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Why We Love 1080p?

Before we decide if 1080p flat panels are worth your hard earned cash, I should probably explain 1080p in the first instance. The best place to start is to familiarise yourself with EICTA (European Information & Communications Technology Industry Association) HD ready specifications. After this you will understand that it is important that a HDTV accepts 1080p source signal as well as being able to display it.

 

 

HD Ready Requirements

1. Display

The minimum native resolution of the display is 720 physical lines in wide aspect ratio.

2. Video Interfaces

The display device accepts HD input via:

Analogue YPbPr: “HD ready” displays support analogue YPbPr as a HD input format to allow full compatibility with today's HD video sources in the market. Support of the YPbPr signal should be through common industry standard connectors directly on the HD ready display or through an adaptor easily accessible to the consumer; and:

DVI or HDMI: HD capable inputs accept the following HD video formats: 1280x720 @ 50 and 60Hz progressive scan (“720p”), and 1920x1080 @ 50 and 60Hz interlaced (“1080i”); and the DVI or HDMI input supports copy protection (HDCP)

High Definition means having up to 5 times more pixels than Standard Definition. This is calculated by dividing the best HD resolution material (1920 x 1080 = 2073600 pixels) by (720 x 576 = 414720). The immediate result is having more detail and sharpness in your picture. An analogy to this is that if I asked you to recreate a Mona Lisa with paint dots on a canvas, you will be able to do a better job with more dots, on the same canvas size.

Ok back to HD ready specifications. The first requirement is that the HD ready displays must have a minimum horizontal resolution of 720 physical lines in wide aspect ratio (16:9). That means the HDTV should be able to display 1280 x 720 material or 720p format material. There is a small debate regarding the interpretation of wide aspect ratio especially on some plasma TVs. These TVs have native resolution of 1024 x 768. But because the plasma pixels are rectangular, they come in wide aspect ratio of 16:9. The most important thing to realise is that while the screens can accept 720p signals or higher, the signal will have to formatted or downscaled to `fit' the native 1024 x 768 resolution of these TVs, with resulting loss of detail and clarity.

Are you still with me?

I'll use the dots on the canvas analogy again. Imagine that the perfect Mona Lisa picture will be created by a maximum number of dots on a certain canvas size. If the canvas size if reduced, you'll have to throw away some dots, which is a bad thing. Note that the above condition is only a minimum requirement, If I had a choice, I would want to watch 1080 material everyday. There is just so much more detail (so much that Vanessa William is complaining) to see. To do that you will need a display that can show 1920x1080 resolution (16:9 wide aspect ratio).

Right, the next section deals with video interfaces and summarizes the minimum connection specifications that a HDTV must have to be HD Ready. Before we tackle that you should have a basic understanding of interlaced and progressive signals (the i or p behind the number). Interlaced signals arose from a combination of technological limitations in the past. In a Cathode Ray Tube display (earliest mass market TV), the electron gun produced a beam that is scanned across a phosphor screen, lighting it up and producing an image. Now for a PAL signal in UK, the standard definition resolution is 720 x 576. So the beam will need to sweep through 576 horizontal lines (top to bottom, left to right sequentially) to produce a single frame of picture. Early TVs electron beams were unable to do this fast enough in a single frame without causing an uneven picture. So the scanning job was divided in time. First scan the odd number horizontal lines starting with 1, 3, 7, 9, etc then even number lines (2, 4, 6, 8, etc). This resulted in the single frame to split to 2 fields. So with the electrical supply in Europe limited to 50Hz (its 60 Hz in US), the scanning process has been configured to show 50 fields of images in one second. And 50 fields will give you 25 full frames of picture in a second.

As technology improves, progressive scan became the norm. Basically, the scanning is now fast enough to accommodate a single frame without a degradation in picture quality, much like the picture you get at cinemas at 24 frames per second.

Now back to video interfaces. you can see that HD ready specifications call for HD inputs via analogue (component YPbPr) and digital (HDMI or DVI) connections. Pay attention to 720p and 1080i section and the frequency it accepts them at. (50 and 60 Hz) It again makes no mention of 1080p connections or their related frequencies. That is because it is concerned with minimum requirements manufacturer's will have to meet and not consumers expectations. So, the worst case scenario is that you can get a TV with 1080 resolution but cannot accept 1080p signals, and still be HD ready. In some other TVs, you can only get 1080p with HDMI inputs and not through DVI or component inputs.

Below, I'm going to give a few reasons why you should get a 1080p ready HDTV:

1) As above, the Mona Lisa analogy shows that if you want the best quality out there now, you need to get 1080p source material and paint it on a 1080 capable HDTV canvas. That's one-to-one matching. So if you get a TV with 720 canvas, you are going to waste all that extra detail.

I hear people say that there is no difference between a 720 and 1080 picture. Unfortunately, enjoying all that extra detail is also a function of your viewing distance, size of TV and the image resolution (see article). So yes, in some conditions that might be the case. But if you sit close enough, then the 720p picture will cross the pixelation threshold and look poor while the 1080 picture will retain its full glory.

