FFmpeg
mj2kdec.c
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1 /*
2  * MJPEG 2000 Demuxer
3  * Copyright (c) 2016 StÃ¥le Kristoffersen
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 "libavutil/intreadwrite.h"
23 #include "avformat.h"
24 #include "rawdec.h"
25 
26 static int mjpeg2000_probe(const AVProbeData *p)
27 {
28  const uint8_t *b = p->buf;
29  int i, marker, marker_size;
30  int frames = 0, invalid = 0;
31 
32  for (i = 0; i < p->buf_size - 5; i++) {
33  if (AV_RB32(b) == 0xff4fff51){
34  marker_size = AV_RB16(b+4);
35  if (marker_size + i < p->buf_size - 4) {
36  marker = AV_RB8(b+4+marker_size);
37  if (marker == 0xff)
38  frames++;
39  else
40  invalid++;
41  }
42  }
43  b += 1;
44  }
45  if (invalid*4 + 1 < frames) {
46  if (invalid == 0 && frames > 2)
47  return AVPROBE_SCORE_EXTENSION / 2;
48  return AVPROBE_SCORE_EXTENSION / 4;
49  }
50  return 0;
51 }
AVFMT_NOTIMESTAMPS
#define AVFMT_NOTIMESTAMPS
Format does not need / have any timestamps.
Definition: avformat.h:481
b
#define b
Definition: input.c:41
AVProbeData::buf_size
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:456
frames
if it could not because there are no more frames
Definition: filter_design.txt:266
AVFMT_GENERIC_INDEX
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:482
intreadwrite.h
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:455
rawdec.h
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:453
AVPROBE_SCORE_EXTENSION
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:463
mjpeg2000_probe
static int mjpeg2000_probe(const AVProbeData *p)
Definition: mj2kdec.c:26
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
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:269
AV_CODEC_ID_JPEG2000
@ AV_CODEC_ID_JPEG2000
Definition: codec_id.h:140
avformat.h
FF_DEF_RAWVIDEO_DEMUXER2
#define FF_DEF_RAWVIDEO_DEMUXER2(shortname, longname, probe, ext, id, flag)
Definition: rawdec.h:52
AV_RB8
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_WB32 unsigned int_TMPL AV_WB24 unsigned int_TMPL AV_WB16 unsigned int_TMPL AV_RB8
Definition: bytestream.h:99
AV_RB16
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_WB32 unsigned int_TMPL AV_WB24 unsigned int_TMPL AV_RB16
Definition: bytestream.h:98