ref: 07382d8c0476840e5a86b3807577c988cc52e28a
dir: /src/spectral/mfcc.c/
/*
Copyright (C) 2007-2009 Paul Brossier <piem@aubio.org>
and Amaury Hazan <ahazan@iua.upf.edu>
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 "fmat.h"
#include "cvec.h"
#include "mathutils.h"
#include "vecutils.h"
#include "spectral/fft.h"
#include "spectral/filterbank.h"
#include "spectral/filterbank_mel.h"
#include "spectral/dct.h"
#include "spectral/mfcc.h"
#ifdef HAVE_NOOPT
#define HAVE_SLOW_DCT 1
#endif
/** Internal structure for mfcc object */
struct _aubio_mfcc_t
{
uint_t win_s; /** grain length */
uint_t samplerate; /** sample rate (needed?) */
uint_t n_filters; /** number of filters */
uint_t n_coefs; /** number of coefficients (<= n_filters/2 +1) */
aubio_filterbank_t *fb; /** filter bank */
fvec_t *in_dct; /** input buffer for dct * [fb->n_filters] */
#if defined(HAVE_SLOW_DCT)
fmat_t *dct_coeffs; /** DCT transform n_filters * n_coeffs */
#else
aubio_dct_t *dct;
fvec_t *output;
#endif
};
aubio_mfcc_t *
new_aubio_mfcc (uint_t win_s, uint_t n_filters, uint_t n_coefs,
uint_t samplerate)
{
/* allocate space for mfcc object */
aubio_mfcc_t *mfcc = AUBIO_NEW (aubio_mfcc_t);
#if defined(HAVE_SLOW_DCT)
smpl_t scaling;
uint_t i, j;
#endif
mfcc->win_s = win_s;
mfcc->samplerate = samplerate;
mfcc->n_filters = n_filters;
mfcc->n_coefs = n_coefs;
/* filterbank allocation */
mfcc->fb = new_aubio_filterbank (n_filters, mfcc->win_s);
aubio_filterbank_set_mel_coeffs_slaney (mfcc->fb, samplerate);
/* allocating buffers */
mfcc->in_dct = new_fvec (n_filters);
#if defined(HAVE_SLOW_DCT)
mfcc->dct_coeffs = new_fmat (n_coefs, n_filters);
/* compute DCT transform dct_coeffs[j][i] as
cos ( j * (i+.5) * PI / n_filters ) */
scaling = 1. / SQRT (n_filters / 2.);
for (i = 0; i < n_filters; i++) {
for (j = 0; j < n_coefs; j++) {
mfcc->dct_coeffs->data[j][i] =
scaling * COS (j * (i + 0.5) * PI / n_filters);
}
mfcc->dct_coeffs->data[0][i] *= SQRT (2.) / 2.;
}
#else
mfcc->dct = new_aubio_dct (n_filters);
mfcc->output = new_fvec (n_filters);
#endif
return mfcc;
}
void
del_aubio_mfcc (aubio_mfcc_t * mf)
{
/* delete filterbank */
del_aubio_filterbank (mf->fb);
/* delete buffers */
del_fvec (mf->in_dct);
#if defined(HAVE_SLOW_DCT)
del_fmat (mf->dct_coeffs);
#else
del_aubio_dct (mf->dct);
del_fvec (mf->output);
#endif
/* delete mfcc object */
AUBIO_FREE (mf);
}
void
aubio_mfcc_do (aubio_mfcc_t * mf, const cvec_t * in, fvec_t * out)
{
#ifndef HAVE_SLOW_DCT
fvec_t tmp;
#endif
/* compute filterbank */
aubio_filterbank_do (mf->fb, in, mf->in_dct);
/* compute log10 */
fvec_log10 (mf->in_dct);
/* raise power */
//fvec_pow (mf->in_dct, 3.);
/* compute mfccs */
#if defined(HAVE_SLOW_DCT)
fmat_vecmul(mf->dct_coeffs, mf->in_dct, out);
#else
aubio_dct_do(mf->dct, mf->in_dct, mf->output);
// copy only first n_coeffs elements
// TODO assert mf->output->length == n_coeffs
tmp.data = mf->output->data;
tmp.length = out->length;
fvec_copy(&tmp, out);
#endif
return;
}