[saltman]

ac3 is discouraged at this point but permitted. LPCM is ideal. Many, if not all, stand alone DVD burners use ac3 and it has become somewhat commonplace due to this.

Restricting the DVDs offered to LPCM only is not as well received by the community as mp3 restriction. There is an argument that using ac3 allows higher bitrate for video to be used. This is true. Not the case with stand alones, but possible with home authored DVDs.

I'm certain that when Blu-ray discs are more common that low bitrate audio will not be permitted.