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 "mathutils.h"
30 aubio_filterbank_set_triangle_bands (aubio_filterbank_t * fb,
31 fvec_t * freqs, smpl_t samplerate)
34 fmat_t *filters = aubio_filterbank_get_coeffs (fb);
35 uint_t n_filters = filters->height, win_s = filters->length;
37 uint_t fn; /* filter counter */
38 uint_t bin; /* bin counter */
40 /* freqs define the bands of triangular overlapping windows.
41 throw a warning if filterbank object fb is too short. */
42 if (freqs->length - 2 > n_filters) {
43 AUBIO_WRN ("not enough filters, %d allocated but %d requested\n",
44 n_filters, freqs->length - 2);
47 if (freqs->length - 2 < n_filters) {
48 AUBIO_WRN ("too many filters, %d allocated but %d requested\n",
49 n_filters, freqs->length - 2);
52 if (freqs->data[freqs->length - 1] > samplerate / 2) {
53 AUBIO_WRN ("Nyquist frequency is %fHz, but highest frequency band ends at \
54 %fHz\n", samplerate / 2, freqs->data[freqs->length - 1]);
57 /* convenience reference to lower/center/upper frequency for each triangle */
58 fvec_t *lower_freqs = new_fvec (n_filters);
59 fvec_t *upper_freqs = new_fvec (n_filters);
60 fvec_t *center_freqs = new_fvec (n_filters);
62 /* height of each triangle */
63 fvec_t *triangle_heights = new_fvec (n_filters);
65 /* lookup table of each bin frequency in hz */
66 fvec_t *fft_freqs = new_fvec (win_s);
68 /* fill up the lower/center/upper */
69 for (fn = 0; fn < n_filters; fn++) {
70 lower_freqs->data[fn] = freqs->data[fn];
71 center_freqs->data[fn] = freqs->data[fn + 1];
72 upper_freqs->data[fn] = freqs->data[fn + 2];
75 /* compute triangle heights so that each triangle has unit area */
76 for (fn = 0; fn < n_filters; fn++) {
77 triangle_heights->data[fn] =
78 2. / (upper_freqs->data[fn] - lower_freqs->data[fn]);
81 /* fill fft_freqs lookup table, which assigns the frequency in hz to each bin */
82 for (bin = 0; bin < win_s; bin++) {
83 fft_freqs->data[bin] =
84 aubio_bintofreq (bin, samplerate, (win_s - 1) * 2);
87 /* zeroing of all filters */
90 if (fft_freqs->data[1] >= lower_freqs->data[0]) {
91 /* - 1 to make sure we don't miss the smallest power of two */
93 (uint_t) FLOOR (samplerate / lower_freqs->data[0]) - 1;
94 AUBIO_WRN ("Lowest frequency bin (%.2fHz) is higher than lowest frequency \
95 band (%.2f-%.2fHz). Consider increasing the window size from %d to %d.\n",
96 fft_freqs->data[1], lower_freqs->data[0],
97 upper_freqs->data[0], (win_s - 1) * 2,
98 aubio_next_power_of_two (min_win_s));
101 /* building each filter table */
102 for (fn = 0; fn < n_filters; fn++) {
104 /* skip first elements */
105 for (bin = 0; bin < win_s - 1; bin++) {
106 if (fft_freqs->data[bin] <= lower_freqs->data[fn] &&
107 fft_freqs->data[bin + 1] > lower_freqs->data[fn]) {
113 /* compute positive slope step size */
115 triangle_heights->data[fn] /
116 (center_freqs->data[fn] - lower_freqs->data[fn]);
118 /* compute coefficients in positive slope */
119 for (; bin < win_s - 1; bin++) {
120 filters->data[fn][bin] =
121 (fft_freqs->data[bin] - lower_freqs->data[fn]) * riseInc;
123 if (fft_freqs->data[bin + 1] >= center_freqs->data[fn]) {
129 /* compute negative slope step size */
131 triangle_heights->data[fn] /
132 (upper_freqs->data[fn] - center_freqs->data[fn]);
134 /* compute coefficents in negative slope */
135 for (; bin < win_s - 1; bin++) {
136 filters->data[fn][bin] +=
137 (upper_freqs->data[fn] - fft_freqs->data[bin]) * downInc;
139 if (filters->data[fn][bin] < 0.) {
140 filters->data[fn][bin] = 0.;
143 if (fft_freqs->data[bin + 1] >= upper_freqs->data[fn])
146 /* nothing else to do */
150 /* destroy temporarly allocated vectors */
151 del_fvec (lower_freqs);
152 del_fvec (upper_freqs);
153 del_fvec (center_freqs);
155 del_fvec (triangle_heights);
156 del_fvec (fft_freqs);
162 aubio_filterbank_set_mel_coeffs_slaney (aubio_filterbank_t * fb,
167 /* Malcolm Slaney parameters */
168 smpl_t lowestFrequency = 133.3333;
169 smpl_t linearSpacing = 66.66666666;
170 smpl_t logSpacing = 1.0711703;
172 uint_t linearFilters = 13;
173 uint_t logFilters = 27;
174 uint_t n_filters = linearFilters + logFilters;
176 uint_t fn; /* filter counter */
178 /* buffers to compute filter frequencies */
179 fvec_t *freqs = new_fvec (n_filters + 2);
181 /* first step: fill all the linear filter frequencies */
182 for (fn = 0; fn < linearFilters; fn++) {
183 freqs->data[fn] = lowestFrequency + fn * linearSpacing;
185 smpl_t lastlinearCF = freqs->data[fn - 1];
187 /* second step: fill all the log filter frequencies */
188 for (fn = 0; fn < logFilters + 2; fn++) {
189 freqs->data[fn + linearFilters] =
190 lastlinearCF * (POW (logSpacing, fn + 1));
193 /* now compute the actual coefficients */
194 retval = aubio_filterbank_set_triangle_bands (fb, freqs, samplerate);
196 /* destroy vector used to store frequency limits */