A: Other than a BD player, you’ll probably want an HDTV, to get the full quality and widescreen effect. (When watched on a older, standard-shaped tube set, the image is severely letterboxed with dark bands above and below.) Before buying a Blu-ray player to connect to an older TV, check the player’s back panel: Not all have the kinds of outputs needed to connect to older sets. Most players send audio and video to newer TVs and displays via a single cable called HDMI. And don’t get caught up in the various flavors of HDTV — 720p, 1080i and 1080p — because Blu-ray players can send an HD signal to any of them. As for screen size, most viewers won’t get much benefit, Bracke says, unless it’s at least 40 inches (diagonally).

A: Because Blu-ray Disc players and PC drives, as well as Sony’s PlayStation 3, use a blue laser beam to read data from discs, rather than the older red lasers used for DVDs. A blue laser can be focused more tightly, so disc makers can pack more data on a disc the same size as a DVD. Blu-ray Discs can hold up to 50 gigabytes, compared to a DVD, which holds less than 10 GB. That added capacity can hold video up to six times the resolution of DVD, plus more bonus features and improved surround soundtracks.

Stay tuned for next weeks question:Q: Can you really see the difference between Blu-ray and DVD?