The MCI_OVLY_OPEN_PARMS structure contains information for the MCI_OPEN command for video-overlay devices.
typedef struct {
    DWORD  dwCallback; 
    MCIDEVICEID wDeviceID; 
    LPCSTR lpstrDeviceType; 
    LPCSTR lpstrElementName; 
    LPCSTR lpstrAlias; 
    DWORD  dwStyle; 
    DWORD  hWndParent; 
} MCI_OVLY_OPEN_PARMS; 
 When assigning data to the members of this structure, set the corresponding flags in the fdwCommand parameter of the mciSendCommand function to validate the members.
You can use the MCI_OPEN_PARMS structure in place of MCI_OVLY_OPEN_PARMS if you are not using the extended data members.
  Windows NT: Requires version 3.1 or later.
  Windows: Requires Windows 95 or later.
  Windows CE: Unsupported.
  Header: Declared in mmsystem.h.
  Unicode: Defined as Unicode and ANSI structures.
MCI Overview, MCI Structures, MCI_OPEN, MCI_OPEN_PARMS, mciSendCommand