Quick ? - 1080i vs 720p output

asmcbride

SatelliteGuys Pro
Original poster
Jan 20, 2005
161
8
WV/VA
just a real quick poll or tech question. Are most people outputing 1080i or 720p from their HD receivers to their HD sets? I dont recall noticing a viewable difference when switching between the two. Has any technical tests been done to prove if one or the other provides a better picture to the set? The TV I'm using is a 1080P plasma Panasonic S1 series. On my old Sony GIII rear projection I think I always output 720P since it's a 720 set. Thanks in advance.

-mcbride
 
If you have a large 1080i/p display, then 1080i out will reveal more detail (and compression artifacts) for 1080i channels. It won't add more information to 720p or 480i channels because there's nothing to add.

If you're sitting 14' away from a 50" 1080p set, then it won't really matter.
 
Your TV's scaler takes whatever input it receives and converts to the set's native resolution, in your case 1080p. Most of the time it is hard to tell the difference between 720p and 1080i input after most sets rescale. It is trivial for your set to scale 1080i to 1080p. Scaling 720p to 1080i is only a little more work. Usually I would recommend using 1080i for a 1080p set and 720p for a 720p set. Comparing the two selections on your receiver and choosing the one that looks best to you is really an appropriate way to go as sometimes the quality of scalers varies.
 
Well, I found on my 768p 32" Magnavox that my 622 looks best on 480p
My 1080p 42 inch Philips looks best on 1080i setting with a 722
And my 1080p 52 inch Sony looks best while on 1080i with a 722
 
Theoretically, if most of your viewing is 720p content (Fox, ABC, ESPN), setting the receiver to 720p output will "mangle" the signal less. The TV will do a fine job of upscaling the 720p content for your 1080p panel. If most of your content is 1080i (NBC, CBS, Discovery), setting the receiver to 1080i will be better. The only thing that your TV's scaler does better than upscaling 720p to 1080p is de-interlacing 1080i content and presenting it as 1080p.
 
the place to tell the difference is looking at thin almost horizontal lines. p resolutions will be almost solid and i resolutions will look like rope.
 
I have a Samsung 1080p DLP set from a few years ago. It has what basically amounts to a pixel-for-pixel mode, but it's only available when the input is at a 1080 resolution (either 1080i or 1080p). So with the Dish box set to 1080i, I get the full picture. With the box at 720p I lose a decent amount on all 4 sides to overscan that I can't adjust.
 
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