I have just Bought this Pioneer Elite Pro-920HD. I have Cablevision Cable with a Scientific-Atlanta 8300HD DVR set-top box. The problem I'm having is the picture size changes from channel to channel & Show to show. One time it the the whole screen the next channel it has the two bars on each side. I did advance setup with my cablebox selecting all formats 1080 720 480. I want it to fit the screen automaticly with out doing it manually or streching it. Any suggestions? Thanks,