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Technology Stocks : C-Cube -- Ignore unavailable to you. Want to Upgrade?

To: DiViT who wrote (41557)	5/26/1999 9:42:00 PM
From: John Rieman	Read Replies (1) \| Respond to of 50808

720p................................. tvbroadcast.com HDTV: 720 Progressive As Networks Decide What Should Be Done, What Should You Do? By Michael Silbergleid By now, we all know that both HDTV and SDTV multicasting will be a reality in most, if not all, of our futures. CBS has made their decision--1080-line interlace. I applaud them having made and announced a decision (even if it is wrong). Word on the street says that both ABC and Fox will be going 720-line progressive for HDTV and 480-line progressive for SDTV/multicasting. NBC is keeping quiet (at least they won't have to worry about football in high definition). PBS says plans are still under development, but will be making an announcement soon. Those of you who attended the CES show (and there were a great number of broadcasters there) have seen how good and how bad HDTV can look. But now is the time when stations and groups will have to make two very important decisions: Do we produce HDTV locally? If we produce HDTV locally, which format? First, keep in mind that we are very critical viewers of television. As I've said before, we will see things that Joe Sixpack won't. But what Joe Sixpack will see is the brightness and lower cost of a 480-line progressive television set versus either 720p or 1080i HDTV sets. And I'll bet you that good ol' Joe will think that he's watching HDTV--but that's a subject for another time. Producing HDTV Locally Assuming you're not going to cheat and upconvert to HDTV, you'll need to make a very tough decision--720p or 1080i. You might just choose what your network chooses. Or your group owner may make the decision for you. But if you decide, your decision should be 720-line progressive. Why? It looks better, even if it is a lower number. Looks can be deceiving. And 1080i looks great, at least when there is not a lot of motion in the shot. Remember, an interlace frame is made of two fields that contain half as many lines as a frame that occur at different moments in time. Alvy Ray Smith, on his website at Microsoft (www.research.microsoft.com/research/graphics/Alvy/DigitalTV/Naming%20Proposal.htm) says that, to be fair, 1080i should be renamed 540i and 480i should be renamed 240i. The reason for this is simple: In 1/60th of a second, the eye is presented the entire 720 lines of a progressive frame. But in that same 1/60th of a second, the eye is presented only one field--540 lines--of the 1080 interlace frame. So what we are basically comparing in 1/60th of a second is 720 lines versus 540 lines, both progressive (a field from an interlace frame is drawn on the screen progressively). Why should you worry about what happens in 1/60th of a second? For the same reason that when you need a still frame of a shot with motion in it today (in 525-line interlace) you freeze the field and line double it--temporal motion blur. A freeze frame would be blurry. Now imagine the crystal clarity of an HDTV picture that starts to look less sharp as there is more motion in the picture. Sure , you can use your electronic shutter to death, but then your picture starts to look very stroboscopic. Oh, by the way, progressive has some other benefits as well: It compresses easier, there are no interlace artifacts, and it converts to interlace a lot easier than interlace converts to progressive. Yes, I do realize that there are not a lot of 720p cameras or VTRs or monitors or anything...yet (notice that I didn't say there was none--I've seen two cameras and three VCRs so far). But to be fair, there's not a lot of 1080i equipment either...it's all 1035i. But just wait until NAB.