Indivision MK3 - VGA versus HDMI - Vsync

shan2752 · Mar 24th 2023

Hello,

Is there any difference in picture or vsync capability between the VGA and HDMI outputs? I’ve tried several newer LCD monitors with VGA inputs and can’t get vsync to function. When I select the vsync setting, the monitors display out of range messages. With the same settings and deselecting vsync I get a great picture, but I notice text scrolling isn’t as smooth.

Is there a game or application that can help verify screen tearing? I’ve been using the text scroll at the start of Shadow of the Beast for reference.

Thanks!

Jens · Mar 24th 2023

Shadow of the Beast is a good test, as the side-scrolling backgroud will show tearing easily.

There may actually be a difference in capabilities, as HDMI requires 50Hz to be supported. Instead of VSync, you might want to try "auto resolution", as that will not alter the number of lines, but generate a pixel clock that will result in VSync to be in perfect lockstep with the original vertical sync signal. All HDMI monitors should be able to show a picture generated with this method (well, if they actually passed all the testing that is required for the HDMI logo).

Jens

shan2752 · Mar 28th 2023

I recently learned that the Dell SE2722H monitor is 15khz capable and can display 50 Hz for PAL. I purchased one and can confirm that it works great and the picture doesn’t require any pixel clock or phase manipulation like the BenQ monitors that everyone was purchasing several years ago.

The picture isn’t as sharp as with the MK3 though, but it’s nice to have the ability to switch between the VGA authentic signal and the HDMI scaler/flicker fixer signal.

I’m still not able to use vsync or auto resolution for the 1920 x 1080 VGA modes I’m using, but I can’t notice any screen tearing with this setup.

The only issue I see is that the scanlines don’t look quite right. They appear to be too close together and there’s no option to tweak them further. The picture is crystal clear though so great job on engineering this product!