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-rw-r--r--src/tempo/beattracking.c443
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diff --git a/src/tempo/beattracking.c b/src/tempo/beattracking.c
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+/*
+ Copyright (C) 2005-2009 Matthew Davies and Paul Brossier <piem@aubio.org>
+
+ This file is part of aubio.
+
+ aubio 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 3 of the License, or
+ (at your option) any later version.
+
+ aubio 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 aubio. If not, see <http://www.gnu.org/licenses/>.
+
+*/
+
+#include "aubio_priv.h"
+#include "fvec.h"
+#include "mathutils.h"
+#include "tempo/beattracking.h"
+
+/** define to 1 to print out tracking difficulties */
+#define AUBIO_BEAT_WARNINGS 0
+
+uint_t fvec_gettimesig (fvec_t * acf, uint_t acflen, uint_t gp);
+void aubio_beattracking_checkstate (aubio_beattracking_t * bt);
+
+struct _aubio_beattracking_t
+{
+ uint_t hop_size; /** length of one tempo detection function sample, in audio samples */
+ uint_t samplerate; /** samplerate of the original signal */
+ fvec_t *rwv; /** rayleigh weighting for beat period in general model */
+ fvec_t *dfwv; /** exponential weighting for beat alignment in general model */
+ fvec_t *gwv; /** gaussian weighting for beat period in context dependant model */
+ fvec_t *phwv; /** gaussian weighting for beat alignment in context dependant model */
+ 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 *phout;
+ uint_t timesig; /** time signature of input, set to zero until context dependent model activated */
+ uint_t step;
+ uint_t rayparam; /** Rayleigh parameter */
+ smpl_t lastbeat;
+ sint_t counter;
+ uint_t flagstep;
+ smpl_t g_var;
+ smpl_t gp;
+ smpl_t bp;
+ smpl_t rp;
+ smpl_t rp1;
+ smpl_t rp2;
+};
+
+aubio_beattracking_t *
+new_aubio_beattracking (uint_t winlen, uint_t hop_size, uint_t samplerate)
+{
+
+ aubio_beattracking_t *p = AUBIO_NEW (aubio_beattracking_t);
+ uint_t i = 0;
+ /* default value for rayleigh weighting - sets preferred tempo to 120bpm */
+ smpl_t rayparam = 60. * samplerate / 120. / hop_size;
+ 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 */
+
+ p->hop_size = hop_size;
+ p->samplerate = samplerate;
+ 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);
+ p->gwv = new_fvec (laglen);
+ p->dfwv = new_fvec (winlen);
+ p->dfrev = new_fvec (winlen);
+ p->acf = new_fvec (winlen);
+ p->acfout = new_fvec (laglen);
+ p->phwv = new_fvec (2 * laglen);
+ p->phout = new_fvec (winlen);
+
+ p->timesig = 0;
+
+ /* exponential weighting, dfwv = 0.5 when i = 43 */
+ for (i = 0; i < winlen; i++) {
+ p->dfwv->data[i] = (EXP ((LOG (2.0) / rayparam) * (i + 1)))
+ / dfwvnorm;
+ }
+
+ for (i = 0; i < (laglen); i++) {
+ p->rwv->data[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);
+ AUBIO_FREE (p);
+}
+
+
+void
+aubio_beattracking_do (aubio_beattracking_t * bt, const fvec_t * dfframe,
+ fvec_t * output)
+{
+
+ uint_t i, k;
+ uint_t step = bt->step;
+ uint_t laglen = bt->rwv->length;
+ uint_t winlen = bt->dfwv->length;
+ uint_t maxindex = 0;
+ //number of harmonics in shift invariant comb filterbank
