Swap out the cable box. I have found I need to replace the box (HD DVR) once every year or two. As mass-produced rental equipment I find they just fail constantly. Sound issues, check. HDMI failure, check. Component color flickering, check. Before you go nuts, just run by and get a new box. If it does not help, at least you got a newer toy and can move down the signal path.

Panny 3000 PJ, 118" Carada, Denon 3300, PS3, Axiom QS8, PSB 5T, B&W sub, levitating speaker wire