Pixelated channels

I have Pixelated channels 396 & 1301 ( ESPNU) and 477 & 1217 ( NHL). Is there anyway to clear the pixelation? The audio comes in with channels correctly, no video, only the last channel viewed, which pixelates. I noticed if you forward or reverse the proper channel somehow plays correctly until it goes live, then, you guessed it, pixelated channel. Please advise, thanks