Requesting Time Formats
Windows uses the MMTIME structure to represent time in one or more different formats, including milliseconds, samples, SMPTE, and MIDI song pointer formats. The wType member specifies the time format.
The midiStreamPosition function uses the MMTIME structure. Before calling this function, you must set the wType member to indicate your requested time format. To see if the requested time format is supported, check wType after the call. If the requested time format is not supported, the time is specified in an alternate time format selected by the device driver and the wType member is changed to indicate the selected time format.
For more information about the MMTIME structure, see Multimedia Timers.