ffmpeg/libavformat/srtdec.c

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/*
* SubRip subtitle demuxer
* Copyright (c) 2010 Aurelien Jacobs <aurel@gnuage.org>
*
* 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 "avformat.h"
#include "internal.h"
#include "libavutil/intreadwrite.h"
static int srt_probe(AVProbeData *p)
{
unsigned char *ptr = p->buf;
int i, v, num = 0;
if (AV_RB24(ptr) == 0xEFBBBF)
ptr += 3; /* skip UTF-8 BOM */
for (i=0; i<2; i++) {
if (num == i && sscanf(ptr, "%*d:%*2d:%*2d%*1[,.]%*3d --> %*d:%*2d:%*2d%*1[,.]%3d", &v) == 1)
return AVPROBE_SCORE_MAX;
num = atoi(ptr);
ptr += strcspn(ptr, "\n") + 1;
}
return 0;
}
static int srt_read_header(AVFormatContext *s)
{
AVStream *st = avformat_new_stream(s, NULL);
if (!st)
return AVERROR(ENOMEM);
avpriv_set_pts_info(st, 64, 1, 1000);
st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
st->codec->codec_id = CODEC_ID_SRT;
return 0;
}
static int64_t get_pts(const char *buf)
{
int i, v, hour, min, sec, hsec;
for (i=0; i<2; i++) {
if (sscanf(buf, "%d:%2d:%2d%*1[,.]%3d --> %*d:%*2d:%*2d%*1[,.]%3d",
&hour, &min, &sec, &hsec, &v) == 5) {
min += 60*hour;
sec += 60*min;
return sec*1000+hsec;
}
buf += strcspn(buf, "\n") + 1;
}
return AV_NOPTS_VALUE;
}
static inline int is_eol(char c)
{
return c == '\r' || c == '\n';
}
static int srt_read_packet(AVFormatContext *s, AVPacket *pkt)
{
char buffer[2048], *ptr = buffer, *ptr2;
int64_t pos = avio_tell(s->pb);
int res = AVERROR_EOF;
do {
ptr2 = ptr;
ptr += ff_get_line(s->pb, ptr, sizeof(buffer)+buffer-ptr);
} while (!is_eol(*ptr2) && !url_feof(s->pb) && ptr-buffer<sizeof(buffer)-1);
if (buffer[0] && !(res = av_new_packet(pkt, ptr-buffer))) {
memcpy(pkt->data, buffer, pkt->size);
pkt->flags |= AV_PKT_FLAG_KEY;
pkt->pos = pos;
pkt->pts = pkt->dts = get_pts(pkt->data);
}
return res;
}
AVInputFormat ff_srt_demuxer = {
.name = "srt",
.long_name = NULL_IF_CONFIG_SMALL("SubRip subtitle"),
.read_probe = srt_probe,
.read_header = srt_read_header,
.read_packet = srt_read_packet,
.flags = AVFMT_GENERIC_INDEX,
};