Comment by Firehawke

Problem with this theory is that it's not taking into account what the artists were designing their art to be. Not every circle is meant to be a proper circle in the end-- sometimes there's a mix of PAR (Pixel Aspect Ratio) art and 4:3 in the same SCENE much less the same game: For instance, Chrono Trigger has mostly 4:3 artwork, but the moon seen behind Magus's Tower is actually 8:7 PAR.

I'd argue that in the end the whole game was meant to be seen by players on a 4:3 display, and thus 4:3 is "always" the correct answer for NES/SNES.. but your mileage may vary considerably.

I think the one thing I CAN have a hardline stance on is that stretching out 4:3 to 16:9 completely and absolutely distorts the intended look of the4 game and is ill-advised.

That said, there's one fly in the ointment. Systems like the TRS-80 Color Computer had a massive block of overscan that's visible by default on all displays. How MUCH of that overscan is visible depends on the display you're using (different TV plus different H/V size knob settings) and so actually working out what the correct display is and should be.. is a LOT harder and will vary a lot across different software on the same system. I'm not sure that just picking an aspect ratio per-game is correct; most users didn't exactly go and recalibrate their TV for each game they were playing, they'd pick a good baseline and live with it unless something was offscreen and thus required adjustment.