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HDTV confusion

Fri, 05/31/2002 - 8:00pm
Walter S. Ciciora, Ph.D., Recognized Industry Expert on Cable and Consumer Electronics Issues

By Walter S. Ciciora, Ph.D., Recognized Industry Expert on Cable and Consumer Electronics Issues
High Definition Television (HDTV) was the start of it all. We were promised twice the vertical resolution, twice the horizontal resolution, a wide screen and CD-quality sound. It's been downhill from there. Now the biggest threat to HDTV or broadcast digital TV (BDTV) is confusion. It's Beta Max vs. VHS all over again, but expanded and intensified because there are much more than just two choices.

I personally would be a terrific candidate for HDTV. I can appreciate it, and I can afford it. I just don't know what to buy and how long I'd be allowed to use it before some change in regulation, industry fiat, or advancement of technology would make my purchase a contribution to the hazardous waste dump.

I've spent my whole professional life with television, first in consumer electronics, then in cable, and now as a consultant. When I say I am "watching television," it doesn't always mean I am watching a program. I sometimes watch the video for quality and artifacts with no concern about the program itself. So if I don't know what to do about HDTV, what should the average consumer do?

Probably my biggest concern is that the digital rights issues will cripple my purchase. If I buy an HDTV display, will it have continued access to signals, or will it be rendered obsolete by the need to have an encrypted connection between the display and the signal processing box?

My second biggest concern is how to arrange the viewing area. NTSC and standard definition digital TV (SDTV) will look substantially inferior on the HDTV display. (If they don't, there isn't much point in buying the HDTV display!) Even if the NTSC or SDTV signals are processed to line double, they will still look relatively poor.

Then there is the issue of aspect ratio. The NTSC and SDTV pictures have a width-to-height ratio of 4:3, while the HDTV images are 16:9. One common approach is to stretch the 4:3 image to fit the wide screen. This makes people look fatter and circles become ovals. It just isn't right! The other alternative is to leave black or gray bars on the side of the screen. This leaves me worried about screen burn-in. When screen burn-in happens, the wide screen display will look a little different in the 4:3 part of the picture where the NTSC and SDTV images have burned in the screen, compared to the relatively less used side panels.

As an aside, I was watching CNN the other day. A large panel TV screen was used as a background for the announcer. The panel screen usually had white letters spelling out CNN Head Line News on a dark background. When video was placed on that screen, the letters remained. They were burned into the display. There has even been some discussion in the trade literature about the little network logos currently placed in the lower right hand corner of the screen also burning in when the screen is primarily used for one channel. Then, when a different channel is tuned, the heavily used logo is faintly visible. So there's a dilemma regarding the display device.

It seems the logical solution is to keep the old 35-inch NTSC screen for most uses and have a separate screen for HDTV viewing. That avoids the aspect ratio and screen burn-in issues and also prevents the expectation of an HDTV image when viewing SDTV or NTSC on the large screen. One possibility is to put one of those flat panels on the wall above the NTSC set, but that's not quite big enough. It also could require looking up at an uncomfortable angle. Another alternative is to use an electric roll down screen and a front projection unit mounted at the back of the room. The digital micro mirror devices seem to do a good job. On the positive side, this would provide a really big screen.

This is what HDTV needs to be worth the bandwidth. Without the big screen, you might as well have NTSC or SDTV. But a front projection system really needs a darkened room. That's because room light prevents black areas of the picture from being totally black. They end up gray. The contrast ratio is the ratio of light brightness in the whitest area, divided by the light brightness in the darkest area. A high contrast ratio gives the image the appearance of sharpness or "snap." Room light ruins it. This phenomenon does not happen in direct view picture tubes because they are so bright, they can afford to put a neutral density filter (gray glass) in front of the screen. Room light passes through the neutral density filter, is reflected off of the light emitting phosphors, and then passes through the neutral density filter again. Since light attenuation is a multiplicative phenomenon, this really cuts down on the light. The light from the tube itself only goes through the neutral density filter once, so the contrast ratio is enhanced.

This now brings me to my other big concern. What is there to watch? I can't imagine Jay Leno adds much to HDTV (and I hardly ever watch him anyway). Come to think of it, I almost never watch TV except through the TiVo. I don't think I could go back to watching TV the old-fashioned way! In fact, I find the utility of time shifting, pause, visible fast forward and rewind so valuable, I usually use the third-best level of TiVo quality on the machine connected to cable in order to have more storage time. I happily trade video quality for this utility.

I think I'll just forget it for a while and wait for some of the confusion to sort out. In the meantime, prices will come down, and maybe the programming I really am interested in will be available in HDTV. And most importantly, maybe I can have an HDTV TiVo!


Author Information
Have a comment? Contact Walt by e-mail at: Walt@Ciciora.com

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