Perfect* 3DO Scaling with the RetroTink 2x, OSSC, and Framemeister

[kgenthe]

The Quest for Perfect Pixels

On my quest to achieve “perfect” 3DO scaling without using mods I stumbled upon the Japanese 3DO variant which outputs native 240p. You can read more about that here on AtariAge or watch the excellent My Life in Gaming video here. Sadly, there is no native 3DO with RGB output, only S-Video.

While the Framemeister is pretty great at upscaling 240p S-Video content, it isn’t quite perfect and I would prefer something even sharper.

To achieve what I’m after, I’m using a Retrotink 2x (convert S-Video to RGB), an Open Source Scan Converter (line triple/quadruple), and the trusty Framemeister.

RetroTink 2x

The RetroTink 2x is generally a super simple Line Doubler, taking a 240p input (composite, S-Video, or Component) and outputting a 480p signal over HDMI which most (all?) modern displays can display. Honestly, for most this is a terrific way to play the 3DO.

For my purposes, I just want it to convert the 240p signal, and not line double it (press the "processing" button until both lights are off).

One can then use a cheap HDMI to VGA converter to get back to an analog signal. I’m using one available at any Walmart. Why would one want an analog 240p RGB signal over VGA?

Open Source Scan Converter (OSSC)

To feed into the OSSC of course. The OSSC has a VGA input. With it, we can process that sweet 240p analog signal and attempt to perfectly sample the 3DO’s video output, and then line triple (720p) or line quadruple it (960p). Here are the settings I’m using on the OSSC:

240p/228p Proc: Line 4x

Line 4x Mode: 320x240 optim. (basically, we want to sample the 320 horizontal “resolution”, rather than sample the entire 720 signal)

H. Samplerate: 398 (attempting to sample the 320 pixels)

Sampling Phase: 281 (again, attempting to sample the perfect 320 pixels)

H. Backporch: 30 (shift image horizontally)

The OSSC will now be outputting a 1280x960p image over HDMI and each 3DO pixel will now be a 4x4 square.

Framemeister

This step may or may not be needed depending on your Television, Capture Card, or image processing preferences.

At this point, the 960p image is probably washed out. I believe the RetroTink 2x outputs in the limited RGB range (16-239). The VGA converter probably outputs in full RGB range (0-255) meaning whites are now light grey, and blacks are now dark grey. The Framemeister can be used to correct this. For the sake of perfect “4x” pixels I’ll also leave the 960p image in a bordered 1080p “frame”:

Output: 1080p_60

Image_Mode: Picture

Screen_Set: Smart_X1

Black: 8

So, with the RetroTink 2X converting S-Video into RGB, the OSSC sampling and scaling to 960p, and the Framemeister correcting the color and correcting the video signal, we get “perfect” 4x captures of the 3DO.

I've cropped these back down to 1280x960p in photoshop. Click the images for full size.

Issues:

I don’t think the colors are correct. The mid-range color look noticeably “hotter” than feeding S-Video straight into a Framemeister. I’m not sure if this can be fixed, or if it is in fact correct as-is.

It doesn’t seem the OSSC can perfectly sample the 320 horizontal resolution of the signal. There is some horizontal blur most noticeable on the left side of the image. This might be resolved with better sampling settings on the OSSC, or this might be as good as it gets. Still, the checkerboards in Soccer Kid and Blade Force are spot on.

Somewhere along the line, the top row of pixels is getting cut off. I don’t know if this can be fixed either.

If you have any improvements in terms of better hardware or better OSSC/Framemeister settings, please share them.

Thank you.

[Austin]

Seriously great information. I honestly can't justify a RetroTINK on top of my Framemeister and OSSC, but this is great info nonetheless.

[+chicgamer]

Wow. I've never seen anyone use all three of these together. Not something I would ever do, but I appreciate the amount of work you put into this!

 

Most of the time, I play my 3DO via s-video on a Sony Trinitron, but I plan to 240p and RGB mod my FZ-1 and run that through the OSSC for video capture.

[mindscan]

I was actually trying to do this same thing using my retrotink5x (in 240p downscale mode) and hdmi to component adapter.. I got a really noisy signal on the OSSC though, while your settings helped sharpen the pixels, for some reason I had a lot of vibrating pixels from the analog noise.. 

kinda strange.. I feel like it should've worked fine, I'm basically doing the same thing you are, just using slightly different devices.. 

 

on retrotink5x itself it looks decent enough, however pixels are quite blurry as it doesn't have an optimal sampling mode for 3DO yet..