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
35using namespace std;
36
37namespace WebCore {
38
39const double AudioResampler::MaxRate = 8.0;
40
41AudioResampler::AudioResampler()
42    : m_rate(1.0)
43{
44    m_kernels.append(adoptPtr(new AudioResamplerKernel(this)));
45    m_sourceBus = AudioBus::create(1, 0, false);
46}
47
48AudioResampler::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 = AudioBus::create(numberOfChannels, 0, false);
55}
56
57void 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 = AudioBus::create(numberOfChannels, 0, false);
72}
73
74void 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)->mutableData();
107        m_kernels[i]->process(destination, framesToProcess);
108    }
109}
110
111void AudioResampler::setRate(double rate)
112{
113    if (std::isnan(rate) || std::isinf(rate) || rate <= 0.0)
114        return;
115
116    m_rate = min(AudioResampler::MaxRate, rate);
117}
118
119void 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