[INFO] Feature, add/update rife frame interpolation

[Brutoloco]

Hi,

Version 4.0 of the RIFE frame interpolation engine in Vulkan allows to multiply by a fractional number, this allows to obtain an output in FPS of the exact value you want with very decent quality without having to crop frames by eliminating excess images.

I think that would be a very useful feature, the fractional option seems to only work on Vulkan API.

https://github.com/HomeOfVapourSynthEvol...cnn-Vulkan
https://github.com/nihui/rife-ncnn-vulkan

Thanks