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/*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. 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 INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "platform/audio/AudioResampler.h"
#include <algorithm>
#include "wtf/MathExtras.h"
namespace blink {
const double AudioResampler::MaxRate = 8.0;
AudioResampler::AudioResampler()
: m_rate(1.0)
{
m_kernels.append(adoptPtr(new AudioResamplerKernel(this)));
m_sourceBus = AudioBus::create(1, 0, false);
}
AudioResampler::AudioResampler(unsigned numberOfChannels)
: m_rate(1.0)
{
for (unsigned i = 0; i < numberOfChannels; ++i)
m_kernels.append(adoptPtr(new AudioResamplerKernel(this)));
m_sourceBus = AudioBus::create(numberOfChannels, 0, false);
}
void AudioResampler::configureChannels(unsigned numberOfChannels)
{
unsigned currentSize = m_kernels.size();
if (numberOfChannels == currentSize)
return; // already setup
// First deal with adding or removing kernels.
if (numberOfChannels > currentSize) {
for (unsigned i = currentSize; i < numberOfChannels; ++i)
m_kernels.append(adoptPtr(new AudioResamplerKernel(this)));
} else
m_kernels.resize(numberOfChannels);
// Reconfigure our source bus to the new channel size.
m_sourceBus = AudioBus::create(numberOfChannels, 0, false);
}
void AudioResampler::process(AudioSourceProvider* provider, AudioBus* destinationBus, size_t framesToProcess)
{
ASSERT(provider);
if (!provider)
return;
unsigned numberOfChannels = m_kernels.size();
// Make sure our configuration matches the bus we're rendering to.
bool channelsMatch = (destinationBus && destinationBus->numberOfChannels() == numberOfChannels);
ASSERT(channelsMatch);
if (!channelsMatch)
return;
// Setup the source bus.
for (unsigned i = 0; i < numberOfChannels; ++i) {
// Figure out how many frames we need to get from the provider, and a pointer to the buffer.
size_t framesNeeded;
float* fillPointer = m_kernels[i]->getSourcePointer(framesToProcess, &framesNeeded);
ASSERT(fillPointer);
if (!fillPointer)
return;
m_sourceBus->setChannelMemory(i, fillPointer, framesNeeded);
}
// Ask the provider to supply the desired number of source frames.
provider->provideInput(m_sourceBus.get(), m_sourceBus->length());
// Now that we have the source data, resample each channel into the destination bus.
// FIXME: optimize for the common stereo case where it's faster to process both left/right channels in the same inner loop.
for (unsigned i = 0; i < numberOfChannels; ++i) {
float* destination = destinationBus->channel(i)->mutableData();
m_kernels[i]->process(destination, framesToProcess);
}
}
void AudioResampler::setRate(double rate)
{
if (std::isnan(rate) || std::isinf(rate) || rate <= 0.0)
return;
m_rate = std::min(AudioResampler::MaxRate, rate);
}
void AudioResampler::reset()
{
unsigned numberOfChannels = m_kernels.size();
for (unsigned i = 0; i < numberOfChannels; ++i)
m_kernels[i]->reset();
}
} // namespace blink
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