func: int ff_mpeg4_decode_picture_header(MpegEncContext * s, GetBitContext *gb)
  
  {
  
      int startcode, v;
  
  
  
      /* search next start code */
  
      align_get_bits(gb);
  
      startcode = 0xff;
  
      for(;;) {
  
          v = get_bits(gb, 8);
  
          startcode = ((startcode << 8) | v) & 0xffffffff;
  
          
  
          if(get_bits_count(gb) >= gb->size*8){
  
              if(gb->size==1 && s->divx_version){
  
                  printf("frame skip %d\n", gb->size);
  
                  return FRAME_SKIPED; //divx bug
  
              }else
  
                  return -1; //end of stream
  
          }
  
  
  
          if((startcode&0xFFFFFF00) != 0x100)
  
              continue; //no startcode
  
          
  
          if(s->avctx->debug&FF_DEBUG_STARTCODE){
  
              printf("startcode: %3X ", startcode);
  
              if     (startcode<=0x11F) printf("Video Object Start");
  
              else if(startcode<=0x12F) printf("Video Object Layer Start");
  
              else if(startcode<=0x13F) printf("Reserved");
  
              else if(startcode<=0x15F) printf("FGS bp start");
  
              else if(startcode<=0x1AF) printf("Reserved");
  
              else if(startcode==0x1B0) printf("Visual Object Seq Start");
  
              else if(startcode==0x1B1) printf("Visual Object Seq End");
  
              else if(startcode==0x1B2) printf("User Data");
  
              else if(startcode==0x1B3) printf("Group of VOP start");
  
              else if(startcode==0x1B4) printf("Video Session Error");
  
              else if(startcode==0x1B5) printf("Visual Object Start");
  
              else if(startcode==0x1B6) printf("Video Object Plane start");
  
              else if(startcode==0x1B7) printf("slice start");
  
              else if(startcode==0x1B8) printf("extension start");
  
              else if(startcode==0x1B9) printf("fgs start");
  
              else if(startcode==0x1BA) printf("FBA Object start");
  
              else if(startcode==0x1BB) printf("FBA Object Plane start");
  
              else if(startcode==0x1BC) printf("Mesh Object start");
  
              else if(startcode==0x1BD) printf("Mesh Object Plane start");
  
              else if(startcode==0x1BE) printf("Still Textutre Object start");
  
              else if(startcode==0x1BF) printf("Textutre Spatial Layer start");
  
              else if(startcode==0x1C0) printf("Textutre SNR Layer start");
  
              else if(startcode==0x1C1) printf("Textutre Tile start");
  
              else if(startcode==0x1C2) printf("Textutre Shape Layer start");
  
              else if(startcode==0x1C3) printf("stuffing start");
  
              else if(startcode<=0x1C5) printf("reserved");
  
              else if(startcode<=0x1FF) printf("System start");
  
              printf(" at %d\n", get_bits_count(gb));
  
          }
  
  
  
          switch(startcode){
  
          case 0x120:
  
              decode_vol_header(s, gb);
  
              break;
  
          case USER_DATA_STARTCODE:
  
              decode_user_data(s, gb);
  
              break;
  
          case GOP_STARTCODE:
  
              mpeg4_decode_gop_header(s, gb);
  
              break;
  
          case VOP_STARTCODE:
  
              return decode_vop_header(s, gb);
  
          default:
  
              break;
  
          }
  
  
  
          align_get_bits(gb);
  
          startcode = 0xff;
  
      }
  
  }
  