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1080i vs. 1080p clearly explained - finally!

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Old 08-19-2006, 12:27 PM   #16  
What's all this, then?...
 
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Oops, I see the Panasonic 65" plasma doesn't support a 1080p input, so I misinterpreted your statement. Your use of 1080p was simply referring to a progressive display with 1920 x 1080 resolution, not one that necessarily supports a 1080p input.

Well, like I said, as long as the de-interlacer works properly, the Panasonic should be way cool...
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Old 08-19-2006, 03:41 PM   #17  
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Quote:
Originally Posted by BobY
Now, if you want to avoid the trouble of determining whether a particular display de-interlaces 1080i properly (as the manufacturers are not going to tell you if they cheated so you must rely on independent testing), then get a display with 1080p input, which is what I'm going to do
I'm not sure that would guarantee you would get a proper de-interlacer. Just because a given set will support 1080p would not necessarily determine the de-interlacer used.
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Old 08-19-2006, 05:00 PM   #18  
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I know, I know, I just forgot to include my typical caveat, which is: I'm only concerned with HD discs, not 1080i broadcast.

You are, of course, correct that even if it has a 1080p input, you still need to have a good de-interlacer for 1080i broadcast...
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Old 08-19-2006, 06:25 PM   #19  
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Most people would be more interested in how a set handled 1080i broadcast over HD DVDs and the way that was worded implied that a 1080p input would also have a proper de-interlacer. Just trying to be clear for the majority of folks.
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Old 08-19-2006, 06:48 PM   #20  
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Of course I must add that even if a display does have a bad de-interlacer, if it has a 1080p input you can always add an external de-interlacer that works...

My concern is for HD discs because there is no reason you shouldn't be able to see them exactly as captured (the exact 1920 x 1080 pixels per frame stored on the disc).

Broadcast captured at 1080i/30 and displayed at 1080p will always be a compromise because you can't display all of the spatial resolution without affecting the temporal resolution and you can't display all of the temporal resolution without affecting the spatial resolution, so the best thing you can do is err on the side of spatial resolution for static images and err on the side of temporal resolution for dynamic images.

Last edited by BobY; 08-19-2006 at 06:56 PM..
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Old 08-19-2006, 07:51 PM   #21  
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Quote:
Originally Posted by hdrichtv
That's why I say--1080p, much ado about nothing. Let's all relax and enjoy our HD TV's.
...would it be safe to assume that your TV is only 1080i?
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Old 08-19-2006, 08:57 PM   #22  
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Originally Posted by powderrun
...would it be safe to assume that your TV is only 1080i?
Yes, you assume correctly, and I am enjoying its 1080p display.
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Old 08-21-2006, 07:34 AM   #23  
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There ya go bobbing and weaving BobY!

Seriously, I do find it curious that it appears none of the display manufacturers seem to ever even mention the de-interlacer, much less tout the "superiority" of their unit. Have you eve seen any way, method, published results comparing how sets "de-interlace?"
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Old 08-21-2006, 01:44 PM   #24  
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There are only a few methods:

1) Cheating and only weaving (which will give you full spatial resolution and cut the temporal resolution in half). This will work fine with HD discs and will damage HD broadcasts captured at 1080i/30 (sports, live video, news, talk shows, etc.).

2) Cheating and only bobbing (which will give you full temporal resolution and cut the vertical resolution in half). This will damage all HD sources, but is the easiest way to avoid problems that occur when weaving content captured at 1080i/30.

3) Weaving slow moving/static content and bobbing fast moving content. This is the best compromise. The previous generation de-interlacers that did this didn't do it very well, though, as they only compared at most two frames, and in some cases only the two fields of a single frame, to determine what was moving "fast". As a result, you could often see artifacts if you looked carefully (staircasing, pixelation, tearing). Even if you didn't look carefully, the end result was an inferior image on scenes with motion compared to static scenes.

The latest generation de-interlacer chips examine multiple frames to determine what elements in a scene are moving at a rate that would cause artifacts. Not all manufacturers use these chips and even the ones that do don't necessarily use them in all of their models. In some cases they use their own proprietary chips and algorithms.

The only source of infomation on who is doing what are the articles by Gary Merson where he uses an HD test pattern to determine what approach a display uses. He uses an alternating-line test pattern with a motion component that will immediately show whether the display is only weaving or bobbing, or doing both as needed.

Personally I like to see him add a test to insure the display is capable of detecting film cadence on HD content and switching to purely weaving when displaying 1080p/24 content that has been interlaced and pulled-down to 1080i/30. If a 1080p display that only has a 1080i input doesn't do this properly, then you will never see the HD image as good as it could be, as the display will still be bobbing moving images when it doesn't need to.
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Old 08-25-2006, 01:54 PM   #25  
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I'm a little late on this post, but thanks Sammy, good info, definately cleared some things up for me
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Old 08-25-2006, 02:50 PM   #26  
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Quote:
Originally Posted by hdrichtv
Yes, you assume correctly, and I am enjoying its 1080p display.
It is either a 1080i or a 1080p. Cannot be both. 1080i is CRT only.
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Old 08-26-2006, 04:13 PM   #27  
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Quote:
Originally Posted by stchman
It is either a 1080i or a 1080p. Cannot be both. 1080i is CRT only.
The SXRD KDS-R50XBR1 accepts a 1080i signal only, but displays it in 1080p. That was the context of my statement.
Thanks
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Old 08-26-2006, 10:57 PM   #28  
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Exclamation All of this talk pretty much meaningless without frame/field rates specified

You guys need to specify what form of 1080P you are talking about.
true 1080P/60 is not possible from deinterlaced 1080i/60 broadcasts. Another thing, the standard 1080i/60 is best seen/displayed as 1080i/60 if the cameras/broadcasts are 1080i/60
live ( read sports, news, etc.) This is because each of the 60 fields is independent and camera and/or subject motion looks better if the interlacing is done on display instead of trying to combine uncorrelated pairs into a singe progressive frame for every two
fields.
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Old 08-27-2006, 05:34 AM   #29  
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Actually, there is no such thing as a 1080p/60 broadcast, and there won't be for years if not decades to come.
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Old 08-27-2006, 02:16 PM   #30  
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Yes, the context here is 1080p/24 Hi-Def disc content (which, depending on product, can be transmitted as either 1080p/24 or pulled-down and interlaced to 1080i/30) and 1080i/30 broadcast content.

The issue is, how does it look on a 1920 x 1080 progressive display (which, for convenience, is referred to as a 1080p display--regardless of whether it accepts both 1080i and 1080p signals, or just 1080i signals).
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