2 * Direct Stream Digital (DSD) decoder
3 * based on BSD licensed dsd2pcm by Sebastian Gesemann
4 * Copyright (c) 2009, 2011 Sebastian Gesemann. All rights reserved.
5 * Copyright (c) 2014 Peter Ross
7 * This file is part of FFmpeg.
9 * FFmpeg is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Lesser General Public
11 * License as published by the Free Software Foundation; either
12 * version 2.1 of the License, or (at your option) any later version.
14 * FFmpeg is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Lesser General Public License for more details.
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with FFmpeg; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24 #include "libavcodec/internal.h"
25 #include "libavcodec/mathops.h"
27 #include "dsd_tablegen.h"
30 static av_cold void dsd_ctables_tableinit(void)
34 for (e = 0; e < 256; ++e) {
35 memset(acc, 0, sizeof(acc));
36 for (m = 0; m < 8; ++m) {
37 sign = (((e >> (7 - m)) & 1) * 2 - 1);
38 for (t = 0; t < CTABLES; ++t)
39 acc[t] += sign * htaps[t * 8 + m];
41 for (t = 0; t < CTABLES; ++t)
42 ctables[CTABLES - 1 - t][e] = acc[t];
46 av_cold void ff_init_dsd_data(void)
51 dsd_ctables_tableinit();
55 void ff_dsd2pcm_translate(DSDContext* s, size_t samples, int lsbf,
56 const unsigned char *src, ptrdiff_t src_stride,
57 float *dst, ptrdiff_t dst_stride)
65 while (samples-- > 0) {
66 s->buf[pos] = lsbf ? ff_reverse[*src] : *src;
69 p = s->buf + ((pos - CTABLES) & FIFOMASK);
73 for (i = 0; i < CTABLES; i++) {
74 unsigned char a = s->buf[(pos - i) & FIFOMASK];
75 unsigned char b = s->buf[(pos - (CTABLES*2 - 1) + i) & FIFOMASK];
76 sum += ctables[i][a] + ctables[i][b];
82 pos = (pos + 1) & FIFOMASK;