Watching DVB-T live on W7 media centre after 15-20min the sound starts to get choppy then the screen does the same.  
I can fix the problem by changing channels and then go back to what i was watching.
I left it playing for an hour and it completely stalls but i can still change channels and it plays normally.

It may be a codec issue but not sure what one. I can record fine and play back fine its just live. Any ideas?