FFmpeg
vc1dec.c
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1 /*
2  * VC-1 demuxer
3  * Copyright (c) 2015 Carl Eugen Hoyos
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 "libavutil/intreadwrite.h"
25 #include "libavcodec/vc1_common.h"
26 
27 static int vc1_probe(const AVProbeData *p)
28 {
29  int seq = 0, entry = 0, invalid = 0, frame = 0, i;
30 
31  for (i = 0; i < p->buf_size + 5; i++) {
32  uint32_t code = AV_RB32(p->buf + i);
33  if ((code & 0xffffffe0) == 0x100) {
34  int type = code & 0x11f;
35  i += 4;
36  switch (type) {
37  case VC1_CODE_SEQHDR: {
38  int profile, level, chromaformat;
39  profile = (p->buf[i] & 0xc0) >> 6;
40  if (profile != PROFILE_ADVANCED) {
41  seq = 0;
42  invalid++;
43  continue;
44  }
45  level = (p->buf[i] & 0x38) >> 3;
46  if (level >= 5) {
47  seq = 0;
48  invalid++;
49  continue;
50  }
51  chromaformat = (p->buf[i] & 0x6) >> 1;
52  if (chromaformat != 1) {
53  seq = 0;
54  invalid++;
55  continue;
56  }
57  seq++;
58  i += 6;
59  break;
60  }
62  if (!seq) {
63  invalid++;
64  continue;
65  }
66  entry++;
67  i += 2;
68  break;
69  case VC1_CODE_FRAME:
70  case VC1_CODE_FIELD:
71  case VC1_CODE_SLICE:
72  if (seq && entry)
73  frame++;
74  break;
75  }
76  }
77  }
78 
79  if (frame > 1 && frame >> 1 > invalid)
80  return AVPROBE_SCORE_EXTENSION / 2 + 1;
81  if (frame >= 1)
82  return AVPROBE_SCORE_EXTENSION / 4;
83  return 0;
84 }
85 
level
uint8_t level
Definition: svq3.c:204
AVFMT_NOTIMESTAMPS
#define AVFMT_NOTIMESTAMPS
Format does not need / have any timestamps.
Definition: avformat.h:480
AVProbeData::buf_size
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:455
AVFMT_GENERIC_INDEX
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:481
type
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf type
Definition: writing_filters.txt:86
VC1_CODE_SLICE
@ VC1_CODE_SLICE
Definition: vc1_common.h:36
intreadwrite.h
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:454
PROFILE_ADVANCED
@ PROFILE_ADVANCED
Definition: vc1_common.h:52
frame
static AVFrame * frame
Definition: demux_decode.c:54
rawdec.h
VC1_CODE_SEQHDR
@ VC1_CODE_SEQHDR
Definition: vc1_common.h:40
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:452
VC1_CODE_FIELD
@ VC1_CODE_FIELD
Definition: vc1_common.h:37
VC1_CODE_ENTRYPOINT
@ VC1_CODE_ENTRYPOINT
Definition: vc1_common.h:39
VC1_CODE_FRAME
@ VC1_CODE_FRAME
Definition: vc1_common.h:38
AVPROBE_SCORE_EXTENSION
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:462
vc1_probe
static int vc1_probe(const AVProbeData *p)
Definition: vc1dec.c:27
AV_RB32
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_WB64 unsigned int_TMPL AV_RB32
Definition: bytestream.h:96
vc1_common.h
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:255
code
and forward the test the status of outputs and forward it to the corresponding return FFERROR_NOT_READY If the filters stores internally one or a few frame for some it can consider them to be part of the FIFO and delay acknowledging a status change accordingly Example code
Definition: filter_design.txt:178
AV_CODEC_ID_VC1
@ AV_CODEC_ID_VC1
Definition: codec_id.h:122
profile
int profile
Definition: mxfenc.c:2226
avformat.h
FF_DEF_RAWVIDEO_DEMUXER2
#define FF_DEF_RAWVIDEO_DEMUXER2(shortname, longname, probe, ext, id, flag)
Definition: rawdec.h:52