The IDirectMusicPerformance::RhythmToTime method converts rhythm time to music time.
HRESULT RhythmToTime(
  WORD wMeasure,
  BYTE bBeat,
  BYTE bGrid,
  short nOffset,
  DMUS_TIMESIGNATURE *pTimeSig,
  MUSIC_TIME *pmtTime)
);
 If the method succeeds, the return value is S_OK.
  Windows NT/2000: Requires Windows 2000.
  Windows 95/98: Requires Windows 95 or later. Available as a redistributable for Windows 95.
  Header: Declared in dmusici.h.