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FFmpeg/libavformat/dvbsub.c

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/*
* RAW dvbsub demuxer
* Copyright (c) 2015 Michael Niedermayer <michaelni@gmx.at>
*
* 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 "libavutil/intreadwrite.h"
#include "avformat.h"
#include "rawdec.h"
static int dvbsub_probe(const AVProbeData *p)
{
int i, j, k;
const uint8_t *end = p->buf + p->buf_size;
int type, len;
int max_score = 0;
for(i=0; i<p->buf_size; i++){
if (p->buf[i] == 0x0f) {
const uint8_t *ptr = p->buf + i;
uint8_t histogram[6] = {0};
int min = 255;
for(j=0; 6 < end - ptr; j++) {
if (*ptr != 0x0f)
break;
type = ptr[1];
//page_id = AV_RB16(ptr + 2);
len = AV_RB16(ptr + 4);
if (type == 0x80) {
;
} else if (type >= 0x10 && type <= 0x14) {
histogram[type - 0x10] ++;
} else
break;
if (6 + len > end - ptr)
break;
ptr += 6 + len;
}
for (k=0; k < 4; k++) {
min = FFMIN(min, histogram[k]);
}
if (min && j > max_score)
max_score = j;
}
}
if (max_score > 5)
return AVPROBE_SCORE_EXTENSION;
return 0;
}
FF_DEF_RAWSUB_DEMUXER(dvbsub, "raw dvbsub", dvbsub_probe, NULL, AV_CODEC_ID_DVB_SUBTITLE, AVFMT_GENERIC_INDEX)