Suspected you were dealing with proprietary formats and when that's
the case you really are up against the wall :-( Same with the blocking
of recording channels that are protected from recording - though if
you have composite output that can be taken to a video capture card
but the quality will be much lower.

Not much help I know, but you can be assured it's not an Ubuntu ( or
Windows ) fault as such - that old DRM bogey man at work :-(