Module file

For other uses, see Module.

Module files (MODs) are a class of file formats used to represent music on a computer. They store several patterns or pages of music data in a form similar to that of a spreadsheet. These patterns contain note numbers, instrument numbers, and controller messages. The number of notes that can be played simultaneously depends on how many tracks there are per pattern.

Module files also give a list of the order in which to play the patterns. However, the biggest advantage of MOD family over standard MIDI files is that MODs include their own audio samples and should sound exactly the same from one player to another barring interpolation methods and any errors in players.

Module files are often referred to as tracker modules, and composing modules is known as tracking, simply because the first ever module creating program was Soundtracker, created by Karsten Obarski in 1987. Soundtracker was cloned many times, with programs such as Noisetracker and Protracker being direct descendants from the original Soundtracker code, and others such as MED/OctaMED and Oktalyzer being written from scratch. Such programs are called trackers in general.

Popular formats

Each format builds on concepts introduced in its predecessors.

Sound/Pro/Noisetracker module (file extension: .mod) (suffixes usually substituting prefixes outside of Amiga systems)

The format that started it all. Uses inverse-frequency note numbers. 4 voices, up to 32 in later variations of the format. Pattern data is not packed. Instruments are simple volume levels; samples and instruments correspond one-to-one. 15 instruments in the original Soundtracker, 31 in later trackers. This format was originally created to be easily playable with the Amiga hardware, since it was equipped with a four-channel DAC. The CPU has to do very little work to play these modules on an Amiga. Many games utilize this format - with possibly cut down replayers - and not only on the Amiga platform, either.

(The original .mod extension is actually not a suffix on the Amiga, but a prefix; mod.* is the standard naming convention on the Amiga, and same prefix standard is used in basically all the other various sample/synth-trackers ever made for the Amiga - Art of Noise, AHX/THX, Musicline, Startrekker, FutureComposer, SidMon, Brian Postma's SoundMon etc. Sadly the majority of the "oldschool format"-players for Windows, Linux, Mac OS etc. do not care to check filenames closer, and will when trying to load an "original" mod.*-file (or ahx.*, bp.*, fc14.* and so on) simply not play it due not analysing the file to determine the type - they only check for a filename extension as a suffix.)

Oktalyzer (originated on Amiga computers)

This was an early effort to bring 8 channel sound to the Amiga. Later replayers have improved on the sound quality attainable from these modules by more demanding mixing technologies.

MED/OctaMED (originated on Amiga computers)

This format is very similar to sound/pro/noisetracker, but the way the data is stored is different. MED was not a direct clone of soundtracker, and had different features and fileformats. OctaMED was an 8 channel version of MED, which eventually evolved into OctaMED soundstudio (which offers 128 channel sound, optional synth sounds, MIDI support and lots of other high-end features).

AHX (originated on Amiga computers)

This format is a synth-tracker. That is, there are no samples in the module file, rather descriptions of how to synthesize the required sound. This results in very small audio files (AHX modules are typically 1k - 4k in size), and a very characteristic sound. AHX is designed to sound as much like a Commodore 64 as possible.

.s3m (originated in ScreamTracker version 3 for PC)

Up to 16 or more voices. Samples can specify any playback frequency for middle C. Simple run-length packing of pattern data. Introduction of several new controllers and a dedicated "volume column" in each voice to replace volume controllers. Predictable support for stereo panning.

.xm (originated in Fast Tracker)

Introduction of instruments with volume and panning envelopes. Basic sample compression.

.it (originated in Impulse Tracker; not to be confused with the country code for Italy)

New Note Actions let the previous note in a track fade out on top of the next note (providing greater effective polyphony). Instruments can now share a sample. Adds some new effects such as a resonant filter. Better sample compression.

.ned (Nerd Tracker II)

Designed for playback on Nintendo Entertainment System. No samples in basic format (just tone generator instrument specification); extended format uses compressed samples but limits playback frequencies to the 16 rates that the NES hardware is capable of reproducing. Each channel has its own order list.

Software module file players and converters

• CocoModX for Mac OS X [1]
• dbpoweramp for Windows/Linux [2]
• Deliplayer for Windows [3]
• DeliTracker for AmigaOS [4]
• Extended Module Player (XMP) for UNIX/Linux [5]
• MikMod for MS-DOS/Linux [6]
• ModPlug Player for Windows [7]
• Mod4Win for Windows [8]
• PlayerPro for Mac OS X (PPC/Intel) and Mac OS Classic [9]
• Psycle for linux, bsd, mswindows
• Universal Module Player (UModPlayer) for UNIX/Linux [10]
• Unix Amiga Delitracker Emulator for UNIX/Linux [11]
• Winamp for Windows [12]
• XimpleMOD for Mac OS X [13]
• XMPlay for Windows [14]
• amaroK for Unix/Linux variants [15]

Module file converters

• PlayerPro for Mac OS X (PPC/Intel) and Mac OS Classic [16]

...

Hardware module file players

• TRAXMOD Portable Digital Audio Player for dsPIC/ARM [17]

External links

• Amiga Music Preservation - Tens of thousands of Amiga music modules to download
• Exotica - Lots of music modules, dedicated to "unusual" tracker formats from the Amiga
• Chiptune.com - Lots of chiptunes
• Mod Archive - Not the largest mod file site but seems to be the hub for new music
• Scene Music - "Nectarine" - An internet radio station playing modules
• Aminet's MOD Archive - Aminet archive's mod file section - the hub of the modscene for years
• Modland - FTP server with more than 250000 modules in several formats, mostly MOD, XM, S3M and IT, sorted on author.
• United Trackers - Non-profit organization of musicians supporting the tracking scene (est. 1997).
• Kohina - Scandinavian internet radio site that hosts module tunes.