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Old 2006-11-28, 02:59 PM   #1
badkarma
 
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Default 1080i LCD displays?

I never really investigated this just because I've never been in the market for one, but before all the 1080p displays came out, there were several 1080i LCD RPTV's. I always thought that digital displays were inherently progressive, so what's the difference between say a 1080i Sony XBR and a 1080p Sony SXRD from 05. They both only take 1080i input, but do they both deinterlace the 1080i input and output 1080p? I'm just curious since a 1080i LCD display sounds like an oxymoron or a marketing reword.
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Old 2006-11-28, 03:36 PM   #2
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There are no 1080i LCD displays. All fixed pixel displays (LCDs, DLPs, Plasmas, LCoS) are progressive.

They may accept 1080i signals, however, that signal gets converted to the native format be it 720P, 768P, 788P, 1024P, 1080P.

The only HDTVs that have a native 1080i resolution are CRTs.
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Old 2006-11-28, 03:49 PM   #3
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That's exactly what I thought, except there were 1080i LCD RPTV's sold a few years back. When I find an example of what I'm talking about I'll post a link.

Last edited by 57; 2006-11-28 at 03:51 PM. Reason: Unnecessary Quote Removed
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Old 2006-11-28, 03:53 PM   #4
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There is no way that a fixed pixel display would be interlaced. What would you have it do, scan one (odd numbered) set of pixel lines and then one (even numbered) set of pixel lines. It makes no sense.
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Old 2006-11-28, 03:56 PM   #5
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Quote:
Originally Posted by 57 View Post
There is no way that a fixed pixel display would be interlaced. What would you have it do, scan one (odd numbered) set of pixel lines and then one (even numbered) set of pixel lines. It makes no sense.
That's what I'm trying to figure out. Was this marketing speak for "able to accept 1080i" but native res is actually 720p or 1080p?
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Old 2006-11-28, 03:59 PM   #6
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I always thought Hitachi's LCD rear projection sets were 1080i
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Old 2006-11-29, 01:28 PM   #7
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Well, interestingly, it looks like Hitachi does use a sort of interlaced method on some of their fixed-pixel displays. They call it "ALIS" (Alternate LIghting of Surfaces). From this article:

Quote:
"ALIS 1024x1024 (now 1024x1080) plasma panels use alternate lighting of the plasma lines, which is NOT the same as video interlacing on a standard CRT. Plasma displays are a digital device, where entire lines are drawn at once, unlike conventional CRTs which use a single electron beam to draw the entire screen. Properly installed plasma displays have no noticeable flicker. ALIS was developed in 1999 to supersede 480 line low resolution W-VGA panels, with HD video content and XGA computer resolutions in mind.
There's a more detailed explanation of the how "ALIS drives alternating rows of pixels 60 times a second in a fashion similar to an interlaced CRT scan" at Ultimate AV's review of the Hitachi 42HDT20, an older 1024x1024 model.

Consumer Reports has a review of "the first 1080i plasma TV," the Hitachi 42HDS69 with 1024x1080 pixels.

Apparently it can't be called 1080p because it doesn't have the full 1920x1080 of the official spec.

Here is Hitachi's brief description of their tech:



It looks to me like they're fudging something to get the 1080 "pixels", but I can't say that I fully understand it.

Last edited by gesundheit; 2006-11-29 at 01:38 PM.
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Old 2007-05-24, 10:19 PM   #8
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What is the HDTV resolution broadcast by most networks - 1920x1080.
What scan rate is used by the majority of HDTV networks - 1080i (not 720p)

1080i products do have a logical fit. 1080/60p isn't even an HDTV format.

Most HDTV is distributed as 1080i. If TVs could only accept 720p you'd only be able to watch about 10% of HDTV stations.
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Old 2007-05-25, 12:02 PM   #9
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Hitachi's ALIS and DLP's wobulation technique are just ways to achieve higher effective resolution with less actual physical elements. The end result is progressive display. It has no relation to interlaced in any way.

As it's been mentioned, there are no (and never have been) interlaced display technologies other than CRT. The 1080i that you see on the specs of most LCDs, plasmas, DLPs etc. means that the set can accept MAXIMUM 1920x1080i signal, but it converts it to its own progressive native resolution.
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Old 2007-05-25, 01:07 PM   #10
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Arthur, interesting that you mention ALiS since that was the exception to the "rule". It was not a CRT, but a fixed pixel display that claimed to actually DISPLAY, not only accept, 1080i.

Quote:
The Hitachi 42HDS69 comes fairly well equipped with convenience features. Many entry-level panels omit picture-in-picture nowadays, but the Hitachi still has it, allowing you to watch two sources simultaneously. The set's selection of aspect ratio modes is excellent, including six for standard-def and four for high-def, one of which shows every line of 1080i sources without any scaling or overscan--a great option since it lets you see the entire picture.
http://reviews.cnet.com/flat-panel-a...4.html?tag=txt

That's the only one that did this though from what I recall.
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Old 2007-05-25, 02:00 PM   #11
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Quote:
Originally Posted by Arthur Dent View Post
Hitachi's ALIS and DLP's wobulation technique are just ways to achieve higher effective resolution with less actual physical elements. The end result is progressive display. It has no relation to interlaced in any way.

As it's been mentioned, there are no (and never have been) interlaced display technologies other than CRT. The 1080i that you see on the specs of most LCDs, plasmas, DLPs etc. means that the set can accept MAXIMUM 1920x1080i signal, but it converts it to its own progressive native resolution.
The Hitachi 42HDS69 has 1024 x 1080 resolution. There's no wobulation... there's 1080 actual vertical pixels there. It accepts 1080i (as broadcast) and displays it as 1080i. That set can also accept 1080p (via HDMI).

Quote:
Originally Posted by 57 View Post
Arthur, interesting that you mention ALiS since that was the exception to the "rule". It was not a CRT, but a fixed pixel display that claimed to actually DISPLAY, not only accept, 1080i.

http://reviews.cnet.com/flat-panel-a...4.html?tag=txt

That's the only one that did this though from what I recall.
Interesting quote from Cnet, but they fail to mention this set only has 1 tuner, so the PIP function is pretty useless for most applications.
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Old 2007-06-01, 06:25 PM   #12
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I haven't said that Hitachi's ALIS does wobulation. Although intended to give better presentation of 1080i signals, ALis plasmas are not considered to be interlaced displays natively.
And, of course, this technology is only available on Hitachi plasmas. No such thing for LCD.
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