2) 1080p sources are not rare. Home Theatre PCs (at least the powerful ones) are capable of sending 1080p material to your TV. There is some HD material out on the internet, and if I were betting man, in a few years, we will be able to watch HD downloads over the internet via streaming. 1080p BluRay and HD DVD players are on the horizon. Current HD players send out 1080i signals at the present but futures ones will convert them to progressive for output (disc players tend to do this better than TVs). Game consoles will quickly go down the 1080p route as well. Video purists will be able to use the external video processors to improve quality and deliver the final signal to the HDTV in 1080p format.

3) What is 1080p in 24Hz I'm hearing about? Basically, for the ultimate picture quality, 1080p material is decoded directly from the discs (BluRay or HD DVD) at 24 frames per second (the way it was prepared for cinema) and then sent to your HDTV. Here, the TV will multiply the number of frames to either 48 or 72 frames per second to prevent flicker.

4) What about 1080i material, in sports, documentaries etc.? Most video material is shot in 1080 interlaced mode due to bandwidth restrictions. The thing to remember is that 1080i material on a 1080 display will still look better than the 720p material, if the internal TV processing is up to the task.

So where are we again after all this? I am not a big fan of futureproofing as I believe with shorter technology cycles nowadays, you can be wasting your hard-earned money on useless products that are here today, gone tomorrow. But I think that 1080p HDTV is here to stay and that you don't have to pay a premium for this. Just look at how many 1080p TVs are already flooding the market.

In conclusion, when you're thinking of getting a 1080p HDTV, you will want to consider the following points:

1) HD vs SD source. If you watch more HD, a 1080 HDTV is a good investement.

2) Look for 1920x1080 resolution for the HDTV.

3) It has to accept 1080p signal on HDMI and preferably on component YPbPr and VGA interface as well. The latter two are perfectly capable of delivering 1080p data on their bandwidth, albeit without audio.

4) 1080p signal is accepted in 50 and 60 Hz. Movie fans may want the extra feature of receiving 24 Hz input for the TV. This ensures that the TV is futureproof for 1080p/24 HD players for judder-free motion picture.

5) For HTPC fans, the TV must be able to do 1:1 pixel mapping (Dot-by-Dot). This means that every pixel from the source is represented on the screen without any up or down-scaling. This promises the sharpest pictures, especially for LCD TVs.


Questions/Comments

Adam Bartlett says: 03/01/2007 - 07:48

I'm looking for a HDTV and am considering the Philips 37PF9731D - I can't accomodate a larger screen size than 37". However, I think this set is 1080i rather than 1080p. Will I be able to connect 1080p sources to it (with them displayed interlaced) or will I be unable to accept 1080p inputs at all?
Colin Tang says: 03/01/2007 - 17:18

Very important to realise that ALL LCDs and plasma display in progessive. That means if you feed it a 1080i or 1080p source, the final output is always progressive. (in 1080i case, the TV `deinterlaces' it for you). However it does not mean it can accept 1080p, unless specified.

We haven't tested the Philips 9731 model but as far as I'm aware, it can only accept 1080i as listed in specifications. In fact it looks like it can only do 1024x768 on PC without 1:1 mapping. Currently there are a few sources of 1080p and that would be HTPC, PS3, Xbox 360 and external scalers. To be sure you can check it yourself or find existing owners to confirm this.

Based on published specifications on their website, i would not expect the philips to accept 1080p input, you should get a blank screen.


Bjorn von Haartman says: 03/07/2007 - 04:59

There are a few caveats to the 1080p ideal, first and foremost is content availability HD content on a 1080 screen is great but the sheer amount of processing needed for SD material combined with the price pressure on the screens makes for a mixed experience. The only LCD I have seen so far that looks good with SD content are the Sharp 540 resolution screens. Going "all HD" (and preferrably 1080p) really limits you to either only BD/HD_DVD content or rescaling in the PC (as i have not yet seen anything but the top of the line Phillips have acceptable picture handling on SD). On DVB-T there isn't sufficient bandwidth to do even 720p until we can move to H.264 encoding along with evacuation of the frequencies currently occupied by analogue TV. The first H.264 DVB-T transmissions are planned for end 2009 (at least in Scandinavia) and the last analogue transmissions will be terminated by the end of this year (Scandinavia as well). This leaves satellite where the norm seems to be at best 1080i. My guess due to having to weigh a desire for higher bandwidths with available bandwidth per channel on the satellites. IPTV is currently limited by DSL speeds maxing out at around 24 Mbps. The 720p transmissions from the world cup this summer peaked at 20Mbps. In IPTV the chipsets being released during this year are capable of handling up to 1080i with bitrates limited to 3Mbps average and 5-8 Mbps peaks. My 5 cents is that it will be a long time until we see 1080p content delivery as the norm and that we will be stuck with a lot of SD content for the foreseeable future (well 5 years anyway) and that it will take at least a couple of years until we see 1080 screens with enough processing power on board to do deinterlacing/scaling of SD material to 1080 resolution in an acceptable way.
Colin Tang says: 03/09/2007 - 12:18

Yes, Bjorn these are very valid points.

