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FFmpeg/libavcodec/vpx_rac.c
Andreas Rheinhardt 7ab9b30800 avcodec/vp56: Move VP5-9 range coder functions to a header of their own
Also use a vpx prefix for them.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2022-07-28 03:49:54 +02:00

54 lines
1.8 KiB
C

/*
* VP5/6/8 decoder
* Copyright (c) 2010 Fiona Glaser <fiona@x264.com>
*
* 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 <stdint.h>
#include "libavutil/error.h"
#include "bytestream.h"
#include "vpx_rac.h"
const uint8_t ff_vpx_norm_shift[256]= {
8,7,6,6,5,5,5,5,4,4,4,4,4,4,4,4,
3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,
2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
};
int ff_vpx_init_range_decoder(VPXRangeCoder *c, const uint8_t *buf, int buf_size)
{
c->high = 255;
c->bits = -16;
c->buffer = buf;
c->end = buf + buf_size;
c->end_reached = 0;
if (buf_size < 1)
return AVERROR_INVALIDDATA;
c->code_word = bytestream_get_be24(&c->buffer);
return 0;
}