If you are still having trouble with video recording. just try OBS Studio:https://obsproject.com/
Take 5 minutes to setup everything, in Output/Recording, just use the 2 highest recording qualities (the other ones are ***), use hardware encoder and be done with it.
Then in Sources, just add an item with Mode "Capture any fullscreen application", click Start Recording, go and forget about this codec thing.
NVidia Shadowplay is messed up with this login requirement, and an older version (2.1) doesn't seem to work with new driver.