assenc.c
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1 /*
2  * SSA/ASS muxer
3  * Copyright (c) 2008 Michael Niedermayer
4  *
5  * This file is part of Libav.
6  *
7  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include "avformat.h"
23 
24 typedef struct ASSContext{
25  unsigned int extra_index;
26 }ASSContext;
27 
29 {
30  ASSContext *ass = s->priv_data;
31  AVCodecContext *avctx= s->streams[0]->codec;
32  uint8_t *last= NULL;
33 
34  if(s->nb_streams != 1 || avctx->codec_id != AV_CODEC_ID_SSA){
35  av_log(s, AV_LOG_ERROR, "Exactly one ASS/SSA stream is needed.\n");
36  return -1;
37  }
38 
39  while(ass->extra_index < avctx->extradata_size){
40  uint8_t *p = avctx->extradata + ass->extra_index;
41  uint8_t *end= strchr(p, '\n');
42  if(!end) end= avctx->extradata + avctx->extradata_size;
43  else end++;
44 
45  avio_write(s->pb, p, end-p);
46  ass->extra_index += end-p;
47 
48  if(last && !memcmp(last, "[Events]", 8))
49  break;
50  last=p;
51  }
52 
53  avio_flush(s->pb);
54 
55  return 0;
56 }
57 
59 {
60  avio_write(s->pb, pkt->data, pkt->size);
61 
62  avio_flush(s->pb);
63 
64  return 0;
65 }
66 
68 {
69  ASSContext *ass = s->priv_data;
70  AVCodecContext *avctx= s->streams[0]->codec;
71 
72  avio_write(s->pb, avctx->extradata + ass->extra_index,
73  avctx->extradata_size - ass->extra_index);
74 
75  return 0;
76 }
77 
79  .name = "ass",
80  .long_name = NULL_IF_CONFIG_SMALL("SSA (SubStation Alpha) subtitle"),
81  .mime_type = "text/x-ssa",
82  .extensions = "ass,ssa",
83  .priv_data_size = sizeof(ASSContext),
84  .subtitle_codec = AV_CODEC_ID_SSA,
89 };
static int write_header(AVFormatContext *s)
Definition: assenc.c:28
static int write_packet(AVFormatContext *s, AVPacket *pkt)
Definition: assenc.c:58
int size
Definition: avcodec.h:916
AVOutputFormat ff_ass_muxer
Definition: assenc.c:78
Format I/O context.
Definition: avformat.h:828
uint8_t
uint8_t * extradata
some codecs need / can use extradata like Huffman tables.
Definition: avcodec.h:1454
AVStream ** streams
Definition: avformat.h:876
uint8_t * data
Definition: avcodec.h:915
static int flags
Definition: log.c:42
void avio_write(AVIOContext *s, const unsigned char *buf, int size)
Definition: aviobuf.c:165
static int write_trailer(AVFormatContext *s)
Definition: assenc.c:67
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:88
void av_log(void *avcl, int level, const char *fmt,...)
Definition: log.c:146
AVCodecContext * codec
Codec context associated with this stream.
Definition: avformat.h:641
unsigned int nb_streams
A list of all streams in the file.
Definition: avformat.h:875
int void avio_flush(AVIOContext *s)
Definition: aviobuf.c:180
const char * name
Definition: avformat.h:376
unsigned int extra_index
Definition: assenc.c:25
NULL
Definition: eval.c:52
enum AVCodecID codec_id
Definition: avcodec.h:1350
AVIOContext * pb
I/O context.
Definition: avformat.h:861
main external API structure.
Definition: avcodec.h:1339
int extradata_size
Definition: avcodec.h:1455
struct ASSContext ASSContext
Main libavformat public API header.
void * priv_data
Format private data.
Definition: avformat.h:848
This structure stores compressed data.
Definition: avcodec.h:898