FFmpeg4/libavformat/dvbtxt.c

51 lines
1.6 KiB
C

/*
* RAW dvb teletext demuxer
* Copyright (c) 2016 Marton Balnt <cus@passwd.hu>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavcodec/dvbtxt.h"
#include "avformat.h"
#include "rawdec.h"
static int dvbtxt_probe(const AVProbeData *p)
{
const uint8_t *end = p->buf + p->buf_size;
const uint8_t *buf;
/* The purpose of this is demuxer is to detect DVB teletext streams in
* mpegts, so we reject invalid buffer sizes */
if ((p->buf_size + 45) % 184 != 0)
return 0;
if (!ff_data_identifier_is_teletext(p->buf[0]))
return 0;
for (buf = p->buf + 1; buf < end; buf += 46) {
if (!ff_data_unit_id_is_teletext(buf[0]) && buf[0] != 0xff)
return 0;
if (buf[1] != 0x2c) // data_unit_length
return 0;
}
return AVPROBE_SCORE_MAX / 2;
}
FF_DEF_RAWSUB_DEMUXER(dvbtxt, "dvbtxt", dvbtxt_probe, NULL, AV_CODEC_ID_DVB_TELETEXT, 0)