1/*
2 * SubRip subtitle demuxer
3 * Copyright (c) 2010  Aurelien Jacobs <aurel@gnuage.org>
4 *
5 * This file is part of Libav.
6 *
7 * Libav 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 * Libav 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 Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22#include "avformat.h"
23#include "internal.h"
24#include "libavutil/intreadwrite.h"
25
26static int srt_probe(AVProbeData *p)
27{
28    unsigned char *ptr = p->buf;
29    int i, v, num = 0;
30
31    if (AV_RB24(ptr) == 0xEFBBBF)
32        ptr += 3;  /* skip UTF-8 BOM */
33
34    for (i=0; i<2; i++) {
35        if (num == i && sscanf(ptr, "%*d:%*2d:%*2d%*1[,.]%*3d --> %*d:%*2d:%*2d%*1[,.]%3d", &v) == 1)
36            return AVPROBE_SCORE_MAX;
37        num = atoi(ptr);
38        ptr += strcspn(ptr, "\n") + 1;
39    }
40    return 0;
41}
42
43static int srt_read_header(AVFormatContext *s, AVFormatParameters *ap)
44{
45    AVStream *st = avformat_new_stream(s, NULL);
46    if (!st)
47        return -1;
48    avpriv_set_pts_info(st, 64, 1, 1000);
49    st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
50    st->codec->codec_id   = CODEC_ID_SRT;
51    return 0;
52}
53
54static int64_t get_pts(const char *buf)
55{
56    int i, v, hour, min, sec, hsec;
57
58    for (i=0; i<2; i++) {
59        if (sscanf(buf, "%d:%2d:%2d%*1[,.]%3d --> %*d:%*2d:%*2d%*1[,.]%3d",
60                   &hour, &min, &sec, &hsec, &v) == 5) {
61            min += 60*hour;
62            sec += 60*min;
63            return sec*1000+hsec;
64        }
65        buf += strcspn(buf, "\n") + 1;
66    }
67    return AV_NOPTS_VALUE;
68}
69
70static inline int is_eol(char c)
71{
72    return c == '\r' || c == '\n';
73}
74
75static int srt_read_packet(AVFormatContext *s, AVPacket *pkt)
76{
77    char buffer[2048], *ptr = buffer, *ptr2;
78    int64_t pos = avio_tell(s->pb);
79    int res = AVERROR_EOF;
80
81    do {
82        ptr2 = ptr;
83        ptr += ff_get_line(s->pb, ptr, sizeof(buffer)+buffer-ptr);
84    } while (!is_eol(*ptr2) && !s->pb->eof_reached && ptr-buffer<sizeof(buffer)-1);
85
86    if (buffer[0] && !(res = av_new_packet(pkt, ptr-buffer))) {
87        memcpy(pkt->data, buffer, pkt->size);
88        pkt->flags |= AV_PKT_FLAG_KEY;
89        pkt->pos = pos;
90        pkt->pts = pkt->dts = get_pts(pkt->data);
91    }
92    return res;
93}
94
95AVInputFormat ff_srt_demuxer = {
96    .name        = "srt",
97    .long_name   = NULL_IF_CONFIG_SMALL("SubRip subtitle format"),
98    .read_probe  = srt_probe,
99    .read_header = srt_read_header,
100    .read_packet = srt_read_packet,
101    .flags       = AVFMT_GENERIC_INDEX,
102};
103