Video bits from that 1926 Dvorák "Humoresque", a 1932 Tchaikovsky, and interviews.
The audio for the Tchaikovsky video clip is dubbed in from one of his commercial sound recordings (I'm sure of it, I've heard it dozens of times!).
go here to see this Dvorak clip in it's entirety (though in poorer quality):
http://www.youtube.com/watch?v=yHAOyTESpmc
Tags: MischaElman Tchaikovsky Concerto violin classical Dvorák Humoresque