1 /*
2 * SSA/ASS muxer
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 "libavutil/avstring.h"
23 #include "avformat.h"
24 #include "internal.h"
25
26 #include "libavutil/opt.h"
27
28 typedef struct DialogueLine {
29 int readorder;
30 char *line;
31 struct DialogueLine *prev, *next;
32 } DialogueLine;
33
34 typedef struct ASSContext {
35 const AVClass *class;
36 int expected_readorder;
37 DialogueLine *dialogue_cache;
38 DialogueLine *last_added_dialogue;
39 int cache_size;
40 int ssa_mode;
41 int ignore_readorder;
42 uint8_t *trailer;
43 size_t trailer_size;
44 } ASSContext;
45
write_header(AVFormatContext * s)46 static int write_header(AVFormatContext *s)
47 {
48 ASSContext *ass = s->priv_data;
49 AVCodecParameters *par = s->streams[0]->codecpar;
50
51 if (s->nb_streams != 1 || par->codec_id != AV_CODEC_ID_ASS) {
52 av_log(s, AV_LOG_ERROR, "Exactly one ASS/SSA stream is needed.\n");
53 return AVERROR(EINVAL);
54 }
55 avpriv_set_pts_info(s->streams[0], 64, 1, 100);
56 if (par->extradata_size > 0) {
57 size_t header_size = par->extradata_size;
58 uint8_t *trailer = strstr(par->extradata, "\n[Events]");
59
60 if (trailer)
61 trailer = strstr(trailer, "Format:");
62 if (trailer)
63 trailer = strstr(trailer, "\n");
64
65 if (trailer++) {
66 header_size = (trailer - par->extradata);
67 ass->trailer_size = par->extradata_size - header_size;
68 if (ass->trailer_size)
69 ass->trailer = trailer;
70 }
71
72 avio_write(s->pb, par->extradata, header_size);
73 if (par->extradata[header_size - 1] != '\n')
74 avio_write(s->pb, "\r\n", 2);
75 ass->ssa_mode = !strstr(par->extradata, "\n[V4+ Styles]");
76 if (!strstr(par->extradata, "\n[Events]"))
77 avio_printf(s->pb, "[Events]\r\nFormat: %s, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text\r\n",
78 ass->ssa_mode ? "Marked" : "Layer");
79 }
80
81 return 0;
82 }
83
purge_dialogues(AVFormatContext * s,int force)84 static void purge_dialogues(AVFormatContext *s, int force)
85 {
86 int n = 0;
87 ASSContext *ass = s->priv_data;
88 DialogueLine *dialogue = ass->dialogue_cache;
89
90 while (dialogue && (dialogue->readorder == ass->expected_readorder || force)) {
91 DialogueLine *next = dialogue->next;
92 if (dialogue->readorder != ass->expected_readorder) {
93 av_log(s, AV_LOG_WARNING, "ReadOrder gap found between %d and %d\n",
94 ass->expected_readorder, dialogue->readorder);
95 ass->expected_readorder = dialogue->readorder;
96 }
97 avio_print(s->pb, "Dialogue: ", dialogue->line, "\r\n");
98 if (dialogue == ass->last_added_dialogue)
99 ass->last_added_dialogue = next;
100 av_freep(&dialogue->line);
101 av_free(dialogue);
102 if (next)
103 next->prev = NULL;
104 dialogue = ass->dialogue_cache = next;
105 ass->expected_readorder++;
106 n++;
107 }
108 ass->cache_size -= n;
109 if (n > 1)
110 av_log(s, AV_LOG_DEBUG, "wrote %d ASS lines, cached dialogues: %d, waiting for event id %d\n",
111 n, ass->cache_size, ass->expected_readorder);
112 }
113
insert_dialogue(ASSContext * ass,DialogueLine * dialogue)114 static void insert_dialogue(ASSContext *ass, DialogueLine *dialogue)
115 {
116 DialogueLine *cur, *next = NULL, *prev = NULL;
117
118 /* from the last added to the end of the list */
119 if (ass->last_added_dialogue) {
120 for (cur = ass->last_added_dialogue; cur; cur = cur->next) {
121 if (cur->readorder > dialogue->readorder)
122 break;
123 prev = cur;
124 next = cur->next;
125 }
126 }
