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 are
6 * met:
7 *
8 *     * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 *     * Redistributions in binary form must reproduce the above
11 * copyright notice, this list of conditions and the following disclaimer
12 * in the documentation and/or other materials provided with the
13 * distribution.
14 *     * Neither the name of Google Inc. nor the names of its
15 * contributors may be used to endorse or promote products derived from
16 * this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31#ifndef AudioProcessor_h
32#define AudioProcessor_h
33
34#include "platform/PlatformExport.h"
35
36namespace WebCore {
37
38class AudioBus;
39
40// AudioProcessor is an abstract base class representing an audio signal processing object with a single input and a single output,
41// where the number of input channels equals the number of output channels.  It can be used as one part of a complex DSP algorithm,
42// or as the processor for a basic (one input - one output) AudioNode.
43
44class PLATFORM_EXPORT AudioProcessor {
45public:
46    AudioProcessor(float sampleRate, unsigned numberOfChannels)
47        : m_initialized(false)
48        , m_numberOfChannels(numberOfChannels)
49        , m_sampleRate(sampleRate)
50    {
51    }
52
53    virtual ~AudioProcessor();
54
55    // Full initialization can be done here instead of in the constructor.
56    virtual void initialize() = 0;
57    virtual void uninitialize() = 0;
58
59    // Processes the source to destination bus.  The number of channels must match in source and destination.
60    virtual void process(const AudioBus* source, AudioBus* destination, size_t framesToProcess) = 0;
61
62    // Resets filter state
63    virtual void reset() = 0;
64
65    virtual void setNumberOfChannels(unsigned) = 0;
66    virtual unsigned numberOfChannels() const = 0;
67
68    bool isInitialized() const { return m_initialized; }
69
70    float sampleRate() const { return m_sampleRate; }
71
72    virtual double tailTime() const = 0;
73    virtual double latencyTime() const = 0;
74
75protected:
76    bool m_initialized;
77    unsigned m_numberOfChannels;
78    float m_sampleRate;
79};
80
81} // namespace WebCore
82
83#endif // AudioProcessor_h
84