Originally Posted by jlwine
Thats very interesting. I had always read that DVD's were 480p.
You need to think back. The DVD spec was created before any 480p TVs existed for the home market. Composite video and S-video are only 480i, as are the RF-modulated outputs (e.g., Channel 3).
The first "progressive" DVD players were godawful at de-interlacing the content off disc. So bad that most buyers ended up turning off the "progressive" feature since the results looked better on their CRT TVs with it turned off -- particularly when they used 480i S-video from the player to a TV that had that input but no Component inputs.
[However, those "progressive" players came with COMPONENT video outputs which made them look even better -- even when only used as older, traditional, non-progressive, 480i players when connected to the newest consumer TVs with Component video inputs.]
DVDs include flags which are supposed to make it EASY for "progressive" DVD players to de-interlace the content -- particularly for film content. The idea was that the "progressive" players could do a better job because they could depend on the flags -- flags which the TV never got to see. This was back before it was anywhere near practical to put the kind of processing power into a marketably priced DVD player to actually analyze the video stream and do de-interlacing based on the real content.
The problem was, and is, that bogus flags and bad edits mean that flag based de-interlacing was virtually guaranteed to produce very visible glitches. That's why it was better to turn that off and let de-interlacing "just happen" in the CRT TVs without regard to whether the original content was film or video based. And even if the flags and edits didn't get you, the poor implementation in the "progressive" players -- CUE problems being the most notable -- invariably did.
It's only relatively recently that the kind of processing power necessary to do de-interlacing by actually analyzing the real video stream has been available cheaply enough to include in players. More powerful processing systems like that are still the realm of advanced video processors like the D2.