/vr/ - Retro Games

>>5089987
>>5089997
You don't seem to actually know what you're talking about yet you're really aggressive about it for some reason. I don't know how to explain it super well but I can try.

CRTs can do aspect ratio correction on the hardware itself. The art is drawn at 320x200 and then the monitor is meant to correct it to 4:3.
If you're doing aspect correction through software to a non-integer resolution you're going to have to either use linear filtering to smooth it out or you'll have random lines doubled. Notice how the font at the bottom here is inconsistent? It's because of aspect ratio correction. The art is 320x200 stretched.
640x400 on a CRT means you're getting pixel perfect picture. 640x480 means you're getting either a blurred image or having random line doubling. It's 4:3 in both cases but one is correct and the other is not.