third_party/WebKit/Source/platform/audio/AudioResampler.cpp

   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 "platform/audio/AudioResampler.h"
  30
  31 #include <algorithm>
  32 #include "wtf/MathExtras.h"
  33
  34 namespace blink {
  35
  36 const double AudioResampler::MaxRate = 8.0;
  37
  38 AudioResampler::AudioResampler()
  39     : m_rate(1.0)
  40 {
  41     m_kernels.append(adoptPtr(new AudioResamplerKernel(this)));
  42     m_sourceBus = AudioBus::create(1, 0, false);
  43 }
  44
  45 AudioResampler::AudioResampler(unsigned numberOfChannels)
  46     : m_rate(1.0)
  47 {
  48     for (unsigned i = 0; i < numberOfChannels; ++i)
  49         m_kernels.append(adoptPtr(new AudioResamplerKernel(this)));
  50
  51     m_sourceBus = AudioBus::create(numberOfChannels, 0, false);
  52 }
  53
  54 void AudioResampler::configureChannels(unsigned numberOfChannels)
  55 {
  56     unsigned currentSize = m_kernels.size();
  57     if (numberOfChannels == currentSize)
  58         return; // already setup
  59
  60     // First deal with adding or removing kernels.
  61     if (numberOfChannels > currentSize) {
  62         for (unsigned i = currentSize; i < numberOfChannels; ++i)
  63             m_kernels.append(adoptPtr(new AudioResamplerKernel(this)));
  64     } else
  65         m_kernels.resize(numberOfChannels);
  66
  67     // Reconfigure our source bus to the new channel size.
  68     m_sourceBus = AudioBus::create(numberOfChannels, 0, false);
  69 }
  70
  71 void AudioResampler::process(AudioSourceProvider* provider, AudioBus* destinationBus, size_t framesToProcess)
  72 {
  73     ASSERT(provider);
  74     if (!provider)
  75         return;
  76
  77     unsigned numberOfChannels = m_kernels.size();
  78
  79     // Make sure our configuration matches the bus we're rendering to.
  80     bool channelsMatch = (destinationBus && destinationBus->numberOfChannels() == numberOfChannels);
  81     ASSERT(channelsMatch);
  82     if (!channelsMatch)
  83         return;
  84
  85     // Setup the source bus.
  86     for (unsigned i = 0; i < numberOfChannels; ++i) {
  87         // Figure out how many frames we need to get from the provider, and a pointer to the buffer.
  88         size_t framesNeeded;
  89         float* fillPointer = m_kernels[i]->getSourcePointer(framesToProcess, &framesNeeded);
  90         ASSERT(fillPointer);
  91         if (!fillPointer)
  92             return;
  93
  94         m_sourceBus->setChannelMemory(i, fillPointer, framesNeeded);
  95     }
  96
  97     // Ask the provider to supply the desired number of source frames.
  98     provider->provideInput(m_sourceBus.get(), m_sourceBus->length());
  99
 100     // Now that we have the source data, resample each channel into the destination bus.
 101     // FIXME: optimize for the common stereo case where it's faster to process both left/right channels in the same inner loop.
 102     for (unsigned i = 0; i < numberOfChannels; ++i) {
 103         float* destination = destinationBus->channel(i)->mutableData();
 104         m_kernels[i]->process(destination, framesToProcess);
 105     }
 106 }
 107
 108 void AudioResampler::setRate(double rate)
 109 {
 110     if (std::isnan(rate) || std::isinf(rate) || rate <= 0.0)
 111         return;
 112
 113     m_rate = std::min(AudioResampler::MaxRate, rate);
 114 }
 115
 116 void AudioResampler::reset()
 117 {
 118     unsigned numberOfChannels = m_kernels.size();
 119     for (unsigned i = 0; i < numberOfChannels; ++i)
 120         m_kernels[i]->reset();
 121 }
 122
 123 } // namespace blink
 124
 125 #endif // ENABLE(WEB_AUDIO)