Picodrive: cropping overscan crops too much!


Hey guys, when I disable the “Show Overscan” option in PicoDrive, a bit of the image gets lost at the bottom.

Here’s Turrican with the “Show Overscan” option turned on:

Here it is, turned off (i.e., overscan gets cropped):

Is there a way to crop the overscan, but not part of the screen?


Is that a consistent thing? That is, is it always the same overscan with every game?

Overscan varied from TV to TV, so programmers were aware that anywhere from 5% to 15% of their image was going to be lost to it and to avoid placing important information where it might get partially chopped off.


Hey Hunterk, thanks for your quick response.

The other games I’ve tried are QuackShot (World), Sonic & Knuckles (World), ToeJam & Earl (World), Zero Tolerance (USA, Europe), Golden Axe (World), Golden Axe II (World), Golden Axe III (Japan) and Mickey Mouse - World of Illusion (Europe).

Seems like they’re all equally affected.

EDIT: The good news is that none of these have junk data in the overscan, as far as I can see. :slight_smile:


Looks like this is pertinent code:

I suppose this could be turned into an option instead of a hardcoded value.


overscan has always been -8px, in some rare cases even 16 (aka sm3 on NES) so the cutoff should be expected (havent look at code and what it should look like with overscans shown)


Hello, gentlemen! Yeah, it would be great if this could become customizable in the future, since it seems Picodrive at least crops parts off the game graphics consistently (based on the set of data I have).