summaryrefslogtreecommitdiff
path: root/libavformat/srtdec.c
blob: 908933184999169cae8bf76a90ffe7df42dfeeaf (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
/*
 * 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 || num + 1 == 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   = AV_CODEC_ID_SUBRIP;
    return 0;
}

static int64_t get_pts(char **buf, int *duration,
                       int32_t *x1, int32_t *y1, int32_t *x2, int32_t *y2)
{
    int i;

    for (i=0; i<2; i++) {
        int hh1, mm1, ss1, ms1;
        int hh2, mm2, ss2, ms2;
        if (sscanf(*buf, "%d:%2d:%2d%*1[,.]%3d --> %d:%2d:%2d%*1[,.]%3d"
                   "%*[ ]X1:%u X2:%u Y1:%u Y2:%u",
                   &hh1, &mm1, &ss1, &ms1,
                   &hh2, &mm2, &ss2, &ms2,
                   x1, x2, y1, y2) >= 8) {
            int64_t start = (hh1*3600LL + mm1*60LL + ss1) * 1000LL + ms1;
            int64_t end   = (hh2*3600LL + mm2*60LL + ss2) * 1000LL + ms2;
            *duration = end - start;
            *buf += strcspn(*buf, "\n") + 1;
            return start;
        }
        *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]) {
        int64_t pts;
        int duration;
        const char *end = ptr;
        int32_t x1 = -1, y1 = -1, x2 = -1, y2 = -1;

        ptr = buffer;
        pts = get_pts(&ptr, &duration, &x1, &y1, &x2, &y2);
        if (pts != AV_NOPTS_VALUE &&
            !(res = av_new_packet(pkt, end - ptr))) {
            memcpy(pkt->data, ptr, pkt->size);
            pkt->flags |= AV_PKT_FLAG_KEY;
            pkt->pos = pos;
            pkt->pts = pkt->dts = pts;
            pkt->duration = duration;
            if (x1 != -1) {
                uint8_t *p = av_packet_new_side_data(pkt, AV_PKT_DATA_SUBTITLE_POSITION, 16);
                if (p) {
                    AV_WL32(p,      x1);
                    AV_WL32(p +  4, y1);
                    AV_WL32(p +  8, x2);
                    AV_WL32(p + 12, y2);
                }
            }
        }
    }
    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,
};