MED File

.med is the native module format of OctaMED, a tracker music application developed by Teijo Kinnunen for the Commodore Amiga beginning in 1989. Like other tracker formats such as .MOD, it bundles pattern data - note sequences, tempo, and effect commands - alongside digitized instrument samples into a single self-contained binary file.

What set OctaMED apart was its ability to mix eight software channels on hardware that natively supported only four, achieved by pairing two software channels per hardware channel, plus built-in MIDI sequencing via the Amiga serial port. The format evolved through several sub-versions, each identified by a 4-byte magic header: MED2, MED3, and MED4 for the original MED tracker, and MMD0 through MMD3 for OctaMED and OctaMED Sound Studio. The MMD3 variant is the most advanced, supporting up to 64 tracks and multiple sub-songs within a single module.

.med files are big-endian binary, reflecting the Amiga's Motorola 68000 processor architecture. A file begins with a 4-byte magic identifier followed by song metadata, block pointers, instrument descriptors, and embedded PCM sample data. A single module can hold up to 63 instruments and 99 sub-songs sharing a common instrument set.

OctaMED Sound Studio (Windows, RBF Software) was the last commercial application to develop the format. Today, .med files can be played back via XMPlay and OpenMPT, both of which support the full MMD family through libopenmpt. Modern tracker composers typically use .XM or .IT instead.