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 "libavcodec/internal.h"
29 #include "libavutil/bprint.h"
30
31 typedef struct ASSContext {
32 FFDemuxSubtitlesQueue q;
33 unsigned readorder;
34 } ASSContext;
35
ass_probe(const AVProbeData * p)36 static int ass_probe(const AVProbeData *p)
37 {
38 char buf[13];
39 FFTextReader tr;
40 ff_text_init_buf(&tr, p->buf, p->buf_size);
41
42 while (ff_text_peek_r8(&tr) == '\r' || ff_text_peek_r8(&tr) == '\n')
43 ff_text_r8(&tr);
44
45 ff_text_read(&tr, buf, sizeof(buf));
46
47 if (!memcmp(buf, "[Script Info]", 13))
48 return AVPROBE_SCORE_MAX;
49
50 return 0;
51 }
52
ass_read_close(AVFormatContext * s)53 static int ass_read_close(AVFormatContext *s)
54 {
55 ASSContext *ass = s->priv_data;
56 ff_subtitles_queue_clean(&ass->q);
57 return 0;
58 }
59
read_dialogue(ASSContext * ass,AVBPrint * dst,const uint8_t * p,int64_t * start,int * duration)60 static int read_dialogue(ASSContext *ass, AVBPrint *dst, const uint8_t *p,
61 int64_t *start, int *duration)
62 {
63 int pos = 0;
64 int64_t end;
65 int hh1, mm1, ss1, ms1;
66 int hh2, mm2, ss2, ms2;
67
68 if (sscanf(p, "Dialogue: %*[^,],%d:%d:%d%*c%d,%d:%d:%d%*c%d,%n",
69 &hh1, &mm1, &ss1, &ms1,
70 &hh2, &mm2, &ss2, &ms2, &pos) >= 8 && pos > 0) {
71
72 /* This is not part of the sscanf itself in order to handle an actual
73 * number (which would be the Layer) or the form "Marked=N" (which is
74 * the old SSA field, now replaced by Layer, and will lead to Layer
75 * being 0 here). */
76 const int layer = atoi(p + 10);
77
78 end = (hh2*3600LL + mm2*60LL + ss2) * 100LL + ms2;
79 *start = (hh1*3600LL + mm1*60LL + ss1) * 100LL + ms1;
80 *duration = end - *start;
81
82 av_bprint_clear(dst);
83 av_bprintf(dst, "%u,%d,%s", ass->readorder++, layer, p + pos);
84
85 /* right strip the buffer */
86 while (dst->len > 0 &&
87 dst->str[dst->len - 1] == '\r' ||
88 dst->str[dst->len - 1] == '\n')
89 dst->str[--dst->len] = 0;
90 return 0;
91 }
92 return -1;
93 }
94
get_line(AVBPrint * buf,FFTextReader * tr)95 static int64_t get_line(AVBPrint *buf, FFTextReader *tr)
96 {
97 int64_t pos = ff_text_pos(tr);
98
99 av_bprint_clear(buf);
100 for (;;) {
101 char c = ff_text_r8(tr);
102 if (!c)
103 break;
104 av_bprint_chars(buf, c, 1);
105 if (c == '\n')
106 break;
107 }
108 return pos;
109 }
110
ass_read_header(AVFormatContext * s)111 static int ass_read_header(AVFormatContext *s)
112 {
113 ASSContext *ass = s->priv_data;
114 AVBPrint header, line, rline;
115 int res = 0;
116 AVStream *st;
117 FFTextReader tr;
118 ff_text_init_avio(s, &tr, s->pb);
119
120 st = avformat_new_stream(s, NULL);
121 if (!st)
122 return AVERROR(ENOMEM);
123 avpriv_set_pts_info(st, 64, 1, 100);
124 st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;
125 st->codecpar->codec_id = AV_CODEC_ID_ASS;
126
127 av_bprint_init(&header, 0, AV_BPRINT_SIZE_UNLIMITED);
128 av_bprint_init(&line, 0, AV_BPRINT_SIZE_UNLIMITED);
129 av_bprint_init(&rline, 0, AV_BPRINT_SIZE_UNLIMITED);
130
131 ass->q.keep_duplicates = 1;
132
133 for (;;) {
134 int64_t pos = get_line(&line, &tr);
135 int64_t ts_start = AV_NOPTS_VALUE;
136 int duration = -1;
137 AVPacket *sub;
138
139 if (!line.str[0]) // EOF
140 break;
141
142 if (read_dialogue(ass, &rline, line.str, &ts_start, &duration) < 0) {
143 av_bprintf(&header, "%s", line.str);
144 continue;
145 }
146 sub = ff_subtitles_queue_insert(&ass->q, rline.str, rline.len, 0);
147 if (!sub) {
148 res = AVERROR(ENOMEM);
149 goto end;
150 }
151 sub->pos = pos;
152 sub->pts = ts_start;
153 sub->duration = duration;
154 }
155
156 res = ff_bprint_to_codecpar_extradata(st->codecpar, &header);
157 if (res < 0)
158 goto end;
159
160 ff_subtitles_queue_finalize(s, &ass->q);
161
162 end:
163 av_bprint_finalize(&header, NULL);
164 av_bprint_finalize(&line, NULL);
165 av_bprint_finalize(&rline, NULL);
166 return res;
167 }
168
ass_read_packet(AVFormatContext * s,AVPacket * pkt)169 static int ass_read_packet(AVFormatContext *s, AVPacket *pkt)
170 {
171 ASSContext *ass = s->priv_data;
172 return ff_subtitles_queue_read_packet(&ass->q, pkt);
173 }
174
ass_read_seek(AVFormatContext * s,int stream_index,int64_t min_ts,int64_t ts,int64_t max_ts,int flags)175 static int ass_read_seek(AVFormatContext *s, int stream_index,
176 int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
177 {
178 ASSContext *ass = s->priv_data;
179 return ff_subtitles_queue_seek(&ass->q, s, stream_index,
180 min_ts, ts, max_ts, flags);
181 }
182
183 AVInputFormat ff_ass_demuxer = {
184 .name = "ass",
185 .long_name = NULL_IF_CONFIG_SMALL("SSA (SubStation Alpha) subtitle"),
186 .priv_data_size = sizeof(ASSContext),
187 .read_probe = ass_probe,
188 .read_header = ass_read_header,
189 .read_packet = ass_read_packet,
190 .read_close = ass_read_close,
191 .read_seek2 = ass_read_seek,
192 };
193