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 if (aubio_filterbank_get_norm(fb)) {
94 for (fn = 0; fn < n_filters; fn++) {
95 triangle_heights->data[fn] =
96 2. / (upper_freqs->data[fn] - lower_freqs->data[fn]);
99 fvec_ones (triangle_heights);
102 /* fill fft_freqs lookup table, which assigns the frequency in hz to each bin */
103 for (bin = 0; bin < win_s; bin++) {
104 fft_freqs->data[bin] =
105 aubio_bintofreq (bin, samplerate, (win_s - 1) * 2);
108 /* zeroing of all filters */
109 fmat_zeros (filters);
111 /* building each filter table */
112 for (fn = 0; fn < n_filters; fn++) {
114 /* skip first elements */
115 for (bin = 0; bin < win_s - 1; bin++) {
116 if (fft_freqs->data[bin] <= lower_freqs->data[fn] &&
117 fft_freqs->data[bin + 1] > lower_freqs->data[fn]) {
123 /* compute positive slope step size */
124 riseInc = triangle_heights->data[fn]
125 / (center_freqs->data[fn] - lower_freqs->data[fn]);
127 /* compute coefficients in positive slope */
128 for (; bin < win_s - 1; bin++) {
129 filters->data[fn][bin] =
130 (fft_freqs->data[bin] - lower_freqs->data[fn]) * riseInc;
132 if (fft_freqs->data[bin + 1] >= center_freqs->data[fn]) {
138 /* compute negative slope step size */
139 downInc = triangle_heights->data[fn]
140 / (upper_freqs->data[fn] - center_freqs->data[fn]);
142 /* compute coefficents in negative slope */
143 for (; bin < win_s - 1; bin++) {
144 filters->data[fn][bin] +=
145 (upper_freqs->data[fn] - fft_freqs->data[bin]) * downInc;
147 if (filters->data[fn][bin] < 0.) {
148 filters->data[fn][bin] = 0.;
151 if (fft_freqs->data[bin + 1] >= upper_freqs->data[fn])
154 /* nothing else to do */
158 /* destroy temporarly allocated vectors */
159 del_fvec (lower_freqs);
160 del_fvec (upper_freqs);
161 del_fvec (center_freqs);
163 del_fvec (triangle_heights);
164 del_fvec (fft_freqs);
170 aubio_filterbank_set_mel_coeffs_slaney (aubio_filterbank_t * fb,
175 if (samplerate <= 0) {
176 AUBIO_ERR("filterbank: set_mel_coeffs_slaney samplerate should be > 0\n");
180 /* Malcolm Slaney parameters */
181 smpl_t lowestFrequency = 133.3333;
182 smpl_t linearSpacing = 66.66666666;
183 smpl_t logSpacing = 1.0711703;
185 uint_t linearFilters = 13;
186 uint_t logFilters = 27;
187 uint_t n_filters = linearFilters + logFilters;
189 uint_t fn; /* filter counter */
193 /* buffers to compute filter frequencies */
194 fvec_t *freqs = new_fvec (n_filters + 2);
196 /* first step: fill all the linear filter frequencies */
197 for (fn = 0; fn < linearFilters; fn++) {
198 freqs->data[fn] = lowestFrequency + fn * linearSpacing;
200 lastlinearCF = freqs->data[fn - 1];
202 /* second step: fill all the log filter frequencies */
203 for (fn = 0; fn < logFilters + 2; fn++) {
204 freqs->data[fn + linearFilters] =
205 lastlinearCF * (POW (logSpacing, fn + 1));
208 /* now compute the actual coefficients */
209 retval = aubio_filterbank_set_triangle_bands (fb, freqs, samplerate);
211 /* destroy vector used to store frequency limits */
217 static uint_t aubio_filterbank_check_freqs (aubio_filterbank_t *fb UNUSED,
218 smpl_t samplerate, smpl_t *freq_min, smpl_t *freq_max)
220 if (samplerate <= 0) {
221 AUBIO_ERR("filterbank: set_mel_coeffs samplerate should be > 0\n");
225 AUBIO_ERR("filterbank: set_mel_coeffs freq_max should be > 0\n");
227 } else if (*freq_max == 0) {
228 *freq_max = samplerate / 2.;
231 AUBIO_ERR("filterbank: set_mel_coeffs freq_min should be > 0\n");
238 aubio_filterbank_set_mel_coeffs (aubio_filterbank_t * fb, smpl_t samplerate,
239 smpl_t freq_min, smpl_t freq_max)
242 smpl_t start = freq_min, end = freq_max, step;
244 fmat_t *coeffs = aubio_filterbank_get_coeffs(fb);
245 uint_t n_bands = coeffs->height;
247 if (aubio_filterbank_check_freqs(fb, samplerate, &start, &end)) {
251 start = aubio_hztomel(start);
252 end = aubio_hztomel(end);
254 freqs = new_fvec(n_bands + 2);
255 step = (end - start) / (n_bands + 1);
257 for (m = 0; m < n_bands + 2; m++)
259 freqs->data[m] = MIN(aubio_meltohz(start + step * m), samplerate/2.);
262 retval = aubio_filterbank_set_triangle_bands (fb, freqs, samplerate);
264 /* destroy vector used to store frequency limits */
270 aubio_filterbank_set_mel_coeffs_htk (aubio_filterbank_t * fb, smpl_t samplerate,
271 smpl_t freq_min, smpl_t freq_max)
274 smpl_t start = freq_min, end = freq_max, step;
276 fmat_t *coeffs = aubio_filterbank_get_coeffs(fb);
277 uint_t n_bands = coeffs->height;
279 if (aubio_filterbank_check_freqs(fb, samplerate, &start, &end)) {
283 start = aubio_hztomel_htk(start);
284 end = aubio_hztomel_htk(end);
286 freqs = new_fvec (n_bands + 2);
287 step = (end - start) / (n_bands + 1);
289 for (m = 0; m < n_bands + 2; m++)
291 freqs->data[m] = MIN(aubio_meltohz_htk(start + step * m), samplerate/2.);
294 retval = aubio_filterbank_set_triangle_bands (fb, freqs, samplerate);
296 /* destroy vector used to store frequency limits */