October 2000Post-CEDIA Thoughts on the Current State of Video Technologies
by Doug Blackburn
Those in the market for high-quality video displays have some very tough decisions to make. There is no one correct or best answer to the questions, some of which are:
As it is in most cases, money is absolutely the limiting factor here. But just like audio products, there are $10,000 video displays that produce images that are much less impressive than those produced by some less expensive display devices. If you have an unlimited budget though, you can achieve a stunning image given appropriate source material and hardware choice. Of course stunning source material is still relatively scarce. At this level of performance, the very best DVDs on the market only look "good" compared to the best images these state-of-the-art displays can reproduce. And to get to this "good" level of image quality, the 480 interlaced DVD image has to be upsampled to 720 progressive or 1080 progressive using some impressive image processing hardware.
The best ever
CEDIA was worth attending just for one brief demonstration. Vidikron showed a system with a pair of $49,000 Vidikron One projectors fed by Vidikron image processors, using Panasonic high-definition digital tape machines used by the broadcasting industry. A DVD player was a second source. The image quality from the digital HD tape was the most stunning reproduction of images I have ever seen from any imaging format, including movie film. There are not enough superlatives to describe just how incredibly good the image quality was from this setup. The Vidikron projectors use three 9" CRTs to produce images with very black blacks, excellent brightness in a darkened room, and the most free-from-any-type-of-artifact images I have ever seen reproduced. The ONLY artifact I noticed was a slight window-blind flicker at the ridgeline of the roof of a house, as the image panned vertically. The roofline was just slightly off horizontal in this shot. I could see a little jumping during the transition from roof to sky, reminding you ever so gently that you were viewing video images. The artifact was pretty small compared to lower resolution video. If you were not concentrating on finding it, youd probably never notice.
The image in this demo was totally noise free. No grainy, streaky, or ghosty analog artifacts. No vertical jumpiness from variations in framing (something you get from virtually all film-projection systems). No side-to-side weaving (another film-related artifact). Both of these artifacts are visible on just about every DVD, because even the transfer equipment, as good as it is, isnt perfect. Furthermore, 24 frames-per-second film images have to be converted to 30 frames-per-second video images. In the process of doing that, you get some blurriness in the 6 frames that have to be added to the film (to reach 30 fps). This can be seen in certain still frames. When you have a high-definition source that begins at 30 fps, it is immediately sharper and more dimensionally vivid than 24-fps film converted to 30-fps video.
I hate to keep going on and on about the image quality in the Vidikron demo, but it was enough to incite giddiness. Ive seen HDTV demos before, but they have never been up to the standard of this demo for whatever reason. Its interesting that 9" CRT projection can still exceed the quality of any other image-generation device including all the fancy all-digital devices.
Still very expensive at over $10,000 for the larger sizes, plasma technology continues to improve. Everybodys plasma looked better than at previous shows. Smaller and smaller plasma displays are shown at every show. At CEDIA there were 16:9 plasma screens that are about the same height as a 20" 4:3 television tube. This is just what you need in the kitchen for watching the Food Network, When Harry Met Sally, or searching Epicurious.com for a new halibut recipe. Unfortunately, nobody is getting close to overcoming the two main problems I see in plasma displays. First, the blacks are anything but black. Some plasma screens have dark-green blacks, others have dark-red blacks, others have charcoal-gray blacks, but none of them have black blacks and that alone makes the images milky whenever there is more dark area on the screen than bright area. This is why the most impressive plasma demos never contain dark scenes. A couple of plasma demonstrations used fireworks displays as demo material. This immediately revealed the Achilles heel of those displays. The second thing I dont like about plasma displays is that they have a shimmering graininess to the images. Something about the pixels not being reproduced with precisely the same brightness level from frame to frame, I suspect.
Two of the new LCD projectors I saw set new standards, even though I still did not like the image quality. Both of these used a new lens system that claimed to eliminate the visible hexagonal pixel structure used to make LCD images look like they were being projected on a beehive screen. There was a definite reduction of the pixel structure, but some of the pattern of the pixels was still visible. LCD projectors do produce a bright image, but here too, the blacks are not black and they cannot be black. Light shines through the LCD panel. When no red, green, or blue pixels are active you should have black on the screen, but because light has to pass through the LCD panel, light bleeds through the black areas making them dark gray on the projection screen. The newest LCD projectors can be impressive until you compare them to a well-setup CRT projection system. Good LCD demos also stay away from dark images, concentrating on more brightly-lit scenes, which will mask the lack of black blacks.
