Pixelating Live TV

For the past few months my TV has been pixelating only during Live TV like the news or sports. It is fine during the commercials of the shows but the actual shows pixelate. It does not happen with streamed, on-demand, or DVR'd shows. I have refreshed several times and checked connections (although I'm not sure exactly what I'm looking for). It happens on all of the TVs in the house. Any ideas?