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path: root/libavformat/assenc.c (plain)
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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
28typedef struct DialogueLine {
29 int readorder;
30 char *line;
31 struct DialogueLine *prev, *next;
32} DialogueLine;
33
34typedef 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
46static 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 avio_flush(s->pb);
81
82 return 0;
83}
84
85static void purge_dialogues(AVFormatContext *s, int force)
86{
87 int n = 0;
88 ASSContext *ass = s->priv_data;
89 DialogueLine *dialogue = ass->dialogue_cache;
90
91 while (dialogue && (dialogue->readorder == ass->expected_readorder || force)) {
92 DialogueLine *next = dialogue->next;
93 if (dialogue->readorder != ass->expected_readorder) {
94 av_log(s, AV_LOG_WARNING, "ReadOrder gap found between %d and %d\n",
95 ass->expected_readorder, dialogue->readorder);
96 ass->expected_readorder = dialogue->readorder;
97 }
98 avio_printf(s->pb, "Dialogue: %s\r\n", dialogue->line);
99 if (dialogue == ass->last_added_dialogue)
100 ass->last_added_dialogue = next;
101 av_freep(&dialogue->line);
102 av_free(dialogue);
103 if (next)
104 next->prev = NULL;
105 dialogue = ass->dialogue_cache = next;
106 ass->expected_readorder++;
107 n++;
108 }
109 ass->cache_size -= n;
110 if (n > 1)
111 av_log(s, AV_LOG_DEBUG, "wrote %d ASS lines, cached dialogues: %d, waiting for event id %d\n",
112 n, ass->cache_size, ass->expected_readorder);
113}
114
115static void insert_dialogue(ASSContext *ass, DialogueLine *dialogue)
116{
117 DialogueLine *cur, *next = NULL, *prev = NULL;
118
119 /* from the last added to the end of the list */
120 if (ass->last_added_dialogue) {
121 for (cur = ass->last_added_dialogue; cur; cur = cur->next) {
122 if (cur->readorder > dialogue->readorder)
123 break;
124 prev = cur;
125 next = cur->next;
126 }
127 }
128
129 /* from the beginning to the last one added */
130 if (!prev) {
131 next = ass->dialogue_cache;
132 for (cur = next; cur != ass->last_added_dialogue; cur = cur->next) {
133 if (cur->readorder > dialogue->readorder)
134 break;
135 prev = cur;
136 next = cur->next;
137 }
138 }
139
140 if (prev) {
141 prev->next = dialogue;
142 dialogue->prev = prev;
143 } else {
144 dialogue->prev = ass->dialogue_cache;
145 ass->dialogue_cache = dialogue;
146 }
147 if (next) {
148 next->prev = dialogue;
149 dialogue->next = next;
150 }
151 ass->cache_size++;
152 ass->last_added_dialogue = dialogue;
153}
154
155static int write_packet(AVFormatContext *s, AVPacket *pkt)
156{
157 ASSContext *ass = s->priv_data;
158
159 long int layer;
160 char *p = pkt->data;
161 int64_t start = pkt->pts;
162 int64_t end = start + pkt->duration;
163 int hh1, mm1, ss1, ms1;
164 int hh2, mm2, ss2, ms2;
165 DialogueLine *dialogue = av_mallocz(sizeof(*dialogue));
166
167 if (!dialogue)
168 return AVERROR(ENOMEM);
169
170 dialogue->readorder = strtol(p, &p, 10);
171 if (dialogue->readorder < ass->expected_readorder)
172 av_log(s, AV_LOG_WARNING, "Unexpected ReadOrder %d\n",
173 dialogue->readorder);
174 if (*p == ',')
175 p++;
176
177 if (ass->ssa_mode && !strncmp(p, "Marked=", 7))
178 p += 7;
179
180 layer = strtol(p, &p, 10);
181 if (*p == ',')
182 p++;
183 hh1 = (int)(start / 360000); mm1 = (int)(start / 6000) % 60;
184 hh2 = (int)(end / 360000); mm2 = (int)(end / 6000) % 60;
185 ss1 = (int)(start / 100) % 60; ms1 = (int)(start % 100);
186 ss2 = (int)(end / 100) % 60; ms2 = (int)(end % 100);
187 if (hh1 > 9) hh1 = 9, mm1 = 59, ss1 = 59, ms1 = 99;
188 if (hh2 > 9) hh2 = 9, mm2 = 59, ss2 = 59, ms2 = 99;
189
190 dialogue->line = av_asprintf("%s%ld,%d:%02d:%02d.%02d,%d:%02d:%02d.%02d,%s",
191 ass->ssa_mode ? "Marked=" : "",
192 layer, hh1, mm1, ss1, ms1, hh2, mm2, ss2, ms2, p);
193 if (!dialogue->line) {
194 av_free(dialogue);
195 return AVERROR(ENOMEM);
196 }
197 insert_dialogue(ass, dialogue);
198 purge_dialogues(s, ass->ignore_readorder);
199
200 return 0;
201}
202
203static int write_trailer(AVFormatContext *s)
204{
205 ASSContext *ass = s->priv_data;
206
207 purge_dialogues(s, 1);
208
209 if (ass->trailer) {
210 avio_write(s->pb, ass->trailer, ass->trailer_size);
211 }
212
213 return 0;
214}
215
216#define OFFSET(x) offsetof(ASSContext, x)
217#define E AV_OPT_FLAG_ENCODING_PARAM
218static const AVOption options[] = {
219 { "ignore_readorder", "write events immediately, even if they're out-of-order", OFFSET(ignore_readorder), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, E },
220 { NULL },
221};
222
223static const AVClass ass_class = {
224 .class_name = "ass muxer",
225 .item_name = av_default_item_name,
226 .option = options,
227 .version = LIBAVUTIL_VERSION_INT,
228};
229
230AVOutputFormat ff_ass_muxer = {
231 .name = "ass",
232 .long_name = NULL_IF_CONFIG_SMALL("SSA (SubStation Alpha) subtitle"),
233 .mime_type = "text/x-ass",
234 .extensions = "ass,ssa",
235 .priv_data_size = sizeof(ASSContext),
236 .subtitle_codec = AV_CODEC_ID_ASS,
237 .write_header = write_header,
238 .write_packet = write_packet,
239 .write_trailer = write_trailer,
240 .flags = AVFMT_GLOBALHEADER | AVFMT_NOTIMESTAMPS | AVFMT_TS_NONSTRICT,
241 .priv_class = &ass_class,
242};
243
generated by cgit at 2024-05-17 06:32:26 (GMT)