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      1 /*
      2  * Copyright (C) 2011, 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  * 1.  Redistributions of source code must retain the above copyright
      8  *    notice, this list of conditions and the following disclaimer.
      9  * 2.  Redistributions in binary form must reproduce the above copyright
     10  *    notice, this list of conditions and the following disclaimer in the
     11  *    documentation and/or other materials provided with the distribution.
     12  *
     13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
     14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     15  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     16  * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
     17  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
     18  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     19  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
     20  * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     21  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
     22  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     23  */
     24 
     25 #ifndef DynamicsCompressorNode_h
     26 #define DynamicsCompressorNode_h
     27 
     28 #include "modules/webaudio/AudioNode.h"
     29 #include "modules/webaudio/AudioParam.h"
     30 #include "wtf/OwnPtr.h"
     31 
     32 namespace WebCore {
     33 
     34 class DynamicsCompressor;
     35 
     36 class DynamicsCompressorNode : public AudioNode {
     37 public:
     38     static PassRefPtr<DynamicsCompressorNode> create(AudioContext* context, float sampleRate)
     39     {
     40         return adoptRef(new DynamicsCompressorNode(context, sampleRate));
     41     }
     42 
     43     virtual ~DynamicsCompressorNode();
     44 
     45     // AudioNode
     46     virtual void process(size_t framesToProcess);
     47     virtual void reset();
     48     virtual void initialize();
     49     virtual void uninitialize();
     50 
     51     // Static compression curve parameters.
     52     AudioParam* threshold() { return m_threshold.get(); }
     53     AudioParam* knee() { return m_knee.get(); }
     54     AudioParam* ratio() { return m_ratio.get(); }
     55     AudioParam* attack() { return m_attack.get(); }
     56     AudioParam* release() { return m_release.get(); }
     57 
     58     // Amount by which the compressor is currently compressing the signal in decibels.
     59     AudioParam* reduction() { return m_reduction.get(); }
     60 
     61 private:
     62     virtual double tailTime() const OVERRIDE;
     63     virtual double latencyTime() const OVERRIDE;
     64 
     65     DynamicsCompressorNode(AudioContext*, float sampleRate);
     66 
     67     OwnPtr<DynamicsCompressor> m_dynamicsCompressor;
     68     RefPtr<AudioParam> m_threshold;
     69     RefPtr<AudioParam> m_knee;
     70     RefPtr<AudioParam> m_ratio;
     71     RefPtr<AudioParam> m_reduction;
     72     RefPtr<AudioParam> m_attack;
     73     RefPtr<AudioParam> m_release;
     74 };
     75 
     76 } // namespace WebCore
     77 
     78 #endif // DynamicsCompressorNode_h
     79