Weird issue with new LCD TV (1 Viewer)

[ghoward]

Hello all, hoping someone might have an idea what my issue is. I have a new Samsung 46LNA580 LCD 1080p tv that I am connecting to my home theater. I have comcast HD and it goes to my Onkyo TX-SR674 receiver via HDMI. The output from the receiver to the tv is also HDMI. I noticed that my new TV gives me the resolution and I noticed that it said that it was running at 1280x720@60hz, which is 720p. The broadcast was supposed to be 1080i. So I tried hooking up the cable box to the TV directly and the TV correctly reported a resolution of 1920x1080i@60hz. So my first thought was that the receiver was somehow downgrading the resolution, although I have no idea how. But I noticed that even though the TV reported difference resolutions, I couldn't really tell a difference, and I think the difference between 1080i and 720p would be fairly obvious. So I swapped some inputs around so that my Onkyo DVD player ran into the receiver using the same HDMI input that the cable box was. Its an upconverting DVD player and it always outputs at 1080i. Going thru the receiver the TV reported 1920x1080i@60hz, which was correct. My xbox 360 also worked fine. So now I'm stumped. If the receiver was downgrading the signal somehow, why would it only do that for the signal coming from the cable box and not my DVD player or my xbox? And if its not the receiver, then why would my tv falsely report the resolution when getting the cable box signal through the receiver? Has anyone run into anything like this before. Im not even sure which manufacturer to contact first.


Thanks for any and all replies!

 

[Joseph DeMartino]

All fixed-pixel-array TVs, including your LCD flat-panel, display everything at their own native resolution. That is the only resolution they can display. So regardless of what input it is getting, your set is scaling everything to 1080p and deinterlacing the signal where necessary. That's why you can't see a difference between "720p" and "1080i". (And depending on your screen size and viewing distance, there may not be a huge difference between 720p and 1080p in many cases.)

Not sure why you're seeing the difference in reported resoultion with the cable box (I would check the output options on the cable box and all the HDMI options on the receiver to see if something odd isn't going on with the receiver trying to deinterlace and rescale the cable box image.) But clearly it isn't causing any image degradation, and your TV is displaying 1080p anyway, so this may be more of a nagging mystery than an actual problem.

Regards,

Joe