IMF

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IMF (probably) stands for "ID Software Music Format" and is remarkably similar to the Rdos RAW file format.

The format was invented by Id Software in 1991 for Commander Keen 4-6 and was used in the later games Catacomb 3-D, Wolfenstein 3-D and [many others].

IMF files contain raw data that is to be sent to an AdLib or compatible card in order to produce music. The simple nature of this format made it easy to implement and fast to execute in a game.

It contains a list of the data bytes to be sent to the OPL chip on an Adlib or SoundBlaster sound card, as well as how long a delay should be left between sending the bytes.

The end result is a very lightweight music player, which uses very little CPU time - essential in the days when games were required to run smoothly on a 286.

A complete technical description of the format can be found in the ModdingWiki article on the IMF Format.

Utilities

  • IMF Player as the name suggest: an IMF Player.
  • IMF2WAV converts any IMF file to Wave format.
  • IMF2MIDI converts IMF songs into MIDI files.
  • MIDI2IMF converts MIDI songs into IMF files.
  • DRO2IMF converts DRO files to IMF files.
  • IMF Creator converts MIDI songs into IMF files.
  • IMFCrush reduces the file size + converts IMF songs to a different rate and/or format.

Links

  • Adlib-XMMS - a free Adlib player that will play IMF, CMF and DRO files, amongst others (XMMS plug-in source code available)
  • AdPlug - a free Adlib player that will play IMF files (DOS, Winamp and XMMS versions available)
  • Wikipedia:IMF_(music) - Wikipedia article on the IMF format
  • ModdingWiki:IMF Format - technical documentation