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Reply To: 4:3 -> 8:7 Aspect Ratio correction for SNES

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#14140

FBX
Participant

Just wanted to set the record straight about aspect correction on the SNES for the OP: The examples you posted are as you know, games where the artists either could not or forgot to account for aspect correction. So those perfect circles were never perfect back when they were displayed on the current technology of the times. This is mostly due to memory constraints. Tiles were square because memory is stored that way (i.e. 8×8, 16×16).

However, there are several games where the artists did take into account aspect correction. Take the Magus Tower in Chrono Trigger for example. The intro scene that pans down the top of the tower with the moon in the background very CLEARLY was designed for aspect correction. So if you play this game at 1:1 square pixels, you’re just playing it wrong.

Now here comes the important part: People generally get wrong how to aspect correct the SNES. They think you take the 256×224 active area and stretch that to a 4:3 image. That’s not how it works. Instead, a formula is devised based on the pixel clock rate. In the case of the NES, SNES, and Genesis’s 256×224 mode, the formula is 256 * 8/7, which equals about 293×224 for proper aspect correction. When scaling, the most accurate approach is to scale first and then apply the formula. So 2x scale would be (256 * 2) * (8/7) = 585×448 and 3x scale would be (256 * 3) * (8/7) = 878×672 and so on. Of course it’s better to use multiples of 2 when it comes to digital displays, so for 1x scale: 292×224, and 2x scale: 584×448.

But yeah, just wanted to set the record straight that while you may prefer the perfect circles in the handful of games that didn’t account for AR, it’s still technically wrong, and is merely a novelty to see square pixels in this regard.