Because of this fundamental difference, you cannot simply "Save As" a MIDI file as a DMF. You need to and re-interpret the data to fit the tracker's strict channel-based architecture. Additionally, the .dmf extension is historically ambiguous, having been used by X-Tracker previously, but DefleMask's file format is distinct and modern.
Before conversion, optimize your MIDI file for 4-channel or 6-channel tracker limitations: midi to dmf work
: Adjusting octaves per channel to fit the limitations of specific sound chips. Because of this fundamental difference, you cannot simply