1/*
2 * RAW H.263 video demuxer
3 * Copyright (c) 2009 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#include "avformat.h"
23#include "rawdec.h"
24
25static int h263_probe(AVProbeData *p)
26{
27    uint64_t code= -1;
28    int i;
29    int valid_psc=0;
30    int invalid_psc=0;
31    int res_change=0;
32    int src_fmt, last_src_fmt=-1;
33    int last_gn=0;
34    int tr, last_tr = -1;
35
36    for(i=0; i<p->buf_size; i++){
37        code = (code<<8) + p->buf[i];
38        if ((code & 0xfffffc000000) == 0x80000000) {
39            tr = (code >> 18) & 0xFF;
40            src_fmt= (code>>10)&7;
41            if(   src_fmt != last_src_fmt
42               && last_src_fmt>0 && last_src_fmt<6
43               && src_fmt<6)
44                res_change++;
45
46            if (tr == last_tr) {
47                invalid_psc++;
48                continue;
49            }
50
51            if (src_fmt != 7 && !(code&(1<<9)) && (code&(1<<5))) {
52                invalid_psc++;
53                continue;
54            }
55
56            if((code&0x30000)==0x20000 && src_fmt){
57                valid_psc++;
58                last_gn=0;
59            }else
60                invalid_psc++;
61            last_src_fmt= src_fmt;
62            last_tr = tr;
63        } else if((code & 0xffff80000000) == 0x80000000) {
64            int gn= (code>>(31-5)) & 0x1F;
65            if(gn<last_gn){
66                invalid_psc++;
67            }else
68                last_gn= gn;
69        }
70    }
71    if(valid_psc > 2*invalid_psc + 2*res_change + 3){
72        return AVPROBE_SCORE_EXTENSION;
73    }else if(valid_psc > 2*invalid_psc)
74        return AVPROBE_SCORE_EXTENSION / 2;
75    return 0;
76}
77
78FF_DEF_RAWVIDEO_DEMUXER(h263, "raw H.263", h263_probe, NULL, AV_CODEC_ID_H263)
79