source: src/spectral/mfcc.c @ 202ffa5

feature/autosinkfeature/cnnfeature/cnn_orgfeature/constantqfeature/crepefeature/crepe_orgfeature/pitchshiftfeature/pydocstringsfeature/timestretchfix/ffmpeg5pitchshiftsamplertimestretchyinfft+
Last change on this file since 202ffa5 was 202ffa5, checked in by Paul Brossier <piem@piem.org>, 14 years ago

src/spectral/mfcc.c: also loop over channels

  • Property mode set to 100644
File size: 3.2 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 "cvec.h"
25#include "mathutils.h"
26#include "vecutils.h"
27#include "spectral/fft.h"
28#include "spectral/filterbank.h"
29#include "spectral/filterbank_mel.h"
30#include "spectral/mfcc.h"
31
32/** Internal structure for mfcc object */
33
34struct _aubio_mfcc_t
35{
36  uint_t win_s;             /** grain length */
37  uint_t samplerate;        /** sample rate (needed?) */
38  uint_t n_filters;         /** number of  *filters */
39  uint_t n_coefs;           /** number of coefficients (<= n_filters/2 +1) */
40  aubio_filterbank_t *fb;   /** filter bank */
41  fvec_t *in_dct;           /** input buffer for dct * [fb->n_filters] */
42  fvec_t *dct_coeffs;       /** DCT transform n_filters * n_coeffs */
43};
44
45
46aubio_mfcc_t *
47new_aubio_mfcc (uint_t win_s, uint_t samplerate, uint_t n_filters,
48    uint_t n_coefs)
49{
50
51  /* allocate space for mfcc object */
52  aubio_mfcc_t *mfcc = AUBIO_NEW (aubio_mfcc_t);
53
54  uint_t i, j;
55
56  mfcc->win_s = win_s;
57  mfcc->samplerate = samplerate;
58  mfcc->n_filters = n_filters;
59  mfcc->n_coefs = n_coefs;
60
61  /* filterbank allocation */
62  mfcc->fb = new_aubio_filterbank (n_filters, mfcc->win_s);
63  aubio_filterbank_set_mel_coeffs_slaney (mfcc->fb, samplerate);
64
65  /* allocating buffers */
66  mfcc->in_dct = new_fvec (n_filters, 1);
67
68  mfcc->dct_coeffs = new_fvec (n_coefs, n_filters);
69
70  /* compute DCT transform dct_coeffs[i][j] as
71     cos ( j * (i+.5) * PI / n_filters ) */
72  smpl_t scaling = 1. / SQRT (n_filters / 2.);
73  for (i = 0; i < n_filters; i++) {
74    for (j = 0; j < n_coefs; j++) {
75      mfcc->dct_coeffs->data[i][j] =
76          scaling * COS (j * (i + 0.5) * PI / n_filters);
77    }
78    mfcc->dct_coeffs->data[i][0] *= SQRT (2.) / 2.;
79  }
80
81  return mfcc;
82};
83
84void
85del_aubio_mfcc (aubio_mfcc_t * mf)
86{
87
88  /* delete filterbank */
89  del_aubio_filterbank (mf->fb);
90
91  /* delete buffers */
92  del_fvec (mf->in_dct);
93
94  /* delete mfcc object */
95  AUBIO_FREE (mf);
96}
97
98
99void
100aubio_mfcc_do (aubio_mfcc_t * mf, cvec_t * in, fvec_t * out)
101{
102  uint_t i, j, k;
103
104  /* compute filterbank */
105  aubio_filterbank_do (mf->fb, in, mf->in_dct);
106
107  /* compute log10 */
108  fvec_log10 (mf->in_dct);
109
110  /* raise power */
111  //fvec_pow (mf->in_dct, 3.);
112
113  /* zeros output */
114  fvec_zeros(out);
115
116  /* compute discrete cosine transform */
117  for (i = 0; i < out->channels; i++) {
118    for (j = 0; j < mf->n_filters; j++) {
119      for (k = 0; k < mf->n_coefs; k++) {
120        out->data[i][k] += mf->in_dct->data[i][j]
121            * mf->dct_coeffs->data[j][k];
122      }
123    }
124  }
125
126  return;
127}
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