source: src/mathutils.h @ fc6c831

feature/autosinkfeature/constantqfeature/pitchshiftfeature/pydocstringsfeature/timestretchpitchshiftsamplertimestretchyinfft+
Last change on this file since fc6c831 was fc6c831, checked in by Paul Brossier <piem@piem.org>, 12 years ago

moved spectral_centroid to new file

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1/*
2         Copyright (C) 2003 Paul Brossier
3
4         This program is free software; you can redistribute it and/or modify
5         it under the terms of the GNU General Public License as published by
6         the Free Software Foundation; either version 2 of the License, or
7         (at your option) any later version.
8
9         This program is distributed in the hope that it will be useful,
10         but WITHOUT ANY WARRANTY; without even the implied warranty of
11         MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12         GNU General Public License for more details.
13
14         You should have received a copy of the GNU General Public License
15         along with this program; if not, write to the Free Software
16         Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17
18*/
19
20/** @file
21 *  various math functions
22 *
23 *  \todo multichannel (each function should return -or set- an array sized to
24 *  the number of channel in the input vector)
25 *
26 *  \todo appropriate switches depending on types.h content
27 */
28
29#ifndef MATHUTILS_H
30#define MATHUTILS_H
31
32/** Window types
33 *
34 * inspired from
35 *
36 *  - dafx : http://profs.sci.univr.it/%7Edafx/Final-Papers/ps/Bernardini.ps.gz
37 *  - freqtweak : http://freqtweak.sf.net/
38 *  - extace : http://extace.sf.net/
39 */
40
41#ifdef __cplusplus
42extern "C" {
43#endif
44
45typedef enum {
46        aubio_win_rectangle,         
47        aubio_win_hamming,
48        aubio_win_hanning,
49        aubio_win_hanningz,
50        aubio_win_blackman,
51        aubio_win_blackman_harris,
52        aubio_win_gaussian,
53        aubio_win_welch,
54        aubio_win_parzen
55} aubio_window_type;
56
57/** create window */
58void aubio_window(smpl_t *w, uint_t size, aubio_window_type wintype);
59
60/** principal argument
61 *
62 * mod(phase+PI,-TWO_PI)+PI
63 */
64smpl_t aubio_unwrap2pi (smpl_t phase);
65
66/** calculates the mean of a vector
67 *
68 * \bug mono
69 */
70smpl_t vec_mean(fvec_t *s);
71/** returns the max of a vector
72 *
73 * \bug mono
74 */
75smpl_t vec_max(fvec_t *s);
76/** returns the min of a vector
77 *
78 * \bug mono
79 */
80smpl_t vec_min(fvec_t *s);
81/** returns the index of the min of a vector
82 *
83 * \bug mono
84 */
85uint_t vec_min_elem(fvec_t *s);
86/** returns the index of the max of a vector
87 *
88 * \bug mono
89 */
90uint_t vec_max_elem(fvec_t *s);
91/** implement 'fftshift' like function
92 *
93 * a[0]...,a[n/2],a[n/2+1],...a[n]
94 *
95 * becomes
96 *
97 * a[n/2+1],...a[n],a[0]...,a[n/2]
98 */
99void vec_shift(fvec_t *s);
100/** returns sum */
101smpl_t vec_sum(fvec_t *s);
102/** returns energy
103 *
104 * \bug mono
105 */
106smpl_t vec_local_energy(fvec_t * f);
107/** returns High Frequency Energy Content
108 *
109 * \bug mono */
110smpl_t vec_local_hfc(fvec_t * f);
111/** return alpha norm.
112 *
113 * alpha=2 means normalise variance.
114 * alpha=1 means normalise abs value.
115 * as alpha goes large, tends to normalisation
116 * by max value.
117 *
118 * \bug should not use POW :(
119 */
120smpl_t vec_alpha_norm(fvec_t * DF, smpl_t alpha);
121/**  dc(min) removal */
122void vec_dc_removal(fvec_t * mag);
123/**  alpha normalisation */
124void vec_alpha_normalise(fvec_t * mag, uint_t alpha);
125/** add a constant to all members of a vector */
126void vec_add(fvec_t * mag, smpl_t threshold);
