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m4vdec.c
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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 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 VOP+VO > 4 ? AVPROBE_SCORE_EXTENSION : AVPROBE_SCORE_EXTENSION/2;
56 
57  if (VOP >= VISO && VOP >= VOL && VO >= VOL && VOL > 0 && VOP+VO > 4)
58  return AVPROBE_SCORE_EXTENSION/10;
59  return 0;
60 }
61 
62 FF_DEF_RAWVIDEO_DEMUXER2(m4v, "raw MPEG-4 video", mpeg4video_probe, "m4v",
#define FF_DEF_RAWVIDEO_DEMUXER2(shortname, longname, probe, ext, id, flag)
Definition: rawdec.h:54
static int mpeg4video_probe(AVProbeData *probe_packet)
Definition: m4vdec.c:28
#define VOP_START_CODE
Definition: m4vdec.c:26
#define AVFMT_TS_DISCONT
Format allows timestamp discontinuities.
Definition: avformat.h:488
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:464
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:463
#define VISUAL_OBJECT_START_CODE
Definition: m4vdec.c:25
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:487
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:471
This structure contains the data a format has to probe a file.
Definition: avformat.h:461
Main libavformat public API header.
if(ret< 0)
Definition: vf_mcdeint.c:279