source: src/peakpick.c @ 82c588a

/*
   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.

*/

#include "aubio_priv.h"
#include "sample.h"
#include "mathutils.h"
#include "biquad.h"
#include "peakpick.h"

/* peak picking parameters, default values in brackets
 *
 *         [<----post----|--pre-->]
 *      .................|.............
 *      time->           ^now
 */
struct _aubio_pickpeak_t {
        /** thresh: offset threshold [0.033 or 0.01] */
        smpl_t threshold;       
        /** win_post: median filter window length (causal part) [8] */
        uint_t  win_post;                       
        /** pre: median filter window (anti-causal part) [post-1] */
        uint_t  win_pre;                                
        /** threshfn: name or handle of fn for computing adaptive threshold [median]  */
        aubio_thresholdfn_t thresholdfn;
        /** picker: name or handle of fn for picking event times [peakpick] */
        aubio_pickerfn_t pickerfn;

        /** biquad lowpass filter */
        aubio_biquad_t * biquad;
        /** original onsets */
        fvec_t * onset_keep;
        /** modified onsets */
        fvec_t * onset_proc;
        /** peak picked window [3] */
        fvec_t * onset_peek;
        /** scratch pad for biquad and median */
        fvec_t * scratch;

        /** \bug should be used to calculate filter coefficients */
        /* cutoff: low-pass filter cutoff [0.34, 1] */
        /* smpl_t cutoff; */

        /* not used anymore */
        /* time precision [512/44100  winlength/samplerate, fs/buffer_size */
        /* smpl_t tau; */
        /* alpha: normalisation exponent [9] */
        /* smpl_t alpha; */
};


/** modified version for real time, moving mean adaptive threshold this method
 * is slightly more permissive than the offline one, and yelds to an increase
 * of false positives. best  */
uint_t aubio_peakpick_pimrt(fvec_t * onset,  aubio_pickpeak_t * p) {
        fvec_t * onset_keep = (fvec_t *)p->onset_keep;
        fvec_t * onset_proc = (fvec_t *)p->onset_proc;
        fvec_t * onset_peek = (fvec_t *)p->onset_peek;
        fvec_t * scratch    = (fvec_t *)p->scratch;
        smpl_t mean = 0., median = 0.;
        uint_t length = p->win_post + p->win_pre + 1;
        uint_t i = 0, j;

        /* store onset in onset_keep */
        /* shift all elements but last, then write last */
        /* for (i=0;i<channels;i++) { */
        for (j=0;j<length-1;j++) {
                onset_keep->data[i][j] = onset_keep->data[i][j+1];
                onset_proc->data[i][j] = onset_keep->data[i][j];
        }
        onset_keep->data[i][length-1] = onset->data[i][0];
        onset_proc->data[i][length-1] = onset->data[i][0];
        /* } */

        /* filter onset_proc */
        /** \bug filtfilt calculated post+pre times, should be only once !? */
        aubio_biquad_do_filtfilt(p->biquad,onset_proc,scratch);

        /* calculate mean and median for onset_proc */
        /* for (i=0;i<onset_proc->channels;i++) { */
        mean = vec_mean(onset_proc);
        /* copy to scratch */
        for (j = 0; j < length; j++)
                scratch->data[i][j] = onset_proc->data[i][j];
        median = p->thresholdfn(scratch);
        /* } */

        /* for (i=0;i<onset->channels;i++) { */
        /* shift peek array */
        for (j=0;j<3-1;j++) 
                onset_peek->data[i][j] = onset_peek->data[i][j+1];
        /* calculate new peek value */
        onset_peek->data[i][2] = 
                onset_proc->data[i][p->win_post] - median - mean * p->threshold;
        /* } */
        //AUBIO_DBG("%f\n", onset_peek->data[0][2]);
        return (p->pickerfn)(onset_peek,1);
}

/** this method returns the current value in the pick peaking buffer
 * after smoothing
 */
smpl_t aubio_peakpick_pimrt_getval(aubio_pickpeak_t * p) 
{
        uint_t i = 0;
        return p->onset_peek->data[i][1];
}

/** function added by Miguel Ramirez to return the onset detection amplitude in peakval */
uint_t aubio_peakpick_pimrt_wt(fvec_t * onset,  aubio_pickpeak_t * p, smpl_t* peakval) 
{
        uint_t isonset = 0;
        isonset = aubio_peakpick_pimrt(onset,p);

        //if ( isonset && peakval != NULL )
        if ( peakval != NULL )
                *peakval = aubio_peakpick_pimrt_getval(p); 

        return isonset;
}

void aubio_peakpicker_set_threshold(aubio_pickpeak_t * p, smpl_t threshold) {
        p->threshold = threshold;
        return;
}

smpl_t aubio_peakpicker_get_threshold(aubio_pickpeak_t * p) {
        return p->threshold;
}

void aubio_peakpicker_set_thresholdfn(aubio_pickpeak_t * p, aubio_thresholdfn_t thresholdfn) {
        p->thresholdfn = thresholdfn;
        return;
}

aubio_thresholdfn_t aubio_peakpicker_get_thresholdfn(aubio_pickpeak_t * p) {
        return (aubio_thresholdfn_t) (p->thresholdfn);
}

aubio_pickpeak_t * new_aubio_peakpicker(smpl_t threshold) {
        aubio_pickpeak_t * t = AUBIO_NEW(aubio_pickpeak_t);
        t->threshold = 0.1; /* 0.0668; 0.33; 0.082; 0.033; */
        if (threshold > 0. && threshold < 10.)
                t->threshold = threshold;
        t->win_post  = 5;
        t->win_pre   = 1;

        t->thresholdfn = (aubio_thresholdfn_t)(vec_median); /* (vec_mean); */
        t->pickerfn = (aubio_pickerfn_t)(vec_peakpick);

        t->scratch = new_fvec(t->win_post+t->win_pre+1,1);
        t->onset_keep = new_fvec(t->win_post+t->win_pre+1,1);
        t->onset_proc = new_fvec(t->win_post+t->win_pre+1,1);
        t->onset_peek = new_fvec(3,1);

        /* cutoff: low-pass filter cutoff [0.34, 1] */
        /* t->cutoff=0.34; */
        t->biquad = new_aubio_biquad(0.1600,0.3200,0.1600,-0.5949,0.2348);
        return t;
}

void del_aubio_peakpicker(aubio_pickpeak_t * p) {
        del_aubio_biquad(p->biquad);
        del_fvec(p->onset_keep);
        del_fvec(p->onset_proc);
        del_fvec(p->onset_peek);
        del_fvec(p->scratch);
        AUBIO_FREE(p);
}