m4vdec: Check for non-startcode 00 00 00 sequences in probe
[libav.git] / libavformat / m4vdec.c
1 /*
2 * RAW MPEG-4 video demuxer
3 * Copyright (c) 2006 Thijs Vermeir <thijs.vermeir@barco.com>
4 *
5 * This file is part of Libav.
6 *
7 * Libav 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 * Libav 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 Libav; 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 VISUAL_OBJECT_START_CODE 0x000001b5
26 #define VOP_START_CODE 0x000001b6
27
28 static int mpeg4video_probe(AVProbeData *probe_packet)
29 {
30 uint32_t temp_buffer = -1;
31 int VO = 0, VOL = 0, VOP = 0, VISO = 0, res = 0;
32 int i;
33
34 for (i = 0; i < probe_packet->buf_size; i++) {
35 temp_buffer = (temp_buffer << 8) + probe_packet->buf[i];
36 if (temp_buffer & 0xfffffe00)
37 continue;
38 if (temp_buffer < 2)
39 continue;
40
41 if (temp_buffer == VOP_START_CODE)
42 VOP++;
43 else if (temp_buffer == VISUAL_OBJECT_START_CODE)
44 VISO++;
45 else if (temp_buffer >= 0x100 && temp_buffer < 0x120)
46 VO++;
47 else if (temp_buffer >= 0x120 && temp_buffer < 0x130)
48 VOL++;
49 else if (!(0x1AF < temp_buffer && temp_buffer < 0x1B7) &&
50 !(0x1B9 < temp_buffer && temp_buffer < 0x1C4))
51 res++;
52 }
53
54 if (VOP >= VISO && VOP >= VOL && VO >= VOL && VOL > 0 && res == 0)
55 return AVPROBE_SCORE_EXTENSION;
56 return 0;
57 }
58
59 FF_DEF_RAWVIDEO_DEMUXER(m4v, "raw MPEG-4 video", mpeg4video_probe, "m4v",
60 AV_CODEC_ID_MPEG4)