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cavsvideodec.c
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1 /*
2  * RAW Chinese AVS video demuxer
3  * Copyright (c) 2009 Stefan Gehrer <stefan.gehrer@gmx.de>
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 #include "libavcodec/internal.h"
25 
26 #define CAVS_SEQ_START_CODE 0x000001b0
27 #define CAVS_PIC_I_START_CODE 0x000001b3
28 #define CAVS_UNDEF_START_CODE 0x000001b4
29 #define CAVS_PIC_PB_START_CODE 0x000001b6
30 #define CAVS_VIDEO_EDIT_CODE 0x000001b7
31 #define CAVS_PROFILE_JIZHUN 0x20
32 
34 {
35  uint32_t code= -1;
36  int pic=0, seq=0, slice_pos = 0;
37  const uint8_t *ptr = p->buf, *end = p->buf + p->buf_size;
38 
39  while (ptr < end) {
40  ptr = avpriv_find_start_code(ptr, end, &code);
41  if ((code & 0xffffff00) == 0x100) {
42  if(code < CAVS_SEQ_START_CODE) {
43  /* slices have to be consecutive */
44  if(code < slice_pos)
45  return 0;
46  slice_pos = code;
47  } else {
48  slice_pos = 0;
49  }
50  if (code == CAVS_SEQ_START_CODE) {
51  seq++;
52  /* check for the only currently supported profile */
53  if (*ptr != CAVS_PROFILE_JIZHUN)
54  return 0;
55  } else if ((code == CAVS_PIC_I_START_CODE) ||
56  (code == CAVS_PIC_PB_START_CODE)) {
57  pic++;
58  } else if ((code == CAVS_UNDEF_START_CODE) ||
59  (code > CAVS_VIDEO_EDIT_CODE)) {
60  return 0;
61  }
62  }
63  }
64  if(seq && seq*9<=pic*10)
65  return AVPROBE_SCORE_EXTENSION+1;
66  return 0;
67 }
68 
69 FF_DEF_RAWVIDEO_DEMUXER(cavsvideo, "raw Chinese AVS (Audio Video Standard)", cavsvideo_probe, NULL, AV_CODEC_ID_CAVS)