OSSC Pro: Pixel perfect PC VGA 400p to 240p downscaling not possible?

[koodoonas]

Hello!

I’m trying to downscale 400p PC VGA to my CRT

In 480i output mode, integer scaling (underscan) fits the screen perfectly (left/top), while in 240p it looks stretched (right/bottom)

All other scaling modes introduce vertical motion artifacts.

A line dropped 400p to 200p mode on 240p output though should work wonderfully with integer scaling (as source is line doubled anyway)

Is this possible?

Thank you!

[marqs]

At the moment integer scale does not perform division / downscaling, thus almost half of the 400px height gets lost when displayed in 240p. Line dropping could be easily done in A-LM mode, but the resulting refresh rate would match source (70Hz in this case) so I’m not sure if BVMs can handle that (is above SCL mode framelocked or not?).

[koodoonas]

I’m running it at 60hz non framelocked

I’ve been searching for a way to downscale PC VGA to 15Khz CRTs, so as to get rid of the 400p line doubling and enjoy graphics with proper scanlines.

The OSSC Pro already handles the 70->60hz frame rate conversion pretty great, so if it could integer downscale 400p to 240p (200p), it would (also) make it an excellent PC VGA downscale solution, which I’m sure would be a great selling point.

You can count me in you want any testing done on this feature!

[jamonyorke]

+1

Line dropping in order to display VGA 320×200 games in a 15Khz CRT would be an amazing feature to have.

70Hz would be good (and more faithful to the original, without any scrolling artifacts). Some 15Khz monitors support 320×200 @70Hz (eg Commodore 1084S D2).

I don’t have an OSSC Pro yet but I’d purchase one just for this.

 

• This reply was modified 1 year, 9 months ago by jamonyorke.
• This reply was modified 1 year, 9 months ago by jamonyorke.

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