I’ve been having a lot of discussions related to the Quicktime 7.6 and AC3 passthrough problem.
My initial thoughts on AVSForum are here:
http://www.avsforum.com/avs-vb/showthread.php?p=15793868#post15793868
Feedback on the issue for various other apps and products are here:
http://discussions.apple.com/thread.jspa?messageID=8950477
… and here
http://www.avsforum.com/avs-vb/showthread.php?p=15788699#post15788699
… and here
http://forums.cocoaforge.com/viewtopic.php?f=25&t=19226
… and here