+ uint_t numelem = 4;
+
+ smpl_t phase; // beat alignment (step - lastbeat)
+ smpl_t beat; // beat position
+ smpl_t bp; // beat period
+ uint_t a, b; // used to build shift invariant comb filterbank
+ uint_t kmax; // number of elements used to find beat phase
+
+ /* copy dfframe, apply detection function weighting, and revert */
+ fvec_copy (dfframe, bt->dfrev);
+ fvec_weight (bt->dfrev, bt->dfwv);
+ fvec_rev (bt->dfrev);
+
+ /* compute autocorrelation function */
+ aubio_autocorr (dfframe, bt->acf);
+
+ /* if timesig is unknown, use metrically unbiased version of filterbank */
+ if (!bt->timesig) {
+ numelem = 4;
+ } else {
+ numelem = bt->timesig;
+ }
+
+ /* first and last output values are left intentionally as zero */
+ fvec_zeros (bt->acfout);
+
+ /* compute shift invariant comb filterbank */
+ for (i = 1; i < laglen - 1; i++) {
+ for (a = 1; a <= numelem; a++) {
+ for (b = 1; b < 2 * a; b++) {
+ bt->acfout->data[i] += bt->acf->data[i * a + b - 1]
+ * 1. / (2. * a - 1.);
+ }
+ }
+ }
+ /* apply Rayleigh weight */
+ fvec_weight (bt->acfout, bt->rwv);
+
+ /* find non-zero Rayleigh period */
+ maxindex = fvec_max_elem (bt->acfout);
+ if (maxindex > 0 && maxindex < bt->acfout->length - 1) {
+ bt->rp = fvec_quadratic_peak_pos (bt->acfout, maxindex);
+ } else {
+ bt->rp = bt->rayparam;
+ }
+
+ /* activate biased filterbank */
+ aubio_beattracking_checkstate (bt);
+#if 0 // debug metronome mode
+ bt->bp = 36.9142;
+#endif
+ bp = bt->bp;
+ /* end of biased filterbank */
+
+ if (bp == 0) {
+ fvec_zeros(output);
+ return;
+ }
+
+ /* deliberate integer operation, could be set to 3 max eventually */
+ kmax = FLOOR (winlen / bp);
+
+ /* initialize output */
+ fvec_zeros (bt->phout);
+ for (i = 0; i < bp; i++) {
+ for (k = 0; k < kmax; k++) {
+ bt->phout->data[i] += bt->dfrev->data[i + (uint_t) ROUND (bp * k)];
+ }
+ }
+ fvec_weight (bt->phout, bt->phwv);
+
+ /* find Rayleigh period */
+ maxindex = fvec_max_elem (bt->phout);
+ if (maxindex >= winlen - 1) {
+#if AUBIO_BEAT_WARNINGS
+ AUBIO_WRN ("no idea what this groove's phase is\n");
+#endif /* AUBIO_BEAT_WARNINGS */
+ phase = step - bt->lastbeat;
+ } else {
+ phase = fvec_quadratic_peak_pos (bt->phout, maxindex);
+ }
+ /* take back one frame delay */
+ phase += 1.;
+#if 0 // debug metronome mode
+ phase = step - bt->lastbeat;
+#endif
+
+ /* reset output */
+ fvec_zeros (output);
+
+ i = 1;
+ beat = bp - phase;
+
+ // AUBIO_DBG ("bp: %f, phase: %f, lastbeat: %f, step: %d, winlen: %d\n",
+ // bp, phase, bt->lastbeat, step, winlen);
+
+ /* the next beat will be earlier than 60% of the tempo period
+ skip this one */
+ if ( ( step - bt->lastbeat - phase ) < -0.40 * bp ) {
+#if AUBIO_BEAT_WARNINGS
+ AUBIO_WRN ("back off-beat error, skipping this beat\n");
+#endif /* AUBIO_BEAT_WARNINGS */
+ beat += bp;
+ }
+
+ /* start counting the beats */
+ while (beat + bp < 0) {
+ beat += bp;
+ }
+
+ if (beat >= 0) {
+ //AUBIO_DBG ("beat: %d, %f, %f\n", i, bp, beat);
+ output->data[i] = beat;
+ i++;
+ }
+
+ while (beat + bp <= step) {
+ beat += bp;
+ //AUBIO_DBG ("beat: %d, %f, %f\n", i, bp, beat);
+ output->data[i] = beat;
+ i++;
+ }
+
+ bt->lastbeat = beat;
+ /* store the number of beats in this frame as the first element */
