[quote name='propeller_head']uh, no it doesnt
. unless you have a tv w/
no deinterlacer. its not exactly a complicated process; its not like upscaling. all it does is rearrange/weave the scan lines. so instead of getting a,b,c,d,e,f,g,h in 1080p it gets a,c,b,d,e,g,f,h and just rearranges it again to a,b,c,d,e,f,g,h since all lcd, lcos, dlp are
synchronous refreshes. 1080i was designed to make it simpler for tube tvs when it would actually refresh in an interlaced manner (& the electroncics were much slower). but as far as virtually all HDTVs now, 1080i and 1080p are one and the same; theres no degredation. the only degredation comes when you use a 1080i
display (and that degredation would still be there even if you used a 1080p signal). even the earliest 1080p TVs didnt accept 1080p signals, they accepted 1080i. but they were still displaying at 1080p exactly the same as the 1080p sets which accept both now. a large reason players are outputting at 1080p too now is because consumers are naive. many would think that a 1080i signal doesnt work on their new 1080p HDTV; and some of the idiots who work at CC or BB might just try to tell them that (to sell higher priced items).
if a deinterlacer can weave the fields faster than it can receive them there's no temporal interferance. and i dont think youre going to find a deinterlacer in any name brand HDTV which cant do that w/ ease.
so, if a waiter gives your friend 2 8oz glasses of water and you 1 16oz glass of water, do you have more water? if he drinks both and you drink yours, is your stomach abosbing it better because you drank it out of one glass?
i cant make it any clearer than that.
again 1080i
display, yes slightly worse
1080p source material sent as 1080i
signal to a 1080p display
= 1080p source material sent as 1080p
signal to a 1080p display[/quote] ALL 1080p sets have deinterlacers. That's how interlaced sources get displayed on a progressive screen. It's not possible otherwise. And the reason the quality of that deinterlacer matters is because you have to put the RIGHT fields together. With a film-based (24p) source, this is especially difficult because the cadence is all screwy, and if it's done improperly, you get interlacing artifacts (where a frame is improperly built from fields belonging to two different frames), sometimes called stair-stepping or jaggies. It's HORRENDOUS on horizontal pans if the deinterlacing isn't happening properly.
So you need a decent deinterlacer that can recognize the goofy-ass 3:2:2 cadence that film-originated material shows up in, and properly reconstruct the original frames from the fields that are coming in. It's not an easy task, and many (especially low-end) 1080p sets aren't up to it. My 37" Westinghouse, for example, has a god-awful deinterlacer (I believe it's a low-end Genesis). 480i TV looks horrendous, as does 1080i HDTV and HD DVD sent as 1080i. You MUST give my set a 1080p signal, or the result is far beyond ugly. Luckily it's my PC and 360 montior, so I'm all good from that aspect.
On the other hand, some sets have quality deinterlacers such as those from ABT (Anchor Bay Technology) or Silicon Optix (the Reon or Realta), and they perform EXCEPTIONALLY well with interlaced inputs, such that there is absolutely no difference between a 1080i input and a 1080p input. But those sets are still relatively rare and generally more expensive. While videophiles were waiting for such sets to come on the market, the only alternatives were standalone video processors, which run anywhere from $2500 to $10k. That much of the technology in those processors is now starting to show up in high-end displays, receivers (onkyo 875/905), and DVD players (Denon 2930, Toshiba HD-XA2/HD-A35, Samsung BD-P1200/2400) is really quite remarkable.
If a set didn't have a deinterlacer, or more accurately, had a deinterlacer incapable of operating on 1080i inputs, then you have an even worse problem. The first-gen Sony SXRDs are a perfect example. They take a 1080i field, re-flag it as a 540p frame (called "bobbing"), then interpolate the missing lines to create a 1080p picture. You instantly lose half the resolution.