| omg | Sony OpenMG Audio |
| oml | OtsAV Media Library |
| omx | OtsAV Media Library Information |
| opm | FM Operator Type-M Voice Data |
| opu | Opus Audio File |
| opus | Opus Audio File |
| orc | CSound Orchestra Midi Audio |
| orc | TRS-80 Orchestra-90 Audio Data |
| orc | Voyetra Digital Orchestrator Pro Song |
| org | Organya Music Data |
| org | Sound Blaster Pro Organ Audio |
| organ | GrandOrgue Organ Sample Set |
| osb | Sega Dreamcast OSB Audio Data |
| osp | Orion Sampler Program |
| ots | OtsAV Album |
| ots | OtsJuke Audio |
| out | Atari Jaguar Parsed MIDI Audio |
| p | AKAI S900 Program |
| p | Pulsar Audio Data |
| p00 | Roland V-Synth Patch Data |
| p16 | Protracker Studio Module 16 |
| p3k | Kurzweil PC3K8 Audio Data |
| p40 | The Player 4.0 Music Module |
| p41 | The Player 4.1 Music Module |
| p4x | The Player 4.x Music |
| p50 | The Player 5.0a Module |
| p5b | NI Pro-53 Bank |
| p60 | The Player 6.0 Music Module |
| p61 | The Player 6.1a Music Module |
| paal | Cakewalk Pyro Audio Creator Audio Layout |
