ref: fed94339e2b61f175b12cb8e350ec8f4565a3489
dir: /src/mathutils.h/
/*
Copyright (C) 2003 Paul Brossier
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/** @file
* various math functions
*
* \todo multichannel (each function should return -or set- an array sized to
* the number of channel in the input vector)
*
* \todo appropriate switches depending on types.h content
*/
#ifndef MATHUTILS_H
#define MATHUTILS_H
/** Window types
*
* inspired from
*
* - dafx : http://profs.sci.univr.it/%7Edafx/Final-Papers/ps/Bernardini.ps.gz
* - freqtweak : http://freqtweak.sf.net/
* - extace : http://extace.sf.net/
*/
#ifdef __cplusplus
extern "C" {
#endif
typedef enum {
aubio_win_rectangle,
aubio_win_hamming,
aubio_win_hanning,
aubio_win_hanningz,
aubio_win_blackman,
aubio_win_blackman_harris,
aubio_win_gaussian,
aubio_win_welch,
aubio_win_parzen
} aubio_window_type;
/** create window */
void aubio_window(smpl_t *w, uint_t size, aubio_window_type wintype);
/** principal argument
*
* mod(phase+PI,-TWO_PI)+PI
*/
smpl_t aubio_unwrap2pi (smpl_t phase);
/** calculates the mean of a vector
*
* \bug mono
*/
smpl_t vec_mean(fvec_t *s);
/** returns the max of a vector
*
* \bug mono
*/
smpl_t vec_max(fvec_t *s);
/** returns the min of a vector
*
* \bug mono
*/
smpl_t vec_min(fvec_t *s);
/** returns the index of the min of a vector
*
* \bug mono
*/
uint_t vec_min_elem(fvec_t *s);
/** returns the index of the max of a vector
*
* \bug mono
*/
uint_t vec_max_elem(fvec_t *s);
/** implement 'fftshift' like function
*
* a[0]...,a[n/2],a[n/2+1],...a[n]
*
* becomes
*
* a[n/2+1],...a[n],a[0]...,a[n/2]
*/
void vec_shift(fvec_t *s);
/** returns sum */
smpl_t vec_sum(fvec_t *s);
/** returns energy
*
* \bug mono
*/
smpl_t vec_local_energy(fvec_t * f);
/** returns High Frequency Energy Content
*
* \bug mono */
smpl_t vec_local_hfc(fvec_t * f);
/** return alpha norm.
*
* alpha=2 means normalise variance.
* alpha=1 means normalise abs value.
* as alpha goes large, tends to normalisation
* by max value.
*
* \bug should not use POW :(
*/
smpl_t vec_alpha_norm(fvec_t * DF, smpl_t alpha);
/** dc(min) removal */
void vec_dc_removal(fvec_t * mag);
/** alpha normalisation */
void vec_alpha_normalise(fvec_t * mag, uint_t alpha);
/** add a constant to all members of a vector */
void vec_add(fvec_t * mag, smpl_t threshold);
/** compute adaptive threshold of input vector */
void vec_adapt_thres(fvec_t * vec, fvec_t * tmp,
uint_t win_post, uint_t win_pre);
/** adaptative thresholding
*
* y=fn_thresh(fn,x,post,pre)
* compute adaptive threshold at each time
* fn : a function name or pointer, eg 'median'
* x: signal vector
* post: window length, causal part
* pre: window length, anti-causal part
* Returns:
* y: signal the same length as x
*
* Formerly median_thresh, used compute median over a
* window of post+pre+1 samples, but now works with any
* function that takes a vector or matrix and returns a
* 'representative' value for each column, eg
* medians=fn_thresh(median,x,8,8)
* minima=fn_thresh(min,x,8,8)
* see SPARMS for explanation of post and pre
*/
smpl_t vec_moving_thres(fvec_t * vec, fvec_t * tmp,
uint_t win_post, uint_t win_pre, uint_t win_pos);
/** returns the median of the vector
*
* This Quickselect routine is based on the algorithm described in
* "Numerical recipes in C", Second Edition,
* Cambridge University Press, 1992, Section 8.5, ISBN 0-521-43108-5
*
* This code by Nicolas Devillard - 1998. Public domain,
* available at http://ndevilla.free.fr/median/median/
*/
smpl_t vec_median(fvec_t * input);
/** finds exact maximum position by quadratic interpolation*/
smpl_t vec_quadint(fvec_t * x,uint_t pos);
/** finds exact minimum position by quadratic interpolation*/
smpl_t vec_quadint_min(fvec_t * x,uint_t pos, uint_t span);
/** Quadratic interpolation using Lagrange polynomial.
*
* inspired from ``Comparison of interpolation algorithms in real-time sound
* processing'', Vladimir Arnost,
*
* estimate = s0 + (pf/2.)*((pf-3.)*s0-2.*(pf-2.)*s1+(pf-1.)*s2);
* where
* \param s0,s1,s2 are 3 known points on the curve,
* \param pf is the floating point index [0;2]
*/
smpl_t aubio_quadfrac(smpl_t s0, smpl_t s1, smpl_t s2, smpl_t pf);
/** returns 1 if X1 is a peak and positive */
uint_t vec_peakpick(fvec_t * input, uint_t pos);
/** convert frequency bin to midi value */
smpl_t aubio_bintomidi(smpl_t bin, smpl_t samplerate, smpl_t fftsize);
/** convert midi value to frequency bin */
smpl_t aubio_miditobin(smpl_t midi, smpl_t samplerate, smpl_t fftsize);
/** convert frequency bin to frequency (Hz) */
smpl_t aubio_bintofreq(smpl_t bin, smpl_t samplerate, smpl_t fftsize);
/** convert frequency (Hz) to frequency bin */
smpl_t aubio_freqtobin(smpl_t freq, smpl_t samplerate, smpl_t fftsize);
/** convert frequency (Hz) to midi value (0-128) */
smpl_t aubio_freqtomidi(smpl_t freq);
/** convert midi value (0-128) to frequency (Hz) */
smpl_t aubio_miditofreq(smpl_t midi);
/** check if current buffer level is under a given threshold */
uint_t aubio_silence_detection(fvec_t * ibuf, smpl_t threshold);
/** get the current buffer level */
smpl_t aubio_level_detection(fvec_t * ibuf, smpl_t threshold);
/**
* calculate normalised autocorrelation function
*/
void aubio_autocorr(fvec_t * input, fvec_t * output);
/**
* zero-crossing rate (number of zero cross per sample)
*/
smpl_t aubio_zero_crossing_rate(fvec_t * input);
/**
* clean up cached memory at the end of program
*
* use this function at the end of programs to purge all
* cached memory. so far this function is only used to clean
* fftw cache.
*/
void aubio_cleanup(void);
#ifdef __cplusplus
}
#endif
#endif