If the MCI_OPEN_SHAREABLE flag is not specified, the device instance is opened for exclusive use.

If the MCI_OPEN_TYPE_ID flag is not specified and the pszDeviceType field of the open data structure is not NULL, the media control interface attempts to open the device specified by the pszDeviceType string. If pszDeviceType is NULL and MCI_OPEN_ELEMENT flag is specified, the media control interface attempts to select and open a device based on the element extension or EA type of the file specified in the pszElementName field of the open data structure.

If pszDeviceType is a device type ID with a NULL ordinal or a string device name with no ordinals, then the default device of the specified type is opened. The default device can be selected using the Multimedia Setup application.