First off, thanks GRisk for this app!  I saw a demonstration video (the old train video) on Gizmodo earlier this week, and immediately wanted to try it myself.  Sadly, my skills aren't up to building an app from the source code, so I was grateful to see that someone did the hard work for me :)

The frame rate change functions seems to work perfectly.  My RTX2060 card was up to the task of being able to convert a sample video (slow conversion, but I suspect with time you'll optimize things and performance will improve greatly).  The one thing that it didn't seem to do was upscale the video to 1080 (I'm playing around with an episode of The Three Stooges ripped from DVD).  It didn't give any errors or anything while processing but at the end, while it had doubled the frame rate, the resolution was still DVD spec.  I had selected the scale video box, and entered 1080 as the video height.  Did I do something wrong, or does the scaling option not allow up-scaling?  As well, what's the difference between the three interpolation methods, I didn't see anything on the website describing their features.

Anyway, please keep the updates coming!  This is a very cool & fun program to play with!!