Getting the most accurate picture from a CRT monitor

[tccalvin]

Hi there, Dolphin people!

Lately I've been having a lot of fun running dolphin at 480p on a CRT monitor.

A couple of technical-nerdy-purist questions:



I've been doing some research on how to replicate the look that an actual console would have if hooked up via VGA to a CRT monitor but I can't really come up with an answer.

To be a little more specific (or obsessed), i wonder what it would take to make every one of the 480 scanlines line up as they should when displaying a game in progressive scan (just like they would on a Wii, for example).

The issue is primarily how to better emulate the overscan behaviour of the real hardware.

Should "Crop" be enabled? Should I force 4:3? Should I just leave everything on auto?



Secondly, there are some games that only output in widescreen mode. How do they work exactly? I've read that widescreen games keep rendering 640 pixels horizontally by making them stretched rectangles instead of squares. Is this the case? (If so, does it mean that widescreen games are always somehow scaled when displayed on a square pixel display?)

I'm pretty sure that by outputting these games in a 640x480 window I would be losing some lines of resolution due to the letterboxing.

One solution I came up with was to force a 4:3 aspect ratio (thus making the image taller) to then squeeze the image vertically with monitor controls.

Does this make the image use all 480 lines or does it just stretch the game incorrectly?

Any insights and opinions are welcome!

[JosJuice]

(11-04-2021, 12:14 AM)tccalvin Wrote: Secondly, there are some games that only output in widescreen mode. How do they work exactly? I've read that widescreen games keep rendering 640 pixels horizontally by making them stretched rectangles instead of squares. Is this the case? (If so, does it mean that widescreen games are always somehow scaled when displayed on a square pixel display?)

Yes. (Actually, the pixels are non-square even when in 4:3, but they're even more non-square in 16:9.)

(11-04-2021, 12:14 AM)tccalvin Wrote: I'm pretty sure that by outputting these games in a 640x480 window I would be losing some lines of resolution due to the letterboxing.

One solution I came up with was to force a 4:3 aspect ratio (thus making the image taller) to then squeeze the image vertically with monitor controls.

Does this make the image use all 480 lines or does it just stretch the game incorrectly?

If you want to play on a 16:9 CRT, then my recommendation is: Set Dolphin to Force 4:3, do not enable Crop in Dolphin, and set the TV itself to stretch the image to 16:9.

[tccalvin]

(11-04-2021, 02:10 AM)JosJuice Wrote: Yes. (Actually, the pixels are non-square even when in 4:3, but they're even more non-square in 16:9.)


If you want to play on a 16:9 CRT, then my recommendation is: Set Dolphin to Force 4:3, do not enable Crop in Dolphin, and set the TV itself to stretch the image to 16:9.

Thank you very much for the reply. It has helped!

After some digging around I found the proper way to display games on my CRT monitor (which is 4:3 by the way) and I've also uncovered some issues with Dolphin's video modes that I'll probably write down in some feature request.

The trick was using the screenshot function (f9) to capture native-res screenshots of the games to figure out their native resolution. Turns out, many of the games I was testing were using a 584x480 resolution. All I had to do was stretch the image horizontally (either by forcing 4:3 or stretch to window) to get rid of any scaling.