2 Copyright (C) 2003 Paul Brossier
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.
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.
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.
21 * various math functions
23 * \todo multichannel (each function should return -or set- an array sized to
24 * the number of channel in the input vector)
26 * \todo appropriate switches depending on types.h content
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/
51 aubio_win_blackman_harris,
58 void aubio_window(smpl_t *w, uint_t size, aubio_window_type wintype);
60 /** principal argument
62 * mod(phase+PI,-TWO_PI)+PI
64 smpl_t aubio_unwrap2pi (smpl_t phase);
66 /** calculates the mean of a vector
70 smpl_t vec_mean(fvec_t *s);
71 /** returns the max of a vector
75 smpl_t vec_max(fvec_t *s);
76 /** returns the min of a vector
80 smpl_t vec_min(fvec_t *s);
81 /** returns the index of the min of a vector
85 uint_t vec_min_elem(fvec_t *s);
86 /** returns the index of the max of a vector
90 uint_t vec_max_elem(fvec_t *s);
91 /** implement 'fftshift' like function
93 * a[0]...,a[n/2],a[n/2+1],...a[n]
97 * a[n/2+1],...a[n],a[0]...,a[n/2]
99 void vec_shift(fvec_t *s);
101 smpl_t vec_sum(fvec_t *s);
106 smpl_t vec_local_energy(fvec_t * f);
107 /** returns High Frequency Energy Content
110 smpl_t vec_local_hfc(fvec_t * f);
111 /** return alpha norm.
113 * alpha=2 means normalise variance.
114 * alpha=1 means normalise abs value.
115 * as alpha goes large, tends to normalisation
118 * \bug should not use POW :(
120 smpl_t vec_alpha_norm(fvec_t * DF, smpl_t alpha);
121 /** dc(min) removal */
122 void vec_dc_removal(fvec_t * mag);
123 /** alpha normalisation */
124 void vec_alpha_normalise(fvec_t * mag, uint_t alpha);
125 /** add a constant to all members of a vector */
126 void vec_add(fvec_t * mag, smpl_t threshold);
128 /** compute adaptive threshold of input vector */
129 void vec_adapt_thres(fvec_t * vec, fvec_t * tmp,
130 uint_t win_post, uint_t win_pre);
131 /** adaptative thresholding
133 * y=fn_thresh(fn,x,post,pre)
134 * compute adaptive threshold at each time
135 * fn : a function name or pointer, eg 'median'
137 * post: window length, causal part
138 * pre: window length, anti-causal part
140 * y: signal the same length as x
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
150 smpl_t vec_moving_thres(fvec_t * vec, fvec_t * tmp,
151 uint_t win_post, uint_t win_pre, uint_t win_pos);
153 /** returns the median of the vector
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
159 * This code by Nicolas Devillard - 1998. Public domain,
160 * available at http://ndevilla.free.fr/median/median/
162 smpl_t vec_median(fvec_t * input);
164 /** finds exact maximum position by quadratic interpolation*/
165 smpl_t vec_quadint(fvec_t * x,uint_t pos);
167 /** finds exact minimum position by quadratic interpolation*/
168 smpl_t vec_quadint_min(fvec_t * x,uint_t pos, uint_t span);
170 /** Quadratic interpolation using Lagrange polynomial.
172 * inspired from ``Comparison of interpolation algorithms in real-time sound
173 * processing'', Vladimir Arnost,
175 * estimate = s0 + (pf/2.)*((pf-3.)*s0-2.*(pf-2.)*s1+(pf-1.)*s2);
177 * \param s0,s1,s2 are 3 known points on the curve,
178 * \param pf is the floating point index [0;2]
180 smpl_t aubio_quadfrac(smpl_t s0, smpl_t s1, smpl_t s2, smpl_t pf);
182 /** returns 1 if X1 is a peak and positive */
183 uint_t vec_peakpick(fvec_t * input, uint_t pos);
185 /** convert frequency bin to midi value */
186 smpl_t aubio_bintomidi(smpl_t bin, smpl_t samplerate, smpl_t fftsize);
187 /** convert midi value to frequency bin */
188 smpl_t aubio_miditobin(smpl_t midi, smpl_t samplerate, smpl_t fftsize);
189 /** convert frequency bin to frequency (Hz) */
190 smpl_t aubio_bintofreq(smpl_t bin, smpl_t samplerate, smpl_t fftsize);
191 /** convert frequency (Hz) to frequency bin */
192 smpl_t aubio_freqtobin(smpl_t freq, smpl_t samplerate, smpl_t fftsize);
193 /** convert frequency (Hz) to midi value (0-128) */
194 smpl_t aubio_freqtomidi(smpl_t freq);
195 /** convert midi value (0-128) to frequency (Hz) */
196 smpl_t aubio_miditofreq(smpl_t midi);
198 /** check if current buffer level is under a given threshold */
199 uint_t aubio_silence_detection(fvec_t * ibuf, smpl_t threshold);
200 /** get the current buffer level */
201 smpl_t aubio_level_detection(fvec_t * ibuf, smpl_t threshold);
203 * calculate normalised autocorrelation function
205 void aubio_autocorr(fvec_t * input, fvec_t * output);
207 * zero-crossing rate (number of zero cross per sample)
209 smpl_t aubio_zero_crossing_rate(fvec_t * input);
211 * spectrum centroid computed on a cvec
213 smpl_t aubio_spectral_centroid(cvec_t * input, smpl_t samplerate);
215 * clean up cached memory at the end of program
217 * use this function at the end of programs to purge all
218 * cached memory. so far this function is only used to clean
221 void aubio_cleanup(void);