127
128 /* from the beginning to the last one added */
129 if (!prev) {
130 next = ass->dialogue_cache;
131 for (cur = next; cur != ass->last_added_dialogue; cur = cur->next) {
132 if (cur->readorder > dialogue->readorder)
133 break;
134 prev = cur;
135 next = cur->next;
136 }
137 }
138
139 if (prev) {
140 prev->next = dialogue;
141 dialogue->prev = prev;
142 } else {
143 dialogue->prev = ass->dialogue_cache;
144 ass->dialogue_cache = dialogue;
145 }
146 if (next) {
147 next->prev = dialogue;
148 dialogue->next = next;
149 }
150 ass->cache_size++;
151 ass->last_added_dialogue = dialogue;
152 }
153
write_packet(AVFormatContext * s,AVPacket * pkt)154 static int write_packet(AVFormatContext *s, AVPacket *pkt)
155 {
156 ASSContext *ass = s->priv_data;
157
158 long int layer;
159 char *p = pkt->data;
160 int64_t start = pkt->pts;
161 int64_t end = start + pkt->duration;
162 int hh1, mm1, ss1, ms1;
163 int hh2, mm2, ss2, ms2;
164 DialogueLine *dialogue = av_mallocz(sizeof(*dialogue));
165
166 if (!dialogue)
167 return AVERROR(ENOMEM);
168
169 dialogue->readorder = strtol(p, &p, 10);
170 if (dialogue->readorder < ass->expected_readorder)
171 av_log(s, AV_LOG_WARNING, "Unexpected ReadOrder %d\n",
172 dialogue->readorder);
173 if (*p == ',')
174 p++;
175
176 if (ass->ssa_mode && !strncmp(p, "Marked=", 7))
177 p += 7;
178
179 layer = strtol(p, &p, 10);
180 if (*p == ',')
181 p++;
182 hh1 = (int)(start / 360000); mm1 = (int)(start / 6000) % 60;
183 hh2 = (int)(end / 360000); mm2 = (int)(end / 6000) % 60;
184 ss1 = (int)(start / 100) % 60; ms1 = (int)(start % 100);
185 ss2 = (int)(end / 100) % 60; ms2 = (int)(end % 100);
186 if (hh1 > 9) hh1 = 9, mm1 = 59, ss1 = 59, ms1 = 99;
187 if (hh2 > 9) hh2 = 9, mm2 = 59, ss2 = 59, ms2 = 99;
188
189 dialogue->line = av_asprintf("%s%ld,%d:%02d:%02d.%02d,%d:%02d:%02d.%02d,%s",
190 ass->ssa_mode ? "Marked=" : "",
191 layer, hh1, mm1, ss1, ms1, hh2, mm2, ss2, ms2, p);
192 if (!dialogue->line) {
193 av_free(dialogue);
194 return AVERROR(ENOMEM);
195 }
196 insert_dialogue(ass, dialogue);
197 purge_dialogues(s, ass->ignore_readorder);
198
199 return 0;
200 }
201
write_trailer(AVFormatContext * s)202 static int write_trailer(AVFormatContext *s)
203 {
204 ASSContext *ass = s->priv_data;
205
206 purge_dialogues(s, 1);
207
208 if (ass->trailer) {
209 avio_write(s->pb, ass->trailer, ass->trailer_size);
210 }
211
212 return 0;
213 }
214
215 #define OFFSET(x) offsetof(ASSContext, x)
216 #define E AV_OPT_FLAG_ENCODING_PARAM
217 static const AVOption options[] = {
218 { "ignore_readorder", "write events immediately, even if they're out-of-order", OFFSET(ignore_readorder), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, E },
219 { NULL },
220 };
221
222 static const AVClass ass_class = {
223 .class_name = "ass muxer",
224 .item_name = av_default_item_name,
225 .option = options,
226 .version = LIBAVUTIL_VERSION_INT,
227 };
228
229 AVOutputFormat ff_ass_muxer = {
230 .name = "ass",
231 .long_name = NULL_IF_CONFIG_SMALL("SSA (SubStation Alpha) subtitle"),
232 .mime_type = "text/x-ass",
233 .extensions = "ass,ssa",
234 .priv_data_size = sizeof(ASSContext),
235 .subtitle_codec = AV_CODEC_ID_ASS,
236 .write_header = write_header,
237 .write_packet = write_packet,
238 .write_trailer = write_trailer,
239 .flags = AVFMT_GLOBALHEADER | AVFMT_NOTIMESTAMPS | AVFMT_TS_NONSTRICT,
240 .priv_class = &ass_class,
241 };
242