Did some research, found a discussion about it here:
So as of about 8 months ago, there were no software decoders for DVD audio. This is different from normal 24 bit, there are plenty of players with that capability. I know that an earlier release of mplayer said it had "experimental" dvd audio support, but it doesnt sound like later versions kept it. Basically, I couldn't find for you. Sorry. It looks like you might have a tough time finding something.