/*
  * CD Graphics Demuxer
  * Copyright (c) 2009 Michael Tison
  *
  * 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"

 #include "internal.h"

 
 #define CDG_PACKET_SIZE    24

 #define CDG_COMMAND        0x09
 #define CDG_MASK           0x3F

 typedef struct CDGContext {
     int got_first_packet;
 } CDGContext;
 

 static int read_header(AVFormatContext *s)

 {
     AVStream *vst;
     int ret;
 

     vst = avformat_new_stream(s, NULL);

     if (!vst)
         return AVERROR(ENOMEM);
 

     vst->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
     vst->codecpar->codec_id   = AV_CODEC_ID_CDGRAPHICS;

 
     /// 75 sectors/sec * 4 packets/sector = 300 packets/sec

     avpriv_set_pts_info(vst, 32, 1, 300);

     ret = avio_size(s->pb);

     if (ret < 0) {
         av_log(s, AV_LOG_WARNING, "Cannot calculate duration as file size cannot be determined\n");
     } else
         vst->duration = (ret * vst->time_base.den) / (CDG_PACKET_SIZE * 300);

 
     return 0;
 }
 
 static int read_packet(AVFormatContext *s, AVPacket *pkt)
 {

     CDGContext *priv = s->priv_data;

     int ret;
 

     while (1) {
         ret = av_get_packet(s->pb, pkt, CDG_PACKET_SIZE);
         if (ret < 1 || (pkt->data[0] & CDG_MASK) == CDG_COMMAND)
             break;

         av_packet_unref(pkt);

     }

     if (!priv->got_first_packet) {
         pkt->flags |= AV_PKT_FLAG_KEY;
         priv->got_first_packet = 1;
     }
 

     pkt->stream_index = 0;

     pkt->dts=
     pkt->pts= pkt->pos / CDG_PACKET_SIZE;

 
     if(ret>5 && (pkt->data[0]&0x3F) == 9 && (pkt->data[1]&0x3F)==1 && !(pkt->data[2+2+1] & 0x0F)){
         pkt->flags = AV_PKT_FLAG_KEY;
     }

     return ret;
 }
 

 AVInputFormat ff_cdg_demuxer = {

     .name           = "cdg",

     .long_name      = NULL_IF_CONFIG_SMALL("CD Graphics"),

     .priv_data_size = sizeof(CDGContext),

     .read_header    = read_header,
     .read_packet    = read_packet,

     .flags          = AVFMT_GENERIC_INDEX,

     .extensions     = "cdg",

 };