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#ifndef RealtimeAnalyser_h
26#define RealtimeAnalyser_h
27
28#include "AudioArray.h"
29#include <memory>
30#include <runtime/Float32Array.h>
31#include <runtime/Uint8Array.h>
32#include <wtf/Forward.h>
33#include <wtf/Noncopyable.h>
34
35namespace WebCore {
36
37class AudioBus;
38class FFTFrame;
39
40class RealtimeAnalyser {
41    WTF_MAKE_NONCOPYABLE(RealtimeAnalyser);
42public:
43    RealtimeAnalyser();
44    virtual ~RealtimeAnalyser();
45
46    void reset();
47
48    size_t fftSize() const { return m_fftSize; }
49    bool setFftSize(size_t);
50
51    unsigned frequencyBinCount() const { return m_fftSize / 2; }
52
53    void setMinDecibels(double k) { m_minDecibels = k; }
54    double minDecibels() const { return m_minDecibels; }
55
56    void setMaxDecibels(double k) { m_maxDecibels = k; }
57    double maxDecibels() const { return m_maxDecibels; }
58
59    void setSmoothingTimeConstant(double k) { m_smoothingTimeConstant = k; }
60    double smoothingTimeConstant() const { return m_smoothingTimeConstant; }
61
62    void getFloatFrequencyData(JSC::Float32Array*);
63    void getByteFrequencyData(JSC::Uint8Array*);
64    void getByteTimeDomainData(JSC::Uint8Array*);
65
66    // The audio thread writes input data here.
67    void writeInput(AudioBus*, size_t framesToProcess);
68
69    static const double DefaultSmoothingTimeConstant;
70    static const double DefaultMinDecibels;
71    static const double DefaultMaxDecibels;
72
73    static const unsigned DefaultFFTSize;
74    static const unsigned MinFFTSize;
75    static const unsigned MaxFFTSize;
76    static const unsigned InputBufferSize;
77
78private:
79    // The audio thread writes the input audio here.
80    AudioFloatArray m_inputBuffer;
81    unsigned m_writeIndex;
82
83    size_t m_fftSize;
84    std::unique_ptr<FFTFrame> m_analysisFrame;
85    void doFFTAnalysis();
86
87    // doFFTAnalysis() stores the floating-point magnitude analysis data here.
88    AudioFloatArray m_magnitudeBuffer;
89    AudioFloatArray& magnitudeBuffer() { return m_magnitudeBuffer; }
90
91    // A value between 0 and 1 which averages the previous version of m_magnitudeBuffer with the current analysis magnitude data.
92    double m_smoothingTimeConstant;
93
94    // The range used when converting when using getByteFrequencyData().
95    double m_minDecibels;
96    double m_maxDecibels;
97};
98
99} // namespace WebCore
100
101#endif // RealtimeAnalyser_h
102