1/*
2 * SubRip subtitle demuxer
3 * Copyright (c) 2010  Aurelien Jacobs <aurel@gnuage.org>
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg 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 * FFmpeg 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 FFmpeg; 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 "subtitles.h"
25#include "libavutil/bprint.h"
26#include "libavutil/intreadwrite.h"
27
28typedef struct {
29    FFDemuxSubtitlesQueue q;
30} SRTContext;
31
32static int srt_probe(AVProbeData *p)
33{
34    const unsigned char *ptr = p->buf;
35    int i, v, num = 0;
36
37    if (AV_RB24(ptr) == 0xEFBBBF)
38        ptr += 3;  /* skip UTF-8 BOM */
39
40    while (*ptr == '\r' || *ptr == '\n')
41        ptr++;
42    for (i=0; i<2; i++) {
43        if ((num == i || num + 1 == i)
44            && sscanf(ptr, "%*d:%*2d:%*2d%*1[,.]%*3d --> %*d:%*2d:%*2d%*1[,.]%3d", &v) == 1)
45            return AVPROBE_SCORE_MAX;
46        num = atoi(ptr);
47        ptr += ff_subtitles_next_line(ptr);
48    }
49    return 0;
50}
51
52static int64_t get_pts(const char **buf, int *duration,
53                       int32_t *x1, int32_t *y1, int32_t *x2, int32_t *y2)
54{
55    int i;
56
57    for (i=0; i<2; i++) {
58        int hh1, mm1, ss1, ms1;
59        int hh2, mm2, ss2, ms2;
60        if (sscanf(*buf, "%d:%2d:%2d%*1[,.]%3d --> %d:%2d:%2d%*1[,.]%3d"
61                   "%*[ ]X1:%u X2:%u Y1:%u Y2:%u",
62                   &hh1, &mm1, &ss1, &ms1,
63                   &hh2, &mm2, &ss2, &ms2,
64                   x1, x2, y1, y2) >= 8) {
65            int64_t start = (hh1*3600LL + mm1*60LL + ss1) * 1000LL + ms1;
66            int64_t end   = (hh2*3600LL + mm2*60LL + ss2) * 1000LL + ms2;
67            *duration = end - start;
68            *buf += ff_subtitles_next_line(*buf);
69            return start;
70        }
71        *buf += ff_subtitles_next_line(*buf);
72    }
73    return AV_NOPTS_VALUE;
74}
75
76static int srt_read_header(AVFormatContext *s)
77{
78    SRTContext *srt = s->priv_data;
79    AVBPrint buf;
80    AVStream *st = avformat_new_stream(s, NULL);
81    int res = 0;
82
83    if (!st)
84        return AVERROR(ENOMEM);
85    avpriv_set_pts_info(st, 64, 1, 1000);
86    st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
87    st->codec->codec_id   = AV_CODEC_ID_SUBRIP;
88
89    av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
90
91    while (!url_feof(s->pb)) {
92        ff_subtitles_read_chunk(s->pb, &buf);
93
94        if (buf.len) {
95            int64_t pos = avio_tell(s->pb);
96            int64_t pts;
97            int duration;
98            const char *ptr = buf.str;
99            int32_t x1 = -1, y1 = -1, x2 = -1, y2 = -1;
100            AVPacket *sub;
101
102            pts = get_pts(&ptr, &duration, &x1, &y1, &x2, &y2);
103            if (pts != AV_NOPTS_VALUE) {
104                int len = buf.len - (ptr - buf.str);
105                if (len <= 0)
106                    continue;
107                sub = ff_subtitles_queue_insert(&srt->q, ptr, len, 0);
108                if (!sub) {
109                    res = AVERROR(ENOMEM);
110                    goto end;
111                }
112                sub->pos = pos;
113                sub->pts = pts;
114                sub->duration = duration;
115                if (x1 != -1) {
116                    uint8_t *p = av_packet_new_side_data(sub, AV_PKT_DATA_SUBTITLE_POSITION, 16);
117                    if (p) {
118                        AV_WL32(p,      x1);
119                        AV_WL32(p +  4, y1);
120                        AV_WL32(p +  8, x2);
121                        AV_WL32(p + 12, y2);
122                    }
123                }
124            }
125        }
126    }
127
128    ff_subtitles_queue_finalize(&srt->q);
129
130end:
131    av_bprint_finalize(&buf, NULL);
132    return res;
133}
134
135static int srt_read_packet(AVFormatContext *s, AVPacket *pkt)
136{
137    SRTContext *srt = s->priv_data;
138    return ff_subtitles_queue_read_packet(&srt->q, pkt);
139}
140
141static int srt_read_seek(AVFormatContext *s, int stream_index,
142                         int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
143{
144    SRTContext *srt = s->priv_data;
145    return ff_subtitles_queue_seek(&srt->q, s, stream_index,
146                                   min_ts, ts, max_ts, flags);
147}
148
149static int srt_read_close(AVFormatContext *s)
150{
151    SRTContext *srt = s->priv_data;
152    ff_subtitles_queue_clean(&srt->q);
153    return 0;
154}
155
156AVInputFormat ff_srt_demuxer = {
157    .name        = "srt",
158    .long_name   = NULL_IF_CONFIG_SMALL("SubRip subtitle"),
159    .priv_data_size = sizeof(SRTContext),
160    .read_probe  = srt_probe,
161    .read_header = srt_read_header,
162    .read_packet = srt_read_packet,
163    .read_seek2  = srt_read_seek,
164    .read_close  = srt_read_close,
165};
166