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HD TV resolution question

Old 07-23-08, 06:56 PM
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HD TV resolution question

I have a question about HD TV descriptions. (if this is the wrong forum, please don't shoot me.)

I've noticed lately that instead of TVs saying they are 720i, 720p, 1080i or 1080p, they are now saying something like "resolution: 1920 x 1080"

My question is: what the heck does that mean? and how the heck do you compare these numbers to each other and to the standard 720i/p and 1080i/p descriptions?

Thanks for answering.
Old 07-23-08, 07:30 PM
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This is probably the wrong forum, but...

All LCDs and plasmas are fixed-pixel and progressive (the p).

1920x1080 is 1080p, by definition (at least for 16:9 displays). 1080 is the number of vertical lines. And if you have a screen with 1080 vertical lines (as with 1920x1080), you got 1080p. If there are 720 lines ( whatever x 720 or whatever x 768), then you have a 720p display.
Old 07-23-08, 08:00 PM
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Thanks for answering my questions.

When I was at Costco the other day looking at some of their LCD TVs, many of the models didn't say 1080i/p or 720i/p. Instead, it said # x #. When I asked someone that worked in that section, they said that if any of the sets are 1080p, it would say so on the box.

Since you say that 1920x1080 really means 1080p, why wouldn't the manufacturer put "1080p" on the box?
Old 07-23-08, 08:30 PM
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Originally Posted by runner001
Since you say that 1920x1080 really means 1080p, why wouldn't the manufacturer put "1080p" on the box?
I don't know. My Samsung says 1080p on the box.

But all LCDs are progressive and 1080 (1920x1080) vertical lines would make it 1080p.
Old 07-23-08, 11:31 PM
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Originally Posted by runner001
Since you say that 1920x1080 really means 1080p, why wouldn't the manufacturer put "1080p" on the box?
Because they want to trumpet the fact that it's full 1920 x 1080. Some 1080p HDTVs are 1280 x 1080.

I'm all for manufacturers giving us more information on the box rather than less, but that's just me.
Old 07-24-08, 01:06 AM
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Originally Posted by runner001
Since you say that 1920x1080 really means 1080p, why wouldn't the manufacturer put "1080p" on the box?
Because there are so many buzzwords, they can't fit all of them on the little box that holds a 50" TV. You may need to learn more than one to keep up.
Old 07-24-08, 07:35 AM
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so I guess the guy working at Costco was wrong since he basically said that if the box doesn't say 1080p, it isn't full HD. I'm all for learning more, hence the reason for this thread. I'm just trying to figure out how to compare one TV with another if each set and manufacturer has different resolution numbers.
Old 07-24-08, 09:20 AM
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Originally Posted by runner001

Since you say that 1920x1080 really means 1080p, why wouldn't the manufacturer put "1080p" on the box?

Because 1920X1080 can also mean 1080i.
Old 07-24-08, 10:40 AM
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Originally Posted by gimmepilotwings
Because 1920X1080 can also mean 1080i.
How so?

If it's an LCD or plasma, you cannot have an interlaced image (because they are fixed-pixel displays).
Old 07-24-08, 10:43 AM
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Originally Posted by mbs
How so?

If it's an LCD or plasma, you cannot have an interlaced image (because they are fixed-pixel displays).
There's the Hitachi ALiS plasmas which are 1080i actually, and of course CRTs.
Old 07-24-08, 10:48 AM
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Originally Posted by GreenMonkey
There's the Hitachi ALiS plasmas which are 1080i actually, and of course CRTs.
CRTs, of course, but we are talking LCDs and plasmas here.

On that Hitachi plasma,

http://reviews.cnet.com/4531-10921_7-6638050.html

It's technically a 920p. It only has 920 vertical lines. But yes, it accept (and subsequently scale) 1080i images.

