OTHER TECH

Oh my God - it's déjà vu all over again! Only this time, magazines like yours are touting the "benefits" of Blu-ray and HD DVD instead of the "benefits" of SACD. Didn't it seem apparent to you while you were writing and writing and writing about SACD that the buying public wasn't interested? And now there's article after article in magazine after magazine about high-definition discs. Listen, guys - instead of shilling for the mega-companies that are waging yet another format war, how about printing a story about how us little guys are just not going to fall for this marketing crap again?

Here's my two cents: I'm not going to buy a disc player that doesn't have the software to support it or that's not the clear winner of a format war - or can't feed my early-adopter HDTV, can down-rez its picture quality at the will of the anti-piracy contingent, can't deliver 1080p resolution via HDMI, and is supported mainly by high-def movies that I already own or that are soooo bad (Fantastic Four, anyone?) I wouldn't buy them anyway. DON FEINSTEIN RAYNHAM, MA

Everyone keeps saying that the image constraint used in Blu-ray discs and HD DVDs reduces the image sent through the component outputs to 25% of the 1080p signal, giving a 540p signal. That's horrible, isn't it? Early adopters are getting the shaft, right? But then I realized that anyone without digital inputs on his HDTV isn't missing anything. No set with only analog inputs can show a 1080p signal - the best it can get is 720p or 1080i. Well, 540p shows as many lines as a 1080i signal, only without the interlacing.

For the time being, the image constraint seems to work perfectly for the early adopters' needs. And when they do upgrade their TVs (as they inevitably will), they'll then have the full benefit of Blu-ray and HD DVD's 1080p resolution. Am I wrong? STEVEN KIPPEL VIA E-MAIL

For the present, at least, it appears studios are not using the Image Constraint Token, though that could change at any time. And though you're right that folks who bought HDTVs before 1080p sets were available will not be able to take full advantage of the resolution available from 1080p HD DVD and Blu-ray discs, 1080i displays should actually come pretty close (and 720p and near-equivalents are not too shabby, either). It's wrong to equate 540p with 1080i, which actually has twice as many horizontal scan lines, or pixel rows, per frame. The difference is that each video frame in the interlaced 1080i signal is divided into two separate 540-line video "fields" containing the odd- and even-numbered lines, respectively. The odd-line and even-line fields are scanned sequentially, a sixtieth of a second apart, to build the complete frame. Perceived vertical resolution of 1080i is close to that of 1080p; vertical resolution of a 540p signal, on the other hand, is exactly half that of a 1080p signal.

Another important thing to remember about the 540p signal generated when a player down-converts a hi-def disc is that it also has half as many pixel columns as the 1080p (or 1080i) original - 960 instead of 1,920 - and thus only half the horizontal resolution as well.