MiSTer FPGA Forum

I've tested some games with Genesis and MegaCD cores and sometimes the screen just went blank without any indication of what might be wrong. I've used 19" Dell P992 VGA crt with forced_scandoubler set to 1 from mister ini file and vga_scaler set to 0. One of the games with the problem is Sonic 2 (2-player mode or just let the game intro play).

I decided to do some testing with different graphics modes so i had to set vga_scaler to 1. That revealed that the game changes into interlace mode when previously the screen just went blank. I suppose it means that my VGA monitor does not support interlacing and that is quite expected.

Out of curiosity i tested with old Nec Multisync 2A (that is not those famous multisync monitors but just normal old VGA/SVGA monitor) since old SVGA monitors do support interlaced modes. It did show picture, although not correctly, so it did not properly support the graphics mode either. Then i did a quick test with 19" Nokia 920C but the screen went blank just like on Dell.

VGA scaler output is not good since it looks like no deinterlacing is done at all but it is certainly better than just blank picture.

What can be done? Should I just use VGA scaler for cores that use interlacing modes?

I've tested this on my PC CRT (Sony Multiscan GDM-400PS) and I get no display on the interlaced scene regardless of vga_scaler. The only setting that seems to enable displaying that interlaced part of the Sonic 2 game is when I set vga_scaler=1 and vsync_adjust=0

I'm not able to tell if it displays correctly (have no comparison material), please let us know what vsync_adjust setting does for you.

FWIW, here is my experience with Sonic 2 on a flatpanel: viewtopic.php?f=16&t=1312

https://github.com/MiSTer-devel/Genesis ... -630074861

I don't know if this has changed but, at this time of sorg's comment in the linked thread above, interlaced video can't be scandoubled on the mister.

To be honest, this is much more of an issue on the Minimig core than on the Genesis, as many demos and several games do take advantage of interlaced display modes on the Amiga.
I would love having an option to enable bob deinterlacing or motion deinterlacing when the scaler is disabled. Until then, as a workaround, I can have most interlaced resolutions working on my VGA CRT monitor (Compaq S700) with vga_scaler=1, forced_scandoubler=0 and vsync_adjust=2.