/*
  * RAW H.263 video demuxer
  * Copyright (c) 2009 Michael Niedermayer <michaelni@gmx.at>
  *
  * 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 "rawdec.h"

 
 static int h263_probe(AVProbeData *p)
 {
     uint64_t code= -1;
     int i;
     int valid_psc=0;
     int invalid_psc=0;
     int res_change=0;
     int src_fmt, last_src_fmt=-1;
     int last_gn=0;

     int tr, last_tr = -1;

 
     for(i=0; i<p->buf_size; i++){
         code = (code<<8) + p->buf[i];

         if ((code & 0xfffffc000000) == 0x80000000) {

             tr = (code >> 18) & 0xFF;

             src_fmt= (code>>10)&7;

             if(   src_fmt != last_src_fmt
                && last_src_fmt>0 && last_src_fmt<6
                && src_fmt<6)
                 res_change++;
 

             if (tr == last_tr) {
                 invalid_psc++;
                 continue;
             }
 

             if (src_fmt != 7 && !(code&(1<<9)) && (code&(1<<5))) {
                 invalid_psc++;
                 continue;
             }
 

             if((code&0x30000)==0x20000 && src_fmt){

                 valid_psc++;
                 last_gn=0;
             }else
                 invalid_psc++;
             last_src_fmt= src_fmt;

             last_tr = tr;

         } else if((code & 0xffff80000000) == 0x80000000) {
             int gn= (code>>(31-5)) & 0x1F;

             if(gn<last_gn){
                 invalid_psc++;
             }else
                 last_gn= gn;
         }
     }
     if(valid_psc > 2*invalid_psc + 2*res_change + 3){

         return AVPROBE_SCORE_EXTENSION;

     }else if(valid_psc > 2*invalid_psc)

         return AVPROBE_SCORE_EXTENSION / 2;

     return 0;
 }
 

 FF_DEF_RAWVIDEO_DEMUXER(h263, "raw H.263", h263_probe, NULL, AV_CODEC_ID_H263)