Digital Trends

Maybe you already know this—but a lot of folks getting their first exposure to new video display technologies at Best Buy don't—digital television and HDTV are not the same thing. The great unwashed who make that assumption probably also see DTV as some kind of technocratic plot to part them from their hard-earned dollars for something only golden-eyed elitists could appreciate. (Am I being needlessly polemical? Feel free to post and skewer me back.)

This misassumption makes the subject of SDTV, or standard-definition television, all the harder to approach. After all, as a home theater technology critic, I spend a large proportion of my time trying to convince the public that HDTV, or high-definition television, is worth the investment. But I also have a conflicting urge to defend the underdog. OK, so SDTV doesn't provide as much resolution (defined as sharpness and detail) as HDTV. But it's still a form of DTV, and therefore not to be underestimated.

The fact is, SDTV is already massively successful. Do you have a DVD player? Of course you do. So does every member of my family (I've made sure of that during the past few holiday seasons!) The DVD-Video format, to use its full name (I can be pedantic as well as polemical) is only one example of SDTV padding into our lives on silent cat feet. Two dueling high-def-capable DVD formats will be upon us by the year's end, but standard-definition DVD will remain the standard, so to speak, until one of them emerges victorious, and that may take a while.

Has your cable operator talked you into buying one of those DTV packages with "hundreds of channels?"  Odds are good that the vast majority of those channels are DTV all right—but SDTV, not HDTV. In over-the-air TV, most analog channels have been duplicated by HD-capable digital ones, but even they carry SD signals much of the time.

Most satellite channels are also standard-definition, and while the launch of new transponders will increase the proportion of high-def channels, SD will continue to dominate. The one high-def-only satellite service, Voom, has been a conspicuous failure with just 46,000 subscribers—though I wish HBO and Cablevision founder Chuck Dolan well in his attempt to ensure Voom's survival.

What is SDTV? For starters, it's a necessary euphemism. To the founding fathers of DTV, looking to name a lower-resolution format, "standard definition" sounded more appetizing than "low definition" or "sour-milk definition."

Nonetheless, SDTV is very much a part of the ATSC's official DTV specs. It's a format with 480 vertical pixels, and 640-704 horizontal pixels (the latter for widescreen.)  It can use either interlaced scanning, which delivers each frame as a pair of gap-toothed fields, or progressive scanning, which delivers computer-monitor-like full frames.