Hello,
This project is a little out of date. At the moment the current build needs to be patched for a security vulnerability in Unity. There was a remade version of DUCT in the Stride game engine that actually handled video processing through FFMPEG, but this tool was never completed.
My personal recommendation is to instead use the tool and instructions Clark provided for MPEG-1 video streams. https://github.com/CG8516/ImgStreamCreator/releases
If still desired I can make a patched version of the old DUCT public, but I recommend against using it.