ref: d8c21a32aec0fd7e13fb8e45ee5f630dc7bce1dd
dir: /src/spectral/dct_plain.c/
/* 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; #pragma incomplete 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 */ }; void del_aubio_dct_plain (aubio_dct_plain_t *s); 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\n", size); } if ((sint_t)size <= 0) { AUBIO_ERR("dct_plain: can only create with size > 0, requested %d\n", size); goto failure; } 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; failure: del_aubio_dct_plain(s); return NULL; } void del_aubio_dct_plain (aubio_dct_plain_t *s) { if (s->dct_coeffs) del_fmat(s->dct_coeffs); if (s->idct_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\n", 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\n", input->length, output->length, s->size); } fmat_vecmul(s->idct_coeffs, input, output); }