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 "AudioResampler.h"
30
31 #include "AudioBus.h"
32 #include <algorithm>
33 #include <wtf/MathExtras.h>
34
35 using namespace std;
36
37 namespace WebCore {
38
39 const double AudioResampler::MaxRate = 8.0;
40
AudioResampler()41 AudioResampler::AudioResampler()
42 : m_rate(1.0)
43 {
44 m_kernels.append(adoptPtr(new AudioResamplerKernel(this)));
45 m_sourceBus = adoptPtr(new AudioBus(1, 0, false));
46 }
47
AudioResampler(unsigned numberOfChannels)48 AudioResampler::AudioResampler(unsigned numberOfChannels)
49 : m_rate(1.0)
50 {
51 for (unsigned i = 0; i < numberOfChannels; ++i)
52 m_kernels.append(adoptPtr(new AudioResamplerKernel(this)));
53
54 m_sourceBus = adoptPtr(new AudioBus(numberOfChannels, 0, false));
55 }
56
configureChannels(unsigned numberOfChannels)57 void AudioResampler::configureChannels(unsigned numberOfChannels)
58 {
59 unsigned currentSize = m_kernels.size();
60 if (numberOfChannels == currentSize)
61 return; // already setup
62
63 // First deal with adding or removing kernels.
64 if (numberOfChannels > currentSize) {
65 for (unsigned i = currentSize; i < numberOfChannels; ++i)
66 m_kernels.append(adoptPtr(new AudioResamplerKernel(this)));
67 } else
68 m_kernels.resize(numberOfChannels);
69
70 // Reconfigure our source bus to the new channel size.
71 m_sourceBus = adoptPtr(new AudioBus(numberOfChannels, 0, false));
72 }
73
process(AudioSourceProvider * provider,AudioBus * destinationBus,size_t framesToProcess)74 void AudioResampler::process(AudioSourceProvider* provider, AudioBus* destinationBus, size_t framesToProcess)
75 {
76 ASSERT(provider);
77 if (!provider)
78 return;
79
80 unsigned numberOfChannels = m_kernels.size();
81
82 // Make sure our configuration matches the bus we're rendering to.
83 bool channelsMatch = (destinationBus && destinationBus->numberOfChannels() == numberOfChannels);
84 ASSERT(channelsMatch);
85 if (!channelsMatch)
86 return;
87
88 // Setup the source bus.
89 for (unsigned i = 0; i < numberOfChannels; ++i) {
90 // Figure out how many frames we need to get from the provider, and a pointer to the buffer.
91 size_t framesNeeded;
92 float* fillPointer = m_kernels[i]->getSourcePointer(framesToProcess, &framesNeeded);
93 ASSERT(fillPointer);
94 if (!fillPointer)
95 return;
96
97 m_sourceBus->setChannelMemory(i, fillPointer, framesNeeded);
98 }
99
100 // Ask the provider to supply the desired number of source frames.
101 provider->provideInput(m_sourceBus.get(), m_sourceBus->length());
102
103 // Now that we have the source data, resample each channel into the destination bus.
104 // FIXME: optimize for the common stereo case where it's faster to process both left/right channels in the same inner loop.
105 for (unsigned i = 0; i < numberOfChannels; ++i) {
106 float* destination = destinationBus->channel(i)->data();
107 m_kernels[i]->process(destination, framesToProcess);
108 }
109 }
110
setRate(double rate)111 void AudioResampler::setRate(double rate)
112 {
113 if (isnan(rate) || isinf(rate) || rate <= 0.0)
114 return;
115
116 m_rate = min(AudioResampler::MaxRate, rate);
117 }
118
reset()119 void AudioResampler::reset()
120 {
121 unsigned numberOfChannels = m_kernels.size();
122 for (unsigned i = 0; i < numberOfChannels; ++i)
123 m_kernels[i]->reset();
124 }
125
126 } // namespace WebCore
127
128 #endif // ENABLE(WEB_AUDIO)
129