omfg guys please, this is pathetic.
The DVD specs include; VBR Mpeg2 and Mpeg1 from 0kbps to 9000kbps (total stream cannot exceed 9mbps) frame rates of 23.976 progressive and 29.97 interlaced, and resolutions of 720x480, 704x480, 352x480, and 352x240.
ALL commercial DVDs use VBR Mpeg2 at 720x480 and 99% of which are 29.97 interlaced.
SVCD specs include VBR Mpeg2 at 29.97fps and 480x480 res. Bitrate between 0 and 2600 kbps. Total stream cannot exceed 2756 kbps.
VCD spec includes CBR Mpeg1 at 29.97 or 23.976fps, 352x240 res and a fixed bitrate of 1150 kbps (video), 1374kbps total.
All DVD players support DVD (no shit). Most players support VCD. Many support SVCD. Few support miniDVD or DVD video authored on a CD.
What jbone mentioned about CD read speed is correct, a lot of players (especially older ones) don't read past 1x. Similarly, a lot of players will fudge up under 300kbps and a few don't read under 1150kbps. Either way there's no golden rule or logical application that says a DVD player should or shouldn't be able to play something. Different formats that share only the same codec have no guarantee of being cross compatible.
You can check from the compatibility list on
www.vcdhelp.com to see if your player is supposed to support SVCD.
Also, no DVDs contain Mpeg4 video. It isn't part of the spec and couldnt be played in modern players.
As for HDDVD, we've got awhile to wait, but the format is probably going to be based on 20-25gb per layer 400nm lazer discs using 1920x1080i and 1280x720p high definition video at 30mbps. I'd like to say they're using mpeg-4 for this task, but it would take probably > 3 ghz processor to decode 1920x1080 mpeg4 and they're not going to be putting those in standalone players. Maybe by the time they actually get around to releasing the format that won't be so far fetched, but it isnt in the plans.