I want to upscale a Super Nes video in HD

[SuperLumberjack]

Hello

I'm new on this forum and I'm French. I try to upscale video captured with a Super Nes emulator (Snes9x) which are in a resolution of 256x224, in a resolution of 1408x1080.

[with Higan Emulator, the output resolution is 584x448 (or 584x480 with black bars), and it is known to be the more accurate emulator, so I took a proportional resolution]


My principal problem is this :

Pixel Aspect Ratio and Sampling

Analogue RGB signals from retro consoles use composite video or composite sync in addition to the color information. This type of sync doesn't contain information about the horizontal pixels. This is commonly called RGBS as opposed to RGBHV, where H and V stand for the horizontal and vertical sync. RGBHV is used in more modern devices for VGA for example. On CRTs it doesn't matter that there is no horizontal sync information, because each line of the picture is drawn across the whole screen. On LCD screens and for capture this is a problem. In the process of creating a digital version of the signal the picture lines are sampled and pushed into a mask of pixels. The number of pixels is fixed and doesn't take the original console into account. Usually there are 720 or 640 horizontal pixels after the sampling step.
sampling



240p signal with non-square pixels sampled and linedoubled to 720x480 pixel.

Retro consoles usually only have a low amount of pixels in the horizontal resolution. These pixels are stretched to fill a whole line on the screen. In the case of the SNES there are 256 pixels horizontally in each line on the console. To fill the screen the pixels are slightly stretched, resulting in pixels that are wider than tall. The actual pixel ascept ratio (PAR) for the SNES is 11:10. On a PC each pixel has the same width and height, or in other words a pixel aspect ratio of 1:1. In the sampled version of the signal each non-square pixel from the console influences the color of 1 or 2 horizontally adjacent square pixels making it slightly blurry on the horizontal axis.

(source : https://blz.la/rgb/)


Do you see what I mean ?

When I do an enlargement oh the image with classic resize filter, it becomes inaccurate horizontaly.

The best I tried is the SimpleResize, but the YV24 and RGB24 color formats aren't supported, so I have a loss of accuracy for the colors

Have you an idea for this ?

We can took this picture to begin :




Thanks for your help !