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
34namespace blink {
35
36const double AudioResampler::MaxRate = 8.0;
37
38AudioResampler::AudioResampler()
39    : m_rate(1.0)
40{
41    m_kernels.append(adoptPtr(new AudioResamplerKernel(this)));
42    m_sourceBus = AudioBus::create(1, 0, false);
43}
44
45AudioResampler::AudioResampler(unsigned numberOfChannels)
46    : m_rate(1.0)
47{
48    for (unsigned i = 0; i < numberOfChannels; ++i)
49        m_kernels.append(adoptPtr(new AudioResamplerKernel(this)));
50
51    m_sourceBus = AudioBus::create(numberOfChannels, 0, false);
52}
53
54void AudioResampler::configureChannels(unsigned numberOfChannels)
55{
56    unsigned currentSize = m_kernels.size();
57    if (numberOfChannels == currentSize)
58        return; // already setup
59
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)));
64    } else
65        m_kernels.resize(numberOfChannels);
66
67    // Reconfigure our source bus to the new channel size.
68    m_sourceBus = AudioBus::create(numberOfChannels, 0, false);
69}
70
71void AudioResampler::process(AudioSourceProvider* provider, AudioBus* destinationBus, size_t framesToProcess)
72{
73    ASSERT(provider);
74    if (!provider)
75        return;
76
77    unsigned numberOfChannels = m_kernels.size();
78
79    // Make sure our configuration matches the bus we're rendering to.
80    bool channelsMatch = (destinationBus && destinationBus->numberOfChannels() == numberOfChannels);
81    ASSERT(channelsMatch);
82    if (!channelsMatch)
83        return;
84
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.
88        size_t framesNeeded;
89        float* fillPointer = m_kernels[i]->getSourcePointer(framesToProcess, &framesNeeded);
90        ASSERT(fillPointer);
91        if (!fillPointer)
92            return;
93
94        m_sourceBus->setChannelMemory(i, fillPointer, framesNeeded);
95    }
96
97    // Ask the provider to supply the desired number of source frames.
98    provider->provideInput(m_sourceBus.get(), m_sourceBus->length());
99
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);
105    }
106}
107
108void AudioResampler::setRate(double rate)
109{
110    if (std::isnan(rate) || std::isinf(rate) || rate <= 0.0)
111        return;
112
113    m_rate = std::min(AudioResampler::MaxRate, rate);
114}
115
116void AudioResampler::reset()
117{
118    unsigned numberOfChannels = m_kernels.size();
119    for (unsigned i = 0; i < numberOfChannels; ++i)
120        m_kernels[i]->reset();
121}
122
123} // namespace blink
124
125#endif // ENABLE(WEB_AUDIO)
126