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Comment by pavlov | Hacker News Reader

The Amiga MOD sound is quite distinctive because it uses very low-res instrument samples (typically 8-bit, 8 kHz) played back at different sample rates.

Only four channels were available, so each of those crunchy samples gets to be heard in the mix too.

It was amazing at the time and still sounds unique in its way.

A few PC games used Amiga MOD soundtracks too. Star Control II (1992) comes to mind because it was a very early example of Internet crowdsourcing: the music was created by MOD composers around the world.

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I think Lemmings used MODs too (or at least the music was easily converted to MOD format, because there are MODs of the soundtrack available which sound exactly the same as the in-game music) - https://www.camanis.net/lemmings/music.php. Anyway, the original soundtrackers were very much built around the Amiga sound hardware's capabilities, which was pretty good for the time - there was a custom chip that could play 4 channels of 8-bit samples where you only had to supply the memory offset, the frequency, volume etc. and then the actual playing and mixing of the channels would be done automatically. So this was of course ideal for game music, because it used very little CPU time. Later trackers were able to offer up to 8 channels by mixing 2 channels into 1 hardware channel (the first of them being OctaMED - https://en.wikipedia.org/wiki/OctaMED), but these couldn't be used in games on the original Amiga.

> I think Lemmings used MODs too

Lemmings was originally published for Amiga, so that decision makes sense.

Lemmings and its expansion packs used a custom format called "SoundPlayer", written by Scott Johnson of DMA Design. I believe the name comes from a string seen inside the replayer code.

* The music as found on Amiga Lemmings disks: https://www.exotica.org.uk/wiki/SoundPlayer

* Source of replayer code: http://wt.exotica.org.uk/players.html

Lemmings 2 and the All New World of Lemmings used MED by Teijo Kinnunen, as did most later DMA Design titles (Walker, Hired Guns)

The port of Lemmings to the Acorn Archimedes actually used a MOD file, presumably because Protracker is not native to the Acorn, but it was a popular format at the time and several people had written replayers for the Acorn

While you say "the music was easily converted"... that's not always true. The SoundPlayer format, based on reading its replayer code, supports 38 sound samples. Protracker supports 31 samples at most. Had the Lemmings music _used_ 38 samples, converting to Protracker would've come undone.

Similarly, while MED can be converted to Protracker, Protracker doesn't support all MED's commands, timings, synthetic instruments, and it actually does sound different and worse... provided the music made any use of those extra capabilities.

Quite a few games did have CPU-intensive mixing for multiple sound channels, but only as title-screen music, not in-game. Famously there is TFMX 7V format used by Chris Huelsbeck (Turrican 2, Turrican 3, Apidya, Metal Law) but also Hippel 7V used by Jochen Hippel (Amberstar, Ghost Battle, Lethal Xcess) and Oktalyzer. Furthermore, Super Stardust used the increased CPU capabilities of the A1200/A4000 to have its title music in ScreamTracker 3 (S3M) format.

Thanks for the details, and also for the link! I was an Amiga owner/fan in the 1990s, but I'm not that into retrocomputing, so my info is a bit incomplete. Looks like there was a lot of in-house/not widely available software back in the day which was "kind of like SoundTracker, but not quite" - for instance I looked up another old favourite of mine (Lionheart) and found out that the music was composed with a tool called "Sonic Arranger" - the screenshots look familiar, but it looks like it also supported "synthesized" instruments, not only samples.

Pretty sure you could use octaMED music in games as long as they had a little driver?

I know that games often used custom drivers for software mixing to get more channels. The Turrican games (which have really outrageously good music) use a 7-channel system with four of the software channels being mixed into one of the hardware channels.

It was probably a good trade-off to only split one or two of the channels, since you might not need full 8-bit sample resolution for all instruments.

I'm pretty sure Jason Page's driver for the Graftgold games did something similar.

The key point is that when using four tracks, the CPU basically just needed to tell the hardware where in memory a sample was, what frequency to play it at, and how long to go for, and then the hardware would just play it over DMA with no CPU time needed. That's eminently compatible with simultaneously running a game that requires about as much CPU power as the system has available.

Once you start going in to more than four channels, you suddenly start needing to do the mixing in the CPU instead. I remember my original Amiga 500 was capable of only doing 7 channels using OctaMED (six mixed into three, and one native), so the CPU load of mixing was significant. That is why it generally wasn't possible to use more than four channels in games.

Of course, once a bit more CPU power was available, doing the mixing in the CPU became no longer a problem.

One MP3 player used a neat trick for playing sound at better than 8-bit resolution. It would play the more significant bits one one channel, then set the volume of another channel (on the same side) lower and play the least significant bits on that channel, and the hardware would keep them in absolute lock-step. (And obviously do that twice using all four channels for stereo output.)

>Once you start going in to more than four channels, you suddenly start needing to do the mixing in the CPU instead. I remember my original Amiga 500 was capable of only doing 7 channels using OctaMED (six mixed into three, and one native), so the CPU load of mixing was significant. That is why it generally wasn't possible to use more than four channels in games.

A basic A500 can definitely handle 8ch (not just 7) on OctaMED, but not in "HQ" mode.

>octaMED music in games

Yes, there was a player library, easy to use and all.

But the reason octamed was not popular in games nor demoscene is simply because it was optimized for quality and offered costly effects with high cpu usage, unlike e.g. protracker.

Cannon Fodder on PC used the same MODs as the Amiga version for its music. Dr. Awesome from the scene was Team 17's in-house composer for ages. Epic Pinball also used some kind of module format. I think maybe Scream Tracker 3, seeming to remember FastTracker 2 .xm wasn't out yet? But it's not a reliable memory these days...

edit: Unreal Tournament DEFINITELY used some 8-or-more channel module format as well

That's why I wrote "on the original Amiga" - although you could probably make it work if you were willing to sacrifice a bit more of those precious CPU cycles for the audio. On 32 bit PCs, especially those powerful enough to run a 3D game, that wasn't a problem of course...

I remember several PC games with "amiga music". Settlers (the original), SuperFrog, Pinball Fantasies, and so on. Most likely because they were amiga ports. They didn't necessarily use the MOD format all of them, but still. I remember ripping the music from SuperFrog and Settlers at least.

A little later, Unreal, Unreal Tournament, and Deus Ex all used tracker music, to enduring acclaim.

Interesting that UT decided not to just play back an MP3, as that would be too heavy on CPU's time budget, and settled on mods instead. IIRC, Quake's music (by Trent Reznor) was just played back from the game's CD, which means that most people never got to experience it (as most people played the pirated copy of the game, without the audio CD tracks).

>Settlers (the original)

Was written in 68k assembly. The port either implemented an emulator or translated the code ahead of time.

I believe that Crusader: No Remorse and No Regret used MODs for music.

Terminal Velocity was a native PC game with MOD soundtrack.

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