1/*
2 * Copyright (c) 2012 Cl��ment B��sch
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21/**
22 * @file
23 * RealText subtitle demuxer
24 * @see http://service.real.com/help/library/guides/ProductionGuide/prodguide/htmfiles/realtext.htm
25 */
26
27#include "avformat.h"
28#include "internal.h"
29#include "subtitles.h"
30#include "libavutil/avstring.h"
31#include "libavutil/bprint.h"
32#include "libavutil/intreadwrite.h"
33
34typedef struct {
35    FFDemuxSubtitlesQueue q;
36} RealTextContext;
37
38static int realtext_probe(AVProbeData *p)
39{
40    const unsigned char *ptr = p->buf;
41
42    if (AV_RB24(ptr) == 0xEFBBBF)
43        ptr += 3;  /* skip UTF-8 BOM */
44    return !av_strncasecmp(ptr, "<window", 7) ? AVPROBE_SCORE_EXTENSION : 0;
45}
46
47static int read_ts(const char *s)
48{
49    int hh, mm, ss, ms;
50
51    if (sscanf(s, "%u:%u:%u.%u", &hh, &mm, &ss, &ms) == 4) return (hh*3600 + mm*60 + ss) * 100 + ms;
52    if (sscanf(s, "%u:%u:%u"   , &hh, &mm, &ss     ) == 3) return (hh*3600 + mm*60 + ss) * 100;
53    if (sscanf(s,    "%u:%u.%u",      &mm, &ss, &ms) == 3) return (          mm*60 + ss) * 100 + ms;
54    if (sscanf(s,    "%u:%u"   ,      &mm, &ss     ) == 2) return (          mm*60 + ss) * 100;
55    if (sscanf(s,       "%u.%u",           &ss, &ms) == 2) return (                  ss) * 100 + ms;
56    return strtol(s, NULL, 10) * 100;
57}
58
59static int realtext_read_header(AVFormatContext *s)
60{
61    RealTextContext *rt = s->priv_data;
62    AVStream *st = avformat_new_stream(s, NULL);
63    AVBPrint buf;
64    char c = 0;
65    int res = 0, duration = read_ts("60"); // default duration is 60 seconds
66
67    if (!st)
68        return AVERROR(ENOMEM);
69    avpriv_set_pts_info(st, 64, 1, 100);
70    st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
71    st->codec->codec_id   = AV_CODEC_ID_REALTEXT;
72
73    av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
74
75    while (!url_feof(s->pb)) {
76        AVPacket *sub;
77        const int64_t pos = avio_tell(s->pb) - (c != 0);
78        int n = ff_smil_extract_next_chunk(s->pb, &buf, &c);
79
80        if (n == 0)
81            break;
82
83        if (!av_strncasecmp(buf.str, "<window", 7)) {
84            /* save header to extradata */
85            const char *p = ff_smil_get_attr_ptr(buf.str, "duration");
86
87            if (p)
88                duration = read_ts(p);
89            st->codec->extradata = av_strdup(buf.str);
90            if (!st->codec->extradata) {
91                res = AVERROR(ENOMEM);
92                goto end;
93            }
94            st->codec->extradata_size = buf.len + 1;
95        } else {
96            /* if we just read a <time> tag, introduce a new event, otherwise merge
97             * with the previous one */
98            int merge = !av_strncasecmp(buf.str, "<time", 5) ? 0 : 1;
99            sub = ff_subtitles_queue_insert(&rt->q, buf.str, buf.len, merge);
100            if (!sub) {
101                res = AVERROR(ENOMEM);
102                goto end;
103            }
104            if (!merge) {
105                const char *begin = ff_smil_get_attr_ptr(buf.str, "begin");
106                const char *end   = ff_smil_get_attr_ptr(buf.str, "end");
107
108                sub->pos      = pos;
109                sub->pts      = begin ? read_ts(begin) : 0;
110                sub->duration = end ? (read_ts(end) - sub->pts) : duration;
111            }
112        }
113        av_bprint_clear(&buf);
114    }
115    ff_subtitles_queue_finalize(&rt->q);
116
117end:
118    av_bprint_finalize(&buf, NULL);
119    return res;
120}
121
122static int realtext_read_packet(AVFormatContext *s, AVPacket *pkt)
123{
124    RealTextContext *rt = s->priv_data;
125    return ff_subtitles_queue_read_packet(&rt->q, pkt);
126}
127
128static int realtext_read_seek(AVFormatContext *s, int stream_index,
129                             int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
130{
131    RealTextContext *rt = s->priv_data;
132    return ff_subtitles_queue_seek(&rt->q, s, stream_index,
133                                   min_ts, ts, max_ts, flags);
134}
135
136static int realtext_read_close(AVFormatContext *s)
137{
138    RealTextContext *rt = s->priv_data;
139    ff_subtitles_queue_clean(&rt->q);
140    return 0;
141}
142
143AVInputFormat ff_realtext_demuxer = {
144    .name           = "realtext",
145    .long_name      = NULL_IF_CONFIG_SMALL("RealText subtitle format"),
146    .priv_data_size = sizeof(RealTextContext),
147    .read_probe     = realtext_probe,
148    .read_header    = realtext_read_header,
149    .read_packet    = realtext_read_packet,
150    .read_seek2     = realtext_read_seek,
151    .read_close     = realtext_read_close,
152    .extensions     = "rt",
153};
154