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

The “256×240 optim” linetriple mode is what you are asking for; you just need to squish the 1280×720 output to 4:3.

For the optimized linetriple modes custom horizontal scale has already been added to the wiki Other feature request list.

However you can already get 1:1 pixel aspect:

linetriple generic 4:3 with h.samplerate 1110, h.synclen 30, H.active 1000, H.backporch 94.
linetriple 320×240 optimized mode with h.samplerate 341, h.synclen 15, H.active 320, H.backporch 17.

For linedouble you can set h.samplerate to 682 and h.active to 512 so you get 512×480. It depends on your display how that will be scaled. For example my monitor scales everything to 16:9.

Let’s see…

Linetriple mode outputs 1280×720 pixels; “256×240 optim” mode scales/maps the SNES’ 256×224 pixels to 1024×672 (4x256x3x224) of them.
If you squish these 1024×672 pixels from 16:9 to 4:3, you end up with 768×672 pixels (3x256x3x224), and that’s the 8:7 aspect ratio you asked for.

This simply comes together neatly; you can’t do something like that with the linedouble mode’s 720×480 pixels.

I think it would be possible, but the problem is: 720×480 doesn’t have square pixels, so you will never end up with an 8:7 aspect ratio as long as your display scales that res to either 4:3 or 16:9.

I find it hard to believe that developers didn’t know about this, I don’t think Nintendo used special weird monitors when testing SNES games. Trying to correct this just makes it look like an emulator.. but each to their own.

This has been now implemented and will be part of next fw release.

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.