Can you rip just the music off of DVD? and what is the rez of a DVD.
Yes, but it depends on the tool. If the DVD has a linear PCM layer (usually stated on the back, and often from music and/or concert DVD's) then something like DVD Audio Extractor can work. In many cases this is 24/48, but sometimes you find a better 24/96 layer (like neil young's DVD's). If the sound layer is typical Dolby or DTS lossy stuff then those tools will work, but the resultant files will be only playable via a player that decodes AC3 or DTS.
In all cases above I was speaking of typical DVD-V (aka video DVD's). For DVD-A (aka DVD-Audio) the stereo layer can be as high as 24/192 but is protected and requires tools like DVDAExplorer to rip to wav or flac.
See this sticky thread:
http://www.audiocircle.com/index.php?topic=69151.0