Hd Tv

mburke

Since there is so much press these days over HD tv can someone let the uniformed (me) know what is the spec to be looking at for considering purchasing a HD tv.

What size screen is the recommended (I think someone mentioned 37" before)
What pixels to be looking for etc

Which brands to consider, which brands to avoid ??

Any help would be appreciated.

jamesnp

Well, there's not much point getting HD if your tv is less then about 42"... well, I don't think anyway.

If you think about it this way: If you watch normal PAL picture on a 12" screen it'll look crisp and pretty high def. You watch Sky picture on a 28" screen it looks fairly crisp too. So, if you start lookin at HD on something small then the extra pixels that are there will do nothing you can notice. Now, if you scale a PAL picture up to 42" then you will seriously notice how bad it is. So, that's where HD comes into its own.

-jp

watty

Avoid overpriced Widescreen PC monitors that are only 1024 x 768

WS is transmitted as 1440 x720 or more commonly in Europe 1920 x 1080 lines.

Divide your viewing distance by 3 to get the hieght of screen for HDTV, or by 6 for height of ordinary screen, since the VISIBLE size of the lines/pixels depends how far away you are.

HD Ready just means the TV has an HDMI connector and can display both 720p and 1080i HDTV resolutions as well as ordinary TV. Unfortunately it says nothing about the sharpness and quality of the picture. Some 48" plasma that are HD Ready rescale even ordinary 576line PAL TV down to 480 lines.

Try and find a shop actually showing HD content (none will be showing HD / Blu ray DVDs just for a week or two). HD upsampled regular DVD is a useless test.

So really the size needed depends how far you sit from the TV set.

Note that the inches or cm of screen size quoted is NOT the height, but the diagonal. Don't be shy in taking a tape measure!

Also a WS TV needs a larger screen size than a 4:3 as the height is less for the same diagonal size. I.E. a 32" WS is only really the same size as 24" to 26" regular 4:3 TV.

mburke

Have been looking at komplett.ie and at the did store and most of the lcd tv's between 30 to 37" are 1366*768, is this actual hd ws resolution or a stretch version ?

Should I just be looking for 1920 * 1080 resolution if considering an lcd tv ?

watty

The Emperor has no clothes. If you are looking for a true native 1920 x 1080i 25 fps 50Hz set and find one let me know. I think you are limited to Broadcast monitors till Autumn or Next year. A tiny number of LCD/Plasma anyhow.

Indeed 1366 x768 or 1380 x 768 and 1024 x 768 are compromise resolutions.

A TV only has to be able to resample and display all DVB modes/resolutions to be HD ready

Regular Satellite TV is 384 x 288, 544 x 576, 704 x 576 and 720 x 576 among others. (all interlaced).

HD Satellite is mostly 1920 x 1080 interlaced 25 fps / 50 Hz or less often 1440 x 720 progressive (non interlaced) 50 fps / 50Hz.

The USA 1440 x 720 and common low refresh of PC CRT monitors (and vertually all PC LCDs) is 60FPS/60Hz progressive. The USA uses 30fps for 1920 interlace for 1920 x 1050.

Almost all HDTVs resample the input signal losing quality. Most also convert interlace to progressive internally which can't be done without loss of quality either.

Not all sets are equal quality in the resampling, so contrast ration and native resolution are not the only things to consider. A scary number of Plasma and LCDs must also frame rate convert to 60Hz / 60FPS which reduces quality even more.

View the desired screen on Sky HD box on Nat Geo or BBC HD content with Sky HD box set to 1080i. Also view ordinary DVD content.

Doodler

Yes, it's all very complex, just when you wanted a no-brainer decision. I have SKY HD with a HD-Ready 1024*1024 plasma. The picture is seriously and significantly better when watching something like the world cup on BBC HD.

However if you haven't bought yet, I would defnitely wait for a couple of months while the folks at What Hi-Fi etc. get testing with a real HD feed coming from a real satellite. I am guessing this will show that native 1920*1080 screens will out-perform the rest because of the scaling. If you want to see the difference between scaling and non-scaling, set the resolution of your laptop or PC LCD monitor to something other than its native resolution - doesn't that look blurred now?

ixtlan

Yes, it is very complicated. However after several months of reading www.avforums.com you can become quite an expert.

From someone who does not have a HDTV yet or SkyHD, here is my current thinking...