I don't know how they market it, but it isn't a 1080i display. It's a 920p plasma. Plasmas and LCDs cannot display interlaced images, they always deinterlace to their native resolution (in this case, 920p).
Old 07-24-08, 10:52 AM
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Originally Posted by gimmepilotwings
Because 1920X1080 can also mean 1080i.
not really. 1920x1080 on a fixed-pixel display can only mean 1080p. and Costco only sells fixed-pixel displays (at least at my local one and online).
Old 07-24-08, 12:37 PM
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Originally Posted by kefrank
not really. 1920x1080 on a fixed-pixel display can only mean 1080p. and Costco only sells fixed-pixel displays (at least at my local one and online).
My costco still sells DLP's.

At least they did a couple months ago. (Mitsu)
Old 07-24-08, 01:10 PM
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DLP is a fixed pixel technology.
Old 07-24-08, 01:23 PM
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Originally Posted by Spiky
DLP is a fixed pixel technology.
true true, quick brain fart.
Old 07-24-08, 04:51 PM
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Originally Posted by mbs
CRTs, of course, but we are talking LCDs and plasmas here.

On that Hitachi plasma,

http://reviews.cnet.com/4531-10921_7-6638050.html

It's technically a 920p. It only has 920 vertical lines. But yes, it accept (and subsequently scale) 1080i images.

I don't know how they market it, but it isn't a 1080i display. It's a 920p plasma. Plasmas and LCDs cannot display interlaced images, they always deinterlace to their native resolution (in this case, 920p).
That's the newest version. Read more carefully.

The 42-inch model isn't technically "p" because Hitachi's ALiS technology doesn't actually have all 1920 physical pixels of horizontal resolution. Instead, it has 960 pixels, each electronically divided in half on the screen. This is a step up from the 1,024 horizontal resolution offered on current ALiS 42-inch panels, such as the 42HDS69 we reviewed recently.
the AliS panels are interlaced displays - the only exception to the flat panels aren't 1080i rule.

This is a 1920x1080i display produced in its weird way. The older ALiS panels some years ago were interlaced 1024x1024, another funky resolution. I almost bought one on the cheap some years ago.

The ALiS panels have always been interlaced displays. It's funky technology.

This guy explains how it works:

http://whatsonhdtv.blogspot.com/2006...-and-720p.html

There are plasma HDTV models that actually offer 1080i native resolution, even though they're advertised as 1080p. Hitachi plasmas come to mind. Fujitsu plasmas also use the same "ALiS" (Alternating Lighting of Surfaces) plasma technology.

ALiS plasma display panels, unlike other types, don't have gaps separating one pixel row from the next. More of the screen surface is able to be lit up, but only every other pixel row of a 1080p video frame containing 1,080 rows can be displayed at any one time. 1/60 second later, the remaining pixel rows are lit up, slightly offset vertically on the screen. In effect, in each 1/60-second frame of 720p input, either the odd-numbered pixel rows or the even-numbered pixel rows are suppressed. (Notice that no pixel rows need to be suppressed for 1080i input. But pixel-row suppression does take place for 720p input after internal scaling to 1080p.)

For the same reason, ALiS plasmas advertised as "720p" (and actually displaying, typically, 768 rows) are actually "720i" (or "768i") displays. In each 1/60-second frame of 720p input, either the odd-numbered pixel rows or the even-numbered pixel rows are suppressed. Again, this does not adversely affect the already-interlaced video in a 1080i input signal.

Many of the larger ALiS plasmas have only 1,366-pixel horizontal resolution. Some smaller models offer only 1,024-pixel horizontal resolution.

On the other hand, ALiS plasmas offer bright screens with less "screen door effect" than other plasmas have: the ability to see the gaps between the pixels when you sit close to the screen. Also, pixel-row suppression means each pixel is lit only half the time, resulting in longer panel life.


Aside from ALiS plasmas, the only HDTVs I know to use a natively interlaced screen format (1080i, for example) are CRT-based. (A CRT? It's a "cathode ray tube": an old fashioned picture tube.)

...

Last edited by GreenMonkey; 07-24-08 at 04:56 PM.
Old 07-24-08, 11:01 PM
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Neat! Learn something new every day.

Stay far away. The reason we left interlaced is cause it sucks to the eyes.

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