| /* |
| * Copyright (C) 2011 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. |
| * 3. Neither the name of Apple Inc. ("Apple") nor the names of |
| * its contributors may be used to endorse or promote products derived |
| * from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY APPLE 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 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 "config.h" |
| |
| #if ENABLE(WEB_AUDIO) |
| |
| #include "MultiChannelResampler.h" |
| |
| #include "AudioBus.h" |
| #include "SincResampler.h" |
| |
| namespace WebCore { |
| |
| MultiChannelResampler::MultiChannelResampler(double scaleFactor, unsigned numberOfChannels, unsigned requestFrames, Function<void(AudioBus*, size_t framesToProcess)>&& provideInput) |
| : m_numberOfChannels(numberOfChannels) |
| , m_provideInput(WTFMove(provideInput)) |
| , m_multiChannelBus(AudioBus::create(numberOfChannels, requestFrames, false)) |
| { |
| // As an optimization, we will use the buffer passed to provideInputForChannel() as channel memory for the first channel so we |
| // only need to allocate memory if there is more than one channel. |
| if (numberOfChannels > 1) { |
| m_channelsMemory.reserveInitialCapacity(numberOfChannels - 1); |
| for (unsigned channelIndex = 1; channelIndex < numberOfChannels; ++channelIndex) { |
| m_channelsMemory.uncheckedAppend(makeUnique<AudioFloatArray>(requestFrames)); |
| m_multiChannelBus->setChannelMemory(channelIndex, m_channelsMemory.last()->data(), requestFrames); |
| } |
| } |
| |
| // Create each channel's resampler. |
| for (unsigned channelIndex = 0; channelIndex < numberOfChannels; ++channelIndex) |
| m_kernels.append(makeUnique<SincResampler>(scaleFactor, requestFrames, std::bind(&MultiChannelResampler::provideInputForChannel, this, std::placeholders::_1, std::placeholders::_2, channelIndex))); |
| } |
| |
| MultiChannelResampler::~MultiChannelResampler() = default; |
| |
| void MultiChannelResampler::process(AudioBus* destination, size_t framesToProcess) |
| { |
| ASSERT(m_numberOfChannels == destination->numberOfChannels()); |
| if (destination->numberOfChannels() == 1) { |
| // Fast path when the bus is mono to avoid the chunking below. |
| m_kernels[0]->process(destination->channel(0)->mutableData(), framesToProcess); |
| return; |
| } |
| |
| // We need to ensure that SincResampler only calls provideInputForChannel() once for each channel or it will confuse the logic |
| // inside provideInputForChannel(). To ensure this, we chunk the number of requested frames into SincResampler::chunkSize() |
| // sized chunks. SincResampler guarantees it will only call provideInputForChannel() once once we resample this way. |
| m_outputFramesReady = 0; |
| while (m_outputFramesReady < framesToProcess) { |
| size_t chunkSize = m_kernels[0]->chunkSize(); |
| size_t framesThisTime = std::min(framesToProcess - m_outputFramesReady, chunkSize); |
| |
| for (unsigned channelIndex = 0; channelIndex < m_numberOfChannels; ++channelIndex) { |
| ASSERT(chunkSize == m_kernels[channelIndex]->chunkSize()); |
| m_kernels[channelIndex]->process(destination->channel(channelIndex)->mutableData() + m_outputFramesReady, framesThisTime); |
| } |
| |
| m_outputFramesReady += framesThisTime; |
| } |
| } |
| |
| void MultiChannelResampler::provideInputForChannel(float* buffer, size_t framesToProcess, unsigned channelIndex) |
| { |
| ASSERT(channelIndex < m_multiChannelBus->numberOfChannels()); |
| ASSERT(framesToProcess == m_multiChannelBus->length()); |
| |
| if (!channelIndex) { |
| // As an optimization, we use the provided buffer as memory for the first channel in the AudioBus. This avoids |
| // having to memcpy() for the first channel. |
| m_multiChannelBus->setChannelMemory(0, buffer, framesToProcess); |
| m_provideInput(m_multiChannelBus.get(), framesToProcess); |
| return; |
| } |
| |
| // Copy the channel data from what we received from m_multiChannelProvider. |
| memcpy(buffer, m_multiChannelBus->channel(channelIndex)->data(), sizeof(float) * framesToProcess); |
| } |
| |
| } // namespace WebCore |
| |
| #endif // ENABLE(WEB_AUDIO) |