ffmpeg -i in.png -vf scale=3840:2160 -sws_flags lanczos out.png -vf scale=3840x2160:flags=lanczos
I went down the list upscaling a 720p image to 4k using the various ones on the documentation, lanczos is input above. I tried the variation below as well. I noticed 0 difference after tossing them in gimp and zooming in and comparing....exact same. I also noticed it doesn't matter what I type, i could call them something wrong or spell them wrong and the command works the same. They don't seem to be applying at all. Is there any indication in command prompt as to what scaling algorithm is being used so I can confirm ? I didn't see any difference.