Good description of audio formats on hi-def disks/players at HIgh Def Digest. It shows the complicated mess but gives the details to help make decisions (including when HDMI 1.3 is required).
http://www.highdefdigest.com/news/show/Joshua_Zyber/High-Def_FAQ:_Blu-ray_and_HD_DVD_Audio_Explained/1064
Nice straight-forward link Ken...
Thanks!