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| 1 /* | 1 /* |
| 2 * Copyright (C) 2010 Google Inc. All rights reserved. | 2 * Copyright (C) 2010 Google Inc. All rights reserved. |
| 3 * | 3 * |
| 4 * Redistribution and use in source and binary forms, with or without | 4 * Redistribution and use in source and binary forms, with or without |
| 5 * modification, are permitted provided that the following conditions | 5 * modification, are permitted provided that the following conditions |
| 6 * are met: | 6 * are met: |
| 7 * | 7 * |
| 8 * 1. Redistributions of source code must retain the above copyright | 8 * 1. Redistributions of source code must retain the above copyright |
| 9 * notice, this list of conditions and the following disclaimer. | 9 * notice, this list of conditions and the following disclaimer. |
| 10 * 2. Redistributions in binary form must reproduce the above copyright | 10 * 2. Redistributions in binary form must reproduce the above copyright |
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| 67 : m_callback(callback), | 67 : m_callback(callback), |
| 68 m_numberOfOutputChannels(numberOfOutputChannels), | 68 m_numberOfOutputChannels(numberOfOutputChannels), |
| 69 m_inputBus(AudioBus::create(numberOfInputChannels, renderBufferSize)), | 69 m_inputBus(AudioBus::create(numberOfInputChannels, renderBufferSize)), |
| 70 m_renderBus( | 70 m_renderBus( |
| 71 AudioBus::create(numberOfOutputChannels, renderBufferSize, false)), | 71 AudioBus::create(numberOfOutputChannels, renderBufferSize, false)), |
| 72 m_sampleRate(sampleRate), | 72 m_sampleRate(sampleRate), |
| 73 m_isPlaying(false) { | 73 m_isPlaying(false) { |
| 74 // Histogram for audioHardwareBufferSize | 74 // Histogram for audioHardwareBufferSize |
| 75 DEFINE_STATIC_LOCAL(SparseHistogram, hardwareBufferSizeHistogram, | 75 DEFINE_STATIC_LOCAL(SparseHistogram, hardwareBufferSizeHistogram, |
| 76 ("WebAudio.AudioDestination.HardwareBufferSize")); | 76 ("WebAudio.AudioDestination.HardwareBufferSize")); |
| 77 // Histogram for the actual callback size used. Typically, this is the same a
s | 77 // Histogram for the actual callback size used. Typically, this is the same |
| 78 // audioHardwareBufferSize, but can be adjusted depending on some heuristics b
elow. | 78 // as audioHardwareBufferSize, but can be adjusted depending on some |
| 79 // heuristics below. |
| 79 DEFINE_STATIC_LOCAL(SparseHistogram, callbackBufferSizeHistogram, | 80 DEFINE_STATIC_LOCAL(SparseHistogram, callbackBufferSizeHistogram, |
| 80 ("WebAudio.AudioDestination.CallbackBufferSize")); | 81 ("WebAudio.AudioDestination.CallbackBufferSize")); |
| 81 | 82 |
| 82 // Use the optimal buffer size recommended by the audio backend. | 83 // Use the optimal buffer size recommended by the audio backend. |
| 83 size_t recommendedHardwareBufferSize = | 84 size_t recommendedHardwareBufferSize = |
| 84 Platform::current()->audioHardwareBufferSize(); | 85 Platform::current()->audioHardwareBufferSize(); |
| 85 m_callbackBufferSize = recommendedHardwareBufferSize; | 86 m_callbackBufferSize = recommendedHardwareBufferSize; |
| 86 | 87 |
| 87 #if OS(ANDROID) | 88 #if OS(ANDROID) |
| 88 // The optimum low-latency hardware buffer size is usually too small on Androi
d for WebAudio to | 89 // The optimum low-latency hardware buffer size is usually too small on |
| 89 // render without glitching. So, if it is small, use a larger size. If it was
already large, use | 90 // Android for WebAudio to render without glitching. So, if it is small, use |
| 90 // the requested size. | 91 // a larger size. If it was already large, use the requested size. |
| 91 // | 92 // |
| 92 // Since WebAudio renders in 128-frame blocks, the small buffer sizes (144 for
a Galaxy Nexus), | 93 // Since WebAudio renders in 128-frame blocks, the small buffer sizes (144 |
| 93 // cause significant processing jitter. Sometimes multiple blocks will process
ed, but other | 94 // for a Galaxy Nexus), cause significant processing jitter. Sometimes |
