ref: b236757ac4ae678d7f762e1d7cabb18ca22486fc
parent: 98ceec5d61bf2537ecf8e9187a627078c37d3989
author: Paul Brossier <piem@piem.org>
date: Wed Aug 8 13:03:35 EDT 2018
src/spectral/dct_plain.c: add plain dct
--- /dev/null
+++ b/src/spectral/dct_plain.c
@@ -1,0 +1,93 @@
+/*
+ Copyright (C) 2018 Paul Brossier <piem@aubio.org>
+
+ This file is part of aubio.
+
+ aubio is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ aubio is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with aubio. If not, see <http://www.gnu.org/licenses/>.
+
+*/
+
+#include "aubio_priv.h"
+#include "fvec.h"
+#include "fmat.h"
+#include "spectral/dct.h"
+
+typedef struct _aubio_dct_plain_t aubio_dct_plain_t;
+
+struct _aubio_dct_plain_t {+ uint_t size;
+ fmat_t *dct_coeffs; /** DCT type II orthonormal transform, size * size */
+ fmat_t *idct_coeffs; /** DCT type III orthonormal transform, size * size */
+};
+
+aubio_dct_plain_t * new_aubio_dct_plain (uint_t size) {+ aubio_dct_plain_t * s = AUBIO_NEW(aubio_dct_plain_t);
+ uint_t i, j;
+ smpl_t scaling;
+ if (aubio_is_power_of_two (size) == 1 && size > 16) {+ AUBIO_WRN("dct_plain: using plain dct but size %d is a power of two", size);+ }
+
+ s->size = size;
+
+ s->dct_coeffs = new_fmat (size, size);
+ s->idct_coeffs = new_fmat (size, size);
+
+ /* compute DCT type-II transformation matrix
+ dct_coeffs[j][i] = cos ( j * (i+.5) * PI / n_filters )
+ */
+ scaling = SQRT (2. / size);
+ for (i = 0; i < size; i++) {+ for (j = 1; j < size; j++) {+ s->dct_coeffs->data[j][i] =
+ scaling * COS (j * (i + 0.5) * PI / size );
+ }
+ s->dct_coeffs->data[0][i] = 1. / SQRT (size);
+ }
+
+ /* compute DCT type-III transformation matrix
+ idct_coeffs[j][i] = cos ( i * (j+.5) * PI / n_filters )
+ */
+ scaling = SQRT (2. / size);
+ for (j = 0; j < size; j++) {+ for (i = 1; i < size; i++) {+ s->idct_coeffs->data[j][i] =
+ scaling * COS (i * (j + 0.5) * PI / size );
+ }
+ s->idct_coeffs->data[j][0] = 1. / SQRT (size);
+ }
+ return s;
+}
+
+void del_aubio_dct_plain (aubio_dct_plain_t *s) {+ del_fmat(s->dct_coeffs);
+ del_fmat(s->idct_coeffs);
+ AUBIO_FREE(s);
+}
+
+void aubio_dct_plain_do(aubio_dct_plain_t *s, const fvec_t *input, fvec_t *output) {+ if (input->length != output->length || input->length != s->size) {+ AUBIO_WRN("dct_plain: using input length %d, but output length = %d and size = %d",+ input->length, output->length, s->size);
+ }
+ fmat_vecmul(s->dct_coeffs, input, output);
+}
+
+void aubio_dct_plain_rdo(aubio_dct_plain_t *s, const fvec_t *input, fvec_t *output) {+ if (input->length != output->length || input->length != s->size) {+ AUBIO_WRN("dct_plain: using input length %d, but output length = %d and size = %d",+ input->length, output->length, s->size);
+ }
+ fmat_vecmul(s->idct_coeffs, input, output);
+}