[PROBLEM] no picture in live-tv just sound ?

[lotust7]

Hello,
I have the following problem
just intalled xbian beta r2 and activated live-tv
I have a gigablue hd and live tv is working properly on my windows xbmc
on the rasp I get all the channels can play from gigablue library saved movies,
but if I want to see a live tv program only sound can be heared but no picture shows up!

Is that known as a bug or could it be that I need a codec license?

Thanks in advance