1 /*
2 * RAW MPEG video demuxer
3 * Copyright (c) 2002-2003 Fabrice Bellard
4 * Copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 #include "avformat.h"
24 #include "rawdec.h"
25
26 #include "libavutil/intreadwrite.h"
27 #include "libavcodec/internal.h"
28
29 #define SEQ_START_CODE 0x000001b3
30 #define GOP_START_CODE 0x000001b8
31 #define PICTURE_START_CODE 0x00000100
32 #define SLICE_START_CODE 0x00000101
33 #define PACK_START_CODE 0x000001ba
34 #define VIDEO_ID 0x000001e0
35 #define AUDIO_ID 0x000001c0
36
mpegvideo_probe(const AVProbeData * p)37 static int mpegvideo_probe(const AVProbeData *p)
38 {
39 uint32_t code= -1;
40 int pic=0, seq=0, slice=0, pspack=0, vpes=0, apes=0, res=0, sicle=0;
41 const uint8_t *ptr = p->buf, *end = ptr + p->buf_size;
42 uint32_t last = 0;
43 int j;
44
45 while (ptr < end) {
46 ptr = avpriv_find_start_code(ptr, end, &code);
47 if ((code & 0xffffff00) == 0x100) {
48 switch(code){
49 case SEQ_START_CODE:
50 if (!(ptr[3 + 1 + 2] & 0x20))
51 break;
52 j = -1;
53 if (ptr[j + 8] & 2)
54 j+= 64;
55 if (j >= end - ptr)
56 break;
57 if (ptr[j + 8] & 1)
58 j+= 64;
59 if (j >= end - ptr)
60 break;
61 if (AV_RB24(ptr + j + 9) & 0xFFFFFE)
62 break;
63 seq++;
64 break;
65 case PICTURE_START_CODE: pic++; break;
66 case PACK_START_CODE: pspack++; break;
67 case 0x1b6:
68 res++; break;
69 }
70 if (code >= SLICE_START_CODE && code <= 0x1af) {
71 if (last >= SLICE_START_CODE && last <= 0x1af) {
72 if (code >= last) slice++;
73 else sicle++;
74 }else{
75 if (code == SLICE_START_CODE) slice++;
76 else sicle++;
77 }
78 }
79 if ((code & 0x1f0) == VIDEO_ID) vpes++;
80 else if((code & 0x1e0) == AUDIO_ID) apes++;
81 last = code;
82 }
83 }
84 if(seq && seq*9<=pic*10 && pic*9<=slice*10 && !pspack && !apes && !res && slice > sicle) {
85 if(vpes) return AVPROBE_SCORE_EXTENSION / 4;
86 else return pic>1 ? AVPROBE_SCORE_EXTENSION + 1 : AVPROBE_SCORE_EXTENSION / 2; // +1 for .mpg
87 }
88 return 0;
89 }
90
91 FF_DEF_RAWVIDEO_DEMUXER(mpegvideo, "raw MPEG video", mpegvideo_probe, NULL, AV_CODEC_ID_MPEG1VIDEO)
92