There should be xBR and xBRZ "Resize Methods" or plugins in future Avidemux releases to enlarge pixel-art or videos of 2D retro games.
(https://i.postimg.cc/RZFbcfZb/xbr.png)
ffmpeg does support xBR frame upscale by using the following command...
4xEnlarge example:
ffmpeg -i input.png -vf "xbr=4" output.png
Here are some examples...
Original screenshot:
(https://i.postimg.cc/DyPfHVFb/s.png)
Nearest Neighbor upscale:
(https://i.postimg.cc/t4mbGpc7/s-Nearest-Neighbour.png) (https://postimg.cc/PCZ9msTk)
Lanczos upscale:
(https://i.postimg.cc/cLzp5TKn/s-Lanczos.jpg) (https://postimg.cc/RWcpW7LS)
xBR upscale:
(https://i.postimg.cc/xdbwrHHF/s-xBR.png) (https://postimg.cc/67tjn8Md)
xBRZ upscale:
(https://i.postimg.cc/Y96T0Hd6/s-xBRZ.png) (https://postimg.cc/bDvmVKcr)
It is impossible to add xBR to the libswscale-based plugin. The feature is provided by a different library – libavfilter – not used by Avidemux. A capable developer would need to port the filter.