ref: 8a1f9a4f0ab95572bf1eb8f8b7b6de0ba23d077a
dir: /src/beattracking.c/
/*
Copyright (C) 2005 Matthew Davies and 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 "beattracking.h"
uint_t fvec_gettimesig(smpl_t * acf, uint_t acflen, uint_t gp);
void aubio_beattracking_checkstate(aubio_beattracking_t * bt);
smpl_t fvec_getperiod(aubio_beattracking_t * bt);
struct _aubio_beattracking_t {
fvec_t * rwv; /** rayleigh weight vector - rayleigh distribution function */
fvec_t * gwv; /** rayleigh weight vector - rayleigh distribution function */
fvec_t * dfwv; /** detection function weighting - exponential curve */
fvec_t * dfrev; /** reversed onset detection function */
fvec_t * acf; /** vector for autocorrelation function (of current detection function frame) */
fvec_t * acfout; /** store result of passing acf through s.i.c.f.b. */
fvec_t * phwv; /** beat expectation alignment weighting */
fvec_t * phout;
uint_t timesig; /** time signature of input, set to zero until context dependent model activated */
uint_t step;
fvec_t * locacf; /** vector to store harmonics of filterbank of acf */
fvec_t * inds; /** vector for max index outputs for each harmonic */
uint_t rayparam; /** Rayleigh parameter */
uint_t lastbeat;
sint_t counter;
uint_t flagstep;
smpl_t g_var;
uint_t gp;
uint_t bp;
uint_t rp;
uint_t rp1;
uint_t rp2;
};
aubio_beattracking_t * new_aubio_beattracking(uint_t winlen,
uint_t channels) {
aubio_beattracking_t * p = AUBIO_NEW(aubio_beattracking_t);
uint_t i = 0;
/* parameter for rayleigh weight vector - sets preferred tempo to
* 120bpm [43] */
smpl_t rayparam = 48./512. * winlen;
smpl_t dfwvnorm = EXP((LOG(2.0)/rayparam)*(winlen+2));
/** length over which beat period is found [128] */
uint_t laglen = winlen/4;
/** step increment - both in detection function samples -i.e. 11.6ms or
* 1 onset frame [128] */
uint_t step = winlen/4; /* 1.5 seconds */
uint_t maxnumelem = 4; /* max number of index output */
p->lastbeat = 0;
p->counter = 0;
p->flagstep = 0;
p->g_var = 3.901; // constthresh empirically derived!
p->rp = 1;
p->gp = 0;
p->rayparam = rayparam;
p->step = step;
p->rwv = new_fvec(laglen,channels);
p->gwv = new_fvec(laglen,channels);
p->dfwv = new_fvec(winlen,channels);
p->dfrev = new_fvec(winlen,channels);
p->acf = new_fvec(winlen,channels);
p->acfout = new_fvec(laglen,channels);
p->phwv = new_fvec(2*laglen,channels);
p->phout = new_fvec(winlen,channels);
p->timesig = 0;
p->inds = new_fvec(maxnumelem,channels);
p->locacf = new_fvec(winlen,channels);
/* exponential weighting, dfwv = 0.5 when i = 43 */
for (i=0;i<winlen;i++) {
p->dfwv->data[0][i] = (EXP((LOG(2.0)/rayparam)*(i+1)))
/ dfwvnorm;
}
for (i=0;i<(laglen);i++){
p->rwv->data[0][i] = ((smpl_t)(i+1.) / SQR((smpl_t)rayparam)) *
EXP((-SQR((smpl_t)(i+1.)) / (2.*SQR((smpl_t)rayparam))));
}
return p;
}
void del_aubio_beattracking(aubio_beattracking_t * p) {
del_fvec(p->rwv);
del_fvec(p->gwv);
del_fvec(p->dfwv);
del_fvec(p->dfrev);
del_fvec(p->acf);
del_fvec(p->acfout);
del_fvec(p->phwv);
del_fvec(p->phout);
del_fvec(p->locacf);
del_fvec(p->inds);
AUBIO_FREE(p);
}
void aubio_beattracking_do(aubio_beattracking_t * bt, fvec_t * dfframe, fvec_t * output) {
uint_t i,k;
/* current beat period value found using gaussian weighting (from context dependent model) */
uint_t step = bt->step;
uint_t laglen = bt->rwv->length;
uint_t winlen = bt->dfwv->length;
smpl_t * phout = bt->phout->data[0];
smpl_t * phwv = bt->phwv->data[0];
smpl_t * dfrev = bt->dfrev->data[0];
smpl_t * dfwv = bt->dfwv->data[0];
smpl_t * rwv = bt->rwv->data[0];
smpl_t * acfout = bt->acfout->data[0];
smpl_t * acf = bt->acf->data[0];
uint_t maxindex = 0;
//number of harmonics in shift invariant comb filterbank
uint_t numelem = 4;
//smpl_t myperiod = 0.;
//smpl_t * out = output->data[0];
//parameters for making s.i.c.f.b.
