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assenc.c
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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 
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 write_ts; // 0: ssa (timing in payload), 1: ass (matroska like)
41  int ssa_mode;
43 }ASSContext;
44 
46 {
47  ASSContext *ass = s->priv_data;
48  AVCodecContext *avctx= s->streams[0]->codec;
49 
50  if (s->nb_streams != 1 || (avctx->codec_id != AV_CODEC_ID_SSA &&
51  avctx->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  ass->write_ts = avctx->codec_id == AV_CODEC_ID_ASS;
56  avpriv_set_pts_info(s->streams[0], 64, 1, 100);
57  if (avctx->extradata_size > 0) {
58  avio_write(s->pb, avctx->extradata, avctx->extradata_size);
59  if (avctx->extradata[avctx->extradata_size - 1] != '\n')
60  avio_write(s->pb, "\r\n", 2);
61  ass->ssa_mode = !strstr(avctx->extradata, "\n[V4+ Styles]");
62  if (!strstr(avctx->extradata, "\n[Events]"))
63  avio_printf(s->pb, "[Events]\r\nFormat: %s, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text\r\n",
64  ass->ssa_mode ? "Marked" : "Layer");
65  }
66  avio_flush(s->pb);
67 
68  return 0;
69 }
70 
71 static void purge_dialogues(AVFormatContext *s, int force)
72 {
73  int n = 0;
74  ASSContext *ass = s->priv_data;
75  DialogueLine *dialogue = ass->dialogue_cache;
76 
77  while (dialogue && (dialogue->readorder == ass->expected_readorder || force)) {
78  DialogueLine *next = dialogue->next;
79  if (dialogue->readorder != ass->expected_readorder) {
80  av_log(s, AV_LOG_WARNING, "ReadOrder gap found between %d and %d\n",
81  ass->expected_readorder, dialogue->readorder);
82  ass->expected_readorder = dialogue->readorder;
83  }
84  avio_printf(s->pb, "Dialogue: %s\r\n", dialogue->line);
85  if (dialogue == ass->last_added_dialogue)
86  ass->last_added_dialogue = next;
87  av_freep(&dialogue->line);
88  av_free(dialogue);
89  if (next)
90  next->prev = NULL;
91  dialogue = ass->dialogue_cache = next;
92  ass->expected_readorder++;
93  n++;
94  }
95  ass->cache_size -= n;
96  if (n > 1)
97  av_log(s, AV_LOG_DEBUG, "wrote %d ASS lines, cached dialogues: %d, waiting for event id %d\n",
98  n, ass->cache_size, ass->expected_readorder);
99 }
100 
101 static void insert_dialogue(ASSContext *ass, DialogueLine *dialogue)
102 {
103  DialogueLine *cur, *next = NULL, *prev = NULL;
104 
105  /* from the last added to the end of the list */
106  if (ass->last_added_dialogue) {
107  for (cur = ass->last_added_dialogue; cur; cur = cur->next) {
108  if (cur->readorder > dialogue->readorder)
109  break;
110  prev = cur;
111  next = cur->next;
112  }
113  }
114 
115  /* from the beginning to the last one added */
116  if (!prev) {
117  next = ass->dialogue_cache;
118  for (cur = next; cur != ass->last_added_dialogue; cur = cur->next) {
119  if (cur->readorder > dialogue->readorder)
120  break;
121  prev = cur;
122  next = cur->next;
123  }
124  }
125 
126  if (prev) {
127  prev->next = dialogue;
128  dialogue->prev = prev;
129  } else {
130  dialogue->prev = ass->dialogue_cache;
131  ass->dialogue_cache = dialogue;
132  }
133  if (next) {
134  next->prev = dialogue;
135  dialogue->next = next;
136  }
137  ass->cache_size++;
138  ass->last_added_dialogue = dialogue;
139 }
140 
142 {
143  ASSContext *ass = s->priv_data;
144 
145  if (ass->write_ts) {
146  long int layer;
147  char *p = pkt->data;
148  int64_t start = pkt->pts;
149  int64_t end = start + pkt->duration;
150  int hh1, mm1, ss1, ms1;
151  int hh2, mm2, ss2, ms2;
152  DialogueLine *dialogue = av_mallocz(sizeof(*dialogue));
153 
154  if (!dialogue)
155  return AVERROR(ENOMEM);
156 
157  dialogue->readorder = strtol(p, &p, 10);
158  if (dialogue->readorder < ass->expected_readorder)
159  av_log(s, AV_LOG_WARNING, "Unexpected ReadOrder %d\n",
160  dialogue->readorder);
161  if (*p == ',')
162  p++;
163 
164  if (ass->ssa_mode && !strncmp(p, "Marked=", 7))
165  p += 7;
166 
167  layer = strtol(p, &p, 10);
168  if (*p == ',')
169  p++;
170  hh1 = (int)(start / 360000); mm1 = (int)(start / 6000) % 60;
171  hh2 = (int)(end / 360000); mm2 = (int)(end / 6000) % 60;
172  ss1 = (int)(start / 100) % 60; ms1 = (int)(start % 100);
173  ss2 = (int)(end / 100) % 60; ms2 = (int)(end % 100);
174  if (hh1 > 9) hh1 = 9, mm1 = 59, ss1 = 59, ms1 = 99;
175  if (hh2 > 9) hh2 = 9, mm2 = 59, ss2 = 59, ms2 = 99;
176 
177  dialogue->line = av_asprintf("%s%ld,%d:%02d:%02d.%02d,%d:%02d:%02d.%02d,%s",
178  ass->ssa_mode ? "Marked=" : "",
179  layer, hh1, mm1, ss1, ms1, hh2, mm2, ss2, ms2, p);
180  if (!dialogue->line) {
181  av_free(dialogue);
182  return AVERROR(ENOMEM);
183  }
184  insert_dialogue(ass, dialogue);
186  } else {
187  avio_write(s->pb, pkt->data, pkt->size);
188  }
189 
190  return 0;
191 }
192 
194 {
195  purge_dialogues(s, 1);
196  return 0;
197 }
198 
199 #define OFFSET(x) offsetof(ASSContext, x)
200 #define E AV_OPT_FLAG_ENCODING_PARAM
201 static const AVOption options[] = {
202  { "ignore_readorder", "write events immediately, even if they're out-of-order", OFFSET(ignore_readorder), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, E },
203  { NULL },
204 };
205 
206 static const AVClass ass_class = {
207  .class_name = "ass muxer",
208  .item_name = av_default_item_name,
209  .option = options,
210  .version = LIBAVUTIL_VERSION_INT,
211 };
212 
214  .name = "ass",
215  .long_name = NULL_IF_CONFIG_SMALL("SSA (SubStation Alpha) subtitle"),
216  .mime_type = "text/x-ssa",
217  .extensions = "ass,ssa",
218  .priv_data_size = sizeof(ASSContext),
219  .subtitle_codec = AV_CODEC_ID_SSA,
224  .priv_class = &ass_class,
225 };