What is a .MO3 file?
MO3 is a compressed tracker-module format that stores a MOD/XM/IT/S3M song’s samples as MP3 or Ogg Vorbis to shrink the file. Used widely in the demoscene.
- Did you know
- MO3 kept the tracker patterns intact but compressed the bulky samples, often roughly halving a module’s size.
- MO3 comes from Un4seen, the makers of the XMPlay player and BASS audio library, where it remains a natively supported format.
- Because it re-encodes the samples as MP3 or Ogg Vorbis, MO3 is technically lossy even though the song's pattern data is preserved exactly.
- What Analyser reads
- Identify many more audio formats: lossless/hi-res codecs (Monkey’s Audio, WavPack, TAK, True Audio, DSD/SACD, Musepack), pro containers (Core Audio, RF64/BW64, Wave64, Sun AU, Broadcast Wave with timecode), speech/mobile (Speex, AMR-WB, QCP, 3GA, M4R, GSM), MPEG Layer I/II, instrument banks (SoundFont, SFZ, DLS, RIFF MIDI, GigaStudio), ringtones (RTTTL, iMelody, SAP), tracker modules (MOD, XM, IT, S3M, OctaMED, 669, Oktalyzer), chiptunes (NES NSF, SNES SPC, VGM, Game Boy GBS, AY, YM) and Audacity projects. DJI waveform peak sidecars (PKF - the overview a DJI recorder writes beside its audio) are drawn as a waveform; Adobe Audition peak caches (also PKF) are identified.
- Depth of analysis
- .MO3 is an identification-grade format: Analyser recognises it from its bytes and decodes the header metadata it carries, rather than opening it in a full viewer. Formats that do get a full viewer are marked "Full" on the formats page.
- Open a .MO3 file
- Drag a .MO3 file onto the Analyser home page (or tap to pick one). It is identified entirely in your browser - nothing is uploaded, there is no account, and it works offline once installed.