Muzz, alas, I found no FREE program worth a shit. So I bought this suite
http://www.avs4you.com/Register.aspxHas a ton of tools, including the handy dandy video editor. It appears they are running a special right now, and yes it is not free, but for $59 for a lifetime worth of progams and updates it is well worth it.
Does shadow play do a good job? When I tried it, audio recording was an issue...have not gone back to it.
Action! Will use your Nvidia cards hardware and save you the trouble of converting....
https://mirillis.com/en/products/action.html It is only $29. Save time and money. Just an FYI...support sucks donkey dicks for them though.
Cheers!
Dobs