IT2AGI sound converter script - some fixes

[lskovlun]

Portability.

A sound file consisting of chip-level commands being played on a platform without that chip would need to be converted to something else in order to play it. If it is even feasible, it would drain the CPU. No, there needs to be a platform-neutral file format.

[Sinus]

Iskovlun: File format, maybe. But the CHIP itself is exactly the same, or, well, a manageable variant of one. Thus, whatever works on consoles, should work - at least to a good extent - on a PC with the same chip embedded.

Well, I went digging in bits. This is far from complete, but here is Aladdin on a Sega Master System, in VGM format. And it plays in AGI after being run through a VGM-to-AGS script I jerry-rigged today. It sounds horrible, I've yet to figure out why, but the song structure holds, and it's arguably already far ahead of the usual AGI music complexity. So, my point seems to stand.

[Kawa]

And on what kind of system did you play the song to record it?

[Sinus]

DOSBox. Sadly, I don't have a true DOS machine available.
I can record one in ScummVM, too, but it has a raspy sound emulation, similar to a bug I -think- I fixed in WinAGI, but I've yet to understand ScummVM's C++ code well enoug to see if a similar buffer flaw manifests there.

[Kawa]

DOSBox. That's what I thought.

Unless you have DOSBox set to a cycle count that, on your host system, gives roughly 8088 to 286 speed results, with a game scene that's not just a static image like a title screen, it seems my point still stands.

[Sinus]

But it's still Sierra AGI, with its 60/sec music timing, nothing more than that! I don't suppose a sound file following AGI rules could possibly "overload" the engine, so that it wouldn't play on a regular hardware.

[Sinus]

There we go! Attached: 'One Jump Ahead' in AGI sound format, ready to import into a homebrew Sierra for nonbelievers.
I guess, with proof of concept like thhis, my VGM2AGI script will be joining IT2AGI in the GitHub repo soon.

[AGKorson]

It's less a matter of overloading the processor and more about the limited heap space. aladdin-onejump.ags is an awesome sound resource, but at 29K, it would take up more than half the heap. AGI game programming has always been about balancing the demands of all the active resources in a room (scripts, views, sounds) and engine overhead (logic0, words.tok, objects and animation) to stay within memory limits.

With the possible exception of an intro scene, there's not much room for large sound resources. Sound effects and short music clips are where AGI sound lives.

[Sinus]

Oh, I'm well aware of the memory footprint. That little song crashes my tested copy of KQ6AGI
That was simply a proof of concept, demonstrating that the VGM and AGI sound formats are very closely related, and the rare AGI authors can benefit from the comparably vast area of VGM chiptunes.

[Sinus]

New version out, now with Sega VGM support (see SMSPower for some Sega Master System musics).

[Sinus]

In related news, my patch enabling 16-bit noise shifting, sounding nice and resonant as in SEGA consoles (as opposed to the discordant noises of true PCjr) is in ScummVM now, for some future release.

[Sinus]

And another new feature coming up: "disable AGI fading" - generates extra notes to keep sound at target volume, instead of letting AGIv2 start to "dissolve" them after their 5th tick. This should be useful in tandem with IT format's NOTE-OFF and NOTE-CUT commands. NOTE-CUT will still terminate a note instantly, but NOTE-OFF will re-enable the fading (or, rather: stop keeping it alive), letting the note fade as it would. This should make it dead easy to control when and how we want to sustain our notes, instead of letting AGI break stuff.

[MusicallyInspired]

Dude.....I have been waiting DECADES for someone to dive this far into AGI sound resource creation! The reason that some of the crazy SMS shenanigans have never been done in AGI is simply because nobody tried it. Or knew how to do it. As long as the sound resource size itself is manageable and not huge or long (most AGI sounds aren't very long at all), I've always felt this should be possible.

It would have been wonderful (still would be!) to get an AGI demo scene going showing off what it could do.

Thank you for this tool!! As an old tracker myself, this pleases me greatly. 

[Sinus]

Oh, I would like nothing more than to see the AGI scene take off! Sadly, the AGI heap limits are terribly tight, so anything more complex would be limited to a minute tops.
I took a bit of a break on other projects (and life), but I'll pick up soon-ish. Destination: IT being the go-to format for tracking AGI music, with as many effects supported as possible.