From what I know, the game uses a tweaked resolution in-game which will appear as a new resolution to the monitor and thus there are no geometry presets for it unless something is set before which seems not to be the case.

Hmm I suppose it depends on my monitor, but I wonder if I can stretch, squeeze and adjust this thing to appropriately fill the screen, while not having it effect the display in other resolutions which already appear correctly. Will give it a shot tonight.

It's not really a tweaked mode, it's 320x240 (@60Hz) with vertical blanking so only 200 lines are visible. It's normal for it to appear letterboxed.

Didn't Jazz have this 320x199 resolution thing going on to make it run in 60 Hz?
Because 200 line modes are 70 Hz by default (on VGA; CGA and EGA were all 60 Hz)?

I was able to adjust this via the monitor settings to fill the screen without ruining settings for other resolutions btw. I was just surprised by the screen here. I've played Jazz off and on since it came out on various monitors and don't remember it ever coming up this way by default.

When you say "other resolutions", did you make sure to test 640x480 (since that's what the monitor would be seeing it as) ?

jmarsh wrote on 2024-11-12, 03:18:

When you say "other resolutions", did you make sure to test 640x480 (since that's what the monitor would be seeing it as) ?

Yes, that's exactly what I was worried about, but it seems ok when I try other 640x480 stuff.

The 60hz letterboxing is real. There's a few other games that do similar (like The Incredible Machine / Sid & Al's Incredible Toons)

Well how about that, heres a clip of jazz on my particular monitor around 20.10, with the letterboxing. The initial treatment of the game by my monitor was wrong but I guess full screen stretch is wrong too.

https://youtu.be/CaNDeyYP98A?si=CsHdhqAgPXDQxkiA

Here's what comes out from the digital Feature Connector when playing Jazz Jackrabbit on a Tseng ET4000/W32p adapter:

Effectively the game is outputting 320x224 pixels (if one crops 4 pixels of black VGA border from all sides).

But overall, it is like a 320x240 60Hz Mode-x style geometry (i.e. square pixels), but with effectively only 320x199 pixels being actively rendered to. The rest at the bottom are held black.

dukeofurl wrote on 2024-11-11, 23:29:

Hmm I suppose it depends on my monitor, but I wonder if I can stretch, squeeze and adjust this thing to appropriately fill the screen, while not having it effect the display in other resolutions which already appear correctly. Will give it a shot tonight.

I think part of the tweaked resolution is that the intended aspect ratio is 16:10 (-ish) so all the squares are square etc., and filling the whole 4:3 screen is not how the game should look like.

Hello, I stumbled on this post as I seem to have encountered same issue, mine seems fish eye geometry.

I am using the ARK 2000MT 2MB Video card on an AOC 7 VLR CRT on my recent Pentium MMX build. Other games run fine.

This issue only appears during the demos and actual gameplay, but not during game options and game credits.

Attached photos showing Jazz Jack rabbit during settings screen, demo and during gameplay.

Access the OSD geometry controls and use the pincushion setting to remove the curved edges. I'm guessing the slightly strange display timing means the monitor is not applying the saved geometry settings by default and it needs to be adjusted manually.

NeoG_ wrote on Yesterday, 05:11:

Access the OSD geometry controls and use the pincushion setting to remove the curved edges. I'm guessing the slightly strange display timing means the monitor is not applying the saved geometry settings by default and it needs to be adjusted manually.

Ok thanks all for your support. Managed to adjust using the actual monitor pincussion settings, and also tweaked other settings to make the image large enough to fill the black borders. When reverted back to plain ms-dos prompt all was OK and visible.