1 /*
2 * Copyright (C) 2010, Google Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
15 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
16 * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
17 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
18 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
19 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
20 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
22 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23 */
24
25 #include "config.h"
26
27 #if ENABLE(WEB_AUDIO)
28
29 #include "platform/audio/AudioResampler.h"
30
31 #include <algorithm>
32 #include "wtf/MathExtras.h"
33
34 using namespace std;
35
36 namespace WebCore {
37
38 const double AudioResampler::MaxRate = 8.0;
39
AudioResampler()40 AudioResampler::AudioResampler()
41 : m_rate(1.0)
42 {
43 m_kernels.append(adoptPtr(new AudioResamplerKernel(this)));
44 m_sourceBus = AudioBus::create(1, 0, false);
45 }
46
AudioResampler(unsigned numberOfChannels)47 AudioResampler::AudioResampler(unsigned numberOfChannels)
48 : m_rate(1.0)
49 {
50 for (unsigned i = 0; i < numberOfChannels; ++i)
51 m_kernels.append(adoptPtr(new AudioResamplerKernel(this)));
52
53 m_sourceBus = AudioBus::create(numberOfChannels, 0, false);
54 }
55
configureChannels(unsigned numberOfChannels)56 void AudioResampler::configureChannels(unsigned numberOfChannels)
57 {
58 unsigned currentSize = m_kernels.size();
59 if (numberOfChannels == currentSize)
60 return; // already setup
61
62 // First deal with adding or removing kernels.
63 if (numberOfChannels > currentSize) {
64 for (unsigned i = currentSize; i < numberOfChannels; ++i)
65 m_kernels.append(adoptPtr(new AudioResamplerKernel(this)));
66 } else
67 m_kernels.resize(numberOfChannels);
68
69 // Reconfigure our source bus to the new channel size.
70 m_sourceBus = AudioBus::create(numberOfChannels, 0, false);
71 }
72
process(AudioSourceProvider * provider,AudioBus * destinationBus,size_t framesToProcess)73 void AudioResampler::process(AudioSourceProvider* provider, AudioBus* destinationBus, size_t framesToProcess)
74 {
75 ASSERT(provider);
76 if (!provider)
77 return;
78
79 unsigned numberOfChannels = m_kernels.size();
80
81 // Make sure our configuration matches the bus we're rendering to.
82 bool channelsMatch = (destinationBus && destinationBus->numberOfChannels() == numberOfChannels);
83 ASSERT(channelsMatch);
84 if (!channelsMatch)
85 return;
86
87 // Setup the source bus.
88 for (unsigned i = 0; i < numberOfChannels; ++i) {
89 // Figure out how many frames we need to get from the provider, and a pointer to the buffer.
90 size_t framesNeeded;
91 float* fillPointer = m_kernels[i]->getSourcePointer(framesToProcess, &framesNeeded);
92 ASSERT(fillPointer);
93 if (!fillPointer)
94 return;
95
96 m_sourceBus->setChannelMemory(i, fillPointer, framesNeeded);
97 }
98
99 // Ask the provider to supply the desired number of source frames.
100 provider->provideInput(m_sourceBus.get(), m_sourceBus->length());
101
102 // Now that we have the source data, resample each channel into the destination bus.
103 // FIXME: optimize for the common stereo case where it's faster to process both left/right channels in the same inner loop.
104 for (unsigned i = 0; i < numberOfChannels; ++i) {
105 float* destination = destinationBus->channel(i)->mutableData();
106 m_kernels[i]->process(destination, framesToProcess);
107 }
108 }
109
setRate(double rate)110 void AudioResampler::setRate(double rate)
111 {
112 if (std::isnan(rate) || std::isinf(rate) || rate <= 0.0)
113 return;
114
115 m_rate = min(AudioResampler::MaxRate, rate);
116 }
117
reset()118 void AudioResampler::reset()
119 {
120 unsigned numberOfChannels = m_kernels.size();
121 for (unsigned i = 0; i < numberOfChannels; ++i)
122 m_kernels[i]->reset();
123 }
124
125 } // namespace WebCore
126
127 #endif // ENABLE(WEB_AUDIO)
128