source: src/spectral/mfcc.c @ 3aa60b2

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Last change on this file since 3aa60b2 was 3aa60b2, checked in by Paul Brossier <piem@piem.org>, 19 months ago

src/spectral/mfcc.c: move declaration up

  • Property mode set to 100644
File size: 3.7 KB
Line 
1/*
2  Copyright (C) 2007-2009 Paul Brossier <piem@aubio.org>
3                      and Amaury Hazan <ahazan@iua.upf.edu>
4
5  This file is part of aubio.
6
7  aubio is free software: you can redistribute it and/or modify
8  it under the terms of the GNU General Public License as published by
9  the Free Software Foundation, either version 3 of the License, or
10  (at your option) any later version.
11
12  aubio is distributed in the hope that it will be useful,
13  but WITHOUT ANY WARRANTY; without even the implied warranty of
14  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  GNU General Public License for more details.
16
17  You should have received a copy of the GNU General Public License
18  along with aubio.  If not, see <http://www.gnu.org/licenses/>.
19
20*/
21
22#include "aubio_priv.h"
23#include "fvec.h"
24#include "fmat.h"
25#include "cvec.h"
26#include "mathutils.h"
27#include "vecutils.h"
28#include "spectral/fft.h"
29#include "spectral/filterbank.h"
30#include "spectral/filterbank_mel.h"
31#include "spectral/dct.h"
32#include "spectral/mfcc.h"
33
34#undef HAVE_SLOW_DCT
35
36/** Internal structure for mfcc object */
37
38struct _aubio_mfcc_t
39{
40  uint_t win_s;             /** grain length */
41  uint_t samplerate;        /** sample rate (needed?) */
42  uint_t n_filters;         /** number of filters */
43  uint_t n_coefs;           /** number of coefficients (<= n_filters/2 +1) */
44  aubio_filterbank_t *fb;   /** filter bank */
45  fvec_t *in_dct;           /** input buffer for dct * [fb->n_filters] */
46#if defined(HAVE_SLOW_DCT)
47  fmat_t *dct_coeffs;       /** DCT transform n_filters * n_coeffs */
48#else
49  aubio_dct_t *dct;
50  fvec_t *output;
51#endif
52};
53
54
55aubio_mfcc_t *
56new_aubio_mfcc (uint_t win_s, uint_t n_filters, uint_t n_coefs,
57    uint_t samplerate)
58{
59
60  /* allocate space for mfcc object */
61  aubio_mfcc_t *mfcc = AUBIO_NEW (aubio_mfcc_t);
62#if defined(HAVE_SLOW_DCT)
63  smpl_t scaling;
64
65  uint_t i, j;
66#endif
67
68  mfcc->win_s = win_s;
69  mfcc->samplerate = samplerate;
70  mfcc->n_filters = n_filters;
71  mfcc->n_coefs = n_coefs;
72
73  /* filterbank allocation */
74  mfcc->fb = new_aubio_filterbank (n_filters, mfcc->win_s);
75  aubio_filterbank_set_mel_coeffs_slaney (mfcc->fb, samplerate);
76
77  /* allocating buffers */
78  mfcc->in_dct = new_fvec (n_filters);
79
80#if defined(HAVE_SLOW_DCT)
81  mfcc->dct_coeffs = new_fmat (n_coefs, n_filters);
82
83  /* compute DCT transform dct_coeffs[j][i] as
84     cos ( j * (i+.5) * PI / n_filters ) */
85  scaling = 1. / SQRT (n_filters / 2.);
86  for (i = 0; i < n_filters; i++) {
87    for (j = 0; j < n_coefs; j++) {
88      mfcc->dct_coeffs->data[j][i] =
89          scaling * COS (j * (i + 0.5) * PI / n_filters);
90    }
91    mfcc->dct_coeffs->data[0][i] *= SQRT (2.) / 2.;
92  }
93#else
94  mfcc->dct = new_aubio_dct (n_filters);
95  mfcc->output = new_fvec (n_filters);
96#endif
97
98  return mfcc;
99}
100
101void
102del_aubio_mfcc (aubio_mfcc_t * mf)
103{
104
105  /* delete filterbank */
106  del_aubio_filterbank (mf->fb);
107
108  /* delete buffers */
109  del_fvec (mf->in_dct);
110#if defined(HAVE_SLOW_DCT)
111  del_fmat (mf->dct_coeffs);
112#else
113  del_aubio_dct (mf->dct);
114  del_fvec (mf->output);
115#endif
116
117  /* delete mfcc object */
118  AUBIO_FREE (mf);
119}
120
121
122void
123aubio_mfcc_do (aubio_mfcc_t * mf, const cvec_t * in, fvec_t * out)
124{
125#ifndef HAVE_SLOW_DCT
126  fvec_t tmp;
127#endif
128  /* compute filterbank */
129  aubio_filterbank_do (mf->fb, in, mf->in_dct);
130
131  /* compute log10 */
132  fvec_log10 (mf->in_dct);
133
134  /* raise power */
135  //fvec_pow (mf->in_dct, 3.);
136
137  /* compute mfccs */
138#if defined(HAVE_SLOW_DCT)
139  fmat_vecmul(mf->dct_coeffs, mf->in_dct, out);
140#else
141  aubio_dct_do(mf->dct, mf->in_dct, mf->output);
142  // copy only first n_coeffs elements
143  // TODO assert mf->output->length == n_coeffs
144  tmp.data = mf->output->data;
145  tmp.length = out->length;
146  fvec_copy(&tmp, out);
147#endif
148
149  return;
150}
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