| /* |
| * Direct Stream Digital (DSD) decoder |
| * based on BSD licensed dsd2pcm by Sebastian Gesemann |
| * Copyright (c) 2009, 2011 Sebastian Gesemann. All rights reserved. |
| * Copyright (c) 2014 Peter Ross |
| * |
| * This file is part of FFmpeg. |
| * |
| * FFmpeg is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2.1 of the License, or (at your option) any later version. |
| * |
| * FFmpeg 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 |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with FFmpeg; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| #include "libavutil/thread.h" |
| #include "libavcodec/internal.h" |
| #include "libavcodec/mathops.h" |
| #include "avcodec.h" |
| #include "dsd_tablegen.h" |
| #include "dsd.h" |
| |
| static av_cold void dsd_ctables_tableinit(void) |
| { |
| int t, e, m, sign; |
| double acc[CTABLES]; |
| for (e = 0; e < 256; ++e) { |
| memset(acc, 0, sizeof(acc)); |
| for (m = 0; m < 8; ++m) { |
| sign = (((e >> (7 - m)) & 1) * 2 - 1); |
| for (t = 0; t < CTABLES; ++t) |
| acc[t] += sign * htaps[t * 8 + m]; |
| } |
| for (t = 0; t < CTABLES; ++t) |
| ctables[CTABLES - 1 - t][e] = acc[t]; |
| } |
| } |
| |
| av_cold void ff_init_dsd_data(void) |
| { |
| static AVOnce init_static_once = AV_ONCE_INIT; |
| ff_thread_once(&init_static_once, dsd_ctables_tableinit); |
| } |
| |
| void ff_dsd2pcm_translate(DSDContext* s, size_t samples, int lsbf, |
| const uint8_t *src, ptrdiff_t src_stride, |
| float *dst, ptrdiff_t dst_stride) |
| { |
| uint8_t buf[FIFOSIZE]; |
| unsigned pos, i; |
| uint8_t* p; |
| double sum; |
| |
| pos = s->pos; |
| |
| memcpy(buf, s->buf, sizeof(buf)); |
| |
| while (samples-- > 0) { |
| buf[pos] = lsbf ? ff_reverse[*src] : *src; |
| src += src_stride; |
| |
| p = buf + ((pos - CTABLES) & FIFOMASK); |
| *p = ff_reverse[*p]; |
| |
| sum = 0.0; |
| for (i = 0; i < CTABLES; i++) { |
| uint8_t a = buf[(pos - i) & FIFOMASK]; |
| uint8_t b = buf[(pos - (CTABLES*2 - 1) + i) & FIFOMASK]; |
| sum += ctables[i][a] + ctables[i][b]; |
| } |
| |
| *dst = (float)sum; |
| dst += dst_stride; |
| |
| pos = (pos + 1) & FIFOMASK; |
| } |
| |
| s->pos = pos; |
| memcpy(s->buf, buf, sizeof(buf)); |
| } |