| 94 // times will not be since the FIFO can satisfy the request. By using a larger | 95 // multiple blocks will processed, but other times will not be since the FIFO |
| 95 // callbackBufferSize, we smooth out the jitter. | 96 // can satisfy the request. By using a larger callbackBufferSize, we smooth |
| 97 // out the jitter. |
| 96 const size_t kSmallBufferSize = 1024; | 98 const size_t kSmallBufferSize = 1024; |
| 97 const size_t kDefaultCallbackBufferSize = 2048; | 99 const size_t kDefaultCallbackBufferSize = 2048; |
| 98 | 100 |
| 99 if (m_callbackBufferSize <= kSmallBufferSize) | 101 if (m_callbackBufferSize <= kSmallBufferSize) |
| 100 m_callbackBufferSize = kDefaultCallbackBufferSize; | 102 m_callbackBufferSize = kDefaultCallbackBufferSize; |
| 101 #endif | 103 #endif |
| 102 | 104 |
| 103 // Quick exit if the requested size is too large. | 105 // Quick exit if the requested size is too large. |
| 104 ASSERT(m_callbackBufferSize + renderBufferSize <= fifoSize); | 106 ASSERT(m_callbackBufferSize + renderBufferSize <= fifoSize); |
| 105 if (m_callbackBufferSize + renderBufferSize > fifoSize) | 107 if (m_callbackBufferSize + renderBufferSize > fifoSize) |
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| 118 // not being a multiple of the render size. If the FIFO already | 120 // not being a multiple of the render size. If the FIFO already |
| 119 // contains enough data, the data will be provided directly. | 121 // contains enough data, the data will be provided directly. |
| 120 // Otherwise, the FIFO will call the provider enough times to | 122 // Otherwise, the FIFO will call the provider enough times to |
| 121 // satisfy the request for data. | 123 // satisfy the request for data. |
| 122 m_fifo = wrapUnique(new AudioPullFIFO(*this, numberOfOutputChannels, fifoSize, | 124 m_fifo = wrapUnique(new AudioPullFIFO(*this, numberOfOutputChannels, fifoSize, |
| 123 renderBufferSize)); | 125 renderBufferSize)); |
| 124 | 126 |
| 125 // Input buffering. | 127 // Input buffering. |
| 126 m_inputFifo = wrapUnique(new AudioFIFO(numberOfInputChannels, fifoSize)); | 128 m_inputFifo = wrapUnique(new AudioFIFO(numberOfInputChannels, fifoSize)); |
| 127 | 129 |
| 128 // If the callback size does not match the render size, then we need to buffer
some | 130 // If the callback size does not match the render size, then we need to |
| 129 // extra silence for the input. Otherwise, we can over-consume the input FIFO. | 131 // buffer some extra silence for the input. Otherwise, we can over-consume |
| 132 // the input FIFO. |
| 130 if (m_callbackBufferSize != renderBufferSize) { | 133 if (m_callbackBufferSize != renderBufferSize) { |
| 131 // FIXME: handle multi-channel input and don't hard-code to stereo. | 134 // FIXME: handle multi-channel input and don't hard-code to stereo. |
| 132 RefPtr<AudioBus> silence = AudioBus::create(2, renderBufferSize); | 135 RefPtr<AudioBus> silence = AudioBus::create(2, renderBufferSize); |
| 133 m_inputFifo->push(silence.get()); | 136 m_inputFifo->push(silence.get()); |
| 134 } | 137 } |
| 135 } | 138 } |
| 136 | 139 |
| 137 AudioDestination::~AudioDestination() { | 140 AudioDestination::~AudioDestination() { |
| 138 stop(); | 141 stop(); |
| 139 } | 142 } |
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| 194 AudioBus* sourceBus = nullptr; | 197 AudioBus* sourceBus = nullptr; |
| 195 if (m_inputFifo->framesInFifo() >= framesToProcess) { | 198 if (m_inputFifo->framesInFifo() >= framesToProcess) { |
| 196 m_inputFifo->consume(m_inputBus.get(), framesToProcess); | 199 m_inputFifo->consume(m_inputBus.get(), framesToProcess); |
| 197 sourceBus = m_inputBus.get(); | 200 sourceBus = m_inputBus.get(); |
| 198 } | 201 } |
| 199 | 202 |
| 200 m_callback.render(sourceBus, bus, framesToProcess); | 203 m_callback.render(sourceBus, bus, framesToProcess); |
| 201 } | 204 } |
| 202 | 205 |
| 203 } // namespace blink | 206 } // namespace blink |
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