127
128/** compute adaptive threshold of input vector */ 
129void vec_adapt_thres(fvec_t * vec, fvec_t * tmp, 
130    uint_t win_post, uint_t win_pre);
131/**  adaptative thresholding
132 *
133 * y=fn_thresh(fn,x,post,pre)
134 * compute adaptive threshold at each time
135 *    fn : a function name or pointer, eg 'median'
136 *    x:   signal vector
137 *    post: window length, causal part
138 *    pre: window length, anti-causal part
139 * Returns:
140 *    y:   signal the same length as x
141 *
142 * Formerly median_thresh, used compute median over a
143 * window of post+pre+1 samples, but now works with any
144 * function that takes a vector or matrix and returns a
145 * 'representative' value for each column, eg
146 *    medians=fn_thresh(median,x,8,8) 
147 *    minima=fn_thresh(min,x,8,8) 
148 * see SPARMS for explanation of post and pre
149 */
150smpl_t vec_moving_thres(fvec_t * vec, fvec_t * tmp, 
151    uint_t win_post, uint_t win_pre, uint_t win_pos);
152
153/** returns the median of the vector
154 *
155 *  This Quickselect routine is based on the algorithm described in
156 *  "Numerical recipes in C", Second Edition,
157 *  Cambridge University Press, 1992, Section 8.5, ISBN 0-521-43108-5
158 *
159 *  This code by Nicolas Devillard - 1998. Public domain,
160 *  available at http://ndevilla.free.fr/median/median/
161 */
162smpl_t vec_median(fvec_t * input);
163
164/** finds exact maximum position by quadratic interpolation*/
165smpl_t vec_quadint(fvec_t * x,uint_t pos);
166
167/** finds exact minimum position by quadratic interpolation*/
168smpl_t vec_quadint_min(fvec_t * x,uint_t pos, uint_t span);
169
170/** Quadratic interpolation using Lagrange polynomial.
171 *
172 * inspired from ``Comparison of interpolation algorithms in real-time sound
173 * processing'', Vladimir Arnost,
174 *
175 * estimate = s0 + (pf/2.)*((pf-3.)*s0-2.*(pf-2.)*s1+(pf-1.)*s2);
176 *    where
177 *    \param s0,s1,s2 are 3 known points on the curve,
178 *    \param pf is the floating point index [0;2]
179 */
180smpl_t aubio_quadfrac(smpl_t s0, smpl_t s1, smpl_t s2, smpl_t pf);
181
182/** returns 1 if X1 is a peak and positive */
183uint_t vec_peakpick(fvec_t * input, uint_t pos);
184
185/** convert frequency bin to midi value */
186smpl_t aubio_bintomidi(smpl_t bin, smpl_t samplerate, smpl_t fftsize);
187/** convert midi value to frequency bin */
188smpl_t aubio_miditobin(smpl_t midi, smpl_t samplerate, smpl_t fftsize);
189/** convert frequency bin to frequency (Hz) */
190smpl_t aubio_bintofreq(smpl_t bin, smpl_t samplerate, smpl_t fftsize);
191/** convert frequency (Hz) to frequency bin */
192smpl_t aubio_freqtobin(smpl_t freq, smpl_t samplerate, smpl_t fftsize);
193/** convert frequency (Hz) to midi value (0-128) */
194smpl_t aubio_freqtomidi(smpl_t freq);
195/** convert midi value (0-128) to frequency (Hz) */
196smpl_t aubio_miditofreq(smpl_t midi);
197
198/** check if current buffer level is under a given threshold */
199uint_t aubio_silence_detection(fvec_t * ibuf, smpl_t threshold);
200/** get the current buffer level */
201smpl_t aubio_level_detection(fvec_t * ibuf, smpl_t threshold);
202/**
203 * calculate normalised autocorrelation function
204 */
205void aubio_autocorr(fvec_t * input, fvec_t * output);
206/**
207 * zero-crossing rate (number of zero cross per sample)
208 */
209smpl_t aubio_zero_crossing_rate(fvec_t * input);
210/**
211 * clean up cached memory at the end of program
212 *
213 * use this function at the end of programs to purge all
214 * cached memory. so far this function is only used to clean
215 * fftw cache.
216 */
217void aubio_cleanup(void);
218
219#ifdef __cplusplus
220}
221#endif
222
223#endif
224
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