• Width in pixels,
• Empty string ("") if an error occurred.
  To find out the error number, use MCIErr.
  To find out the error details, use MCIMsgErr or ErrorInfo associated with the errMessage constant.
  The status report of the command is returned by MCIRetrieve.

Name of multimedia file to use (AVI, MP3, ...) or alias defined when opening the file (MCIOpen).

Additional parameters if necessary. These parameters can be known by checking the documentation of the Windows MCI function named "Status".
The MciWait constant can be added to this string. This constant is used to indicate that the program must wait for the end of the MCI command to run the rest of application.

Name of window used to intercept and manage the different messages sent by MMSYSTEM.DLL. These messages are in MM_xxxxxx format and they can be retrieved via Event. You can for example get messages regarding the management of the CD ROM or Joystick.