source: src/pitch/pitchyin.c @ dddf1f5

/*
   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 "fvec.h"
#include "mathutils.h"
#include "pitch/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 */
smpl_t aubio_pitchyin_getpitchfast(fvec_t * input, fvec_t * yin, smpl_t tol){
  uint_t c=0,j,tau = 0;
  sint_t period;
  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;
    period = tau-3;
    if(tau > 4 && (yin->data[c][period] < tol) && 
        (yin->data[c][period] < yin->data[c][period+1])) {
      return vec_quadint_min(yin,period,1);
    }
  }
  return vec_quadint_min(yin,vec_min_elem(yin),1);
  //return 0;
}