Notice or not, you may encounter a file with .mod extension, esp. you are a gaming enthusiast or a music fan. It's a music module file once prevalent decades ago. Even though it ceased today, many people still use it for high-quality audio playback and music synthesis.
This article is about what a MOD file is, how to play it, and other frequently asked questions.
1. What Is a MOD File
MOD is a digital audio format (generally with a .mod file extension) for music modules made in music tracker software. It consists of a set of digitalized samples (voice or instrument) and sequencing information telling the player which, when, and for how long to play a sample at what pitch, optionally performing an effect like an arpeggio.
MOD file format was created for presenting game music with an Amiga program - Ultimate Soundtracker by a German developer Karsten Obarski in 1987. Later, it was supported by more players and trackers and became a popular way of producing game and dance music in the late 90s and the early 00s. And still, many musicians use some tracks of MOD files back in the days to produce old-school music or game background music.
Note: The .mod extension can be used in conjunction with videos created by some camcorders like JVC, Panasonic, and Canon. And the MOD files are MPEG-2 Program Stream (PS) containers with compressed video and audio data. But in the article, we are mainly talking about the MOD as an audio format.
2. MOD File Structure
The first version of MOD file format (the Amiga MOD format) has up to 4 tracks of simultaneous audio playback, 15 samples, and 64 rows (which formed a pattern), later extended to up to 32 tracks and 31 samples. Each track is independent of the rest and contains descriptions of a selected sample (pitch, speed, timing, duration, effect, etc.)
Below is an excerpt of MOD file specification from which we can see:
- The number of patterns in the song position under Offset.
- Notes stored as 4 bytes under Bytes.
- Sample playback command incl. length, volume, etc. under Description.
For a better understanding of the sequencing structure of a Mod file, let's have a look at how it works on the tracker software. Since many music trackers creating MOD files are too old to run on recent devices, the demonstration is carried on a modern app called VividTracker which works in the same way as aged programs.
The columns under each track represent the note, sample, control parameter (like volume, effect, and BPM), and the value of the parameter in each step.
The leftmost column POS is for step sequencer. When you play the pattern, it reads one step at a time.
Every tracker may have different codes for controls, please check their manuals for detailed information.
3. Variations of Mod File Format
After the Amiga MOD format got popular in the demo world, which indicated a new way of making music of an acceptable level of quality rather cheaply, new generations of MODs came up and rose to a sound quality nearing that of professional equipment.
Now MODs can contain more tracks and samples and are available in many formats such as S3M, 669, MTM, XM, IT, OKT…
4. Advantages and Disadvantages of MOD Files
Advantages of MOD Files
- Better and consistent audio quality than sequencing file format.
- More space-saving for high-quality audio files than pure sample formats.
- It's easy to compose music collaborating with others.
Disadvantages of MOD Files
- It's obsolete and not very popular at present.
- Poor compatibility for its varied formats.
- It may cause some copy-protection issues due to some technical limitations.
5. How to Open MOD Files
To open and edit.mod music module files, you can use tracker software like Schism Tracker, MilkyTrcker, and Cog (macOS) or hardware such as Polyend Tracker.
To play MOD files on Windows and Mac, you need audio players that support this format. For instance, VLC media player (cross-platform), MikMod (cross-platform), and Nullsoft Winamp (Windows-only). But some audio players that support MOD files may no longer be developed and do not work well on modern operating systems.
If you are going to play MOD files on your iPhone or Android smartphone, Xmp Mod Player (Android), PureModPlay (iOS), and VividTracker (iOS) are practical and free MOD players for you.
Note: MOD video files can be opened with any player that supports MPEG-2, but may be changed into a .mpg extension. For better compatibility, you can convert MOD to MP4 and other universal formats.
6. Comparison of MOD, MIDI, and WAV
A MOD file is like a hybrid between the pure sample data file (WAV) and the pure sequencing information (MIDI). It contains both audio samples and sample playback "commands".
Partly like MIDI, a MOD file has "a sheet of music", recording when a note is played, when it is stopped, and a series of control information for each note, such as timbre, intensity, sound, expression, sustain, and so on.
But MIDI files do not carry the specific sounds of a sample and only give a number that tells you which instrument to play. The quality of the MIDI file playback is determined by the tone library on your computer. While, MOD files solved this issue with samples of instruments, noises, and human voices which can be looked upon as short WAV files.
And now the quality depends on the sample rate and the sample value like things in WAV files. The sample rate tells you how many slices of a one-second sound wave are cut. More samples/second (thinner slices) mean better preservation of the sound quality. The samples in a MOD file are raw, 8-bit, signed, headerless, linear digital data. And there is no standard sampling rate for these samples, thus different from WAV files.