source: src/spectral/filterbank.c @ 3b3b03e

feature/autosinkfeature/constantqfeature/pitchshiftfeature/pydocstringsfeature/timestretchpitchshiftsamplertimestretchyinfft+
Last change on this file since 3b3b03e was 3b3b03e, checked in by Paul Brossier <piem@piem.org>, 11 years ago

src/spectral/filterbank.{c,h}: indent

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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 "spectral/filterbank.h"
26#include "mathutils.h"
27
28#define VERY_SMALL_NUMBER 2e-42
29
30/** \brief A structure to store a set of n_filters filters of lenghts win_s */
31struct aubio_filterbank_t_
32{
33  uint_t win_s;
34  uint_t n_filters;
35  fvec_t *filters;
36};
37
38aubio_filterbank_t *
39new_aubio_filterbank (uint_t n_filters, uint_t win_s)
40{
41  /* allocate space for filterbank object */
42  aubio_filterbank_t *fb = AUBIO_NEW (aubio_filterbank_t);
43  fb->win_s = win_s;
44  fb->n_filters = n_filters;
45
46  /* allocate filter tables, an fvec of length win_s and of filter_cnt channel */
47  fb->filters = new_fvec (win_s, n_filters);
48
49  return fb;
50}
51
52void
53del_aubio_filterbank (aubio_filterbank_t * fb)
54{
55  del_fvec (fb->filters);
56  AUBIO_FREE (fb);
57}
58
59void
60aubio_filterbank_do (aubio_filterbank_t * f, cvec_t * in, fvec_t * out)
61{
62  uint_t i, j, fn;
63
64  /* apply filter to all input channel, provided out has enough channels */
65  uint_t max_channels = MIN (in->channels, out->channels);
66  uint_t max_filters = MIN (f->n_filters, out->length);
67
68  /* reset all values in output vector */
69  fvec_zeros (out);
70
71  /* apply filters on all channels */
72  for (i = 0; i < max_channels; i++) {
73
74    /* for each filter */
75    for (fn = 0; fn < max_filters; fn++) {
76
77      /* for each sample */
78      for (j = 0; j < in->length; j++) {
79        out->data[i][fn] += in->norm[i][j] * f->filters->data[fn][j];
80      }
81
82      /* threshold to VERY_SMALL_NUMBER to avoid log oveflow */
83      out->data[i][fn] = MAX (VERY_SMALL_NUMBER, out->data[i][fn]);
84
85      /* compute logarithm */
86      out->data[i][fn] = LOG (out->data[i][fn]);
87    }
88  }
89
90  return;
91}
92
93fvec_t *
94aubio_filterbank_get_coeffs (aubio_filterbank_t * f)
95{
96  return f->filters;
97}
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