Home | History | Annotate | Download | only in webaudio
      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  * 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 #include "config.h"
     26 
     27 #if ENABLE(WEB_AUDIO)
     28 
     29 #include "modules/webaudio/DelayDSPKernel.h"
     30 
     31 #include "platform/audio/AudioUtilities.h"
     32 #include "wtf/MathExtras.h"
     33 #include <algorithm>
     34 
     35 namespace blink {
     36 
     37 const float SmoothingTimeConstant = 0.020f; // 20ms
     38 
     39 DelayDSPKernel::DelayDSPKernel(DelayProcessor* processor)
     40     : AudioDelayDSPKernel(processor, AudioNode::ProcessingSizeInFrames)
     41 {
     42     ASSERT(processor && processor->sampleRate() > 0);
     43     if (!(processor && processor->sampleRate() > 0))
     44         return;
     45 
     46     m_maxDelayTime = processor->maxDelayTime();
     47     ASSERT(m_maxDelayTime >= 0 && !std::isnan(m_maxDelayTime));
     48     if (m_maxDelayTime < 0 || std::isnan(m_maxDelayTime))
     49         return;
     50 
     51     m_buffer.allocate(bufferLengthForDelay(m_maxDelayTime, processor->sampleRate()));
     52     m_buffer.zero();
     53 
     54     m_smoothingRate = AudioUtilities::discreteTimeConstantForSampleRate(SmoothingTimeConstant, processor->sampleRate());
     55 }
     56 
     57 bool DelayDSPKernel::hasSampleAccurateValues()
     58 {
     59     return delayProcessor()->delayTime()->hasSampleAccurateValues();
     60 }
     61 
     62 void DelayDSPKernel::calculateSampleAccurateValues(float* delayTimes, size_t framesToProcess)
     63 {
     64     delayProcessor()->delayTime()->calculateSampleAccurateValues(delayTimes, framesToProcess);
     65 }
     66 
     67 double DelayDSPKernel::delayTime(float)
     68 {
     69     return delayProcessor()->delayTime()->finalValue();
     70 }
     71 
     72 } // namespace blink
     73 
     74 #endif // ENABLE(WEB_AUDIO)
     75