I’ve been playing A free Zelda Rogue-like and A fast-paced, Rogue-like FPS: Mullet Madjack

Both are fantastic games with a lot of replay value!

On second thought, If you use the same source 1080p video and lock one in at 1920 x 1080 window and expand the other one to as full screen as possible. The full screen video will be up-scaled so you should be able to compare directly on one set.

Ah, I see. No problem. You’d have to switch back and forth in that case or have two of the exact same TVs to compare at the same time. (Some sets do a better or worse job of up-scaling). You’d also have to take into account viewing distance from the TV. At a certain distance it won’t matter, but as you get closer, it matters more and more. There are view distance calculators available online to help with that.

I don’t think so because you’re not forcing the 1080p video to be upscaled since it’s stuck with 1920 x 1080 pixels in my example.

Start with a 4K screen. Play a 4K video in VLC. Keep it in windowed mode but make it as big as you possibly can on your screen. Fire up the same video but at 1080p quality. Force that window to be 1920 x 1080 in size. There will be some overlap of the windows, but you can look at the non-overlapped parts and directly compare the video. You can also alt-tab back and forth. Not perfect, but it should give you a pretty good idea. Others - feel free to chime in if this is a good idea or not. I think that so long as the 1080p window is locked in at 1920 x 1080 then it won’t be up-scaled.

Careful Nintendo. If backing up a game I purchased and playing it any way I want is stealing, then I might as well skip the first step.