source: src/mathutils.h @ c0b295c

feature/autosinkfeature/constantqfeature/pitchshiftfeature/pydocstringsfeature/timestretchpitchshiftsamplertimestretchyinfft+
Last change on this file since c0b295c was c0b295c, checked in by Paul Brossier <piem@piem.org>, 10 years ago

src/mathutils.c: rename fvec_dc_removal to fvec_min_removal

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File size: 6.1 KB
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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 math functions
23 *
24 *  \todo multichannel (each function should return -or set- an array sized to
25 *  the number of channel in the input vector)
26 *
27 *  \todo appropriate switches depending on types.h content
28 */
29
30#ifndef MATHUTILS_H
31#define MATHUTILS_H
32
33#ifdef __cplusplus
34extern "C" {
35#endif
36
37/** Window types
38 *
39 * inspired from
40 *
41 *  - dafx : http://profs.sci.univr.it/%7Edafx/Final-Papers/ps/Bernardini.ps.gz
42 *  - freqtweak : http://freqtweak.sf.net/
43 *  - extace : http://extace.sf.net/
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 */
58fvec_t * new_aubio_window(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 fvec_mean(fvec_t *s);
71/** returns the max of a vector
72 *
73 * \bug mono
74 */
75smpl_t fvec_max(fvec_t *s);
76/** returns the min of a vector
77 *
78 * \bug mono
79 */
80smpl_t fvec_min(fvec_t *s);
81/** returns the index of the min of a vector
82 *
83 * \bug mono
84 */
85uint_t fvec_min_elem(fvec_t *s);
86/** returns the index of the max of a vector
87 *
88 * \bug mono
89 */
90uint_t fvec_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 fvec_shift(fvec_t *s);
100/** returns sum */
101smpl_t fvec_sum(fvec_t *s);
102
103/** returns energy
104 *
105 * \bug mono
106 */
107smpl_t fvec_local_energy(fvec_t * f);
108/** returns High Frequency Energy Content
109 *
110 * \bug mono */
111smpl_t fvec_local_hfc(fvec_t * f);
112/** return alpha norm.
113 *
114 * alpha=2 means normalise variance.
115 * alpha=1 means normalise abs value.
116 * as alpha goes large, tends to normalisation
117 * by max value.
118 *
119 * \bug should not use POW :(
120 */
121smpl_t fvec_alpha_norm(fvec_t * DF, smpl_t alpha);
122/**  min removal */
123void fvec_min_removal(fvec_t * mag);
124/**  alpha normalisation */
125void fvec_alpha_normalise(fvec_t * mag, uint_t alpha);
126/** add a constant to all members of a vector */
127void fvec_add(fvec_t * mag, smpl_t threshold);
128
129/** compute adaptive threshold of input vector */ 
130void fvec_adapt_thres(fvec_t * vec, fvec_t * tmp, 
131    uint_t win_post, uint_t win_pre);
132/**  adaptative thresholding
133 *
134 * y=fn_thresh(fn,x,post,pre)
135 * compute adaptive threshold at each time
136 *    fn : a function name or pointer, eg 'median'
137 *    x:   signal vector
138 *    post: window length, causal part
139 *    pre: window length, anti-causal part
140 * Returns:
141 *    y:   signal the same length as x
142 *
143 * Formerly median_thresh, used compute median over a
144 * window of post+pre+1 samples, but now works with any
145 * function that takes a vector or matrix and returns a
146 * 'representative' value for each column, eg
147 *    medians=fn_thresh(median,x,8,8) 
148 *    minima=fn_thresh(min,x,8,8) 
149 * see SPARMS for explanation of post and pre
150 */
151smpl_t fvec_moving_thres(fvec_t * vec, fvec_t * tmp, 
152    uint_t win_post, uint_t win_pre, uint_t win_pos);
153
154/** returns the median of the vector
155 *
156 *  This Quickselect routine is based on the algorithm described in
157 *  "Numerical recipes in C", Second Edition,
158 *  Cambridge University Press, 1992, Section 8.5, ISBN 0-521-43108-5
159 *
160 *  This code by Nicolas Devillard - 1998. Public domain,
161 *  available at http://ndevilla.free.fr/median/median/
162 */
163smpl_t fvec_median(fvec_t * input);
164
165/** finds exact peak index by quadratic interpolation*/
166smpl_t fvec_quadint(fvec_t * x, uint_t pos, uint_t span);
167
168/** Quadratic interpolation using Lagrange polynomial.
169 *
170 * inspired from ``Comparison of interpolation algorithms in real-time sound
171 * processing'', Vladimir Arnost,
172 *
173 * estimate = s0 + (pf/2.)*((pf-3.)*s0-2.*(pf-2.)*s1+(pf-1.)*s2);
174 *    where
175 *    \param s0,s1,s2 are 3 known points on the curve,
176 *    \param pf is the floating point index [0;2]
177 */
178smpl_t aubio_quadfrac(smpl_t s0, smpl_t s1, smpl_t s2, smpl_t pf);
179
180/** returns 1 if X1 is a peak and positive */
181uint_t fvec_peakpick(fvec_t * input, uint_t pos);
182
183/** convert frequency bin to midi value */
184smpl_t aubio_bintomidi(smpl_t bin, smpl_t samplerate, smpl_t fftsize);
185/** convert midi value to frequency bin */
186smpl_t aubio_miditobin(smpl_t midi, smpl_t samplerate, smpl_t fftsize);
187/** convert frequency bin to frequency (Hz) */
188smpl_t aubio_bintofreq(smpl_t bin, smpl_t samplerate, smpl_t fftsize);
189/** convert frequency (Hz) to frequency bin */
190smpl_t aubio_freqtobin(smpl_t freq, smpl_t samplerate, smpl_t fftsize);
191/** convert frequency (Hz) to midi value (0-128) */
192smpl_t aubio_freqtomidi(smpl_t freq);
193/** convert midi value (0-128) to frequency (Hz) */
194smpl_t aubio_miditofreq(smpl_t midi);
195
196/** check if current buffer level is under a given threshold */
197uint_t aubio_silence_detection(fvec_t * ibuf, smpl_t threshold);
198/** get the current buffer level */
199smpl_t aubio_level_detection(fvec_t * ibuf, smpl_t threshold);
200/**
201 * calculate normalised autocorrelation function
202 */
203void aubio_autocorr(fvec_t * input, fvec_t * output);
204/**
205 * zero-crossing rate (number of zero cross per sample)
206 */
207smpl_t aubio_zero_crossing_rate(fvec_t * input);
208/**
209 * clean up cached memory at the end of program
210 *
211 * use this function at the end of programs to purge all
212 * cached memory. so far this function is only used to clean
213 * fftw cache.
214 */
215void aubio_cleanup(void);
216
217#ifdef __cplusplus
218}
219#endif
220
221#endif
222
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