Just purchased a new Vizio 47" sv470xvt (120hz) for my parents which is connected to a cablevision HD box. When I set the cablebox to 480 stretch, 720 or 1080i the picture does not fill the screen (black bars on left and right) and does not appear to be in HD. The only time the picture fils the screen is when I set the cablebox to 480 std. We watched a HD movie last night (88 minutes) via pay per view and the TV made the film look like it was shot on a home video camera - very unusual. This is my 3rd Vizio LCD and I have never experienced a problem like this before. Is it possible that the chip in the tv is simply broken?
IMO the least likely cause is the TV. It is most likely 1) the cablevision HD box setup, 2) the TV setup or 3) the source material. I am not familiar enough with your equipment to make specific recommendations. Knowing where to look is half the battle.
If it isn't 720p or 1080i/p it isn't HD. If it is 720p or 1080i/p it may not be HD content.
I was able to find Component cables and after conducting a test with them the results are the same. I did just test a DVD and everything seems fine which leads me to believe the problem might be with the cable box. I am going to test a different cable box on this tv