it can probably be the codec which u use to rip the dvd??
Most likely its the codec, but also you may neeed to change programs that do the ripping. That could be the problem. Crappy program crappy recording...
If you have an old and slow computer or an old or slow CD ROM drive (you know, those white things from the past), it can produce some pretty lousy encodings. This is the case for me on my Pentium II. Cracking is the result of slight fluctuations in the encoding engines settings due to your sound card. One thing that helps is to use VBR encoding instead, the cracking will be significantly reduced.
did u reduce the quality a bit 2 much?
If you have a slow computer, make sure you don't run anything else while ripping.
It sounds like the music is "clipping", so you are not getting the full part of the sound's wave form. This is usually due to the compression being too high, try encoding with a higher bitrate.
anytime you need to encode an MP3 from WAV (or even from a diferent type of MP3), a good program to try is CDex. google search it. it is very good and provides a nice GUI for using the LAME mp3 compression codec. it does all the different types of VBR/ABR nicely.
this is prolly very basic but is the dvd scratched or dirty?? is ur dvd drive up 2 scratch - like a decent one e.g. lg, sony, pioneer, asus, gigabyte not a cheapie equivalent
if not, your problems might be caused by a bad encoder (try LAME - free)
check ur bitrate and see what it is 128kbps shud b fine if its 96 or lower, u probably need to rerip it