source: src/pitchyin.c @ c29dae2

/*
   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.
*/

/* This algorithm was developped by A. de Cheveigne and H. Kawahara and
 * published in:
 * 
 * de Cheveigné, A., Kawahara, H. (2002) "YIN, a fundamental frequency
 * estimator for speech and music", J. Acoust. Soc. Am. 111, 1917-1930.  
 *
 * see http://recherche.ircam.fr/equipes/pcm/pub/people/cheveign.html
 */

#include "aubio_priv.h"
#include "sample.h"
#include "mathutils.h"
#include "pitchyin.h"

/* outputs the difference function */
void aubio_pitchyin_diff(fvec_t * input, fvec_t * yin){
        uint_t c,j,tau;
        smpl_t tmp;
        for (c=0;c<input->channels;c++)
        {
                for (tau=0;tau<yin->length;tau++)
                {
                        yin->data[c][tau] = 0.;
                }
                for (tau=1;tau<yin->length;tau++)
                {
                        for (j=0;j<yin->length;j++)
                        {
                                tmp = input->data[c][j] - input->data[c][j+tau];
                                yin->data[c][tau] += SQR(tmp);
                        }
                }
        }
}

/* cumulative mean normalized difference function */
void aubio_pitchyin_getcum(fvec_t * yin) {
        uint_t c,tau;
        smpl_t tmp;
        for (c=0;c<yin->channels;c++)
        {
                tmp = 0.;
                yin->data[c][0] = 1.;
                //AUBIO_DBG("%f\t",yin->data[c][0]);
                for (tau=1;tau<yin->length;tau++)
                {
                        tmp += yin->data[c][tau];
                        yin->data[c][tau] *= tau/tmp;
                        //AUBIO_DBG("%f\t",yin->data[c][tau]);
                }
                //AUBIO_DBG("\n");
        }
}

uint_t aubio_pitchyin_getpitch(fvec_t * yin) {
        uint_t c=0,tau=1;
        do 
        {
                if(yin->data[c][tau] < 0.1) { 
                        while (yin->data[c][tau+1] < yin->data[c][tau]) {
                                tau++;
                        }
                        return tau;
                }
                tau++;
        } while (tau<yin->length);
        //AUBIO_DBG("No pitch found");
        return 0;
}


/* all the above in one */
uint_t aubio_pitchyin_getpitchfast(fvec_t * input, fvec_t * yin, smpl_t tol){
        uint_t c=0,j,tau = 0;
        smpl_t tmp = 0., tmp2 = 0.;
        yin->data[c][0] = 1.;
        for (tau=1;tau<yin->length;tau++)
        {
                yin->data[c][tau] = 0.;
                for (j=0;j<yin->length;j++)
                {
                        tmp = input->data[c][j] - input->data[c][j+tau];
                        yin->data[c][tau] += SQR(tmp);
                }
                tmp2 += yin->data[c][tau];
                yin->data[c][tau] *= tau/tmp2;
                if((yin->data[c][tau] < tol) && 
                                (yin->data[c][tau-1] < yin->data[c][tau])) {
                        return tau-1;
                }
        }
        return 0;
}