- On my old computer KDEnlive shows it is using MLT 7.1.0. Everything is working fine, especially rendering files with vaap.
- On my new computer KDEnlive shows using MLT 7.0.0. I get billions of errors when rendering files with vaapi.

I suppose the errors are connected with the different MLT-libraries. How can I make KDEnlive make use of MLT 7.1.0 on my second Computer. I already installed MLT 7.0.1 but KDEnlive still insists on using the 7.0.0 version?

Found the problem with vaapi not working on my newer Computer.
It wasn't MLT but the window manager causing frustration.

It seems like vaapi is having problems with wayland window-manager (which was used on my manjaro system). I switched the windowmanager from wayland to x11 and the error messages are gone.