[jdmcdonald]

It looks like the first HDTV around here will be 720p.


What set (CRT) should I get that does native 720p? I am prepared to

wait until Christmas or after the new year.


Doug McDonald

 

[Stanton]

Princeton and Sampo.

The rest are RPTV's (which I don't like).

BTW, I assume you're talking about an ABC feed (which has some *great* HDTV shows in 5.1)

 

[tvguys]

I wouldnt buy a new crt based on the 720p. It will not be long for this world, as all of the other major HDTV players are leaning towards 1080i format. Eventually all programming will be in 1080i. Wouldnt you rather have more pixels and "interlacing" (the i in 1080i) as opposed to less pixels and "progressive scan" (the p in 720p). Kinda sounds like the old beta versus VHS wars of early vcr's but then I date myself.

 

[automagic]

It's not like you have to settle for either 720p or 1080i. My Sampo will do both natively. Looks beautiful.


Automagic

 

[Speedy]

Quote:

Originally posted by automagic It's not like you have to settle for either 720p or 1080i. My Sampo will do both natively.

Are you sure about this?


Native means: picture resolution = monitor resolution


So there will be some upsampling or downsampling dependant on your equipment.


Correct me if I'm wrong

 

[Delicious2]

 Sampo 34WHD5 Specs


With no internal doubler and a wide scanning range, it's what-you-feed-it-is-what-you-get with the Sampo! Just got mine last week from Ubid. Looks great on DVD from HTPC and on OTA HDTV. Whether or not you see true 720p depends on what your set-top receiver of choice can out-put.


Mark H

 

[Speedy]

Out of the specs I gather that the native resulution is 1024 x 768 (XGA). The signal compatibility is 480i, 480p, 720p, 1080i SDTV/HDTV*, NTSC/PAL.


I'd be carefull about the PAL statement because PAL has 576i and 576p.


Just my thoughts

 

[automagic]

Hello Speedy,


I may have used the wrong terminology but what I am saying is if ABC sends a signal out at 720p, then that is what I see. It does not get upconverted to 1080i or down converted to anything else.


Thank you,

Paul

 

[Mr.Poindexter]

Native resolution will only apply to fixed pixel displays, such as LCD, DLP and Dila/LCOS displays.


CRTs are multi-synch, such as your computer monitor. They have a maximum RGB bandwidth and can display anything at or below that number, as long as you don't exceed the horizontal and vertical scan rate maximums. (i.e you cannot display 8x6 pizels a quarter-million updates/second).


Most RPTV sets do not do 720p, but rather convert the signal to 1080i w/their scaler and run just that one resolution. They also scale 480i and 480p to 1080i and display that. Since their internal scalers are of marginal quality, this results in an unfortunate probem:


HDTV sets don't display as nice a picture as older NTSC analog sets when fed a standard 480i signal.


I can only compare ABC's 720p to the 1080i coming off the sat, but I am not at all disappointed in ABC's quality. Unfortunately, although Digital TV had the wonderful opportunity to rid the country of interlaced signals and switch everything over to progressive scan, it seems as though interlaced isn't dead and won't die.


For some things, interlacing is not that bad, but there is a reason that all computer displays run progressive - it eliminates flicker. Another thing about 720p is that is compresses better than 1080i, which may be the reason I see compression artifacts off 1080i sat feed, but not from ABC. Of course, there may be another reason, but I don't have enough sources to test this theory.


Ideally, you want a TV that can handle 720p, as you can use it as a monitor for a computer, which is great for HTPC. When they send a 540p signal at the same bandwidth as 1080i, you loose a lot of resolution you could have had with 720p.

 

[Speedy]

Paul, never mind. I too make mistakes and find it sometimes difficult to express myself correctly.


Mr. Pointdexter, thank you for your explanation. But CRT's do have a so called native resolution, they also have a dot pitch distance.

http://computers.cnet.com/hardware/0...8101913-1.html


However, I know what you meant

 

[RSawdey]

The other advantage of 720p, besides being a progressive res, are that it supports twice the frame rate of 1080i. 720p supports 24, 30, 60 fps, while 1080i supports only 24 & 30. A trade off of spatial resolution for temporal. This should make for much smoother motion.

 

[qball]

Quote:

Mr. Pointdexter, thank you for your explanation. But CRT's do have a so called native resolution, they also have a dot pitch distance.

No, that report uses misleading termonology. LCD displays have a native resolution. That is, there are actual pixels on the panel itself that light up to display images. If you want to display a signal at some other resolution, well too bad, you have only those pixels on the screen, so you had better scale the picture to fit in that size, or simply have cropping on the panel if you want to keep a 1:1 mapping of pixels (i.e. if the display's native resolution is 1024x768 and you want to display 800x600, then you can just use the 800x600 pixels in the middle of the screen and leave the ones on the outside off).


