DGQ with a young, thin DG. So good. I wish I could play a quarter, even an eight, as well as that. I'm not sure who the other mandolin player is - Andy Statman, Sam Bush? I wish I could find a bunch of people who wanted to play that kind of stuff. Update: It's Mike Marshall,(see comments) which I should probably have guessed from the virtuosity. He is stupendous.
The second mandolin player is Mike Marshall or his doppelganger.
Jay Votel