A variation of the LCD projector, these reflect light off the LCD panel rather than passing light through it. I did not see what I thought was a decent demo of a D-ILA projector at CEDIA so I cant comment on their performance. In theory, they should be able to do blacker black than standard LCD projectors.
I remain completely unimpressed. Loaded with shimmering pixel artifacts, really bad artifacting on 45-degree motion, blacks that arent as black as CRT projectors, and an overall odd look to the image, DLP technology remains sub-par for movies as far as I can see. DLP can be excellent as a projection device for still computer monitor images, but on movies, there was constant and highly distracting artifacting.
CRT front projectors
These produce the best images you can get from readily available sources today. Larger tubes produce better images and will last a lot longer provided you take it easy on the brightness. Tubes can lose 50% of their light output in 1500 to 2500 hours, and replacements can cost about one-third of the original cost of the product. Not for the budget constrained home-theater enthusiast, but if your budget can handle them, front-projection CRTs are still the class act of video-display devices for movies. Most of the better projectors require outboard processors that increase the cost of the projection system by 50% to 100%.
CRT rear projectors
16:9 sets were more numerous than ever but there were still tons of 4:3 projectors. HD-ready sets dominate the market now with prices not quite as stupefying as last year. CRT rear-projector sets can range from terrible to excellent. Their main problem is that the center-third of the image is twice as bright as the outer two-thirds. Im not sure why so many people can overlook this, as it drives me crazy. Only the best and most worthy CRT rear-projector sets manage to even-out the illumination across the image. When you see one of those, you are seeing something really special. Unfortunately, 90% of the rear-projection sets you will see will resemble plasma displays, with a noisy pixel structure and blacks that are far from being black. This is almost always a setup issue, the set could be much better looking but people will never know. As with front-projection systems, the larger the CRTs, the better the image quality. The very best rear-projection systems can achieve image quality that gets you about 97% of what the very best front-projection systems can do. Setup correctly, rear-projector sets can be very impressive.
Direct view sets
Strides continue to be made in the direct-view arena. 16:9 screens in a variety of sizes are finally starting to appear in the US after being available elsewhere in larger numbers. Most impressive are 16:9 flat-screen sets. The flat screen reduces screen reflections to such a degree that the image appears immediately better even in darkened viewing conditions. Direct-view sets have a resolution deficit compared to CRT projection systems. The best direct-view sets, however, with flat screens and 720p resolution can produce vivid images with dimensionality that is incredibly compelling. You may never match the resolution of CRT projectors with a direct-view set, but the black blacks and high brightness capability gives the best of them an advantage in realism that other systems cant yet match. Direct-view sets that can handle HD signals tend to be priced in the $2500 to $5000 range (down a bit from last year). But understand that none of these can do full HD resolution. They reproduce the HD image but at lower resolution. The stability, brightness, and color saturation direct-view sets can produce will make for very pleasing viewing of HD sources, but you just cant get 100% of the HD resolution. In spite of this limitation, direct-view sets will probably end up being the most common display device for home HDTV due to the higher cost of projection systems.
There is one thing Im waiting for -- laser projection systems -- no tubes, black blacks, incredible brightness capability, 100% digital from the outset, equally good for front or rear projection. This system will have all the benefits of projection and direct-view systems in one glorious package. Laser video requires the development of long-lasting blue lasers. These are just beginning to come to the marketplace so they are still pretty expensive. The red and green lasers that would be used are fairly economical at this point. The resolution of these devices may well exceed HDTV specifications; therefore the spots may have to be larger to fill the HDCD pixel size for a given screen size. We should be able to get images that are magically real looking. Furthermore, laser projection systems will probably fuel the digital cinema revolution and even replace IMAX projectors. Its going to be an interesting next 10 years or so, as laser video technology develops.
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