| m3u8 | M3U Playlist File |
| m4a | Mpeg-4 Audio |
| m4b | Mpeg-4 Audio Book |
| m4e | Yamaha Motif ES Multi Part Editor File |
| m4p | DRM Protected AAC File |
| m4r | iPhone Ringtone |
| m7a | Yamaha MO8 Internal User Memory Data |
| mamx | Music Animation Machine Music |
| maud | Commodore Amiga IFF Audio |
| maxpat | Max Patch |
| mcg | Compressed CD+G Karaoke File |
| mct | Musicator Music |
| mdi | MIDI Music |
| med | OctaMED Music Module |
| mg1 | Band-in-a-Box Song |
| mg2 | Band-in-a-Box Song |
| mg3 | Band-in-a-Box Song |
| mg4 | Band-in-a-Box Song |
| mgb | Paragon 5 Gameboy Tracker Audio |
| mgu | Band-in-a-Box Song |
| mgv | Yamaha MegaVoice Audio |
| mia | MusicIndiaOnline Trident Player Music |
| mid | MIDI Music |
| midi | MIDI Music |
| minigsf | Game Boy Advance GSF Song |
| minipsf | Miniature Portable Sound Format Data |
| mjf | Mjuice Secure Music File |
| mka | Matroska Audio |
| mkf | KaraBox Karaoke Audio |
| mkj | MKJamz Audio File |
| mkw | MKW Compressed Audio |
| mld | MFi Phone Ringtone |
| mlp | Meridian Lossless Packing Audio |
| mmf | SMAF Audio |
| mo3 | MO3 Audio |
