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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  * 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 "BiquadProcessor.h"
     30 
     31 #include "BiquadDSPKernel.h"
     32 
     33 namespace WebCore {
     34 
     35 BiquadProcessor::BiquadProcessor(FilterType type, double sampleRate, size_t numberOfChannels, bool autoInitialize)
     36     : AudioDSPKernelProcessor(sampleRate, numberOfChannels)
     37     , m_type(type)
     38     , m_parameter1(0)
     39     , m_parameter2(0)
     40     , m_parameter3(0)
     41     , m_filterCoefficientsDirty(true)
     42 {
     43     double nyquist = 0.5 * this->sampleRate();
     44 
     45     switch (type) {
     46     // Highpass and lowpass share the same parameters and only differ in filter type.
     47     case LowPass2:
     48     case HighPass2:
     49         m_parameter1 = AudioParam::create("frequency", 350.0, 20.0, nyquist);
     50         m_parameter2 = AudioParam::create("resonance", 0.0, -20.0, 20.0);
     51         m_parameter3 = AudioParam::create("unused", 0.0, 0.0, 1.0);
     52         break;
     53 
     54     case Peaking:
     55         m_parameter1 = AudioParam::create("frequency", 2500.0, 20.0, nyquist);
     56         m_parameter2 = AudioParam::create("gain", 0.0, -20.0, 20.0);
     57         m_parameter3 = AudioParam::create("Q", 0.5, 0.0, 1000.0);
     58         break;
     59     case Allpass:
     60         m_parameter1 = AudioParam::create("frequency", 2500.0, 20.0, nyquist);
     61         m_parameter2 = AudioParam::create("Q", 0.5, 0.0, 1000.0);
     62         m_parameter3 = AudioParam::create("unused", 0.0, 0.0, 1.0);
     63         break;
     64     case LowShelf:
     65         m_parameter1 = AudioParam::create("frequency", 80.0, 20.0, nyquist);
     66         m_parameter2 = AudioParam::create("gain", 0.0, 0.0, 1.0);
     67         m_parameter3 = AudioParam::create("unused", 0.0, 0.0, 1.0);
     68         break;
     69     case HighShelf:
     70         m_parameter1 = AudioParam::create("frequency", 10000.0, 20.0, nyquist);
     71         m_parameter2 = AudioParam::create("gain", 0.0, 0.0, 1.0);
     72         m_parameter3 = AudioParam::create("unused", 0.0, 0.0, 1.0);
     73         break;
     74     }
     75 
     76     if (autoInitialize)
     77         initialize();
     78 }
     79 
     80 BiquadProcessor::~BiquadProcessor()
     81 {
     82     if (isInitialized())
     83         uninitialize();
     84 }
     85 
     86 PassOwnPtr<AudioDSPKernel> BiquadProcessor::createKernel()
     87 {
     88     return adoptPtr(new BiquadDSPKernel(this));
     89 }
     90 
     91 void BiquadProcessor::process(AudioBus* source, AudioBus* destination, size_t framesToProcess)
     92 {
     93     if (!isInitialized()) {
     94         destination->zero();
     95         return;
     96     }
     97 
     98     // Deal with smoothing / de-zippering.  Start out assuming filter parameters are not changing.
     99     // The BiquadDSPKernel objects rely on this value to see if they need to re-compute their internal filter coefficients.
    100     m_filterCoefficientsDirty = false;
    101 
    102     if (m_hasJustReset) {
    103         // Snap to exact values first time after reset, then smooth for subsequent changes.
    104         m_parameter1->resetSmoothedValue();
    105         m_parameter2->resetSmoothedValue();
    106         m_parameter3->resetSmoothedValue();
    107         m_filterCoefficientsDirty = true;
    108         m_hasJustReset = false;
    109     } else {
    110         // Smooth all of the filter parameters.  If they haven't yet converged to their target value then mark coefficients as dirty.
    111         bool isStable1 = m_parameter1->smooth();
    112         bool isStable2 = m_parameter2->smooth();
    113         bool isStable3 = m_parameter3->smooth();
    114         if (!(isStable1 && isStable2 && isStable3))
    115             m_filterCoefficientsDirty = true;
    116     }
    117 
    118     // For each channel of our input, process using the corresponding BiquadDSPKernel into the output channel.
    119     for (unsigned i = 0; i < m_kernels.size(); ++i)
    120         m_kernels[i]->process(source->channel(i)->data(), destination->channel(i)->data(), framesToProcess);
    121 }
    122 
    123 } // namespace WebCore
    124 
    125 #endif // ENABLE(WEB_AUDIO)
    126