Deinterlacing on PSX Core?

[hooxxx]

is there any chance for more option to deinterlace 480i games? Both bob and weave have heavy downsides but bob+weave is kinda best of both words so...

[Sigismond0]

To add to that, it'd be nice if there was some way to make this play well with filters. Bob with alternating scanlines is great if you want the CRT look, but right now the filters always stay on the same fields. So with bob, you get static scanlines and a hopping image instead of a static image with hopping scanlines. And scanlines don't work at all with weave.

[FPGAzumSpass]

No one has stepped up to build a better deinterlacer that costs only few ressources. Until then, we have to live with what we have.

[softtest9]

Should deinterlacing perhaps be moved to the MiSTer's scaler? This might make it easier for others to contribute and deinterlacing filters could also be shared with other cores.

[dmckean]

Anything more complex than bob or weave is going to add multiple frames of delay. This is fine for menus but not for Tekken.

[hooxxx]

retrotink 5x has some interesting deinterlacing techniques (blend. motion adaptive), are any of them possible on mister? showcase starts at 2:50 https://youtu.be/ilsXDNaK0QY?t=170

[Sigismond0]

I'd be happy enough with bob, so long as filters could be updated to support alternating scanlines.

[dmckean]

What would be nice is an optimized bob that shifts the odd/even fields toward each other by one pixel to reduce the bobbing effect. That at least should be able to be done without adding lag.

[Telemachus]

Weave you have the combing mess and Bob you have a softer image combined with risk of damaging IPS or OLED displays.

I have had image retention on an IPS display from Bob and thankfully I got rid of it but it was there for hours.
Bob should come with a warning.

Motion Adaptive isn't really a silver bullet either as it will still show combing, The only fix for this is to do what Sony did
and force interlaced modes into progressive but such a mode or hack would be altering the hardware.
It is really the the best catch all fix for modern displays, unless you want to buy an analog display.

I know other cores have implemented such techniques to display interlaced as progressive so it should be possible on PS1.

Or do some kind of framebuffer technique and accept a frame of lag or maybe half a frame. I'd probably say it is worth it vs
what we have now.

Or get a flicker fixer https://en.wikipedia.org/wiki/Flicker_fixer

[FoxbatStargazer]

We did just get a 480p hack, that seems like the ideal way to fix the issue if a game is compatible.

[Telemachus]

We did just get a 480p hack, that seems like the ideal way to fix the issue if a game is compatible.

You should probably try that hack for yourself. It doesn't work with a lot of games and the games it does somewhat work with the 2D elements
are not displayed progressively. So combing artefacts still exist. e.g. it only works with polygons.

t1-1.png (1.22 MiB) Viewed 1980 times

t1-3.png (1.09 MiB) Viewed 1980 times

br-1.png (1.61 MiB) Viewed 1980 times

br-2.png (1.11 MiB) Viewed 1980 times

It is stated as a hack so you get the idea.

[FPGAzumSpass]

You cannot force 480p for all elements, unless you can copy in (near) zero time, like emulators can.

That's why the 480p hack is a hack: it doesn't work on static elements, only on elements that are rendered with each frame.

Also it doesn't work for some games where our GPU power isn't enough.
True 480p would require one additional GPU renderer or 100% faster GPu rendering, but we only have about 60% more GPU power, so it's not fast enough for all games.

[Neocaron]

I'd be happy enough with bob, so long as filters could be updated to support alternating scanlines.

Same here! I only use bob, because it looks "truer" with filters, but alternating scanlines would be MUCH better imo.
The 480p hack is really convenient in some games where it works well.

[Telemachus]

I'd be happy enough with bob, so long as filters could be updated to support alternating scanlines.

Same here! I only use bob, because it looks "truer" with filters, but alternating scanlines would be MUCH better imo.
The 480p hack is really convenient in some games where it works well.

Even if you are willing to risk using Bob on your display it doesn't work for all games either. [Not 480p hack]
Bob in this case will get you a black screen.

[FPGAzumSpass]

Some games like this racing game use a squashed resolution to be able to fit 2 framebuffers in VRAM to run at 30fps in interlaced mode(15 full images per second only).
The current Bob implementation cannot handle that, neither can the 480p hack.

To support such weird cases on HDMI with better than weave, you need a very wide range general purpose deinterlacer which we dont have and which would very likely not fit together with the PSX core.

[Jingsing]

is there any chance for more option to deinterlace 480i games? Both bob and weave have heavy downsides but bob+weave is kinda best of both words so...

You can try the 480p mode but really its more of a novelty and will probably disappoint you more than impress.

If you are just into mister for PS1 you are probably better off with the latest PS1 Digital as it removes most of the headache associated with this interlacing stuff and is cheaper overall and doesn't have this issue of no solution for certain games you might play. Anyway that's is what I did. Mister is better for 16-bit stuff imho. PSX Core is still in development and I'll keep an eye on it but the interlaced handling and losing image sync for various reasons led me to get a PS1 Digital it makes it a breeze.

There are also games like ghoul panic were interlaced screens seem to blend into each other at least on the intro logo credits (probably a bug). I think it might be possible to address some of this with motion adaptive deinterlacing as the OSSC Pro has it and the source is on GitHub so it is probably just a matter of time before someone takes that FPGA implementation to mister.