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 "fmat.h"
24 #include "fvec.h"
25 #include "cvec.h"
26 #include "spectral/filterbank.h"
27 #include "spectral/filterbank_mel.h"
28 #include "mathutils.h"
29
30 uint_t
aubio_filterbank_set_triangle_bands(aubio_filterbank_t * fb,const fvec_t * freqs,smpl_t samplerate)31 aubio_filterbank_set_triangle_bands (aubio_filterbank_t * fb,
32 const fvec_t * freqs, smpl_t samplerate)
33 {
34
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;
39
40 uint_t fn; /* filter counter */
41 uint_t bin; /* bin counter */
42
43 smpl_t riseInc, downInc;
44
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);
50 }
51
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);
55 }
56
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");
60 return AUBIO_FAIL;
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);
67 return AUBIO_FAIL;
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]);
71 }
72 }
73
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);
78
79 /* height of each triangle */
80 triangle_heights = new_fvec (n_filters);
81
82 /* lookup table of each bin frequency in hz */
83 fft_freqs = new_fvec (win_s);
84
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];
90 }
91
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]);
97 }
98 } else {
99 fvec_ones (triangle_heights);
100 }
101
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);
106 }
107
108 /* zeroing of all filters */
109 fmat_zeros (filters);
110
111 /* building each filter table */
112 for (fn = 0; fn < n_filters; fn++) {
113
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]) {
118 bin++;
119 break;
120 }
121 }
122
123 /* compute positive slope step size */
124 riseInc = triangle_heights->data[fn]
125 / (center_freqs->data[fn] - lower_freqs->data[fn]);
126
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;
131
132 if (fft_freqs->data[bin + 1] >= center_freqs->data[fn]) {
133 bin++;
134 break;
135 }
136 }
137
138 /* compute negative slope step size */
139 downInc = triangle_heights->data[fn]
140 / (upper_freqs->data[fn] - center_freqs->data[fn]);
141
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;
146
147 if (filters->data[fn][bin] < 0.) {
148 filters->data[fn][bin] = 0.;
149 }
150
151 if (fft_freqs->data[bin + 1] >= upper_freqs->data[fn])
152 break;
153 }
154 /* nothing else to do */
155
156 }
157
158 /* destroy temporarly allocated vectors */
159 del_fvec (lower_freqs);
160 del_fvec (upper_freqs);
161 del_fvec (center_freqs);
162
163 del_fvec (triangle_heights);
164 del_fvec (fft_freqs);
165
166 return AUBIO_OK;
167 }
168
169 uint_t
aubio_filterbank_set_mel_coeffs_slaney(aubio_filterbank_t * fb,smpl_t samplerate)170 aubio_filterbank_set_mel_coeffs_slaney (aubio_filterbank_t * fb,
171 smpl_t samplerate)
172 {
173 /* Malcolm Slaney parameters */
174 const smpl_t lowestFrequency = 133.3333;
175 const smpl_t linearSpacing = 66.66666666;
176 const smpl_t logSpacing = 1.0711703;
177
178 const uint_t linearFilters = 13;
179 const uint_t logFilters = 27;
180 const uint_t n_filters = linearFilters + logFilters;
181
182 uint_t fn, retval;
183 smpl_t lastlinearCF;
184
185 /* buffers to compute filter frequencies */
186 fvec_t *freqs;
187
188 if (samplerate <= 0) {
189 AUBIO_ERR("filterbank: set_mel_coeffs_slaney samplerate should be > 0\n");
190 return AUBIO_FAIL;
191 }
192
193 freqs = new_fvec (n_filters + 2);
