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29 #include "platform/audio/AudioResampler.h"
32 #include "wtf/MathExtras.h"
36 const double AudioResampler::MaxRate = 8.0;
38 AudioResampler::AudioResampler()
41 m_kernels.append(adoptPtr(new AudioResamplerKernel(this)));
42 m_sourceBus = AudioBus::create(1, 0, false);
45 AudioResampler::AudioResampler(unsigned numberOfChannels)
48 for (unsigned i = 0; i < numberOfChannels; ++i)
49 m_kernels.append(adoptPtr(new AudioResamplerKernel(this)));
51 m_sourceBus = AudioBus::create(numberOfChannels, 0, false);
54 void AudioResampler::configureChannels(unsigned numberOfChannels)
56 unsigned currentSize = m_kernels.size();
57 if (numberOfChannels == currentSize)
58 return; // already setup
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)));
65 m_kernels.resize(numberOfChannels);
67 // Reconfigure our source bus to the new channel size.
68 m_sourceBus = AudioBus::create(numberOfChannels, 0, false);
71 void AudioResampler::process(AudioSourceProvider* provider, AudioBus* destinationBus, size_t framesToProcess)
77 unsigned numberOfChannels = m_kernels.size();
79 // Make sure our configuration matches the bus we're rendering to.
80 bool channelsMatch = (destinationBus && destinationBus->numberOfChannels() == numberOfChannels);
81 ASSERT(channelsMatch);
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.
89 float* fillPointer = m_kernels[i]->getSourcePointer(framesToProcess, &framesNeeded);
94 m_sourceBus->setChannelMemory(i, fillPointer, framesNeeded);
97 // Ask the provider to supply the desired number of source frames.
98 provider->provideInput(m_sourceBus.get(), m_sourceBus->length());
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);
108 void AudioResampler::setRate(double rate)
110 if (std::isnan(rate) || std::isinf(rate) || rate <= 0.0)
113 m_rate = std::min(AudioResampler::MaxRate, rate);
116 void AudioResampler::reset()
118 unsigned numberOfChannels = m_kernels.size();
119 for (unsigned i = 0; i < numberOfChannels; ++i)
120 m_kernels[i]->reset();
125 #endif // ENABLE(WEB_AUDIO)