uint_t a,b;
//beat alignment
uint_t phase;
uint_t kmax;
sint_t beat;
uint_t bp;
for (i = 0; i < winlen; i++){
dfrev[winlen-1-i] = 0.;
dfrev[winlen-1-i] = dfframe->data[0][i]*dfwv[i];
}
/* find autocorrelation function */
aubio_autocorr(dfframe,bt->acf);
/*
for (i = 0; i < winlen; i++){
AUBIO_DBG("%f,",acf[i]);
}
AUBIO_DBG("\n");
*/
/* get acfout - assume Rayleigh weightvector only */
/* if timesig is unknown, use metrically unbiased version of filterbank */
if(!bt->timesig)
numelem = 4;
// AUBIO_DBG("using unbiased filterbank, timesig: %d\n", timesig);
else
numelem = bt->timesig;
// AUBIO_DBG("using biased filterbank, timesig: %d\n", timesig);
/* first and last output values are left intentionally as zero */
for (i=0; i < bt->acfout->length; i++)
acfout[i] = 0.;
for(i=1;i<laglen-1;i++){
for (a=1; a<=numelem; a++){
for(b=(1-a); b<a; b++){
acfout[i] += acf[a*(i+1)+b-1]
* 1./(2.*a-1.)*rwv[i];
}
}
}
/* find non-zero Rayleigh period */
maxindex = vec_max_elem(bt->acfout);
bt->rp = maxindex ? maxindex : 1;
//rp = (maxindex==127) ? 43 : maxindex; //rayparam
bt->rp = (maxindex==bt->acfout->length-1) ? bt->rayparam : maxindex; //rayparam
// get float period
//myperiod = fvec_getperiod(bt);
//AUBIO_DBG("\nrp = %d myperiod = %f\n",bt->rp,myperiod);
//AUBIO_DBG("accurate tempo is %f bpm\n",5168./myperiod);
/* activate biased filterbank */
aubio_beattracking_checkstate(bt);
bp = bt->bp;
/* end of biased filterbank */
/* initialize output */
for(i=0;i<bt->phout->length;i++) {phout[i] = 0.;}
/* deliberate integer operation, could be set to 3 max eventually */
kmax = winlen/bp;
for(i=0;i<bp;i++){
phout[i] = 0.;
for(k=0;k<kmax;k++){
phout[i] += dfrev[i+bp*k] * phwv[i];
}
}
/* find Rayleigh period */
maxindex = vec_max_elem(bt->phout);
if (maxindex == winlen-1) maxindex = 0;
phase = 1 + maxindex;
/* debug */
//AUBIO_DBG("beat period = %d, rp1 = %d, rp2 = %d\n", bp, rp1, rp2);
//AUBIO_DBG("rp = %d, gp = %d, phase = %d\n", bt->rp, bt->gp, phase);
/* reset output */
for (i = 0; i < laglen; i++)
output->data[0][i] = 0.;
i = 1;
beat = bp - phase;
/* start counting the beats */
if(beat >= 0)
{
output->data[0][i] = (smpl_t)beat;
i++;
}
while( beat+bp < step )
{
beat += bp;
output->data[0][i] = (smpl_t)beat;
i++;
}
bt->lastbeat = beat;
/* store the number of beat found in this frame as the first element */
output->data[0][0] = i;
}
uint_t fvec_gettimesig(smpl_t * acf, uint_t acflen, uint_t gp){
sint_t k = 0;
smpl_t three_energy = 0., four_energy = 0.;
if( acflen > 6 * gp + 2 ){
for(k=-2;k<2;k++){
three_energy += acf[3*gp+k];
four_energy += acf[4*gp+k];
}
}
else{ /*Expanded to be more accurate in time sig estimation*/
for(k=-2;k<2;k++){
three_energy += acf[3*gp+k]+acf[6*gp+k];
four_energy += acf[4*gp+k]+acf[2*gp+k];
}
}
return (three_energy > four_energy) ? 3 : 4;
}
smpl_t fvec_getperiod(aubio_beattracking_t * bt){
/*function to make a more accurate beat period measurement.*/
smpl_t period = 0.;
smpl_t maxval = 0.;
uint_t numelem = 4;
sint_t a,b;
uint_t i,j;
uint_t acfmi = bt->rp; //acfout max index
uint_t maxind = 0;
if(!bt->timesig)
numelem = 4;
else
numelem = bt->timesig;
for (i=0;i<numelem;i++) // initialize
bt->inds->data[0][i] = 0.;
for (i=0;i<bt->locacf->length;i++) // initialize
bt->locacf->data[0][i] = 0.;
// get appropriate acf elements from acf and store in locacf
for (a=1;a<=4;a++){
for(b=(1-a);b<a;b++){
bt->locacf->data[0][a*(acfmi)+b-1] =
bt->acf->data[0][a*(acfmi)+b-1];
}
}
for(i=0;i<numelem;i++){
maxind = 0;
maxval = 0.0;
for (j=0;j<(acfmi*(i+1)+(i)); j++){
if(bt->locacf->data[0][j]>maxval){
maxval = bt->locacf->data[0][j];
