2 Copyright (C) 2017 Paul Brossier <piem@aubio.org>
4 This file is part of aubio.
6 aubio is free software: you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation, either version 3 of the License, or
9 (at your option) any later version.
11 aubio is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with aubio. If not, see <http://www.gnu.org/licenses/>.
21 #include "aubio_priv.h"
24 #include "spectral/dct.h"
26 extern void aubio_ooura_ddct(int, int, smpl_t *, int *, smpl_t *);
36 aubio_dct_t * new_aubio_dct (uint_t size) {
37 aubio_dct_t * s = AUBIO_NEW(aubio_dct_t);
38 if (aubio_is_power_of_two(size) != 1) {
39 AUBIO_ERR("dct: can only create with sizes power of two, requested %d\n",
44 s->input = new_fvec(s->size);
45 s->w = AUBIO_ARRAY(smpl_t, s->size * 5 / 4);
46 s->ip = AUBIO_ARRAY(int, 3 + (1 << (int)FLOOR(LOG(s->size/2) / LOG(2))) / 2);
48 s->scalers[0] = 2. * SQRT(1./(4.*s->size));
49 s->scalers[1] = 2. * SQRT(1./(2.*s->size));
50 s->scalers[2] = 1. / s->scalers[0];
51 s->scalers[3] = 1. / s->scalers[1];
52 s->scalers[4] = 2. / s->size;
59 void del_aubio_dct(aubio_dct_t *s) {
66 void aubio_dct_do(aubio_dct_t *s, const fvec_t *input, fvec_t *output) {
68 fvec_copy(input, s->input);
69 aubio_ooura_ddct(s->size, -1, s->input->data, s->ip, s->w);
70 // apply orthonormal scaling
71 s->input->data[0] *= s->scalers[0];
72 for (i = 1; i < s->input->length; i++) {
73 s->input->data[i] *= s->scalers[1];
75 fvec_copy(s->input, output);
78 void aubio_dct_rdo(aubio_dct_t *s, const fvec_t *input, fvec_t *output) {
80 fvec_copy(input, s->input);
81 s->input->data[0] *= s->scalers[2];
82 for (i = 1; i < s->input->length; i++) {
83 s->input->data[i] *= s->scalers[3];
85 s->input->data[0] *= .5;
86 aubio_ooura_ddct(s->size, 1, s->input->data, s->ip, s->w);
87 for (i = 0; i < s->input->length; i++) {
88 s->input->data[i] *= s->scalers[4];
90 fvec_copy(s->input, output);