+ output->data[0] = i;
+}
+
+uint_t
+fvec_gettimesig (fvec_t * acf, uint_t acflen, uint_t gp)
+{
+ sint_t k = 0;
+ smpl_t three_energy = 0., four_energy = 0.;
+ if (gp < 2) return 4;
+ if (acflen > 6 * gp + 2) {
+ for (k = -2; k < 2; k++) {
+ three_energy += acf->data[3 * gp + k];
+ four_energy += acf->data[4 * gp + k];
+ }
+ } else {
+ /*Expanded to be more accurate in time sig estimation */
+ for (k = -2; k < 2; k++) {
+ three_energy += acf->data[3 * gp + k] + acf->data[6 * gp + k];
+ four_energy += acf->data[4 * gp + k] + acf->data[2 * gp + k];
+ }
+ }
+ return (three_energy > four_energy) ? 3 : 4;
+}
+
+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;
+ smpl_t gp = bt->gp;
+ smpl_t bp = bt->bp;
+ smpl_t rp = bt->rp;
+ smpl_t rp1 = bt->rp1;
+ smpl_t rp2 = bt->rp2;
+ uint_t laglen = bt->rwv->length;
+ uint_t acflen = bt->acf->length;
+ uint_t step = bt->step;
+ fvec_t *acf = bt->acf;
+ fvec_t *acfout = bt->acfout;
+
+ if (gp) {
+ // compute shift invariant comb filterbank
+ fvec_zeros (acfout);
+ for (i = 1; i < laglen - 1; i++) {
+ for (a = 1; a <= bt->timesig; a++) {
+ for (b = 1; b < 2 * a; b++) {
+ acfout->data[i] += acf->data[i * a + b - 1];
+ }
+ }
+ }
+ // since gp is set, gwv has been computed in previous checkstate
+ fvec_weight (acfout, bt->gwv);
+ gp = fvec_quadratic_peak_pos (acfout, fvec_max_elem (acfout));
+ } 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++)
+ bt->gwv->data[j] =
+ EXP (-.5 * SQR ((smpl_t) (j + 1. - gp)) / SQR (bt->g_var));
+ flagconst = 0;
+ bp = gp;
+ /* flat phase weighting */
+ fvec_ones (bt->phwv);
+ } else if (bt->timesig) {
+ /* context dependant model */
+ bp = gp;
+ /* gaussian phase weighting */
+ if (step > bt->lastbeat) {
+ for (j = 0; j < 2 * laglen; j++) {
+ bt->phwv->data[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);
+ fvec_ones (bt->phwv);
+ }
+ } else {
+ /* initial state */
+ bp = rp;
+ /* flat phase weighting */
+ fvec_ones (bt->phwv);
+ }
+
+ /* do some further checks on the final bp value */
+
+ /* if tempo is > 206 bpm, half it */
+ while (0 < bp && bp < 25) {
+#if AUBIO_BEAT_WARNINGS
+ AUBIO_WRN ("doubling from %f (%f bpm) to %f (%f bpm)\n",
+ bp, 60.*44100./512./bp, bp/2., 60.*44100./512./bp/2. );
+ //AUBIO_DBG("warning, halving the tempo from %f\n", 60.*samplerate/hopsize/bp);
+#endif /* AUBIO_BEAT_WARNINGS */
+ 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;
+}
+
+smpl_t
+aubio_beattracking_get_period (const aubio_beattracking_t * bt)
+{
+ return bt->hop_size * bt->bp;
+}
+
+smpl_t
+aubio_beattracking_get_period_s (const aubio_beattracking_t * bt)
+{
+ return aubio_beattracking_get_period(bt) / (smpl_t) bt->samplerate;
+}
+
+smpl_t
+aubio_beattracking_get_bpm (const aubio_beattracking_t * bt)
+{
+ if (bt->bp != 0) {
+ return 60. / aubio_beattracking_get_period_s(bt);
+ } else {
+ return 0.;
+ }
+}
+
+smpl_t
+aubio_beattracking_get_confidence (const aubio_beattracking_t * bt)
+{
+ if (bt->gp) {
+ smpl_t acf_sum = fvec_sum(bt->acfout);
+ if (acf_sum != 0.) {
+ return fvec_quadratic_peak_mag (bt->acfout, bt->gp) / acf_sum;
+ }
+ }
+ return 0.;
+}
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