Hdtv question!?

Question

so i have a hdtv with a native resolution of 720p should i leave my comcast cable box on 720p and let the 1080i signale omfg i cant spell that word signel anyways should i let 1080i prgrams down convert to 720p or keep my comcast cable box on 1080i since my tv can also support 1080i

2nd question does downconverting ruin the picture or does up converting ruin the picture more or is the a miniscule diffrence

3rd question if i have a 50000 dollar hd tv will it look better than my friend 5000 dollar hd tv or does it have to due with the cable hd singnle again cant spell signale since its the exact same info will it really make a diffrence hypotheticaly of course lol srry i c so many red lines under all these mispelled words

Answer 1

It depends on the program/network.  For FOX, ABC, and ESPN I would set the cable box to 720p.  For most others, I would set the cable box to 1080i.

My Comcast box doesn't automatically adjust its output format to match the program that is sent to the box on the cable.

It's a very little known fact that 720p is broadcast at 60 frames (images) a second.  1080i is broadcast at only 30 frames a second.  Those are the only two broadcast formats.  If the cable box is upconverting 720p (60fps) broadcasts to 1080i (30fps) then half the images are being thrown away.  I'd rather let my HDTV get all the images and then upscale them.

Answer 2

The above answer is not exactly correct.  1080i is 30 frames per second, but it is also 60 FIELDS per second.  Each field is 1920x540.  A properly-scaled 1080i output should de-interlace first to produce 60 full frames per second (60p), and then scale to 720p.  However, not all cable boxes and not all TVs do this (but the newer ones are more likely to do so).  You can't be sure that the TV automatically will do a better job of scaling.  So you should really try it both ways and judge by the appearance of the picture.

Up- or down-converting always can cause deterioration of the picture, but I have yet to notice any significant effects.

An expensive TV may not have better resolution than the inexpensive one (most sets are now 1080p displays).  However, the main differences will be in brightness and contrast capability and color purity.   It is unlikely that you will see a big difference.