1/*
2 * SSA/ASS demuxer
3 * Copyright (c) 2008 Michael Niedermayer
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 <stdint.h>
23
24#include "avformat.h"
25#include "internal.h"
26#include "subtitles.h"
27#include "libavcodec/internal.h"
28#include "libavutil/bprint.h"
29
30typedef struct ASSContext {
31    FFDemuxSubtitlesQueue q;
32} ASSContext;
33
34static int ass_probe(AVProbeData *p)
35{
36    const char *header = "[Script Info]";
37
38    if (!memcmp(p->buf, header, strlen(header)) ||
39        !memcmp(p->buf + 3, header, strlen(header)))
40        return AVPROBE_SCORE_MAX;
41
42    return 0;
43}
44
45static int ass_read_close(AVFormatContext *s)
46{
47    ASSContext *ass = s->priv_data;
48    ff_subtitles_queue_clean(&ass->q);
49    return 0;
50}
51
52static int read_ts(const uint8_t *p, int64_t *start, int *duration)
53{
54    int64_t end;
55    int hh1, mm1, ss1, ms1;
56    int hh2, mm2, ss2, ms2;
57
58    if (sscanf(p, "%*[^,],%d:%d:%d%*c%d,%d:%d:%d%*c%d",
59               &hh1, &mm1, &ss1, &ms1,
60               &hh2, &mm2, &ss2, &ms2) == 8) {
61        end    = (hh2*3600LL + mm2*60LL + ss2) * 100LL + ms2;
62        *start = (hh1*3600LL + mm1*60LL + ss1) * 100LL + ms1;
63        *duration = end - *start;
64        return 0;
65    }
66    return -1;
67}
68
69static int64_t get_line(AVBPrint *buf, AVIOContext *pb)
70{
71    int64_t pos = avio_tell(pb);
72
73    av_bprint_clear(buf);
74    for (;;) {
75        char c = avio_r8(pb);
76        if (!c)
77            break;
78        av_bprint_chars(buf, c, 1);
79        if (c == '\n')
80            break;
81    }
82    return pos;
83}
84
85static int ass_read_header(AVFormatContext *s)
86{
87    ASSContext *ass = s->priv_data;
88    AVBPrint header, line;
89    int header_remaining, res = 0;
90    AVStream *st;
91
92    st = avformat_new_stream(s, NULL);
93    if (!st)
94        return AVERROR(ENOMEM);
95    avpriv_set_pts_info(st, 64, 1, 100);
96    st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
97    st->codec->codec_id   = AV_CODEC_ID_SSA;
98
99    header_remaining = INT_MAX;
100
101    av_bprint_init(&header, 0, AV_BPRINT_SIZE_UNLIMITED);
102    av_bprint_init(&line,   0, AV_BPRINT_SIZE_UNLIMITED);
103
104    for (;;) {
105        int64_t pos = get_line(&line, s->pb);
106
107        if (!line.str[0]) // EOF
108            break;
109
110        if (!memcmp(line.str, "[Events]", 8))
111            header_remaining = 2;
112        else if (line.str[0] == '[')
113            header_remaining = INT_MAX;
114
115        if (header_remaining) {
116            av_bprintf(&header, "%s", line.str);
117            header_remaining--;
118        } else {
119            int64_t ts_start = AV_NOPTS_VALUE;
120            int duration = -1;
121            AVPacket *sub;
122
123            if (read_ts(line.str, &ts_start, &duration) < 0)
124                continue;
125            sub = ff_subtitles_queue_insert(&ass->q, line.str, line.len, 0);
126            if (!sub) {
127                res = AVERROR(ENOMEM);
128                goto end;
129            }
130            sub->pos = pos;
131            sub->pts = ts_start;
132            sub->duration = duration;
133        }
134    }
135
136    av_bprint_finalize(&line, NULL);
137
138    res = avpriv_bprint_to_extradata(st->codec, &header);
139    if (res < 0)
140        goto end;
141
142    ff_subtitles_queue_finalize(&ass->q);
143
144end:
145    return res;
146}
147
148static int ass_read_packet(AVFormatContext *s, AVPacket *pkt)
149{
150    ASSContext *ass = s->priv_data;
151    return ff_subtitles_queue_read_packet(&ass->q, pkt);
152}
153
154static int ass_read_seek(AVFormatContext *s, int stream_index,
155                         int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
156{
157    ASSContext *ass = s->priv_data;
158    return ff_subtitles_queue_seek(&ass->q, s, stream_index,
159                                   min_ts, ts, max_ts, flags);
160}
161
162AVInputFormat ff_ass_demuxer = {
163    .name           = "ass",
164    .long_name      = NULL_IF_CONFIG_SMALL("SSA (SubStation Alpha) subtitle"),
165    .priv_data_size = sizeof(ASSContext),
166    .read_probe     = ass_probe,
167    .read_header    = ass_read_header,
168    .read_packet    = ass_read_packet,
169    .read_close     = ass_read_close,
170    .read_seek2     = ass_read_seek,
171};
172