third_party/WebKit/Source/platform/audio/ReverbConvolver.h

/*
 * Copyright (C) 2010 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 * 2.  Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
 *     its contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
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 */

#ifndef ReverbConvolver_h
#define ReverbConvolver_h

#include "platform/audio/AudioArray.h"
#include "platform/audio/DirectConvolver.h"
#include "platform/audio/FFTConvolver.h"
#include "platform/audio/ReverbAccumulationBuffer.h"
#include "platform/audio/ReverbConvolverStage.h"
#include "platform/audio/ReverbInputBuffer.h"
#include "wtf/Allocator.h"
#include "wtf/Vector.h"
#include <memory>

namespace blink {

class AudioChannel;
class WebThread;

class PLATFORM_EXPORT ReverbConvolver {
  USING_FAST_MALLOC(ReverbConvolver);
  WTF_MAKE_NONCOPYABLE(ReverbConvolver);

 public:
  // maxFFTSize can be adjusted (from say 2048 to 32768) depending on how much
  // precision is necessary.  For certain tweaky de-convolving applications the
  // phase errors add up quickly and lead to non-sensical results with larger
  // FFT sizes and single-precision floats.  In these cases 2048 is a good
  // size.  If not doing multi-threaded convolution, then should not go > 8192.
  ReverbConvolver(AudioChannel* impulseResponse,
                  size_t renderSliceSize,
                  size_t maxFFTSize,
                  size_t convolverRenderPhase,
                  bool useBackgroundThreads);
  ~ReverbConvolver();

  void process(const AudioChannel* sourceChannel,
               AudioChannel* destinationChannel,
               size_t framesToProcess);
  void reset();

  ReverbInputBuffer* inputBuffer() { return &m_inputBuffer; }

  size_t latencyFrames() const;

 private:
  void processInBackground();

  Vector<std::unique_ptr<ReverbConvolverStage>> m_stages;
  Vector<std::unique_ptr<ReverbConvolverStage>> m_backgroundStages;
  size_t m_impulseResponseLength;

  ReverbAccumulationBuffer m_accumulationBuffer;

  // One or more background threads read from this input buffer which is fed
  // from the realtime thread.
  ReverbInputBuffer m_inputBuffer;

  // First stage will be of size m_minFFTSize.  Each next stage will be twice as
  // big until we hit m_maxFFTSize.
  size_t m_minFFTSize;
  size_t m_maxFFTSize;

  // But don't exceed this size in the real-time thread (if we're doing
  // background processing).
  size_t m_maxRealtimeFFTSize;

  // Background thread and synchronization
  std::unique_ptr<WebThread> m_backgroundThread;
};

}  // namespace blink

#endif  // ReverbConvolver_h