cant get mp3 encoding to work

I am having trouble using gKnot when trying to encode a vob file to one cd, as the quality is really bad. i think it is because i am using AC3 for the sound so i would like to use mp3. however, when i look in the box for what to use to encode the sound, the only option i get is AC3. Does anybody know what i can do to make mp3 available? Thanks in advance Andy

Did you read the ? It tell's you exactly how to do that! greetz, Piscator

Not quite the right link, Piscator, as the guide at that point assumes Robot4Rip has done the demux and transcode of the AC3 to MP3. That guide shows "Just Mux" since at that point the MP3 file exists. Two choices:Use R4R to convert the audio... click on for the start of the guide, and for configuring audio format, be sure to click on the configuration link in that guide, which will take you to Have Gknot set up the conversion from ac3 to mp3 for you. Instead of selecting "Just Mux" on the Audio 1 tab, select one of the 3 MP3 options beneath it.