MO3 is a file format encapsulating the features of several "MOD" formats (IT, XM, S3M, MTM, MOD, MPTM), but with one big difference: MP3 and OGG compressed samples. A lossless codec is also incorporated for any samples that don't like lossy encoding, and the whole file structure is compressed too.

All of this makes it possible to have great reductions in file sizes with practically identical sound quality. In fact, MO3 allows greater quality compositions because MP3/OGG encoding works better with 16-bit samples, so there's no reason to use low quality 8-bit samples anymore.

• MP3/OGG compression
  Any command-line MP3 or OGG encoder can be used with the MO3 encoder
• Lossless compression
  Samples that don't compress well with MP3/OGG encoding can still be reduced in size with the lossless codec
• Structure compression
  All the non-sample data is also compressed
• Sample specific tuning
  The encoding sample/bit rates are individually adjustable for each sample, with visual comparison of original/encoded samples
• Text removal
  Message/instrument/sample texts can optionally be removed for a further size reduction
• Decompression
  MO3 files can be decoded back to their original formats using UNMO3 (included), an UNMO3 library is also available below
• Playable
  MO3 files can be played by XMPlay and any software that uses the BASS library, also by other software in conjunction with UNMO3

DownloadUNMO3 library 2.4.2

A library that allows other software to decompress MO3 files. The following platforms are supported: Windows, macOS, Linux, iOS, Android.

Win32macOSOGGENC 1.4.0 (libvorbis 1.3.2)

OGG encoder for creating MO3 files. It will generally come preinstalled with Linux distributions.

LinkLAME

The recommended MP3 encoder for creating MO3 files.