What is the the MOD music file format? Exactly how does it relate to the Amiga 1000 audio hardware?

Did the MOD format become popular on non-Amiga computers? If so, why?

  • 2
    Have you tried doing any research, like googling "MOD music file format"? – Leo B. Jun 28 '17 at 2:47
  • @LeoB. perhaps we should invoke the opposite. We should all down-vote the people who answered such an obviously "Google-able" question for encouraging such behavior. – cbmeeks Jun 30 '17 at 19:09
  • For the future, it would be better if you asked specific questions about things you could not find with a web search for "MOD music format", "MOD file format", "MOD format" etc. on any one of many popular search engines (Google, DuckDuckGo, Bing, Yahoo etc.) as opposed to general, broad, three-part questions. – wizzwizz4 Jun 30 '17 at 19:30
  • 3
    @cbmeeks Was that suggestion in jest? If people want to earn reputation and are willing to spend time writing coherent answers, even containing easily searchable information, more power to them. – Leo B. Jun 30 '17 at 21:13

MOD is the file extension for SoundTracker modules. SoundTracker and its successors (NoiseTracker and ProTracker predominantly, although there are other derivatives) are sequencers, and load and save files in this format. It was originally designed for games and demo programmers - assembly code to play back the modules was commonly available and worked efficiently, and the module itself contained all the data needed.

Modules embed all the required sound samples, and the "patterns", essentially multiple 4x64 grids of musical notes and attributes. The 4 columns are matched to the Amiga's 4 audio channels; each of the 64 rows are a "beat" and the player steps through each row in time with the beat. Each cell has a musical note, a reference to the sample, and possibly some attributes which cause special behaviour. On each beat, the player takes the note and the sample reference in each column(channel) and tells the audio hardware to play it, and the frequency equivalent to the musical note. Also in the module file is the playlist, which tells the player in what order to play the patterns.

The format was very popular with game and demo writers, and later for musicians in general, so there ended up with a very large body of music modules that were freely available.

It is very closely tied to the Amiga's hardware, specifically the Paula chip which was largely unchanged throughout the Amiga's product line:

  • Modules have 4 channels, like Paula
  • The samples are 8-bit sampled voices, like Paula, and Paula can DMA the samples straight out of the module to play them
  • Notes are stored as period values which are what Paula uses for sample rate adjustment
  • Volume values range from 0 to 63, which is Paula's range.

For a long time this format was exclusively tied to the Amiga - the Amiga's peers did not have an audio capability that matched or exceeded the Amiga's, so they were impossible to play. However, technology moved forward for other platforms and they developed audio systems that exceeded that of the Amiga. MOD players started to become available for these other systems. That allowed these other systems to play back this large collection of freely-available music modules.

As audio technology moved on and quality improved, new file formats took advantage. MP3 and its successors can represent higher resolution and higher bit rates, but a MOD file will always be 4-channel 8-bit sampled sound. There is still a "scene" for MOD files, similar to the demoscene and retro computing scene, and tools exist for modern platform to create and play MOD files.

  • 3
    I'd add/clarify that the audio hardware would allow playing back the sounds samples at different frequencies (dictated by the note data for each "beat"/line in the pattern data) to allow for different tones. For higher quality sound, different samples might be used for different octaves for the same instrument, for instance a piano would sound better with 3-4 samples to cover its frequency/tone range from bass to treble. – nsandersen Jun 28 '17 at 10:27
  • 4
    It's worth noting that the great MOD music content lives on, independent of the retro hardware community, with many fan sites and players available to modern computers (e.g MilkyTracker). New compositions using MOD are also fairly common. Having an Amiga to experience MOD music is more nostalgia than necessity. Like the demo scene, this scene never really "died". – Brian H Jun 28 '17 at 17:36
  • 8
    "other file formats sound much better these days" Heresy! Citation needed!!! – pipe Jun 28 '17 at 19:06
  • 1
    Other Amiga-specific aspects were that notes were stored as period values which are what Paula uses for sample rate adjustment and volume values from 0-63 (which was Paulas range). – Fuzzy76 Aug 23 at 10:08
  • 1
    Thanks @Fuzzy76 - I've added that detail into the answer. – Richard Downer Aug 24 at 7:53

Your Answer

 

By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.

Not the answer you're looking for? Browse other questions tagged or ask your own question.