ffmpeg/libavformat/assenc.c

92 lines
2.5 KiB
C

/*
* SSA/ASS muxer
* Copyright (c) 2008 Michael Niedermayer
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "avformat.h"
typedef struct ASSContext{
unsigned int extra_index;
}ASSContext;
static int write_header(AVFormatContext *s)
{
ASSContext *ass = s->priv_data;
AVCodecContext *avctx= s->streams[0]->codec;
uint8_t *last= NULL;
if(s->nb_streams != 1 || avctx->codec_id != CODEC_ID_SSA){
av_log(s, AV_LOG_ERROR, "Exactly one ASS/SSA stream is needed.\n");
return -1;
}
while(ass->extra_index < avctx->extradata_size){
uint8_t *p = avctx->extradata + ass->extra_index;
uint8_t *end= strchr(p, '\n');
if(!end) end= avctx->extradata + avctx->extradata_size;
else end++;
avio_write(s->pb, p, end-p);
ass->extra_index += end-p;
if(last && !memcmp(last, "[Events]", 8))
break;
last=p;
}
avio_flush(s->pb);
return 0;
}
static int write_packet(AVFormatContext *s, AVPacket *pkt)
{
avio_write(s->pb, pkt->data, pkt->size);
avio_flush(s->pb);
return 0;
}
static int write_trailer(AVFormatContext *s)
{
ASSContext *ass = s->priv_data;
AVCodecContext *avctx= s->streams[0]->codec;
avio_write(s->pb, avctx->extradata + ass->extra_index,
avctx->extradata_size - ass->extra_index);
avio_flush(s->pb);
return 0;
}
AVOutputFormat ff_ass_muxer = {
.name = "ass",
.long_name = NULL_IF_CONFIG_SMALL("Advanced SubStation Alpha subtitle format"),
.mime_type = "text/x-ssa",
.extensions = "ass,ssa",
.priv_data_size = sizeof(ASSContext),
.subtitle_codec = CODEC_ID_SSA,
.write_header = write_header,
.write_packet = write_packet,
.write_trailer = write_trailer,
.flags = AVFMT_GLOBALHEADER | AVFMT_NOTIMESTAMPS,
};