720 lines plus of a TV plus a HDMI port is a HD ready TV, according to agreed standards.

1080 line TVs will be better, no doubt, but they will be expensive for some time whereas the 768 TVs are going to plummet in price. Also if like most people you are going to get a 32-40" screen then it's still unclear whether a 1080 screen will be noticeably better for normal distance viewing than 768. I agree it WILL be better, but whether you would pay the premium if you were given the chance to compare may be questionable.

You really do need a large screen to see the full benefit of HDTV in theory, but in practice you will see a big improvement over normal broadcasts with 32". This is because normal broadcast TV is so poor. If it was perfect then HD would not be compelling at this price but it's not. Personally though I think you should consider at least a 37".

Scaling 1080 to 720/768 is possibly an issue, but again in real-world situations maybe not a big one. Text does become blurred but video will not seem so bad.

It's very hard to find objective comments about the above. My comments are pure conjecture, and I have not read of anyone carrying out blind tests on TVs. Some people are convinced that the Sharp 540 line PAL optimised TVs are as good as 768 TVs. Others are convinced that the new Sony X-series 1080 TVs are far superior to 768 TVs. However I have to take all of that with a pinch of salt. Everyone convinces themselves their TVs are the best. I would love some magazine to hide TV surrounds, have an expert calibrate them and then test peoples opinions at differrent distances.

Ix.

watty

ixtlan wrote:

Yes, it is very complicated. However after several months of reading www.avforums.com you can become quite an expert.

From someone who does not have a HDTV yet or SkyHD, here is my current thinking...

720 lines plus of a TV plus a HDMI port is a HD ready TV, according to agreed standards.

No.
An "HD Ready" Logo TV can even have as few as 480 lines (really!). It must be able to display normal resolution, 720p50 and 1080i25 lines. USA 720p60 and USA 1080i30 is not required.

It must have not just HDMI, but the also the copy protection decryption too.

Fast moving Sport transmitted in 1440x 720p looks a bit better than 1080i. Almost anything else looks better transmitted in 1920x1080i.

The best quality is a native resolution equalling the transmitted resolution. Antything else is blurred by the resampling process. A number of HDReady TVs are P only (progressive only) and simply do 1080i by throwing away half the vertical resolution to have 1920 x540 resampled to the native pixels at progressive scan.

(Ordinary TV, even VHS is 576 lines. Optical resolution i.e. 250Lines VHS and S-VHS 400 lines refers to a hypothetical square image in terms of resolvable separate vertical lines where the bright & dark is visible. So if HDTV was 1440 x 1440 it would be 720 lines optical resolution. If it was 720 x 720 it would be 360 optical lines resolution. So taking account of Aspect ratio you see how many pixels across relates to same screen area as vertical and divide by two to get the horizontal optical resolution of viewing vertical lines. )

watty

ixtlan wrote:

Some people are convinced that the Sharp 540 line PAL optimised TVs are as good as 768 TVs. Others are convinced that the new Sony X-series 1080 TVs are far superior to 768 TVs. However I have to take all of that with a pinch of salt. Everyone convinces themselves their TVs are the best. I would love some magazine to hide TV surrounds, have an expert calibrate them and then test peoples opinions at differrent distances.

Ix.

Yes double blind testing is the only way, anything else is egotistical rubbish.

540 line TVs can't even display ordinary TV properly.

If you are spending money on a TV insist on seeing the actual picture with:
* Analog TV source.
* DVD via RGB, not composite.

If HDTV, insistion on seeing it with 720p50 and 1080i25 source. Not a upscaled DVD or dodgy PC video feed.

Test sources are available for dealers to purchase that do regular resolution and all four HDTV modes (720p50, 720p60, 1080i25 and 1080i30). 1080p is only for computer games. There won't be broadcasting on than mode inside 10 years, maybe never.

At the least SkyHD/BBCHD feed set to 1080i on digibox (most material is transmitted at 1080i). If it is Sky HD digibox ensure the program is actually HD source and not upscaled.

ixtlan

watty wrote:

No.
An "HD Ready" Logo TV can even have as few as 480 lines (really!). It must be able to display normal resolution, 720p50 and 1080i25 lines. USA 720p60 and USA 1080i30 is not required.
/

This is not correct!!! You are thinking of a "HD compatible" TV which can have fewer lines as long as it can take a HD feed. Or maybe of the very devious "HDTV ready" which means nothing. A "HD ready" logo means it must have 720 lines plus. If you don't get this you can justifiably return the item for a refund. If you see this falsely advertised you should complain. I complained to Komplett about the Sharp PAL LCDs being labelled HD-ready, and I directed them to the organisation that controls the logo, and they were withdrawn from sale though I don't know if I really caused that!!

