1080p a joke?

[Adam Keen]

I can't believe news comes from blogs. I think the article writer is trying to be hip by calling it a "bog", or just can't proofread, or lazy.

[J. Stephen McDonald]

I recently obtained some backdoor information from the maker of my CRT HDTV, that isn't ordinarily made public. It turns out, that although their CRTs are promoted as using 1080i, that the image that is shot on the screen is actually 720p. The dot-pitch of the screen mask and the phosphor dots wouldn't support any more scanning lines, anyway. So, the 720p scanning they use, produces a better image, than if they tried to shoot 1080i on a screen that was inadequate for it. There are many other mysterious and often undisclosed details like this for most HDTV monitors. The pathways from the tuners or inputs to the screens follow different routes. Some of them work better than others, but whether a TV is labeled 720p, 768p, 1080i or 1080p or whatever, doesn't tell the whole story about how the image is actually displayed.

[Marvin Emms]

That is something worth looking into as, in general, 720p TVs display 1080i by simply expanding each 540 line field into a 720 line frame. In other words, treating 1080i as 540p.

You could buy a 1080i TV and end up with sub 540 line performance for films.

I don't suppose you'd give us the model of the TV that does this trick?

Have you verified the TV is really only scanning 720 lines?

[Graeme Nattress]

Turning 1080i60 into 540p60 is a very easy trick to do for a TV manufacturer. That's because doing decent quality deinterlacing is hard, as is picking out whether an image needs deinterlacing (if it's 30p in 60i) or needs pulldown removing.

However, why this is done is not really the TV manufacturers fault, but the people who insist on making interlace cameras and tape formats and broadcasts when the first thing that the HD standard should have done would be to abolish interlace to the bowels of history.

Graeme

[Paulo Teixeira]

I find it mind boggling that there are so many articles that are trying to prevent people from buying 1080p TV sets. I would hope it isn’t because Sony is backing it like they are with Blue Ray. On the Blue Ray side people are saying that it will be like BETA all over again when there are many companies backing it as well. 1080p is here to stay since Sony is releasing all future TVs on 1080p and even Panasonic is excited about their 1080p plasma TV that should be out shortly.

The way I see it, a 1080 60i signal should look a lot better on a 1080 60p TV than it would on a 720/768 60p TV, although I do see a problem when trying to show a 720p signal on a 1080p TV. The solution would be to have a 720p rectangle inside 1080 lines. This way you will see black bars not only on the top and bottom but also on the sides. At least that would prevent you from buying 2 TVs.

[J. Stephen McDonald]

Originally Posted by Marvin Emms

I don't suppose you'd give us the model of the TV that does this trick?

Have you verified the TV is really only scanning 720 lines?

My CRT-HDTV is a JVC AV-30W585. No, I haven't verified that it actually scans 720p. They may well have just been blowing smoke with that brief answer about it having a 720p resolution. The picture it displays is very sharp and was better than the dozens of other CRTs that I considered when I bought it and even looked slightly sharper than the Sony fine-pitch models. When I get my own HDV camcorder and a resolution chart, I should be able to determine these screen specs on my own.

[Marvin Emms]

Paulo, Whoah their, you have the wrong end of the stick.

The point is not that 1080p is in any way a bad thing. The point of the article is that 1080p by most TVs that claim to support it is a lie. Even Sony who are pushing 1080p for Blue-ray are lying when they say their Bravia, which genuinly does have 1080 lines of resolution is 'ready for 1080p' - the very best it can do is 1080i with internal processing.

For displaying 720p on a 1080p set, its fairly trivial just to stretch the image electronically. Don't confuse very easy pixel operations like interpolation (Which produce high quality results), with motion adaptive warp and deinterlace algorithms required for 1080i to display as 1080p even half decently.

Graeme,

I think the blame needs spreading around rather more than that. HDMI the primary standard for getting HD signals to a TV digitally did not force 1080p60 as a requirement and in many ways was not aimed at such high performance at launched. They are now increasing the data rate it can handle but the damage is mostly done, so chip makers didn't support it, and TV makers didn't. Now that 1080p is suddenly the hot thing in media TV makers feel happy about labeling their equipment 1080p ready, a term that has no real meaning, even if they arn't 1080p compatable at any frame rate but simply deinterlace 1080i. Makers of HDTV cameras have long been releasing products based on low resolution chips, upscaling to a 'recognised' format and calling it HiDef. Its still embedded in the industry that analog tricks such as recording a downsampled image, and replaying with interpolation are acceptable even though everything is moving into digital.

The computer industry has had to turn on a dime, the TV industry is an oil tanker. When 405 line was replaced here the major consideration was that it be slightly better than than the new US NTSC standard of 525 lines. So we ended up with 625 lines, 576 of those visible. It didn't seem to matter that 405 line TV lasted for 40 years and PAL that replaced it was not even double the number of visible lines, barely 50% more. Now PAL/NTSC are 40+ years old, 1080 is almost double the number of visible lines of PAL but still interlaced, 720p is progressive but only 50% more lines than NTSC and only 25% more than PAL.

The problem is noone who contributes to the standards or the broadcasting laws seems to be able to see more than a few steps in front of their feet, much less the 40 year road ahead of HiDef TV. Even the BBC are arguing with the average eyesight of viewers and screen sizes being mostly <40inch that they shouldnt have to broadcast in more than 720 lines. With blue semiconductor laser technology taking off, in the next decade we may see laser projectors that alow us to turn an entire wall of a room into a bright TV, should that happen standards like 720p and 1080i are going to look downright dissapointing.

You could also blame the public, that want HDTV before the manufacturers have geared up to do it properly and will kiss the ass of 540p and call it icecream.

