blob: 9104f384767b884f35d10fe5e6ed69ad2554917d
| 1 | /* |
| 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 |
| 6 | * |
| 7 | * This file is part of FFmpeg. |
| 8 | * |
| 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. |
| 13 | * |
| 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. |
| 18 | * |
| 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 |
| 22 | */ |
| 23 | |
| 24 | #include "libavcodec/internal.h" |
| 25 | #include "libavcodec/mathops.h" |
| 26 | #include "avcodec.h" |
| 27 | #include "dsd_tablegen.h" |
| 28 | #include "dsd.h" |
| 29 | |
| 30 | static av_cold void dsd_ctables_tableinit(void) |
| 31 | { |
| 32 | int t, e, m, sign; |
| 33 | double acc[CTABLES]; |
| 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]; |
| 40 | } |
| 41 | for (t = 0; t < CTABLES; ++t) |
| 42 | ctables[CTABLES - 1 - t][e] = acc[t]; |
| 43 | } |
| 44 | } |
| 45 | |
| 46 | av_cold void ff_init_dsd_data(void) |
| 47 | { |
| 48 | static int done = 0; |
| 49 | if (done) |
| 50 | return; |
| 51 | dsd_ctables_tableinit(); |
| 52 | done = 1; |
| 53 | } |
| 54 | |
| 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) |
| 58 | { |
| 59 | unsigned pos, i; |
| 60 | unsigned char* p; |
| 61 | double sum; |
| 62 | |
| 63 | pos = s->pos; |
| 64 | |
| 65 | while (samples-- > 0) { |
| 66 | s->buf[pos] = lsbf ? ff_reverse[*src] : *src; |
| 67 | src += src_stride; |
| 68 | |
| 69 | p = s->buf + ((pos - CTABLES) & FIFOMASK); |
| 70 | *p = ff_reverse[*p]; |
| 71 | |
| 72 | sum = 0.0; |
| 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]; |
| 77 | } |
| 78 | |
| 79 | *dst = (float)sum; |
| 80 | dst += dst_stride; |
| 81 | |
| 82 | pos = (pos + 1) & FIFOMASK; |
| 83 | } |
| 84 | |
| 85 | s->pos = pos; |
| 86 | } |
| 87 |