I worry that you are scare-mongering somewhat! If the guy buys a "HD ready" TV then it should meet those minimal requirements. That's why the logo was invented.

watty wrote:

It must have not just HDMI, but the also the copy protection decryption too.
/

Yes, but a HDMI port by default has HDCP. There's no need to confuse the matter further. I was trying to avoid confusion by not mentioning that a TV could have a DVI port instead of HDMI as long as that port supported HDCP. Far easier just to ensure that it has HDMI, and then you are covered. Whether one HDMI port (which most current TVs have) is enough is a matter for the buyer. I think that might be an issue when people want SkyHD and a HD-DVD/Bluray player.

watty wrote:

The best quality is a native resolution equalling the transmitted resolution. Antything else is blurred by the resampling process. A number of HDReady TVs are P only (progressive only) and simply do 1080i by throwing away half the vertical resolution to have 1920 x540 resampled to the native pixels at progressive scan.

watty wrote:

This is true, but while we may argue about such things, I wonder if it's something of an esoteric argument. We will watch for this when buying a TV because we want the best. However in a blind test I suspect most people would be hard pressed to tell the difference between lower and higher end TVs. The 1080 chopped to 540 and upsampled I have read about exhaustively on avforums, but even there no one has a list of TVs that do this, so it does not seem to be a major practical concern of buyers. It seems more of a theoretical concern.

While do enjoy these discussions I worry that we are unnecessarily confusing potential buyers.

I would say to them, don't get too stressed about it. Here are some pages from the wisdom of Ix.

Make sure the TV is badged "HD ready"
Be aware that prices are going to keep dropping so make sure you want it now. Otherwise wait. Never believe an unbeatable price. Maybe unbeatable until next month.
Accept the fact that standard definition TV may indeed look worse that your existing TV, partly because CRT is better in some ways, but mostly because your much larger TV will show more flaws in the signal.
Accept the fact that LCD TVs are getting better all the time, so not only will it be cheaper in 6 months it will have more features and ports.

Then relax and enjoy your TV.

Ix.

CivilServant

ixtlan is right, you're thinking of HD compatible. The ones that accept HD resolutions but only have 480p pixels which is not part of the HD ready spec.

Aldi had a nice HD ready plasma there a few weeks ago. Some aldis still have them lying around, you could pick yourself up a bargain.

ixtlan

CivilServant wrote:

Aldi had a nice HD ready plasma there a few weeks ago. Some aldis still have them lying around, you could pick yourself up a bargain.

My local still has three... but beware. Look at the thread on avforums about it. People are apparently getting resets from devices connected to the SCART sockets.

Nobody ever seems to be happy with the Aldi/Lidl TVs! I would only get one if the price was really compelling. €1500 is good certainly, but only a few months ahead of the curve for brand name TVs. Maybe if it was €1000. But really I want an LCD (for PC connection).

Ix.

pbirney

watty wrote:

The Emperor has no clothes. If you are looking for a true native 1920 x 1080i 25 fps 50Hz set and find one let me know. I think you are limited to Broadcast monitors till Autumn or Next year. A tiny number of LCD/Plasma anyhow.

Indeed 1366 x768 or 1380 x 768 and 1024 x 768 are compromise resolutions.

A TV only has to be able to resample and display all DVB modes/resolutions to be HD ready

Regular Satellite TV is 384 x 288, 544 x 576, 704 x 576 and 720 x 576 among others. (all interlaced).

HD Satellite is mostly 1920 x 1080 interlaced 25 fps / 50 Hz or less often 1440 x 720 progressive (non interlaced) 50 fps / 50Hz.

The USA 1440 x 720 and common low refresh of PC CRT monitors (and vertually all PC LCDs) is 60FPS/60Hz progressive. The USA uses 30fps for 1920 interlace for 1920 x 1050.

Almost all HDTVs resample the input signal losing quality. Most also convert interlace to progressive internally which can't be done without loss of quality either.

Not all sets are equal quality in the resampling, so contrast ration and native resolution are not the only things to consider. A scary number of Plasma and LCDs must also frame rate convert to 60Hz / 60FPS which reduces quality even more.

