Improve LiveTV quality?

I'm running Eden with MediaPortal LiveTV plugin. I use a Terratec DVB-C USB Stick.

Comparing the LiveTV quality with my stand-alone Technisat receiver, it is a little bit more soft-painted, some kind of unsharpness.......

Is there a way to improve LiveTV quality through xbmc? In MediaPortal i have already changed some codecs with no vissible effect.....