108 lines
5.1 KiB
C++
108 lines
5.1 KiB
C++
/*
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* Copyright (C) 2011 Google Inc. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of Apple Inc. ("Apple") nor the names of
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* its contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "config.h"
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#if ENABLE(WEB_AUDIO)
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#include "MultiChannelResampler.h"
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#include "AudioBus.h"
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#include "SincResampler.h"
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namespace WebCore {
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MultiChannelResampler::MultiChannelResampler(double scaleFactor, unsigned numberOfChannels, unsigned requestFrames, Function<void(AudioBus*, size_t framesToProcess)>&& provideInput)
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: m_numberOfChannels(numberOfChannels)
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, m_provideInput(WTFMove(provideInput))
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, m_multiChannelBus(AudioBus::create(numberOfChannels, requestFrames, false))
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{
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// As an optimization, we will use the buffer passed to provideInputForChannel() as channel memory for the first channel so we
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// only need to allocate memory if there is more than one channel.
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if (numberOfChannels > 1) {
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m_channelsMemory.reserveInitialCapacity(numberOfChannels - 1);
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for (unsigned channelIndex = 1; channelIndex < numberOfChannels; ++channelIndex) {
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m_channelsMemory.uncheckedAppend(makeUnique<AudioFloatArray>(requestFrames));
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m_multiChannelBus->setChannelMemory(channelIndex, m_channelsMemory.last()->data(), requestFrames);
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}
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}
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// Create each channel's resampler.
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for (unsigned channelIndex = 0; channelIndex < numberOfChannels; ++channelIndex)
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m_kernels.append(makeUnique<SincResampler>(scaleFactor, requestFrames, std::bind(&MultiChannelResampler::provideInputForChannel, this, std::placeholders::_1, std::placeholders::_2, channelIndex)));
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}
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MultiChannelResampler::~MultiChannelResampler() = default;
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void MultiChannelResampler::process(AudioBus* destination, size_t framesToProcess)
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{
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ASSERT(m_numberOfChannels == destination->numberOfChannels());
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if (destination->numberOfChannels() == 1) {
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// Fast path when the bus is mono to avoid the chunking below.
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m_kernels[0]->process(destination->channel(0)->mutableData(), framesToProcess);
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return;
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}
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// We need to ensure that SincResampler only calls provideInputForChannel() once for each channel or it will confuse the logic
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// inside provideInputForChannel(). To ensure this, we chunk the number of requested frames into SincResampler::chunkSize()
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// sized chunks. SincResampler guarantees it will only call provideInputForChannel() once once we resample this way.
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m_outputFramesReady = 0;
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while (m_outputFramesReady < framesToProcess) {
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size_t chunkSize = m_kernels[0]->chunkSize();
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size_t framesThisTime = std::min(framesToProcess - m_outputFramesReady, chunkSize);
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for (unsigned channelIndex = 0; channelIndex < m_numberOfChannels; ++channelIndex) {
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ASSERT(chunkSize == m_kernels[channelIndex]->chunkSize());
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m_kernels[channelIndex]->process(destination->channel(channelIndex)->mutableData() + m_outputFramesReady, framesThisTime);
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}
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m_outputFramesReady += framesThisTime;
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}
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}
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void MultiChannelResampler::provideInputForChannel(float* buffer, size_t framesToProcess, unsigned channelIndex)
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{
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ASSERT(channelIndex < m_multiChannelBus->numberOfChannels());
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ASSERT(framesToProcess == m_multiChannelBus->length());
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if (!channelIndex) {
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// As an optimization, we use the provided buffer as memory for the first channel in the AudioBus. This avoids
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// having to memcpy() for the first channel.
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m_multiChannelBus->setChannelMemory(0, buffer, framesToProcess);
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m_provideInput(m_multiChannelBus.get(), framesToProcess);
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return;
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}
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// Copy the channel data from what we received from m_multiChannelProvider.
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memcpy(buffer, m_multiChannelBus->channel(channelIndex)->data(), sizeof(float) * framesToProcess);
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}
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} // namespace WebCore
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#endif // ENABLE(WEB_AUDIO)
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