1 /*
2 * SSA/ASS demuxer
3 * Copyright (c) 2008 Michael Niedermayer
4 * Copyright (c) 2014 Clément Bœsch
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 #include <stdint.h>
24
25 #include "avformat.h"
26 #include "internal.h"
27 #include "subtitles.h"
28 #include "libavutil/bprint.h"
29
30 typedef struct ASSContext {
31 FFDemuxSubtitlesQueue q;
32 unsigned readorder;
33 } ASSContext;
34
ass_probe(const AVProbeData *p)35 static int ass_probe(const AVProbeData *p)
36 {
37 char buf[13];
38 FFTextReader tr;
39 ff_text_init_buf(&tr, p->buf, p->buf_size);
40
41 while (ff_text_peek_r8(&tr) == '\r' || ff_text_peek_r8(&tr) == '\n')
42 ff_text_r8(&tr);
43
44 ff_text_read(&tr, buf, sizeof(buf));
45
46 if (!memcmp(buf, "[Script Info]", 13))
47 return AVPROBE_SCORE_MAX;
48
49 return 0;
50 }
51
read_dialogue(ASSContext *ass, AVBPrint *dst, const uint8_t *p, int64_t *start, int *duration)52 static int read_dialogue(ASSContext *ass, AVBPrint *dst, const uint8_t *p,
53 int64_t *start, int *duration)
54 {
55 int pos = 0;
56 int64_t end;
57 int hh1, mm1, ss1, ms1;
58 int hh2, mm2, ss2, ms2;
59
60 if (sscanf(p, "Dialogue: %*[^,],%d:%d:%d%*c%d,%d:%d:%d%*c%d,%n",
61 &hh1, &mm1, &ss1, &ms1,
62 &hh2, &mm2, &ss2, &ms2, &pos) >= 8 && pos > 0) {
63
64 /* This is not part of the sscanf itself in order to handle an actual
65 * number (which would be the Layer) or the form "Marked=N" (which is
66 * the old SSA field, now replaced by Layer, and will lead to Layer
67 * being 0 here). */
68 const int layer = atoi(p + 10);
69
70 end = (hh2*3600LL + mm2*60LL + ss2) * 100LL + ms2;
71 *start = (hh1*3600LL + mm1*60LL + ss1) * 100LL + ms1;
72 *duration = end - *start;
73
74 av_bprint_clear(dst);
75 av_bprintf(dst, "%u,%d,%s", ass->readorder++, layer, p + pos);
76
77 /* right strip the buffer */
78 while (dst->len > 0 &&
79 dst->str[dst->len - 1] == '\r' ||
80 dst->str[dst->len - 1] == '\n')
81 dst->str[--dst->len] = 0;
82 return 0;
83 }
84 return -1;
85 }
86
get_line(AVBPrint *buf, FFTextReader *tr)87 static int64_t get_line(AVBPrint *buf, FFTextReader *tr)
88 {
89 int64_t pos = ff_text_pos(tr);
90
91 av_bprint_clear(buf);
92 for (;;) {
93 char c = ff_text_r8(tr);
94 if (!c)
95 break;
96 av_bprint_chars(buf, c, 1);
97 if (c == '\n')
98 break;
99 }
100 return pos;
101 }
102
ass_read_header(AVFormatContext *s)103 static int ass_read_header(AVFormatContext *s)
104 {
105 ASSContext *ass = s->priv_data;
106 AVBPrint header, line, rline;
107 int res = 0;
108 AVStream *st;
109 FFTextReader tr;
110 ff_text_init_avio(s, &tr, s->pb);
111
112 st = avformat_new_stream(s, NULL);
113 if (!st)
114 return AVERROR(ENOMEM);
115 avpriv_set_pts_info(st, 64, 1, 100);
116 st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;
117 st->codecpar->codec_id = AV_CODEC_ID_ASS;
118
119 av_bprint_init(&header, 0, AV_BPRINT_SIZE_UNLIMITED);
120 av_bprint_init(&line, 0, AV_BPRINT_SIZE_UNLIMITED);
121 av_bprint_init(&rline, 0, AV_BPRINT_SIZE_UNLIMITED);
122
123 ass->q.keep_duplicates = 1;
124
125 for (;;) {
126 int64_t pos = get_line(&line, &tr);
127 int64_t ts_start = AV_NOPTS_VALUE;
128 int duration = -1;
129 AVPacket *sub;
130
131 if (!line.str[0]) // EOF
132 break;
133
134 if (read_dialogue(ass, &rline, line.str, &ts_start, &duration) < 0) {
135 av_bprintf(&header, "%s", line.str);
136 continue;
137 }
138 sub = ff_subtitles_queue_insert(&ass->q, rline.str, rline.len, 0);
139 if (!sub) {
140 res = AVERROR(ENOMEM);
141 goto end;
142 }
143 sub->pos = pos;
144 sub->pts = ts_start;
145 sub->duration = duration;
146 }
147
148 res = ff_bprint_to_codecpar_extradata(st->codecpar, &header);
149 if (res < 0)
150 goto end;
151
152 ff_subtitles_queue_finalize(s, &ass->q);
153
154 end:
155 av_bprint_finalize(&header, NULL);
156 av_bprint_finalize(&line, NULL);
157 av_bprint_finalize(&rline, NULL);
158 return res;
159 }
160
161 const AVInputFormat ff_ass_demuxer = {
162 .name = "ass",
163 .long_name = NULL_IF_CONFIG_SMALL("SSA (SubStation Alpha) subtitle"),
164 .flags_internal = FF_FMT_INIT_CLEANUP,
165 .priv_data_size = sizeof(ASSContext),
166 .read_probe = ass_probe,
167 .read_header = ass_read_header,
168 .read_packet = ff_subtitles_read_packet,
169 .read_close = ff_subtitles_read_close,
170 .read_seek2 = ff_subtitles_read_seek,
171 };
172