Oh yeah, just explain if not all know.
This Campuchea concert with Queen on Dec. 26th. 1979, was filmed (and recorded), but never offisially released. A 60 min. TV ducumentary was made out from the concert (+ 2 videos), and TV broadcasted around the world.
A video was made out with more tracks, and shown at some of the Queen conventions, tru cabel arount to the rooms where anyone with a video recorder, could copy the show.
This is the way it ended up on DVD's.
'Now I'm Here' from the concert, is on the officially 2LP 'Concert for Kampuchea'. Released by Atlantic (I think it was) in 1980 or 81.
I have the album, but it's upstairs.