View the desired screen on Sky HD box on Nat Geo or BBC HD content with Sky HD box set to 1080i. Also view ordinary DVD content.

Watty,

What's your opinion on the new Philips 37" LCD:

http://medienservice.philips.de/apps%5Cn_dir%5Ce1231501.nsf/pages/646B413978331745C125713E005E8648/$FILE/37PF9731D_datenblatt.pdf

The leaflet says that it offers "LCD True HD display. 1920x1080p"

~Paul.

watty

1) Unless you have a small room, about 1/2 the size of an average living room, it is too small. 32" to 36" is recomended size for a regular WS TV to give same hieght of picture as 26" to 29" 4:3 TV. It is picture hieght that is important for viewing pleasure. If you sit as close as 1.2m to 1.5m (4ft to 5ft) away from screen it is just OK for size.

2) It may be a natively progressive only display. The brochure does not explain how the interlaced images are converted to Progressive (Which can't normally be done without loss of quality). ALL regular and MOST HD is actually Interlaced. Only computer games use 1920 x 1080p (progressive).

Go and see one displaying ordinary TV and real 1080i HDTV and interlaced (ordinary player) DVD playback.

Yes I know you can get a Progressive DVD player. Not the point.

ixtlan

I would not worry about the size. Watty is being very theoretical. Yes, in theory 37" is too small to see all the detail present in a HD signal, but let's get practical here. For the next few years very few TVs will be sold over 40". And those size TVs will most likely give a very poor SD picture, so people will notice a massive improvement with HD.

Regarding the Philips, you should be aware that it will only accept a 1080i signal. I would not worry about this, but you should be aware that people on avforums obsessively talk about 1080p input TVs as the holy grail.

I'd be more concerned that while it has a VGA port, it will only do 1024x768, which is not a widescreen resolution, and hence will not have 1:1 pixel mapping which will mean that text from a PC may be blurrred.

Also, on the 1080 issue, there will be premium for this TV over a 768 model, and you should think hard about whether you want to pay that, especially as Watty says this TV will be too small to show all HD detail. Probably 1080 will be "better" than 768, but I'm unconvinced you will see that at normal viewing distances.

My comments are all theoretical. I have no HDTV.

Ix.

mathias

Just for the record , I have been lurking around these forums now for a while and have seen all the calculations for screen size and viewing distance etc. etc.
I have recently replaced my Panasonic Tau series 32 inch widescreen crt which died ( accident with flowers and water ... girlfriend at fault ..dont ask !! ) with a panasonic 32 inch LCD . I got sky HD installed also , ( gots to milk the guilt while it lasts ) , and the difference in picture quality is stunning.

BBC HD is jaw dropping , so is national geographic , the SD quality is about the same as the panasonic CRT.

Now all the calculations mentioned above tell me I shouldn't see any difference in quality , but frankly thats nonsense , the difference is staggering , and my eyesight is excellent by the way. So I strongly recommend you try one and see , and forget about the calculations , there must be some parameters wrong in there because the reality is so very different from the theory !!

Sparky

I have a 32" HD Lcd tv, and while it may not be huge and not 1080i, I'm relaxed knowing that I can enjoy HD pictures from a Sky HD box, a HD dvd and the Xbox 360 for a few years untill bigger LCDs that have 1080i are cheaper.

Some may say I was mad to buy an LCD tv so early, but as it was in my suitation the tv is planned to be used in the converted attic and a 28in CRT was too bulky for the room, aswell as it being a job to get up a spiral staircase.

Im happy with my TV for the moment. I will upgrade in due course.

ixtlan

mathias wrote:

there must be some parameters wrong in there because the reality is so very different from the theory !!

Glad you are enjoying your TV. Most SkyHD users appear to be happy too. The problem with the theory is that it assumes that current standard definition pictures are perfect, whereas they are far from it.

Even DVD, which is far better than broadcast TV can show noticeable compression artefacts.

Therefore HD on a 32" TV is understandably far superior to SD. It's worth pointing out that you probably don't want to come too close to the screen size where all HD details will be visible, because at that size you will start seeing all those compression artefacts again.

Sparky has a good attitude. Currently I suspect it's not worth the 1080 premium. You can buy 768 now and a 1080 in 2 years probably for less than the 1080 now.

Ix.