Shift MAME image help please!

2huwman

I'm running RetroPie v4.8 downloaded from here on a Pi 4. I'm playing in Tate mode in lr-mame2003, and also have ES rotated. I've got it all installed in a Quarter Arcade Dig Dug cab, and everything works well apart from the positioning of the screen in MAME. The reason I need to do this is because the LCD screen is mounted somewhat off centre in the cab. Can anyone explain which settings I need to adjust to move the image down a bit as it is too high (in Tate mode, which would be to the left in landscape). You can see what I mean in the photo below:

I've tried adjusting various cfg files without success. I thought the 'viewport' settings in the retroarch cfg would achieve this, but they have no effect on the image in mame.

Thanks for any advice!

mahoneyt944

So the image is centered on the monitor, but the monitor is not centered in the cab?

If so, you might be able adjust the overscan border in /boot/config.txt.

Also, some monitors have settings in their menu to adjust the vertical and horizontal position as well as overscan.

2huwman

@mahoneyt944 thanks, yes that's exactly the issue. I did try the overscan settings and was able to bring the top of the picture down, but the bottom didn't move so the image was squashed.

Good idea about the monitor settings, but sadly there isn't any menu button or anything to access any settings.

I was wondering if there was anything I could add to the individual game cfgs to move the image, as I've had to add something for rotation to get them to display the correct way up.

I could physically move the LCD down but that would involve cutting some of the plastic around the bezel which I'd rather not do.

mahoneyt944

@2huwman said in Shift MAME image help please!:

but the bottom didn't move so the image was squashed

Use a negative overscan value on the bottom of the screen equal to the amount you adjusted the top.

2huwman

@mahoneyt944 thanks - I've tried that and it doesn't feed through to ES or MAME (they seem unaffected by the overscan settings).

2huwman

After some trial and error with overscan settings I've made a little progress. Using overscan_scale=1 carries the changes through to MAME, so that's been helpful.

Using the following overscan settings allows me to move the image at the top of the screen down (this would be the right side in landscape mode), but any value for overscan_left (bottom of my screen) pushes the image up - even if I use a negative value! So that just squashes the image more. Leaving overscan_left at 0 results in least squashing, but doesn't move the image down, so I've still got that black border at the bottom of the image, and it's still a bit squashed.

overscan_left=0
overscan_right=80
#overscan_top=16
#overscan_bottom=16
overscan_scale=1

Any more suggestions greatly appreciated!

EDIT: I've found a solution - there are options in the retroarch gui to move the image around the screen, but you have to select window mode rather than full screen, and use a custom aspect ratio. These options are hidden if you're in full screen mode which is why I didn't see them earlier!