1 /* Effect: change sample rate Copyright (c) 2008,12 robs@users.sourceforge.net
2 *
3 * This library is free software; you can redistribute it and/or modify it
4 * under the terms of the GNU Lesser General Public License as published by
5 * the Free Software Foundation; either version 2.1 of the License, or (at
6 * your option) any later version.
7 *
8 * This library is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU Lesser General Public License
14 * along with this library; if not, write to the Free Software Foundation,
15 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
16 */
17
18 /* Resample using a non-interpolated poly-phase FIR with length LEN.*/
19 /* Input must be followed by LEN-1 samples. */
20
21 #define _ sum += (coef(p->shared->poly_fir_coefs, 0, FIR_LENGTH, divided.rem, 0, j)) *at[j], ++j;
22
FUNCTION(stage_t * p,fifo_t * output_fifo)23 static void FUNCTION(stage_t * p, fifo_t * output_fifo)
24 {
25 sample_t const * input = stage_read_p(p);
26 int i, num_in = stage_occupancy(p), max_num_out = 1 + num_in*p->out_in_ratio;
27 sample_t * output = fifo_reserve(output_fifo, max_num_out);
28 div_t divided2;
29
30 for (i = 0; p->at.parts.integer < num_in * p->L; ++i, p->at.parts.integer += p->step.parts.integer) {
31 div_t divided = div(p->at.parts.integer, p->L);
32 sample_t const * at = input + divided.quot;
33 sample_t sum = 0;
34 int j = 0;
35 CONVOLVE
36 output[i] = sum;
37 }
38 assert(max_num_out - i >= 0);
39 fifo_trim_by(output_fifo, max_num_out - i);
40 divided2 = div(p->at.parts.integer, p->L);
41 fifo_read(&p->fifo, divided2.quot, NULL);
42 p->at.parts.integer = divided2.rem;
43 }
44
45 #undef _
46 #undef CONVOLVE
47 #undef FIR_LENGTH
48 #undef FUNCTION
49