FFmpeg
dvbtxt.c
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1 /*
2  * RAW dvb teletext demuxer
3  * Copyright (c) 2016 Marton Balnt <cus@passwd.hu>
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 "libavcodec/dvbtxt.h"
23 
24 #include "avformat.h"
25 #include "rawdec.h"
26 
27 static int dvbtxt_probe(const AVProbeData *p)
28 {
29  const uint8_t *end = p->buf + p->buf_size;
30  const uint8_t *buf;
31 
32  /* The purpose of this is demuxer is to detect DVB teletext streams in
33  * mpegts, so we reject invalid buffer sizes */
34  if ((p->buf_size + 45) % 184 != 0)
35  return 0;
36 
38  return 0;
39 
40  for (buf = p->buf + 1; buf < end; buf += 46) {
41  if (!ff_data_unit_id_is_teletext(buf[0]) && buf[0] != 0xff)
42  return 0;
43  if (buf[1] != 0x2c) // data_unit_length
44  return 0;
45  }
46 
47  return AVPROBE_SCORE_MAX / 2;
48 }
49 
static av_always_inline int ff_data_identifier_is_teletext(int data_identifier)
Definition: dvbtxt.h:28
#define NULL
Definition: coverity.c:32
static av_always_inline int ff_data_unit_id_is_teletext(int data_unit_id)
Definition: dvbtxt.h:36
uint8_t
static av_cold int end(AVCodecContext *avctx)
Definition: avrndec.c:90
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:449
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:448
void * buf
Definition: avisynth_c.h:766
This structure contains the data a format has to probe a file.
Definition: avformat.h:446
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:458
static int dvbtxt_probe(const AVProbeData *p)
Definition: dvbtxt.c:27
Main libavformat public API header.
#define FF_DEF_RAWSUB_DEMUXER(shortname, longname, probe, ext, id, flag)
Definition: rawdec.h:97