What that report meant was that for a given monitor size, people tend to use a specific resolution. This is a personal preference and has nothing to do with the technology of the CRT itself. I personally run my 19" monitor at 1600x1200, but I could run it at virtually any resolution (lower than that) and it would display it for me. Not only would it display it for me, but it would be exactly that resolution, and not scaled to 1600x1200 or any other "native" resolution. If your CRT had to scale signals then you would find that text would only be clear at the native resolution, and this is certainly not the case - try it and see.


-Q

 

[Allan Jayne]

Whether or not you want to call it native, CRT sets' electronics may or may not have different scan rates to match the input. It is common to have one speed scanning, 1080i, and incoming 480p is upscaled to 540p which displays properly at the 1080i scan rate. If such a set accepts 720p, that too is converted to 1080i, probably by downconverting each 720 scan line frame to become 540 scan lines.


Particularly for 480i, if it is deinterlaced first and then converted to 1080i (540p) the result is better compared with converting each video field from 240 to 540 scan lines without specifically doing any deinterlacing. I don't know what makes and models do it which way.


Video hints:
http://members.aol.com/ajaynejr/video.htm

 

[Iaen Sullivan]

You date yourself? Have you considered counseling? Is this related to another facet of interlacing or is it progressive?

 

[RSawdey]

I love myself, and I think I'm grand,

When I go to the movies I hold my hand,

I wrap my arm around my waist,

And when I get fresh, I slap my face!

 

[Speedy]

@ qball


"Native resolution" refers to the physical property of the displaying device. LCD's have fixed pixels while CRT's have a mask with holes. Three pixels on a LCD are equivalent to three mask holes on a CRT. But, dependent on technologie it makes CRT's more flexible than LCD's. It could well be possible that the terminologie "native resolution" is not used for CRT's but there is still a physical resolution.


However, no matter what typ of display, you will have processing to fit the picture to your display device when it is not native.


Let's call it a day and enjoy what can be achieved with todays possibilities

 

[qball]

 http://www.repairfaq.org/REPAIR/F_cr...tml#CRTFAQ_012

Quote:

What many people fail to realize is that the phosphor triads of the screen *do not* correspond to pixels in the image; they are not kept in alignment with the image pixels/lines/whatever, nor is there are reason for them to be. The phosphor dot pitch IS a limiting factor in resolution, but we need to look a little further to determine whether or not a given tube will be usable for a given format (what most people mistakenly call a "resolution".) The true resolution capabilities of a CRT are limited primarily by the dot pitch AND the spot size. For practically all CRTs and monitors in the PC market, the spot size is considerably larger than the dot pitch - up to 2X or so at the corners, if the tube is at or near its specification limits. This doesn't necessarily cause a problem with the image quality, however, since you aren't really resolving individual "pixels" in any case - what you need to resolve are the *differences* between adjacent pixels, or pixel/line pairs. And, oddly enough, it doesn't take a dot pitch of equal or greater size than a logical pixel to do this to most people's satisfaction. In fact, display types sometimes talk about a 'Resolution/Addressibility Ratio', or RAR, hich is in effect the ratio of the actual size of a spot on the display to the size of a "logical" pixel in the image. And for best perceived appearance, this is generally going to be GREATER than 1:1 - say, 1.5:1 or even 2:1. (Too high, and the image is blurred; but too low, and the image takes on a grainy appearance that most people find objectionable.)

-Q

 

[Speedy]

@ Qball


I fully agree with your quotation. In fact, that is the best explanation I've ever read on this subject


I'm sorry for causing any inconvenience due to the fact that I missed the point what you was trying to tell me all the time.


Regards

Speedy

 

[SeanKelly]

Quote:

Originally posted by jdmcdonald It looks like the first HDTV around here will be 720p. What set (CRT) should I get that does native 720p? I am prepared to wait until Christmas or after the new year.

You can get whatever set you'd like. It doesn't matter what the broadcast is; it's the job of your set top box to convert the broadcast into something your set can display.


In general, 1080i sets are cheaper than 720p sets.


Look at both and let your eyes be the judge.


To me, both look absolutely fabulous, but the interlacing artifacts of 1080i are starting to annoy me.

 

[doughnutguy]

First of all, I have to wonder if jdmcdonald - the original poster - is still reading through all this. (It has wandered a little.)


Anyway, after a lot of research and personal e-mails I bought a 34whd5 last nite on U-bid for $1800 delivered. (Some forum members have gotten one for a couple hundred bucks less than that.) In the coming weeks I will post on first impressions and then longer term impressions.


Since the original post asked about 720p I'd like to comment specifically about that. When I first started looking at this set I calculated it has between 1000 and 1100 horizontal "rows" of dots - closer to 1100 if memory serves. (I guess I could rustle up the specs and do the calculation again but it doesn't matter now since I've already bought it.) That is really very good for a direct-view CRT of this size. BUT, it does mean that 600 lines of true, crisp, resolving power is at the outer limits of what can be expected.


That does not mean it won't run at 1280X720p or 1368X768p, just that it will not be fully resolving that many lines. Also, at those resolutions there will certainly be some level of "artifacts" being inserted into the picture. Whether or not you as an individual can detect it is highly variable person to person.