From 86e493a6ffac3b3705ea4b276060c380ee2f5e75 Mon Sep 17 00:00:00 2001 From: Peter Ross Date: Thu, 5 May 2016 21:21:27 +0200 Subject: avcodec: add Direct Stream Transfer (DST) decoder Signed-off-by: Paul B Mahol --- libavcodec/dsd.c | 86 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 86 insertions(+) create mode 100644 libavcodec/dsd.c (limited to 'libavcodec/dsd.c') diff --git a/libavcodec/dsd.c b/libavcodec/dsd.c new file mode 100644 index 0000000000..9104f38476 --- /dev/null +++ b/libavcodec/dsd.c @@ -0,0 +1,86 @@ +/* + * 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 "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 int done = 0; + if (done) + return; + dsd_ctables_tableinit(); + done = 1; +} + +void ff_dsd2pcm_translate(DSDContext* s, size_t samples, int lsbf, + const unsigned char *src, ptrdiff_t src_stride, + float *dst, ptrdiff_t dst_stride) +{ + unsigned pos, i; + unsigned char* p; + double sum; + + pos = s->pos; + + while (samples-- > 0) { + s->buf[pos] = lsbf ? ff_reverse[*src] : *src; + src += src_stride; + + p = s->buf + ((pos - CTABLES) & FIFOMASK); + *p = ff_reverse[*p]; + + sum = 0.0; + for (i = 0; i < CTABLES; i++) { + unsigned char a = s->buf[(pos - i) & FIFOMASK]; + unsigned char b = s->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; +} -- cgit v1.2.3