maxind = j;
}
//bt->locacf->data[0][maxind] = 0.;
bt->locacf->data[0][j] = 0.;
}
//AUBIO_DBG("\n maxind is %d\n",maxind);
bt->inds->data[0][i] = maxind;
}
for (i=0;i<numelem;i++){
period += bt->inds->data[0][i]/(i+1.);}
period = period/numelem;
return (period);
}
void aubio_beattracking_checkstate(aubio_beattracking_t * bt) {
uint_t i,j,a,b;
uint_t flagconst = 0;
sint_t counter = bt->counter;
uint_t flagstep = bt->flagstep;
uint_t gp = bt->gp;
uint_t bp = bt->bp;
uint_t rp = bt->rp;
uint_t rp1 = bt->rp1;
uint_t rp2 = bt->rp2;
uint_t laglen = bt->rwv->length;
uint_t acflen = bt->acf->length;
uint_t step = bt->step;
smpl_t * acf = bt->acf->data[0];
smpl_t * acfout = bt->acfout->data[0];
smpl_t * gwv = bt->gwv->data[0];
smpl_t * phwv = bt->phwv->data[0];
if (gp) {
// doshiftfbank again only if context dependent model is in operation
//acfout = doshiftfbank(acf,gwv,timesig,laglen,acfout);
//don't need acfout now, so can reuse vector
// gwv is, in first loop, definitely all zeros, but will have
// proper values when context dependent model is activated
for (i=0; i < bt->acfout->length; i++)
acfout[i] = 0.;
for(i=1;i<laglen-1;i++){
for (a=1;a<=bt->timesig;a++){
for(b=(1-a);b<a;b++){
acfout[i] += acf[a*(i+1)+b-1]
* 1. * gwv[i];
}
}
}
gp = vec_max_elem(bt->acfout);
/*
while(gp<32) gp =gp*2;
while(gp>64) gp = gp/2;
*/
} else {
//still only using general model
gp = 0;
}
//now look for step change - i.e. a difference between gp and rp that
// is greater than 2*constthresh - always true in first case, since gp = 0
if(counter == 0){
if(ABS(gp - rp) > 2.*bt->g_var) {
flagstep = 1; // have observed step change.
counter = 3; // setup 3 frame counter
} else {
flagstep = 0;
}
}
//i.e. 3rd frame after flagstep initially set
if (counter==1 && flagstep==1) {
//check for consistency between previous beatperiod values
if(ABS(2.*rp - rp1 -rp2) < bt->g_var) {
//if true, can activate context dependent model
flagconst = 1;
counter = 0; // reset counter and flagstep
} else {
//if not consistent, then don't flag consistency!
flagconst = 0;
counter = 2; // let it look next time
}
} else if (counter > 0) {
//if counter doesn't = 1,
counter = counter-1;
}
rp2 = rp1; rp1 = rp;
if (flagconst) {
/* first run of new hypothesis */
gp = rp;
bt->timesig = fvec_gettimesig(acf,acflen, gp);
for(j=0;j<laglen;j++)
gwv[j] = EXP(-.5*SQR((smpl_t)(j+1.-gp))/SQR(bt->g_var));
flagconst = 0;
bp = gp;
/* flat phase weighting */
for(j=0;j<2*laglen;j++) {phwv[j] = 1.;}
} else if (bt->timesig) {
/* context dependant model */
bp = gp;
/* gaussian phase weighting */
if (step > bt->lastbeat) {
for(j=0;j<2*laglen;j++) {
phwv[j] = EXP(-.5*SQR((smpl_t)(1.+j-step+bt->lastbeat))/(bp/8.));
}
} else {
//AUBIO_DBG("NOT using phase weighting as step is %d and lastbeat %d \n",
// step,bt->lastbeat);
for(j=0;j<2*laglen;j++) {phwv[j] = 1.;}
}
} else {
/* initial state */
bp = rp;
/* flat phase weighting */
for(j=0;j<2*laglen;j++) {phwv[j] = 1.;}
}
/* do some further checks on the final bp value */
/* if tempo is > 206 bpm, half it */
while (bp < 25) {
//AUBIO_DBG("warning, doubling the beat period from %d\n", bp);
//AUBIO_DBG("warning, halving the tempo from %f\n", 60.*samplerate/hopsize/bp);
bp = bp*2;
}
//AUBIO_DBG("tempo:\t%3.5f bpm | ", 5168./bp);
/* smoothing */
//bp = (uint_t) (0.8 * (smpl_t)bp + 0.2 * (smpl_t)bp2);
//AUBIO_DBG("tempo:\t%3.5f bpm smoothed | bp2 %d | bp %d | ", 5168./bp, bp2, bp);
//bp2 = bp;
//AUBIO_DBG("time signature: %d \n", bt->timesig);
bt->counter = counter;
bt->flagstep = flagstep;
bt->gp = gp;
bt->bp = bp;
bt->rp1 = rp1;
bt->rp2 = rp2;
}