HD? Hah!

As a followup to my two-week-back writeup on National Semiconductor's video processor chip, I'm saddened to report that the current state of affairs is worse than I thought (my cynical cap must have been slightly atilt on my noggin at the time I did my original writeup). 1080p-capable displays that employ the 'bob' algorithm do give you the entire resolution of the original broadcast signal, just not within a single frame; 540 lines (the 'odd' field, arbitrarily picking a sequence) get doubled up for the first frame, and the other 540 lines (the 'even' field) do double-duty for the subsequent frame. The results, for fine detail, are flicker artifacts, as thin horizontal lines oscillate into and out of oblivion at 30 Hz rates.

But what about 720p displays? In this case, manufacturers are apparently throwing away one fields' worth of data for each two-field frame, and up-scaling the remaining 540-line field to create a 720p variant. Interpolation (aka 'digital zoom' or 'create 6.6 Mpixel images from a 3.2 Mpixel sensor'), as I've hammered home numerous times in the past, can't create additional data where none originally existed, no matter what episodes of 24 might try to make you believe ("Look, Jack, I ran an enhancement algorithm on this QCIF snapshot of Earth taken from a deep orbit satellite, and I'm able to make out the bad guys' license plate number!"). Bottom line? Folks watching 1080i broadcasts on their 720p sets are really seeing image resolutions only slightly better than SDTV.

Of course, one could argue that unless your viewing couch is so close to the display that your nose rubs up against the tube, or you've got a projection screen large enough to serve as a Boeing 747 runway, you won't be able to tell the difference between HDTV and SDTV anyway. My haughtiness hat, you may have noticed by now, is once again firmly planted on my head. Happy Friday, all!