1 | /* |
---|
2 | Copyright (C) 2003-2009 Paul Brossier <piem@aubio.org> |
---|
3 | |
---|
4 | This file is part of aubio. |
---|
5 | |
---|
6 | aubio is free software: you can redistribute it and/or modify |
---|
7 | it under the terms of the GNU General Public License as published by |
---|
8 | the Free Software Foundation, either version 3 of the License, or |
---|
9 | (at your option) any later version. |
---|
10 | |
---|
11 | aubio is distributed in the hope that it will be useful, |
---|
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
---|
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
---|
14 | GNU General Public License for more details. |
---|
15 | |
---|
16 | You should have received a copy of the GNU General Public License |
---|
17 | along with aubio. If not, see <http://www.gnu.org/licenses/>. |
---|
18 | |
---|
19 | */ |
---|
20 | |
---|
21 | /** @file |
---|
22 | * various functions useful in audio signal processing |
---|
23 | */ |
---|
24 | |
---|
25 | #ifndef MUSICUTILS_H |
---|
26 | #define MUSICUTILS_H |
---|
27 | |
---|
28 | #ifdef __cplusplus |
---|
29 | extern "C" { |
---|
30 | #endif |
---|
31 | |
---|
32 | /** create window |
---|
33 | |
---|
34 | References: |
---|
35 | |
---|
36 | - <a href="http://en.wikipedia.org/wiki/Window_function">Window |
---|
37 | function</a> on Wikipedia |
---|
38 | - Amalia de Götzen, Nicolas Bernardini, and Daniel Arfib. Traditional (?) |
---|
39 | implementations of a phase vocoder: the tricks of the trade. In Proceedings of |
---|
40 | the International Conference on Digital Audio Effects (DAFx-00), pages 37–44, |
---|
41 | Uni- versity of Verona, Italy, 2000. |
---|
42 | (<a href="http://profs.sci.univr.it/%7Edafx/Final-Papers/ps/Bernardini.ps.gz"> |
---|
43 | ps.gz</a>) |
---|
44 | |
---|
45 | */ |
---|
46 | fvec_t *new_aubio_window (char_t * window_type, uint_t size); |
---|
47 | |
---|
48 | /** set elements of a vector to window coefficients |
---|
49 | |
---|
50 | */ |
---|
51 | uint_t fvec_set_window (fvec_t * window, char_t * window_type); |
---|
52 | |
---|
53 | /** compute the principal argument |
---|
54 | |
---|
55 | This function maps the input phase to its corresponding value wrapped in the |
---|
56 | range \f$ [-\pi, \pi] \f$. |
---|
57 | |
---|
58 | \param phase unwrapped phase to map to the unit circle |
---|
59 | |
---|
60 | \return equivalent phase wrapped to the unit circle |
---|
61 | |
---|
62 | */ |
---|
63 | smpl_t aubio_unwrap2pi (smpl_t phase); |
---|
64 | |
---|
65 | /** convert frequency bin to midi value */ |
---|
66 | smpl_t aubio_bintomidi (smpl_t bin, smpl_t samplerate, smpl_t fftsize); |
---|
67 | |
---|
68 | /** convert midi value to frequency bin */ |
---|
69 | smpl_t aubio_miditobin (smpl_t midi, smpl_t samplerate, smpl_t fftsize); |
---|
70 | |
---|
71 | /** convert frequency bin to frequency (Hz) */ |
---|
72 | smpl_t aubio_bintofreq (smpl_t bin, smpl_t samplerate, smpl_t fftsize); |
---|
73 | |
---|
74 | /** convert frequency (Hz) to frequency bin */ |
---|
75 | smpl_t aubio_freqtobin (smpl_t freq, smpl_t samplerate, smpl_t fftsize); |
---|
76 | |
---|
77 | /** convert frequency (Hz) to midi value (0-128) */ |
---|
78 | smpl_t aubio_freqtomidi (smpl_t freq); |
---|
79 | |
---|
80 | /** convert midi value (0-128) to frequency (Hz) */ |
---|
81 | smpl_t aubio_miditofreq (smpl_t midi); |
---|
82 | |
---|
83 | /** clean up cached memory at the end of program |
---|
84 | |
---|
85 | This function should be used at the end of programs to purge all cached |
---|
86 | memory. So far it is only useful to clean FFTW's cache. |
---|
87 | |
---|
88 | */ |
---|
89 | void aubio_cleanup (void); |
---|
90 | |
---|
91 | /** zero-crossing rate (ZCR) |
---|
92 | |
---|
93 | The zero-crossing rate is the number of times a signal changes sign, |
---|
94 | divided by the length of this signal. |
---|
95 | |
---|
96 | \param v vector to compute ZCR from |
---|
97 | |
---|
98 | \return zero-crossing rate of v |
---|
99 | |
---|
100 | */ |
---|
101 | smpl_t aubio_zero_crossing_rate (fvec_t * v); |
---|
102 | |
---|
103 | /** compute sound level on a linear |
---|
104 | |
---|
105 | This gives the average of the square amplitudes. |
---|
106 | |
---|
107 | \param v vector to compute dB SPL from |
---|
108 | |
---|
109 | \return level of v |
---|
110 | |
---|
111 | */ |
---|
112 | smpl_t aubio_level_lin (fvec_t * v); |
---|
113 | |
---|
114 | /** compute sound pressure level (SPL) in dB |
---|
115 | |
---|
116 | This quantity is often wrongly called 'loudness'. |
---|
117 | |
---|
118 | This gives ten times the log10 of the average of the square amplitudes. |
---|
119 | |
---|
120 | \param v vector to compute dB SPL from |
---|
121 | |
---|
122 | \return level of v in dB SPL |
---|
123 | |
---|
124 | */ |
---|
125 | smpl_t aubio_db_spl (fvec_t * v); |
---|
126 | |
---|
127 | /** check if buffer level in dB SPL is under a given threshold |
---|
128 | |
---|
129 | \param v vector to get level from |
---|
130 | \param threshold threshold in dB SPL |
---|
131 | |
---|
132 | \return 0 if level is under the given threshold, 1 otherwise |
---|
133 | |
---|
134 | */ |
---|
135 | uint_t aubio_silence_detection (fvec_t * v, smpl_t threshold); |
---|
136 | |
---|
137 | /** get buffer level if level >= threshold, 1. otherwise |
---|
138 | |
---|
139 | \param v vector to get level from |
---|
140 | \param threshold threshold in dB SPL |
---|
141 | |
---|
142 | \return level in dB SPL if level >= threshold, 1. otherwise |
---|
143 | |
---|
144 | */ |
---|
145 | smpl_t aubio_level_detection (fvec_t * v, smpl_t threshold); |
---|
146 | |
---|
147 | #ifdef __cplusplus |
---|
148 | } |
---|
149 | #endif |
---|
150 | |
---|
151 | #endif |
---|
152 | |
---|