Open IMF File
The acronym for the IMF extension stands for id Music File created for use in id Software video games.
id Software LLC (With the lowercase 'i') is an American video game developer based in Richardson, Texas.
The IMF file contains data similar to MIDI files in that the files do not contain sampled digital audio, but instead contain musical notes.
The IMF is used to send music data for playback on AdLib sound cards.
The IMF file format was created by id Software for their video games.
The IMF format is no longer used due to its being a proprietary closed format and also due to the poor quality of the audio associated with its use.
Some programs, like AdPlug, emulate AdLib sound cards and can play IMF files, since it is the only one that plays this type of format.