I have a two-year old Panasonic TC-P55VT60 with 3 hdmi ports to which are connected two dvd players, a blu-ray Panasonic DMP-BDT 220 and an All-Region Pioneer DV-610AV. Recently, when playing a dvd movie, the picture would darken and stay dark. In one case it was after 10" of normal picture. More recently it occurs from the beginning of the movie. I have switched players from one hdmi port to another and determined that both players will play movies accurately but only on the middle hdmi port. This is a new problem for me. I have also changed cables but that does not solve the problem. Most discussions of hdmi problems report either weird colors or no picture at all, rather than the darkening that I am experiencing. Anyone have any ideas as to what is going on and how to solve this problem?