It seems like its working localhost in xbmc. I'm using a special branch of xbmc with pvr support and support for tvheadend as backend. This suddensly seems to be working great. All I did was to turn of signal monitoring on my dvb-c devices. Might something weird there?
I still get a stuttering image when streaming on my local network. My htpc is connected with wifi so that might be the problem. Tvheadend records directly to a smb share that is also connected with wifi and that seems to work but the protocols might work differently. How much bandwidth do I need to stream, I guess streaming over wifi should not be a problem?
I will make som more tests and see if I can pinpoint the problem and also hook up a network cable to the htpc and see if that solves the problem with streaming.