FFmpeg  4.4.5
assenc.c
Go to the documentation of this file.
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;
40  int ssa_mode;
43  size_t trailer_size;
44 } ASSContext;
45 
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 
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 
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 
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);
198 
199  return 0;
200 }
201 
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 
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,
240  .priv_class = &ass_class,
241 };
uint8_t
Main libavformat public API header.
#define AVFMT_TS_NONSTRICT
Format does not require strictly increasing timestamps, but they must still be monotonic.
Definition: avformat.h:472
#define AVFMT_GLOBALHEADER
Format wants global header.
Definition: avformat.h:461
#define AVFMT_NOTIMESTAMPS
Format does not need / have any timestamps.
Definition: avformat.h:462
#define avio_print(s,...)
Write strings (const char *) to the context.
Definition: avio.h:594
int avio_printf(AVIOContext *s, const char *fmt,...) av_printf_format(2
Writes a formatted string to the context.
void avio_write(AVIOContext *s, const unsigned char *buf, int size)
Definition: aviobuf.c:225
char * av_asprintf(const char *fmt,...)
Definition: avstring.c:113
#define flags(name, subs,...)
Definition: cbs_av1.c:572
#define s(width, name)
Definition: cbs_vp9.c:257
#define NULL
Definition: coverity.c:32
long long int64_t
Definition: coverity.c:34
int
@ AV_OPT_TYPE_BOOL
Definition: opt.h:242
@ AV_CODEC_ID_ASS
Definition: codec_id.h:546
#define AVERROR(e)
Definition: error.h:43
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: log.h:215
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:200
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:194
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:235
void * av_mallocz(size_t size)
Allocate a memory block with alignment suitable for all memory accesses (including vectors if availab...
Definition: mem.c:237
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
#define E
Definition: assenc.c:216
static void purge_dialogues(AVFormatContext *s, int force)
Definition: assenc.c:84
static int write_packet(AVFormatContext *s, AVPacket *pkt)
Definition: assenc.c:154
static const AVOption options[]
Definition: assenc.c:217
static void insert_dialogue(ASSContext *ass, DialogueLine *dialogue)
Definition: assenc.c:114
static int write_header(AVFormatContext *s)
Definition: assenc.c:46
AVOutputFormat ff_ass_muxer
Definition: assenc.c:229
static const AVClass ass_class
Definition: assenc.c:222
static int write_trailer(AVFormatContext *s)
Definition: assenc.c:202
#define OFFSET(x)
Definition: assenc.c:215
void avpriv_set_pts_info(AVStream *s, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)
Set the time base and wrapping info for a given stream.
Definition: utils.c:4945
common internal API header
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:117
AVOptions.
int expected_readorder
Definition: assenc.c:36
int cache_size
Definition: assenc.c:39
DialogueLine * last_added_dialogue
Definition: assenc.c:38
uint8_t * trailer
Definition: assenc.c:42
int ssa_mode
Definition: assenc.c:40
size_t trailer_size
Definition: assenc.c:43
int ignore_readorder
Definition: assenc.c:41
DialogueLine * dialogue_cache
Definition: assenc.c:37
Describe the class of an AVClass context structure.
Definition: log.h:67
const char * class_name
The name of the class; usually it is the same name as the context structure type to which the AVClass...
Definition: log.h:72
This struct describes the properties of an encoded stream.
Definition: codec_par.h:52
int extradata_size
Size of the extradata content in bytes.
Definition: codec_par.h:78
uint8_t * extradata
Extra binary data needed for initializing the decoder, codec-dependent.
Definition: codec_par.h:74
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:60
Format I/O context.
Definition: avformat.h:1232
AVOption.
Definition: opt.h:248
const char * name
Definition: avformat.h:491
This structure stores compressed data.
Definition: packet.h:346
int64_t duration
Duration of this packet in AVStream->time_base units, 0 if unknown.
Definition: packet.h:387
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: packet.h:362
uint8_t * data
Definition: packet.h:369
struct DialogueLine * next
Definition: assenc.c:31
struct DialogueLine * prev
Definition: assenc.c:31
char * line
Definition: assenc.c:30
int readorder
Definition: assenc.c:29
#define av_free(p)
#define av_freep(p)
#define av_log(a,...)
AVPacket * pkt
Definition: movenc.c:59