Viewing Issue Advanced Details
ID Category [?] Severity [?] Reproducibility Date Submitted Last Update
07048 Graphics Minor Always 28 days ago 26 days ago
Tester ICEknight View Status Public Platform MAME (Official Binary)
Assigned To Resolution Open OS Windows 10 (64-bit)
Status [?] Acknowledged Driver pce.cpp
Version 0.199 Fixed in Version Build 64-bit
Summary MESS-specific 07048: All machines in pce.cpp: Slightly wrong screen size
Description I've just come across some captured real hardware footage of the PC Engine and, comparing it to MAME's output, noticed that the former shows a tiny bit of additional screen space to the sides:

The actual resolution in this screen mode is 282x242 and MAME's output is 272x242, so it's more than likely just missing those 10 pixels.

Now the weird thing comes with the vertical resolution, which MAME is already rendering fully, but there's this small piece of border that's shown at the bottom while one of the videos has it on top of the picture instead. The capture card may be actually doing some additional cropping (the other video doesn't even show that border anywhere), so perhaps somebody with access to a real system and a way to see the full screen output could check if the border is shown at the bottom, on top or maybe in both places?

I've manually added some additional side borders to a MAME screenshot to make it 282x242 and stretched it to 4:3 aspect so that it can be easily compared with the real hardware grab:

By comparing these, it also looks like the original display might be actually shifted a little to the left, but that may be the capture card's fault.
Steps To Reproduce Load any game.
Additional Information "Kato Chan & Ken Chan"/"J.J. & Jeff" has a colored border at the title screen that may be of help.
Regression Version
Affected Sets / Systems All machines in pce.cpp
Attached Files
png file icon 0010.png (11,798 bytes) 28 days ago Uploaded by ICEknight
7z file icon tricky.7z (508,327 bytes) 26 days ago Uploaded by Tafoid
Tricky Kick - TG16 - Actual Hardware Capture from Video Card (.bmp uploaded as .7z)
There are no relationsihp linked to this issue.
User avatar
27 days ago
Could this be a case of geometry adjustments made in the TVs service mode to eliminate the overscan?
User avatar
27 days ago
edited on: 27 days ago
Hm, I really don't know if capture cards allow to reposition the picture and start showing the opposite side when moving it too much, but I guess it's possible, which would explain both the horizontal shift and the border showing on top.

In that case, the only change needed would be those missing pixels to the sides. But it would be a good idea to check the real hardware just in case that the game window is not actually completely centered (as happens with the Amstrad CPC, I think?).

User avatar
26 days ago
I know many years ago I worked with Kale on the PCE/TG-16 and made a snapshot of a game "Tricky Kick", First Level - First Character, to identify the borders and how much was seen via a capture device vs. what was on screen on a normal TV. I've attached my capture I made (date shows it was just before 0.140 was released) of the game and should serve as a decent reference for screen size. I'd like Kale to chime in to decide for sure what to do or if anything needs to be done - but I'll acknowledge it for the time being based on my capture screen.
User avatar
26 days ago
edited on: 26 days ago
Thanks for that screen grab. So it seems like the picture is indeed shifted a little to the left and that MAME is cropping a few rows of pixels on top (which are not just plain border in this case): -> MAME -> Real hardware

Also, the aspect ratio seems a bit different. Could that be because of the capture device?