aubio: musicutils.h Source File

aubio 0.4.6

musicutils.h
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1 /*
2 Copyright (C) 2003-2015 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 AUBIO_MUSICUTILS_H
26 #define AUBIO_MUSICUTILS_H
27
28 #ifdef __cplusplus
29 extern "C" {
30 #endif
31
32 /** create window
33
34 \param window_type type of the window to create
35 \param size length of the window to create (see fvec_set_window())
36
37 */
38 fvec_t *new_aubio_window (char_t * window_type, uint_t size);
39
40 /** set elements of a vector to window coefficients
41
42 \param window exsting ::fvec_t to use
43 \param window_type type of the window to create
44
45 List of available window types: "rectangle", "hamming", "hanning",
46 "hanningz", "blackman", "blackman_harris", "gaussian", "welch", "parzen",
47 "default".
48
49 "default" is equivalent to "hanningz".
50
51 References:
52
53 - <a href="http://en.wikipedia.org/wiki/Window_function">Window
54 function</a> on Wikipedia
55 - Amalia de Götzen, Nicolas Bernardini, and Daniel Arfib. Traditional (?)
56 implementations of a phase vocoder: the tricks of the trade. In Proceedings of
57 the International Conference on Digital Audio Effects (DAFx-00), pages 37–44,
58 Uni- versity of Verona, Italy, 2000.
59 (<a href="http://www.cs.princeton.edu/courses/archive/spr09/cos325/Bernardini.pdf">
60 pdf</a>)
61
62 */
63 uint_t fvec_set_window (fvec_t * window, char_t * window_type);
64
65 /** compute the principal argument
66
67 This function maps the input phase to its corresponding value wrapped in the
68 range \f$ [-\pi, \pi] \f$.
69
70 \param phase unwrapped phase to map to the unit circle
71
72 \return equivalent phase wrapped to the unit circle
73
74 */
75 smpl_t aubio_unwrap2pi (smpl_t phase);
76
77 /** convert frequency bin to midi value */
78 smpl_t aubio_bintomidi (smpl_t bin, smpl_t samplerate, smpl_t fftsize);
79
80 /** convert midi value to frequency bin */
81 smpl_t aubio_miditobin (smpl_t midi, smpl_t samplerate, smpl_t fftsize);
82
83 /** convert frequency bin to frequency (Hz) */
84 smpl_t aubio_bintofreq (smpl_t bin, smpl_t samplerate, smpl_t fftsize);
85
86 /** convert frequency (Hz) to frequency bin */
87 smpl_t aubio_freqtobin (smpl_t freq, smpl_t samplerate, smpl_t fftsize);
88
89 /** convert frequency (Hz) to midi value (0-128) */
90 smpl_t aubio_freqtomidi (smpl_t freq);
91
92 /** convert midi value (0-128) to frequency (Hz) */
93 smpl_t aubio_miditofreq (smpl_t midi);
94
95 /** clean up cached memory at the end of program
96
97 This function should be used at the end of programs to purge all cached
98 memory. So far it is only useful to clean FFTW's cache.
99
100 */
101 void aubio_cleanup (void);
102
103 /** zero-crossing rate (ZCR)
104
105 The zero-crossing rate is the number of times a signal changes sign,
106 divided by the length of this signal.
107
108 \param v vector to compute ZCR from
109
110 \return zero-crossing rate of v
111
112 */
113 smpl_t aubio_zero_crossing_rate (fvec_t * v);
114
115 /** compute sound level on a linear scale
116
117 This gives the average of the square amplitudes.
118
119 \param v vector to compute level from
120
121 \return level of v
122
123 */
124 smpl_t aubio_level_lin (const fvec_t * v);
125
126 /** compute sound pressure level (SPL) in dB
127
128 This quantity is often wrongly called 'loudness'.
129
130 This gives ten times the log10 of the average of the square amplitudes.
131
132 \param v vector to compute dB SPL from
133
134 \return level of v in dB SPL
135
136 */
137 smpl_t aubio_db_spl (const fvec_t * v);
138
139 /** check if buffer level in dB SPL is under a given threshold
140
141 \param v vector to get level from
142 \param threshold threshold in dB SPL
143
144 \return 0 if level is under the given threshold, 1 otherwise
145
146 */
147 uint_t aubio_silence_detection (const fvec_t * v, smpl_t threshold);
148
149 /** get buffer level if level >= threshold, 1. otherwise
150
151 \param v vector to get level from
152 \param threshold threshold in dB SPL
153
154 \return level in dB SPL if level >= threshold, 1. otherwise
155
156 */
157 smpl_t aubio_level_detection (const fvec_t * v, smpl_t threshold);
158
159 /** clamp the values of a vector within the range [-abs(max), abs(max)]
160
161 \param in vector to clamp
162 \param absmax maximum value over which input vector elements should be clamped
163
164 */
165 void fvec_clamp(fvec_t *in, smpl_t absmax);
166
167 #ifdef __cplusplus
168 }
169 #endif
170
171 #endif /* AUBIO_MUSICUTILS_H */
aubio_bintofreq
smpl_t aubio_bintofreq(smpl_t bin, smpl_t samplerate, smpl_t fftsize)
convert frequency bin to frequency (Hz)
aubio_bintomidi
smpl_t aubio_bintomidi(smpl_t bin, smpl_t samplerate, smpl_t fftsize)
convert frequency bin to midi value
aubio_unwrap2pi
smpl_t aubio_unwrap2pi(smpl_t phase)
compute the principal argument
aubio_level_lin
smpl_t aubio_level_lin(const fvec_t *v)
compute sound level on a linear scale
aubio_cleanup
void aubio_cleanup(void)
clean up cached memory at the end of program
aubio_freqtobin
smpl_t aubio_freqtobin(smpl_t freq, smpl_t samplerate, smpl_t fftsize)
convert frequency (Hz) to frequency bin
aubio_level_detection
smpl_t aubio_level_detection(const fvec_t *v, smpl_t threshold)
get buffer level if level >= threshold, 1.
smpl_t
float smpl_t
short sample format (32 or 64 bits)
Definition: types.h:41
aubio_miditofreq
smpl_t aubio_miditofreq(smpl_t midi)
convert midi value (0-128) to frequency (Hz)
fvec_clamp
void fvec_clamp(fvec_t *in, smpl_t absmax)
clamp the values of a vector within the range [-abs(max), abs(max)]
aubio_freqtomidi
smpl_t aubio_freqtomidi(smpl_t freq)
convert frequency (Hz) to midi value (0-128)
fvec_set_window
uint_t fvec_set_window(fvec_t *window, char_t *window_type)
set elements of a vector to window coefficients
aubio_miditobin
smpl_t aubio_miditobin(smpl_t midi, smpl_t samplerate, smpl_t fftsize)
convert midi value to frequency bin
fvec_t
Buffer for real data.
Definition: fvec.h:67
new_aubio_window
fvec_t * new_aubio_window(char_t *window_type, uint_t size)
create window
aubio_db_spl
smpl_t aubio_db_spl(const fvec_t *v)
compute sound pressure level (SPL) in dB
uint_t
unsigned int uint_t
unsigned integer
Definition: types.h:60
aubio_zero_crossing_rate
smpl_t aubio_zero_crossing_rate(fvec_t *v)
zero-crossing rate (ZCR)
aubio_silence_detection
uint_t aubio_silence_detection(const fvec_t *v, smpl_t threshold)
check if buffer level in dB SPL is under a given threshold
char_t
char char_t
character
Definition: types.h:64