m4vdec: Check for non-startcode 00 00 00 sequences in probe
[libav.git] / libavformat / m4vdec.c
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1/*
2 * RAW MPEG-4 video demuxer
3 * Copyright (c) 2006 Thijs Vermeir <thijs.vermeir@barco.com>
4 *
2912e87a 5 * This file is part of Libav.
e3507058 6 *
2912e87a 7 * Libav is free software; you can redistribute it and/or
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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 *
2912e87a 12 * Libav is distributed in the hope that it will be useful,
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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
2912e87a 18 * License along with Libav; if not, write to the Free Software
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19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22#include "avformat.h"
4ca31edc 23#include "rawdec.h"
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24
25#define VISUAL_OBJECT_START_CODE 0x000001b5
26#define VOP_START_CODE 0x000001b6
27
28static int mpeg4video_probe(AVProbeData *probe_packet)
29{
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30 uint32_t temp_buffer = -1;
31 int VO = 0, VOL = 0, VOP = 0, VISO = 0, res = 0;
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32 int i;
33
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34 for (i = 0; i < probe_packet->buf_size; i++) {
35 temp_buffer = (temp_buffer << 8) + probe_packet->buf[i];
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36 if (temp_buffer & 0xfffffe00)
37 continue;
38 if (temp_buffer < 2)
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39 continue;
40
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41 if (temp_buffer == VOP_START_CODE)
42 VOP++;
43 else if (temp_buffer == VISUAL_OBJECT_START_CODE)
44 VISO++;
e5b01972 45 else if (temp_buffer >= 0x100 && temp_buffer < 0x120)
4620affa 46 VO++;
e5b01972 47 else if (temp_buffer >= 0x120 && temp_buffer < 0x130)
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48 VOL++;
49 else if (!(0x1AF < temp_buffer && temp_buffer < 0x1B7) &&
50 !(0x1B9 < temp_buffer && temp_buffer < 0x1C4))
51 res++;
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52 }
53
4620affa 54 if (VOP >= VISO && VOP >= VOL && VO >= VOL && VOL > 0 && res == 0)
e0f8be64 55 return AVPROBE_SCORE_EXTENSION;
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56 return 0;
57}
58
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59FF_DEF_RAWVIDEO_DEMUXER(m4v, "raw MPEG-4 video", mpeg4video_probe, "m4v",
60 AV_CODEC_ID_MPEG4)