General MIDI and SMF

General MIDI (GM) is a standard mapping: program 1 = Acoustic Piano, 25 = Acoustic Guitar (nylon), 33 = Acoustic Bass, etc. Any GM-compatible device plays a .mid file roughly the same way.

SMF (Standard MIDI File, .mid) packages tracks, tempo, and time signature. Lightweight, universal, still used everywhere from karaoke to game music to DAW interchange.