You said you're using WIFI for TV and can't do direct wire. Can you run an ethernet across the floor just to test it for a night and see if that resolves the problem? Sure, that won't be your long tern solution but it will show the problem is with the router signal or the receiver in the TV.
I had a lot of problems in a former house that had copper pipes in the wall between my router and my living room. I use Apple and had to put an Airport Express to extend the signal from my AirPort Extreme. It was a hassle but solved the problem. In last couple houses I haven't had to worry about that even in bigger houses. I do try to place my router in the family room since that is where we will use it the most from surfing the internet on the couch to NETFLIX.