Bandwidth and encoding practices is probably the main reasons why 1080p will not be available to general broadcast for quite some time. Even if the bandwidth does get larger or encoding gets better, content providers will probably be focused on delivering quantity than quality.

For the benefit of our readers, you can get 1080 material in different encoding bit rates from 6 all the way to 15 Mbits/s or more if you use variable compression. Current HDDVD/ Blu-ray movies are at 15Mbits and will look better on your screen than most HD broadcast.

The question between 1080i and 720p in broadcast is a spatial vs temporal resolution issue, both having really strong points. I hear that compression on progressive 720p produces better pictures although I have not seen this myself. With the lack of motion artifacts inherent in 1080i, this may be the future choice of broadcasters for the next few years.

In the US, Silicon Optix has incorporated a version of their HQV processor in to a consumer LCD TV (although high end) and I read that it handles all the HQV tests very well (as you may expect). I hope the trend will start to catch up with other companies soon, because I think that will be the most important thing during out transition from SD to the 1080 ideal.

It is a shame that broadcast is not going in tandem with the movie industry, because from what I have seen (I am fortunate that way :) a good 1080p transfer is hard to beat.


Robert says: 03/10/2007 - 06:21

I am looking to buy a new HDTV and was considering the Pioneer PDP507XD which has Top reviews but I don't think it supports 1080p? or the Sharp LC52XD1E which I can not find any reviews on but I saw your 1080p shootout and it came last what do you think? Also my TV is around 10 feet away would that matter in the size i'am looking at should i get a 42in.
Cheers Rob
Colin Tang says: 03/10/2007 - 07:53

@ Robert

1) We are currently looking into the smaller PDP4270XD and we like its colours A LOT. It has a decent colour management system that allows you to modify the colour gamut/ range close to HD 709 standards. But to benefit from this fully, you may require ISF calibration or delve into the world of amateur calibration and all that.

2) I think our latest shootout is being misinterpreted by a lot of people. It is a completely linear/simple system, allocating points to many specific areas of the TV. I am all for weighted scoring systems but the thing is that users apply their own `subjective' weighting to every TV set they own. So what I suggest is that you look at what is most important to you and discard the other areas, add the points up for different models and see what you get.

3) Please look at our sitting distance article. You need to consider the source of material you will be watching most of the time, sitting distance and TV size. I know it is complex and perhaps in the future when we have time we will make it easier for readers. Let me know if you have any questions.
Bjorn von Haartman says: 03/13/2007 - 08:10

BTW I did have the opportunity to see Sugiwara's demo of their Ultra HD system at IBC last year. 7680x4320@60Hz with 22.2 channel sound on a 450inch screen, most impressive but with 3.5 TB for 10 minutes I guess its some way off for domestic applications. A presentation may be found at:
http://conferences.iee.org/multimedia/ithd_digest/pdf/Sugawara_Keynote.pdf
Colin Tang says: 03/13/2007 - 08:40

Thx for the link, top class information.
daniel osborne says: 04/11/2007 - 03:11

Hmm. the more i read the more confused i get ! I sit between 1.5m and 4 m away, depending on whether i`m 360ing or watching tv/dvd. I`ve already returned a pio4270xd and samsungps42q7 HD, and currently i don`t have a tv. I had the infamous dirty screen, which i could live with, but the geen ghosting was too much. the samsung was great with the360, but too soft and lousy with sd material, DNIE had a lot to do with this i think, and really loud buzzing, so that went back too. I now want to wait for new pana pz700 1080p plasma, or pio508xd 720p plasma, but i haven`t ruled out a fujitsu, as i`m led to believe the improved picture processing is likely to be more important, and possibly be better than the panas or pios processing. Help,it`s a minefield out there ! Thankyou for a great imformative website. ozzzy.
Dale Clarkson says: 04/11/2007 - 07:35

Hi, Been looking to get the new Samsung LE37M87BDX with it's 1080p capability however I'm seeing some discussions stating that there's no benefit to 1080p unless you go for a screen size of 40"+. Is this anything you've found?
Colin Tang says: 04/13/2007 - 18:10

Depends on where you sit really. If you have a 1080p 37 inch TV (I assume its 1080 resolution), the following conclusions are correct.

1) for 1080p material you need to sit about 5 feet away to benefit from extra detail...and you get wide viewing angle.

2) for 1080p material, you need to buy a 52 inch TV to enjoy the same detail at 7 feet.

3) Pixel grid visibility is reduced for a 37 inch TV with 1080 resolution. Pictures can look sharper as well.

So they are wrong. There is benefit with 1080 on 37inch, only if you sit really close.