xref: /third_party/ffmpeg/libavcodec/cabac.h (revision cabdff1a)
1/*
2 * H.26L/H.264/AVC/JVT/14496-10/... encoder/decoder
3 * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22/**
23 * @file
24 * Context Adaptive Binary Arithmetic Coder.
25 */
26
27#ifndef AVCODEC_CABAC_H
28#define AVCODEC_CABAC_H
29
30#include <stdint.h>
31
32extern const uint8_t ff_h264_cabac_tables[512 + 4*2*64 + 4*64 + 63];
33#define H264_NORM_SHIFT_OFFSET 0
34#define H264_LPS_RANGE_OFFSET 512
35#define H264_MLPS_STATE_OFFSET 1024
36#define H264_LAST_COEFF_FLAG_OFFSET_8x8_OFFSET 1280
37
38#define CABAC_BITS 16
39#define CABAC_MASK ((1<<CABAC_BITS)-1)
40
41typedef struct CABACContext{
42    int low;
43    int range;
44    const uint8_t *bytestream_start;
45    const uint8_t *bytestream;
46    const uint8_t *bytestream_end;
47}CABACContext;
48
49int ff_init_cabac_decoder(CABACContext *c, const uint8_t *buf, int buf_size);
50
51#endif /* AVCODEC_CABAC_H */
52