Pink/Magenta on some (not all) shadow masks

[sparkysanxion]

Hi there.
I originally posted this over in the Amiga core forum, as that was were I was initially having issues) but will split off into here, as this seems the more likely place to get some help.

I don't usualy use scanlines and shadowmasks etc, but thought I would give them a go on the newer versions of the megaAGA/Amiga Vision setups after seeing some photos online of people running them, and it looking great

but the mask gives me a pink/magenta tinge over eveything (obviously more visible on white things) when I have it turned on.... see the attached phto to see what I mean.

Am outputting to my LG tv (game mode on and everything else tuned off) over HDMI. Northing else opf much note I don't think. If I set the mask to X2, the pink goes away, but I guess then the scale is wrong...is that correct?

Have also noticed it on other masks, but not all of them. Weird. Anyone know what I am on about, or had similar?

PXL_20230719_222406911.jpg (1.05 MiB) Viewed 2120 times

[prenetic]

Mine looks the same way. Taking a look into 'Presets/MegaAGS.txt' shows it's using 'Shadow_Masks/MegaAGS.txt', which itself appears to be a copy of the "MG Stripe (Magenta Green)" shadow mask. Applying that shadow mask directly also has this same tint. Seems this may be intentional, or a mistake considering limi's response to your initial post on the subject.

Code: Select all

/media/fat/Presets# cat MegaAGS.ini
# MegaAGS
hfilter=MegaAGS-Horizontal.txt
vfilter=MegaAGS-Vertical.txt
sfilter=off
gamma=off
mask=MegaAGS.txt
maskmode=1x

Code: Select all

/media/fat/Shadow_Masks# cat MegaAGS.txt
# MG Stripe (Magenta Green)
v2
2,1
53d,23d

Code: Select all

/media/fat/Shadow_Masks# cat MG\ Stripe\ \(Magenta\ Green\).txt
####
# Name: MG Stripe (Magenta Green)
# Author: TrashUncle
# Type: CRT
# Genre: Realistic
####
v2
2,1
53d,23d

[limi]

Interestingly, both Optiroc and I are using this preset with LG TVs (the OLEDs) and we’re not seeing this. And as you show, the shadow mask is a copy of the existing MG Stripe.

Do you have any other displays you could test with to figure out if it happens everywhere?

[limi]

Make sure the TV is not using the wrong overscan/zoom setting, it should be what LG calls “Just Scan”. It’s possible that zoom + scaling of the shadow masks would produce weird artifacts. (This is a total speculation on our part, but worth checking)

[prenetic]

I just checked this again on a few different displays and it looks like I don't see the purple tint anymore, but I know this WAS an issue for me in the past and I would have to use a different shadow mask to avoid it. Perhaps I changed something in my video settings since then, or whatever the issue was I'm no longer experiencing it. You're probably on to something with it being a scaling artifact limi.

[sparkysanxion]

Will test on another TV later today. Am just out at the mo
Will report my findings (will also double check my ini settings as suggested)

[sparkysanxion]

I return with findings.

Tried on a 1080p Panasonic tv, and all looks fine!

So it’s deffo a tv issue. I was running into an hdmi switcher, so to rule that out, I tried direct into a port on the tv, but still pink.

Checked the tv settings (mine is the lcd 4K smart tv not the oled) and everything post processing wise if off, picture mode set to “original” but set to “game” mode. So I can’t see how anything there could cause the funkiness. Just as a test, went off game mode, and set it to what they call “standard” and it’s still not correct colour wise.

So whilst still on “standard” however i hit the reset to default setting, and it got …..better…..less pink but still off (have attached a photo of that)

I’m none the wiser. I can only assume it’s something the tv is doing whilst scaling up the 1080p input maybe??? Weird.

IMG_0081.jpeg (875.27 KiB) Viewed 1756 times

[sparkysanxion]

Ok. When I set my modes in the mister ini to be 720p………it looks fine!

[limi]

Possibly the scaler in your TV doing something to the MiSTer output, would be my guess. Does it have a Game mode or a PC mode? What model number of LG TV is it?

[sparkysanxion]

Possibly the scaler in your TV doing something to the MiSTer output, would be my guess. Does it have a Game mode or a PC mode? What model number of LG TV is it?

Yeah, I always have it in “game” mode, no matter what I have connected. (It still does this pink stuff even in non game mode btw)
It’s a - 43UH650V-ZB

Is there any downside to running in 720p?

[limi]

Is there any downside to running in 720p?

Just that shadow masks don't look particularly great in lower resolutions, and you won't get the 5× scaling in AmigaVision. So I'd recommend using 1080p without shadow masks in this case, and also play around a bit with the scaler settings in your TV (Overscan/"Just Scan" settings, etc) to see if you can find something that fixes it.

Since it's a modern 4K TV, you could also see if it handles 1200p resolutions, which will allow you to use 5×240p scaling.

[sparkysanxion]

Thanks for your help and input.
Seems nothing I do or change on the tv seems to solve it. Messing around with the “just scan” setting, does what it’s supposed to, but doesn’t change anything on the colour. Very strange indeed.

Aaaaanyways. I’ve gone back to 1080p and am using the megaags setting for scan lines, but have changed the mask to the retrotink ag2 … which looks pretty nice to my old eyes.