You can also do this with Toast 7. Put VIDEO_TS folder from concert DVD on desktop. Launch Toast. Select Video tab, choose DVD-Video in drawer. Click on Media option in drawer. Select DVD from pop-up list. You will see a list of the DVDs titles and chapters. Drag/drop any title or chapter into the main Toast window. Click the Export button at bottom of Toast window. Export "for iTunes" to strip out the audio from a video.
I found a very easy way to do it, using a very easy-to-use program called Cinematize. This program outputs .aif files, just import those to iTunes and convert.