Take a look at this page (
http://www.videohelp.com/dvd ) - scroll down to the section on PAL DVD's and they list the various rates etc. One thing to be aware of is that not all media can be read at full speed in all players. I have some junk media I got years ago (only use it for simple tests) that will not even play standard rate DVD's past about the first 20% of the disk. There is also a big difference between a "burned" dvd and a "pressed" dvd - some players handle both just fine, others will handle the pressed ones without issue but a burned dvd doesn't play well at all. Also, as Vernon points out, the total data rate is a combination of the audio rate and the video rate. For NTSC DVD's, the audio is supposed to be AC3 or LPCM, however, most of the players today will handle the audio compressed with mpeg (every now and then I run into one that will not play it and you get the owner saying "nice show, but no sound?"). For PAL, I believe your are allowed to use Mpeg-1 as well for the audio (from the PAL info on the page: "One audio track must have MPEG-1, DD or PCM Audio" )
http://www.videohelp.com/dvdmikey