OTHER TECH

In the whole, NBC's high-definition coverage of the Athens Olympics made for pretty dismal TV. The same segments repeated ad nauseam only served to show how few sports bear up to repeated viewing. Who needs to see a failed baton pass, a gymnast falling on his or her butt, or a disappointing basketball game again and again . . . and again. Even the swimming events where Michael Phelps won his medals became tedious once you knew who won them. One of the few highlights of the HDTV programming was Steve Foley's astoundingly knowledge-able, polite, constructive, and instructive commentary on diving - with every dive you learned enough to believe that eventually you, too, could score diving like a real Olympic judge.

Despite the dramatic deficiencies of the coverage, fans of high-def technology still had reason to rejoice. For those lucky enough to receive it, NBC's HDTV feed provided an education in high-definition fully as eye-opening as Foley's diving commentary. Much of the imagery the network aired was superb. And some of it provided acid tests for the whole HDTV system, from camera to the home screen. Some segments could even be used to test an HDTV broadcaster's performance - or that of the home equipment used to watch it.

Any test pattern, static or moving, must be repeatable. The continuously looping NBC feed fulfilled that criterion with a vengeance worthy of a Greek tragedy. If you were using an HDTV hard-disk recorder, like the LG LST-3410A that I had (see review on our Web site), the coverage was even infinitely repeatable. Recorded footage could be viewed in a variety of situations - for example, on different types of monitors - or even used to test other devices (click to read my review of Panasonic's DMR-E95H DVD recorder).

With a test segment, any image degradation should be readily visible, which is not always the case with a casually chosen movie passage. The Olympics provided many situations almost ideally suited for seeing encoding "artifacts," or image distortions caused by errors in MPEG video encoding or decoding. They all involved relatively simple visual situations, where it's obvious what is moving and where, and familiar objects and backgrounds whose distortion would be immediately apparent. A space-opera battle scene with lots of intergalactic cruisers flying around is likely to present an easier challenge for HDTV than a gymnastics or swimming competition. Backgrounds in space are usually black, for one thing, which can hide distortions around the edges of objects like the notorious "mosquito noise," which is a roughness or "busyness" along any sharply defined edge. The moderately lit, single-color backgrounds of many of the Olympic events - such as the blue floor-exercise mats in the gymnastics competition and the back wall of the diving pool - made them ideal for detecting this problem.