2 Copyright (C) 2007-2009 Paul Brossier <piem@aubio.org>
3 and Amaury Hazan <ahazan@iua.upf.edu>
5 This file is part of aubio.
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.
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.
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/>.
22 #include "aubio_priv.h"
26 #include "spectral/filterbank.h"
27 #include "spectral/filterbank_mel.h"
28 #include "mathutils.h"
31 aubio_filterbank_set_triangle_bands (aubio_filterbank_t * fb,
32 const fvec_t * freqs, smpl_t samplerate)
35 fmat_t *filters = aubio_filterbank_get_coeffs (fb);
36 uint_t n_filters = filters->height, win_s = filters->length;
37 fvec_t *lower_freqs, *upper_freqs, *center_freqs;
38 fvec_t *triangle_heights, *fft_freqs;
40 uint_t fn; /* filter counter */
41 uint_t bin; /* bin counter */
43 smpl_t riseInc, downInc;
45 /* freqs define the bands of triangular overlapping windows.
46 throw a warning if filterbank object fb is too short. */
47 if (freqs->length - 2 > n_filters) {
48 AUBIO_WRN ("not enough filters, %d allocated but %d requested\n",
49 n_filters, freqs->length - 2);
52 if (freqs->length - 2 < n_filters) {
53 AUBIO_WRN ("too many filters, %d allocated but %d requested\n",
54 n_filters, freqs->length - 2);
57 for (fn = 0; fn < freqs->length; fn++) {
58 if (freqs->data[fn] < 0) {
59 AUBIO_ERR("filterbank_mel: freqs must contain only positive values.\n");
61 } else if (freqs->data[fn] > samplerate / 2) {
62 AUBIO_WRN("filterbank_mel: freqs should contain only "
63 "values < samplerate / 2.\n");
64 } else if (fn > 0 && freqs->data[fn] < freqs->data[fn-1]) {
65 AUBIO_ERR("filterbank_mel: freqs should be a list of frequencies "
66 "sorted from low to high, but freq[%d] < freq[%d-1]\n", fn, fn);
68 } else if (fn > 0 && freqs->data[fn] == freqs->data[fn-1]) {
69 AUBIO_WRN("filterbank_mel: set_triangle_bands received a list "
70 "with twice the frequency %f\n", freqs->data[fn]);
74 /* convenience reference to lower/center/upper frequency for each triangle */
75 lower_freqs = new_fvec (n_filters);
76 upper_freqs = new_fvec (n_filters);
77 center_freqs = new_fvec (n_filters);
79 /* height of each triangle */
80 triangle_heights = new_fvec (n_filters);
82 /* lookup table of each bin frequency in hz */
83 fft_freqs = new_fvec (win_s);
85 /* fill up the lower/center/upper */
86 for (fn = 0; fn < n_filters; fn++) {
87 lower_freqs->data[fn] = freqs->data[fn];
88 center_freqs->data[fn] = freqs->data[fn + 1];
89 upper_freqs->data[fn] = freqs->data[fn + 2];
92 /* compute triangle heights so that each triangle has unit area */
93 for (fn = 0; fn < n_filters; fn++) {
94 triangle_heights->data[fn] =
95 2. / (upper_freqs->data[fn] - lower_freqs->data[fn]);
98 /* fill fft_freqs lookup table, which assigns the frequency in hz to each bin */
99 for (bin = 0; bin < win_s; bin++) {
100 fft_freqs->data[bin] =
101 aubio_bintofreq (bin, samplerate, (win_s - 1) * 2);
104 /* zeroing of all filters */
105 fmat_zeros (filters);
107 /* building each filter table */
108 for (fn = 0; fn < n_filters; fn++) {
110 /* skip first elements */
111 for (bin = 0; bin < win_s - 1; bin++) {
112 if (fft_freqs->data[bin] <= lower_freqs->data[fn] &&
113 fft_freqs->data[bin + 1] > lower_freqs->data[fn]) {
119 /* compute positive slope step size */
121 triangle_heights->data[fn] /
122 (center_freqs->data[fn] - lower_freqs->data[fn]);
124 /* compute coefficients in positive slope */
125 for (; bin < win_s - 1; bin++) {
126 filters->data[fn][bin] =
127 (fft_freqs->data[bin] - lower_freqs->data[fn]) * riseInc;
129 if (fft_freqs->data[bin + 1] >= center_freqs->data[fn]) {
135 /* compute negative slope step size */
137 triangle_heights->data[fn] /
138 (upper_freqs->data[fn] - center_freqs->data[fn]);
140 /* compute coefficents in negative slope */
141 for (; bin < win_s - 1; bin++) {
142 filters->data[fn][bin] +=
143 (upper_freqs->data[fn] - fft_freqs->data[bin]) * downInc;
145 if (filters->data[fn][bin] < 0.) {
146 filters->data[fn][bin] = 0.;
149 if (fft_freqs->data[bin + 1] >= upper_freqs->data[fn])
152 /* nothing else to do */
156 /* destroy temporarly allocated vectors */
157 del_fvec (lower_freqs);
158 del_fvec (upper_freqs);
159 del_fvec (center_freqs);
161 del_fvec (triangle_heights);
162 del_fvec (fft_freqs);
168 aubio_filterbank_set_mel_coeffs_slaney (aubio_filterbank_t * fb,
173 /* Malcolm Slaney parameters */
174 smpl_t lowestFrequency = 133.3333;
175 smpl_t linearSpacing = 66.66666666;
176 smpl_t logSpacing = 1.0711703;
178 uint_t linearFilters = 13;
179 uint_t logFilters = 27;
180 uint_t n_filters = linearFilters + logFilters;
182 uint_t fn; /* filter counter */
186 /* buffers to compute filter frequencies */
187 fvec_t *freqs = new_fvec (n_filters + 2);
189 /* first step: fill all the linear filter frequencies */
190 for (fn = 0; fn < linearFilters; fn++) {
191 freqs->data[fn] = lowestFrequency + fn * linearSpacing;
193 lastlinearCF = freqs->data[fn - 1];
195 /* second step: fill all the log filter frequencies */
196 for (fn = 0; fn < logFilters + 2; fn++) {
197 freqs->data[fn + linearFilters] =
198 lastlinearCF * (POW (logSpacing, fn + 1));
201 /* now compute the actual coefficients */
202 retval = aubio_filterbank_set_triangle_bands (fb, freqs, samplerate);
204 /* destroy vector used to store frequency limits */