libavformat/assenc.c

   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 "avformat.h"
  23
  24 typedef struct ASSContext{
  25     unsigned int extra_index;
  26 }ASSContext;
  27
  28 static int write_header(AVFormatContext *s)
  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 != 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         put_buffer(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     put_flush_packet(s->pb);
  54
  55     return 0;
  56 }
  57
  58 static int write_packet(AVFormatContext *s, AVPacket *pkt)
  59 {
  60     put_buffer(s->pb, pkt->data, pkt->size);
  61
  62     put_flush_packet(s->pb);
  63
  64     return 0;
  65 }
  66
  67 static int write_trailer(AVFormatContext *s)
  68 {
  69     ASSContext *ass = s->priv_data;
  70     AVCodecContext *avctx= s->streams[0]->codec;
  71
  72     put_buffer(s->pb, avctx->extradata      + ass->extra_index,
  73                       avctx->extradata_size - ass->extra_index);
  74
  75     put_flush_packet(s->pb);
  76
  77     return 0;
  78 }
  79
  80 AVOutputFormat ass_muxer = {
  81     "ass",
  82     NULL_IF_CONFIG_SMALL("SSA/ASS format"),
  83     NULL,
  84     "ass,ssa",
  85     sizeof(ASSContext),
  86     CODEC_ID_NONE,
  87     CODEC_ID_NONE,
  88     write_header,
  89     write_packet,
  90     write_trailer,
  91     .flags = AVFMT_GLOBALHEADER | AVFMT_NOTIMESTAMPS
  92 };