FFTConvolver.h (3348B)
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 "mozilla/FFTBlock.h" 33 #include "mozilla/MemoryReporting.h" 34 #include "nsTArray.h" 35 36 namespace WebCore { 37 38 typedef AlignedTArray<float> AlignedAudioFloatArray; 39 using mozilla::FFTBlock; 40 41 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 56 // requirement... 57 const float* process(FFTBlock* fftKernel, const float* sourceP); 58 59 void reset(); 60 61 size_t fftSize() const { return m_frame.FFTSize(); } 62 63 // The input to output latency is up to fftSize / 2, but alignment of the 64 // FFTs with the blocks reduces this by one block. 65 size_t latencyFrames() const; 66 67 size_t sizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const; 68 size_t sizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const; 69 70 private: 71 FFTBlock m_frame; 72 73 // Buffer input until we get fftSize / 2 samples then do an FFT 74 size_t m_readWriteIndex; 75 AlignedAudioFloatArray m_inputBuffer; 76 77 // Stores output which we read a little at a time 78 AlignedAudioFloatArray m_outputBuffer; 79 80 // Saves the 2nd half of the FFT buffer, so we can do an overlap-add with the 81 // 1st half of the next one 82 AlignedAudioFloatArray m_lastOverlapBuffer; 83 }; 84 85 } // namespace WebCore 86 87 #endif // FFTConvolver_h