/src/ffmpeg/libavformat/mpegvideodec.c
Line | Count | Source |
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/startcode.h" |
28 | | |
29 | 1.47M | #define SEQ_START_CODE 0x000001b3 |
30 | | #define GOP_START_CODE 0x000001b8 |
31 | 8.24M | #define PICTURE_START_CODE 0x00000100 |
32 | 108M | #define SLICE_START_CODE 0x00000101 |
33 | 226k | #define PACK_START_CODE 0x000001ba |
34 | 37.1M | #define VIDEO_ID 0x000001e0 |
35 | 30.7M | #define AUDIO_ID 0x000001c0 |
36 | | |
37 | | static int mpegvideo_probe(const AVProbeData *p) |
38 | 967k | { |
39 | 967k | uint32_t code= -1; |
40 | 967k | int pic=0, seq=0, slice=0, pspack=0, vpes=0, apes=0, res=0, sicle=0; |
41 | 967k | const uint8_t *ptr = p->buf, *end = ptr + p->buf_size; |
42 | 967k | uint32_t last = 0; |
43 | 967k | int j; |
44 | | |
45 | 39.0M | while (ptr < end) { |
46 | 38.1M | ptr = avpriv_find_start_code(ptr, end, &code); |
47 | 38.1M | if ((code & 0xffffff00) == 0x100) { |
48 | 37.1M | switch(code){ |
49 | 1.47M | case SEQ_START_CODE: |
50 | 1.47M | if (!(ptr[3 + 1 + 2] & 0x20)) |
51 | 832k | break; |
52 | 638k | j = -1; |
53 | 638k | if (ptr[j + 8] & 2) |
54 | 246k | j+= 64; |
55 | 638k | if (j >= end - ptr) |
56 | 3.71k | break; |
57 | 634k | if (ptr[j + 8] & 1) |
58 | 174k | j+= 64; |
59 | 634k | if (j >= end - ptr) |
60 | 4.34k | break; |
61 | 630k | if (AV_RB24(ptr + j + 9) & 0xFFFFFE) |
62 | 365k | break; |
63 | 264k | seq++; |
64 | 264k | break; |
65 | 8.24M | case PICTURE_START_CODE: pic++; break; |
66 | 226k | case PACK_START_CODE: pspack++; break; |
67 | 2.70M | case 0x1b6: |
68 | 2.70M | res++; break; |
69 | 37.1M | } |
70 | 37.1M | if (code >= SLICE_START_CODE && code <= 0x1af) { |
71 | 13.9M | if (last >= SLICE_START_CODE && last <= 0x1af) { |
72 | 7.72M | if (code >= last) slice++; |
73 | 1.91M | else sicle++; |
74 | 7.72M | }else{ |
75 | 6.22M | if (code == SLICE_START_CODE) slice++; |
76 | 5.33M | else sicle++; |
77 | 6.22M | } |
78 | 13.9M | } |
79 | 37.1M | if ((code & 0x1f0) == VIDEO_ID) vpes++; |
80 | 30.7M | else if((code & 0x1e0) == AUDIO_ID) apes++; |
81 | 37.1M | last = code; |
82 | 37.1M | } |
83 | 38.1M | } |
84 | 967k | if(seq && seq*9<=pic*10 && pic*9<=slice*10 && !pspack && !apes && !res && slice > sicle) { |
85 | 3.68k | if(vpes) return AVPROBE_SCORE_EXTENSION / 4; |
86 | 3.05k | else return pic>1 ? AVPROBE_SCORE_EXTENSION + 1 : AVPROBE_SCORE_EXTENSION / 2; // +1 for .mpg |
87 | 3.68k | } |
88 | 964k | return 0; |
89 | 967k | } |
90 | | |
91 | | FF_DEF_RAWVIDEO_DEMUXER(mpegvideo, "raw MPEG video", mpegvideo_probe, NULL, AV_CODEC_ID_MPEG1VIDEO) |