Hey folks. According to some websites, like this: http://www.arcaderestoration.com/games/9127/Teenage+Mutant+Ninja+Turtles.aspx
The resolution for TMNT Arcade is 320x224. However, when running the game with integer scaling and 1:1 PAR aspect ratio, the screenshot base size is 304x224.
Can anyone explain this for me please? 
Well, you are using a 18 years old emulator, it’s more likely to be inaccurate. If you are unhappy about that, you should use a more recent emulator.
Also, FWIW, i believe it’s about that change :
- 0.180: System11 changed visible screen back to 320x224 as per MT04790 discussion. Note: The 8 pixels on the left are being drawn in the overscan area, some monitors are correctly not drawing them, others do. It’s clear the intent is for the player not to see them, but the fact remains they’re there, on bad monitors. This as an aside is probably the reason for the infamous and much complained about ‘shadow’ problem on real hardware - the shadows match up with whatever is being drawn into the overscan area, stretched as a faint shadow across the whole screen.
Basically, those 16 missing pixels in width are something that exists in the game, but were never meant to be displayed.
Just tried with FB Neo to confirm same behaviour.
If that’s the case, then the 320 pixels aren’t being drawn, it’s 304 pixels and then 16 blank ones. So is the emulator just outputting black lines in the area, rather than what would actually be there on real hardware? Cutting off the overscan?
I’m asking for confirmation because I’m creating a custom superwide for a CRT at 2560x224, but RA is telling me that 2560 is not 8x scale (when setting a custom aspect ratio), because the base size is not 320, but 304. I don’t want stretched pixels.
It shouldn’t matter. That’s one of the main perks of the super-res concept: It’s so wide that it’s integer for most things, but even when it’s not, the fraction is so small that it gets smooshed out by the physical structure of the CRT. If absolutely necessary, you can also use a shader like sharp-bilinear (or tvout-tweaks) to low-pass filter (i.e., blur) the aliasing.
You can see the content of those 16 rows in current MAME, most of the time they are ok but there will be occasional garbage. FBNeo is cutting that overscan, as did older MAME versions. Accuracy-wise, they should be shown and it should be the job of the user to find a mean to hide them, but FBNeo prefers the user-friendly approach.
Good to know mate, thank you.
Thanks Barbu, that makes sense then.