Many folks hear "widescreen" and "digital" and think "HDTV." Well, DVD isn't HDTV. DVD is digital. It provides a great picture, but it isn't a true high-definition video source. Although DVD looks better than ever before when you play it back on an HDTV (using a progressive-scan DVD player), DVD doesn't give you the same quality of picture that a full-on HDTV signal (coming in over a broadcast TV signal or from your cable or satellite provider) can give.

Why don't traditional DVDs "do" HDTV? Well, for one reason, HDTV wasn't fully finalized and on the market when the DVD was developed, so DVD was designed to work with the TVs of the time (which are still the majority of TVs today). More importantly, HDTV requires a ton of digital data. Using the traditional NTSC signal, you can fit a two-hour movie comfortably onto a DVD, but you wouldn't be able to fit more than a fraction of that movie onto a DVD if it was encoded as an HDTV signal.

Upconverting DVD players give you something approaching HDTV, but the video being fed from these players into your display is not true HDTV.