Generally speaking Nvidia HW decoding and encoding is provided by the Nvidia driver and has nothing to do with Packman. Maybe you need the proprietary Nvidia driver or at least the nvidia-compute-Gxx part.
Whether or not the applications you use must come from Packman remains to be seen, but it is relatively easy to test: just disable Packman (without removing it), do a zypper dup --allow-vendor change and test. If you are not happy you can enable Packman again and zypper dup --from packman-eesentials --allow-vendor change again.