gstreamer-plugins-ugly-orig-addon has been depreciated and all of the codecs it provided have been moved to gstreamer-plugins-ugly but that package only provides audio codecs and you are describing a video issue
check to see if you have gstreamer-plugins-bad and gstreamer-plugins-libav
Code:
zypper se -si gstreamer-plugins-bad
zypper se -si gstreamer-plugins-libav
if you don't have them install them if they're from 42.2 do a system upgrade to 42.3
another thing gstreamer-plugins-ugly-orig-addon never existed for 42.3 that's a 42.2 package I'm guessing your upgrade wasn't quite successful check to see if you have some old packages left behind (assuming you upgraded from 42.2)
Code:
rpm -qa --queryformat "%{Name}:%{Distribution}\n" | grep -F "42.2"
about nvenc as it's a h264 based encoder I don't think it's in OBS and installing ffmpeg from OBS will break multimedia