1 /*
2 * RAW MPEG-4 video demuxer
3 * Copyright (c) 2006 Thijs Vermeir <thijs.vermeir@barco.com>
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
25 #define VOS_STARTCODE 0x1B0
26 #define USER_DATA_STARTCODE 0x1B2
27 #define GOP_STARTCODE 0x1B3
28 #define VISUAL_OBJ_STARTCODE 0x1B5
29 #define VOP_STARTCODE 0x1B6
30 #define SLICE_STARTCODE 0x1B7
31 #define EXT_STARTCODE 0x1B8
32
mpeg4video_probe(const AVProbeData * probe_packet)33 static int mpeg4video_probe(const AVProbeData *probe_packet)
34 {
35 uint32_t temp_buffer = -1;
36 int VO = 0, VOL = 0, VOP = 0, VISO = 0, res = 0;
37 int res_main = 0;
38 int i;
39
40 for (i = 0; i < probe_packet->buf_size; i++) {
41 temp_buffer = (temp_buffer << 8) + probe_packet->buf[i];
42 if (temp_buffer & 0xfffffe00)
43 continue;
44 if (temp_buffer < 2)
45 continue;
46
47 if (temp_buffer == VOP_STARTCODE)
48 VOP++;
49 else if (temp_buffer == VISUAL_OBJ_STARTCODE)
50 VISO++;
51 else if (temp_buffer >= 0x100 && temp_buffer < 0x120)
52 VO++;
53 else if (temp_buffer >= 0x120 && temp_buffer < 0x130)
54 VOL++;
55 else if (temp_buffer == SLICE_STARTCODE || temp_buffer == EXT_STARTCODE)
56 res_main++;
57 else if (!(0x1AF < temp_buffer && temp_buffer < 0x1B7) &&
58 !(0x1B9 < temp_buffer && temp_buffer < 0x1C4))
59 res++;
60 }
61
62 // res_main repesents the reserved codes within the "main" profile, they are
63 // added to the reserved ones if it appears that this is a "main" profile
64 // stream
65 if (res_main && 2*res_main < VOP)
66 res += res_main;
67
68 if (VOP >= VISO && VOP >= VOL && VO >= VOL && VOL > 0 && res == 0)
69 return VOP+VO > 4 ? AVPROBE_SCORE_EXTENSION : AVPROBE_SCORE_EXTENSION/2;
70
71 if (VOP >= VISO && VOP >= VOL && VO >= VOL && VOL > 0 && VOP+VO > 4)
72 return AVPROBE_SCORE_EXTENSION/10;
73 return 0;
74 }
75
76 FF_DEF_RAWVIDEO_DEMUXER2(m4v, "raw MPEG-4 video", mpeg4video_probe, "m4v",
77 AV_CODEC_ID_MPEG4, AVFMT_GENERIC_INDEX | AVFMT_TS_DISCONT)
78