Edit:telemetry wrote:Having watched and read a few UltraHDMI reviews repeatedly (Phonedork, MLIG, retroRGB, videogameperfection) as well as perusing the UltraHDMI website, it's a little confusing how "Integer+" behaves differently from other modes.
I get the scaling (Integer> 2x/720p, Integer+> 3x/720p), which means in Integer+ the vertical pixels don't really align to an even multiple (but an odd multiple) of the display's vertical resolution. So it's understandable why scanlines wouldn't be consistent.
But your captures of the "blurry" scaling doesn't seem consistent with my understanding of the behavior (Integer+ should have vertical alignment issues for scanlines, but the horizontal still sounds like a clean 3x scale).
EDIT: replace 3x scaling with 5x for the 1080p Integer+ mode).
I think the problem is Doom 64 must not technically be a 240p game. Since it has pre-sharpened pixels, it likely uses some sort of internal double scale that then technically makes it a hi-res game even though it appears low res visually speaking. So it ends up with artifacts like a high-res game would in Integer+ mode. That's the best I can figure anyway what's going on.