1080p: The Holy Grail of Video - Part 1
Every year at the CEDIA (Custom Electronics Design and Installation Association) Expo we see new products and new technologies. This year, all the talk was about the Holy Grail. Not the Holy Grail that can be found by cracking the Da Vinci Code, but something entirely different -- 1080p, the Holy Grail of Video.
You may have heard of the popular high definition resolutions 720p (720 progressive) and 1080i (1080 interlaced); 1080p is superior to both. What is 1080p? Quite simply, if you were able to count the vertical pixels [see footnote] on a 1080p display, there would be 1,080 of them while the horizontal pixels total 1,920 (you'll typically see this expressed as 1920 x 1080). 1080p is the highest resolution, high-definition standard, and until we abandon ATSC (the current standard used by all major television stations), this is the best picture you can have in your home.
The total count of pixels that are used at any one time on a 1080p display is 2,073,600, whereas a 720p display (1280x720) has only 921,600. This means that you can sit much closer to a 1080p display than you can a 720p display of the same screen size without seeing the actual pixel structure of the display. You will also not lose any resolution when you display a 1080i signal on your 1080p display -- a1080i high definition signal also has 1,920 pixels horizontally, but the vertical pixels are displayed in two passes, odd and even lines every 60th of a second to make the image. This is why the signal is referred to as an interlaced signal, rather than a progressive signal where every vertical pixel is scanned at the same time.
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The only available high definition-signals right now are 720p and 1080i -- many television programs are broadcast over the air, or via satellite and cable companies in one of these two formats. So, given there is currently no material widely available in the 1080p format, how does the average consumer take advantage of this exciting new technology? Through the use of video processing. By using a 1080p outboard video processor, such as those made by DVDO, a 720p signal, which is 1,280 horizontal pixels by 720 vertical pixels can be scaled up to 1,920 x 1,080 pixels. A 1080i signal needs to be deinterlaced (a process by which the interlaced signal is converted into a progressive one) to 1080p, just like a progressive scan DVD player can deinterlace the signal on a DVD and produce a 480p picture from a 480i disc. All standard definition signals, be it from your satellite or cable box or any other SD source, also need to be converted from their much lower resolution up to 1080p. Forthcoming 1080p displays will naturally have this processing built in, but admittedly this form of internal processing is no match for the quality picture that can be realized when using a quality, outboard video processor. Think of it like adding an after-market high-performance part to your vehicle. Sure, the car from the factory runs just fine the way it is, but adding a product that was specifically designed to give it more horsepower improves the experience in a way the "factory" just can't match.
The digital display technologies which are currently available with a 1080p resolution are LCD (Liquid Crystal Display), DLP (Digital Light Processing), LCoS (Liquid Crystal on Silicon) and, soon, plasma. CRT (Cathode Ray Tube) -based front projectors, which have been available for years, can also display 1080p, but have largely been abandoned by consumers and manufactures due to their physical size and cost of manufacture. It is arguable which display technology is the best but I believe the answer depends on the viewer, the content, and the viewing environment. CRT-based front projection can still deliver the best blacks of any technology but there are headaches to deal with, like aligning (converging) the three CRTs on the screen, not to mention the physical size of the projectors and rear projection TVs. LCDs are limited in size right now to 45" (although Sharp did recently show a new 65" 1080p LCD which should be shipping soon) and are pricey. DLP-based rear projection displays use a technology called "wobulation" to display all of the pixels in 1080p signal. "Wobulation" is a technique, not dissimilar to interlacing, where odd and even vertical lines are displayed alternately, but at twice the speed of an interlaced video signal (1080i).
Why is 1080p the Holy Grail of Video? I believe that most consumers will be thrilled with the picture quality of a 1080p display for the next five years, if not more. I also think that most consumers want to get the absolute best picture but they must balance this desire with the fear of buying a display which may end up being obsolete. If the display does not limit the resolution of the source then all we need are 1080p sources. These sources are coming, like Playstation 3, and potentially the high definition DVD replacements, HD-DVD and/or Blu-Ray. Despite the external sources being developed, I think it will be some time before we receive 1080p broadcast signals.
The bottom line is that high definition is here to stay and if you want to get a display which is capable of giving you all of the detail which is available in the signal, you will want to check out the new crop of 1080p displays. In Part 2 of this article on 1080p, which will appear next Thursday, I will cover what to look out for when buying a new high-definition display and I'll also explain why not all 1080p displays are created equal.
[ Pixels: A digital video image is composed of individual dots called pixels that create the image patterns and colors.]
Read Part II: 1080P Are We There Yet?
- By Josh Allen (reprinted with permission)
Originally published at Electronichouse.com
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