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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 #ifndef ReverbConvolver_h
     30 #define ReverbConvolver_h
     31 
     32 #include "AudioArray.h"
     33 #include "FFTConvolver.h"
     34 #include "ReverbAccumulationBuffer.h"
     35 #include "ReverbConvolverStage.h"
     36 #include "ReverbInputBuffer.h"
     37 #include <wtf/OwnPtr.h>
     38 #include <wtf/RefCounted.h>
     39 #include <wtf/Threading.h>
     40 #include <wtf/Vector.h>
     41 
     42 namespace WebCore {
     43 
     44 class AudioChannel;
     45 
     46 class ReverbConvolver {
     47 public:
     48     // maxFFTSize can be adjusted (from say 2048 to 32768) depending on how much precision is necessary.
     49     // For certain tweaky de-convolving applications the phase errors add up quickly and lead to non-sensical results with
     50     // larger FFT sizes and single-precision floats.  In these cases 2048 is a good size.
     51     // If not doing multi-threaded convolution, then should not go > 8192.
     52     ReverbConvolver(AudioChannel* impulseResponse, size_t renderSliceSize, size_t maxFFTSize, size_t convolverRenderPhase, bool useBackgroundThreads);
     53     ~ReverbConvolver();
     54 
     55     void process(AudioChannel* sourceChannel, AudioChannel* destinationChannel, size_t framesToProcess);
     56     void reset();
     57 
     58     size_t impulseResponseLength() const { return m_impulseResponseLength; }
     59 
     60     ReverbInputBuffer* inputBuffer() { return &m_inputBuffer; }
     61 
     62     bool useBackgroundThreads() const { return m_useBackgroundThreads; }
     63     void backgroundThreadEntry();
     64 
     65 private:
     66     Vector<OwnPtr<ReverbConvolverStage> > m_stages;
     67     Vector<OwnPtr<ReverbConvolverStage> > m_backgroundStages;
     68     size_t m_impulseResponseLength;
     69 
     70     ReverbAccumulationBuffer m_accumulationBuffer;
     71 
     72     // One or more background threads read from this input buffer which is fed from the realtime thread.
     73     ReverbInputBuffer m_inputBuffer;
     74 
     75     // We're given a rendering hint, so the FFTs can be optimized to not all occur at the same time
     76     // (very bad when rendering on a real-time thread).
     77     size_t m_renderSliceSize;
     78 
     79     // First stage will be of size m_minFFTSize.  Each next stage will be twice as big until we hit m_maxFFTSize.
     80     size_t m_minFFTSize;
     81     size_t m_maxFFTSize;
     82 
     83     // But don't exceed this size in the real-time thread (if we're doing background processing).
     84     size_t m_maxRealtimeFFTSize;
     85 
     86     // Background thread and synchronization
     87     bool m_useBackgroundThreads;
     88     ThreadIdentifier m_backgroundThread;
     89     bool m_wantsToExit;
     90     bool m_moreInputBuffered;
     91     mutable Mutex m_backgroundThreadLock;
     92     mutable ThreadCondition m_backgroundThreadCondition;
     93 };
     94 
     95 } // namespace WebCore
     96 
     97 #endif // ReverbConvolver_h
     98