/*
  * H.263 parser
  * Copyright (c) 2002-2004 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
  */
 
 /**

  * @file

  * H.263 parser
  */
 
 #include "parser.h"

 #include "h263_parser.h"

 
 int ff_h263_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size){
     int vop_found, i;
     uint32_t state;
 
     vop_found= pc->frame_start_found;
     state= pc->state;
 
     i=0;
     if(!vop_found){
         for(i=0; i<buf_size; i++){
             state= (state<<8) | buf[i];
             if(state>>(32-22) == 0x20){
                 i++;
                 vop_found=1;
                 break;
             }
         }
     }
 
     if(vop_found){
       for(; i<buf_size; i++){
         state= (state<<8) | buf[i];
         if(state>>(32-22) == 0x20){
             pc->frame_start_found=0;
             pc->state=-1;
             return i-3;
         }
       }
     }
     pc->frame_start_found= vop_found;
     pc->state= state;
 
     return END_NOT_FOUND;
 }
 
 static int h263_parse(AVCodecParserContext *s,
                            AVCodecContext *avctx,

                            const uint8_t **poutbuf, int *poutbuf_size,

                            const uint8_t *buf, int buf_size)
 {
     ParseContext *pc = s->priv_data;
     int next;
 

     if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
         next = buf_size;
     } else {

         next= ff_h263_find_frame_end(pc, buf, buf_size);

         if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
             *poutbuf = NULL;
             *poutbuf_size = 0;
             return buf_size;
         }

     }

     *poutbuf = buf;

     *poutbuf_size = buf_size;
     return next;
 }
 

 AVCodecParser ff_h263_parser = {

     .codec_ids      = { AV_CODEC_ID_H263 },

     .priv_data_size = sizeof(ParseContext),
     .parser_parse   = h263_parse,
     .parser_close   = ff_parse_close,

 };