I have a Mac, but I never import anything directly into iDVD. I generally use Toast, but since your question revolves around a Mac and iDVD, you may get an accurate response if you posed your question in the Mac software forum here at CNET.
Does anyone know the audio format required for iDVD 5.0.1
in the main menu area?
So far I've tried mp3 and mp4 but both formats are greyed out when I try to import them.
Thanks for any tips.