194
195 /* first step: fill all the linear filter frequencies */
196 for (fn = 0; fn < linearFilters; fn++) {
197 freqs->data[fn] = lowestFrequency + fn * linearSpacing;
198 }
199 lastlinearCF = freqs->data[fn - 1];
200
201 /* second step: fill all the log filter frequencies */
202 for (fn = 0; fn < logFilters + 2; fn++) {
203 freqs->data[fn + linearFilters] =
204 lastlinearCF * (POW (logSpacing, fn + 1));
205 }
206
207 /* now compute the actual coefficients */
208 retval = aubio_filterbank_set_triangle_bands (fb, freqs, samplerate);
209
210 /* destroy vector used to store frequency limits */
211 del_fvec (freqs);
212
213 return retval;
214 }
215
aubio_filterbank_check_freqs(aubio_filterbank_t * fb UNUSED,smpl_t samplerate,smpl_t * freq_min,smpl_t * freq_max)216 static uint_t aubio_filterbank_check_freqs (aubio_filterbank_t *fb UNUSED,
217 smpl_t samplerate, smpl_t *freq_min, smpl_t *freq_max)
218 {
219 if (samplerate <= 0) {
220 AUBIO_ERR("filterbank: set_mel_coeffs samplerate should be > 0\n");
221 return AUBIO_FAIL;
222 }
223 if (*freq_max < 0) {
224 AUBIO_ERR("filterbank: set_mel_coeffs freq_max should be > 0\n");
225 return AUBIO_FAIL;
226 } else if (*freq_max == 0) {
227 *freq_max = samplerate / 2.;
228 }
229 if (*freq_min < 0) {
230 AUBIO_ERR("filterbank: set_mel_coeffs freq_min should be > 0\n");
231 return AUBIO_FAIL;
232 }
233 return AUBIO_OK;
234 }
235
236 uint_t
aubio_filterbank_set_mel_coeffs(aubio_filterbank_t * fb,smpl_t samplerate,smpl_t freq_min,smpl_t freq_max)237 aubio_filterbank_set_mel_coeffs (aubio_filterbank_t * fb, smpl_t samplerate,
238 smpl_t freq_min, smpl_t freq_max)
239 {
240 uint_t m, retval;
241 smpl_t start = freq_min, end = freq_max, step;
242 fvec_t *freqs;
243 fmat_t *coeffs = aubio_filterbank_get_coeffs(fb);
244 uint_t n_bands = coeffs->height;
245
246 if (aubio_filterbank_check_freqs(fb, samplerate, &start, &end)) {
247 return AUBIO_FAIL;
248 }
249
250 start = aubio_hztomel(start);
251 end = aubio_hztomel(end);
252
253 freqs = new_fvec(n_bands + 2);
254 step = (end - start) / (n_bands + 1);
255
256 for (m = 0; m < n_bands + 2; m++)
257 {
258 freqs->data[m] = MIN(aubio_meltohz(start + step * m), samplerate/2.);
259 }
260
261 retval = aubio_filterbank_set_triangle_bands (fb, freqs, samplerate);
262
263 /* destroy vector used to store frequency limits */
264 del_fvec (freqs);
265 return retval;
266 }
267
268 uint_t
aubio_filterbank_set_mel_coeffs_htk(aubio_filterbank_t * fb,smpl_t samplerate,smpl_t freq_min,smpl_t freq_max)269 aubio_filterbank_set_mel_coeffs_htk (aubio_filterbank_t * fb, smpl_t samplerate,
270 smpl_t freq_min, smpl_t freq_max)
271 {
272 uint_t m, retval;
273 smpl_t start = freq_min, end = freq_max, step;
274 fvec_t *freqs;
275 fmat_t *coeffs = aubio_filterbank_get_coeffs(fb);
276 uint_t n_bands = coeffs->height;
277
278 if (aubio_filterbank_check_freqs(fb, samplerate, &start, &end)) {
279 return AUBIO_FAIL;
280 }
281
282 start = aubio_hztomel_htk(start);
283 end = aubio_hztomel_htk(end);
284
285 freqs = new_fvec (n_bands + 2);
286 step = (end - start) / (n_bands + 1);
287
288 for (m = 0; m < n_bands + 2; m++)
289 {
290 freqs->data[m] = MIN(aubio_meltohz_htk(start + step * m), samplerate/2.);
291 }
292
293 retval = aubio_filterbank_set_triangle_bands (fb, freqs, samplerate);
294
295 /* destroy vector used to store frequency limits */
296 del_fvec (freqs);
297 return retval;
298 }
299