //
      53             :     // |fftKernel| must be pre-scaled for FFTBlock::GetInverseWithoutScaling().
      54             :     //
      55             :     // FIXME: Later, we can do more sophisticated buffering to relax this requirement...
      56             :     const float* process(FFTBlock* fftKernel, const float* sourceP);
      57             : 
      58             :     void reset();
      59             : 
      60           0 :     size_t fftSize() const { return m_frame.FFTSize(); }
      61             : 
      62             :     // The input to output latency is up to fftSize / 2, but alignment of the
      63             :     // FFTs with the blocks reduces this by one block.
      64             :     size_t latencyFrames() const;
      65             : 
      66             :     size_t sizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
      67             :     size_t sizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
      68             : 
      69             : private:
      70             :     FFTBlock m_frame;
      71             : 
      72             :     // Buffer input until we get fftSize / 2 samples then do an FFT
      73             :     size_t m_readWriteIndex;
      74             :     AlignedAudioFloatArray m_inputBuffer;
      75             : 
      76             :     // Stores output which we read a little at a time
      77             :     AlignedAudioFloatArray m_outputBuffer;
      78             : 
      79             :     // Saves the 2nd half of the FFT buffer, so we can do an overlap-add with the 1st half of the next one
      80             :     AlignedAudioFloatArray m_lastOverlapBuffer;
      81             : };
      82             : 
      83             : } // namespace WebCore
      84             : 
      85             : #endif // FFTConvolver_h