PeerStreamer

/*

 * SSA/ASS muxer

 * Copyright (c) 2008 Michael Niedermayer

 *

 * This file is part of Libav.

 *

 * Libav 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.

 *

 * Libav 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 Libav; 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,

};