[Simon Wyndham]

Depends if you are talking 1080p at 60fps, or 1080p at 24/25fps?

Using 25p as an example because it is easier, if a movie is on the disc that was shot on film etc then each alternate field will be from the same frame. A progressive TV could take those alternate fields and combine them for a true 1080p image. This is exactly how we have been displaying true progressive scan from standard DVD's, and I see no reason why it should be any different for high def.

1080i is just the carrier. 1080p at 60fps is a different matter though.

[Marvin Emms]

If a TV cannot accept a 1080p25 input, only 1080i50, I do not think it should be marketed as a 1080p TV. Even if it has 1080 lines and deinterlaces.

The carrier is important. Feed 1080i50 to a 720line TV and you will be lucky to end up with more than 540 real lines of resolution with most TVs. Certainly the full 720 is a pipe dream without the same level of deinterlacing currently in the most expensive 1080 line TVs. A special case of 1080psf could be supported inside 720p TVs fairly easily, but that would require a TV that was 1080p in everything but final display and its easier and cheaper not to. A 720p TV that supported 1080p25 though would have to be 1080p internally, downsampling to 720 would be fairly trivial and there is no reason the result would not be close to 720 lines performance.

To even have 1080p50/60 as a future option support in the TV hardware must be made mandatory. Failing to do this has kneecapped 1080p either in 24/25 or in 50/60 flavours. Furthurmore 1080psf is not automatically equivelent to 1080p when compressed, though the MPEG standards can rejoin fields to compress whole frames, most of a regular channels broadcasting will be done with 1080i cameras, there is little expectation the encoders will be set up optimally to broadcast film media. Satellite brodcasters in the UK and US have brought new lows to to the expectation of Standard Def, with 488x576 being not unknown for PAL broadcasts in the UK, even in anamorphic widescreen and with the standard for SD DirecTV broadcasts being 480x480pixels.

Even the 540p50 most sports viewers will end up seeing in the UK as a result of Sky's desision to broadcast sports as 1080i, and the majority of affordable TVs being 720p, will look pretty good in comprison to the interlaced 544x576 resolution most Sky channels use.

Its just dissapointing that these half hearted measures will be stuck with us for so long.

[Ron Evans]

I think once again the limits of technology for the price people are prepared to pay will limit what users get, mainly because there is a requirement for one size fits all. We have broadcast and film industries with this mind set when the public are embracing an age of choice in media. Again an industry out of touch with their clients. It used to be that almost everyone I new had much the same TV. Now it is very different. Some have fancy projection TV's in a special room, most have many TV's and still a large number have the same old TV with a VHS player--not even a DVD player!!! Their kids have cell phones with mp3 and MPEG4 video, iPod's and watch most programs on the PC. IF the industry was smart( !!!!! ) they would choose an aquisition format that could easily be transformed into any output format they choose with varying price points. You want cheap you get MPEG4 at 120pixels etc you want the best you get 1080P60 or greater with full PCM 6.1 sound etc. That way users would be able to choose the output format appropriately.

Simon I understand what you are saying about 25P etc but this is the very thing that produces the stuttering that I detest!!! It is electronic emulation of a two blade film projector but the original acquisition is the problem. The frame rate is too slow for motion. If the original was shot at 60 or some easy multiple to get the effect later, then the opposite could be done for people who really like the stutter of the last century, just leave frames out rather than repeat frames as we do now !!!! This could be done in the player or even the TV. There are colour effect/temperature choices now on most TV's adding frame manipulation could be another choice to produce the "old film look"

Ron Evans

[Marvin Emms]

Ron,

Ive never really noticed a problem with 25fps on TV and thats only 4% faster, but then I'm in a PAL region so we get 1 genuine cinema frame in 1 TV frame cleanly. Unless its been shot on video with too high a shutter speed, and then movement can look nasty. Could the artifact you are describing be due to the 3:2 pulldown used to display 24fps material on 60 fields a second NTSC?

[Graeme Nattress]

Simon's right that p over i, ie 25p embedded in 50i should go through all the stages of camera, tape, edit, TV, eye, and look progressive to the viewer without getting nasties. However, when a TV says 1080p, it should be meaning it supports 1080p50 or 1080p60, not the above example of 1080p25 embedded in 1080i50, as really, it's then just a 1080i display.

Yes, the blame can be layed at a lot of places, but really, it's with broadcasters that insist on interlace. They're wrong, but you try telling them that!

As for 720p, done properly, would give the vast majority of home viewers the best all-round experience as it compresses easier, is progressive just like their flat screens, and has just the same vertical resolution as 1080i.

Graeme

[Ron Evans]

Although I live in Canada now ( emigrated from UK in 1970 ) I return frequently and it usually takes me two or three days before the flicker on the TV sets goes away!!! For me it isn't the TV system that I have a problem with it is with the film frame rate itself. Its too slow, just like 50hz is really too slow a refresh rate until ones brain discards the effect. Film in the cinema stutters this is just compounded when transmitted for TV or put onto DVD's. This is a well know issue and results in limitations to the shot angles etc that are used in film to reduce this effect. I shot in film before moving to video when I could afford it. Now I look forward to the next improvement. Smoother motion, more resolution, more latitude. VIdeo for me is being there. I am just advocating an approach that acquires a prestine original that can be degraded anyway one would like after. That way chase sequences could be smooth at realtime and dreamy sequences could have slowed frame rate, even smearing etc. Right now film approach leads to fixed shots that exploit the resolution and colour of the film stock but panning has severe restriction because it magnifies the frame rate problem. Has to be very slow( with plain backround) or very fast.Tracking shots of people need to have shallow depth of field because the backround would stutter badly if everything was in focus etc. etc.

Ron Evans