AC-3 decoder, soc revision 38, Aug 7 00:03:00 2006 UTC by cloud9

major code cleanup.
correct implementation of imdct.
implemented imdct for block switching also.
when coupling is not in use all the
ac3 streams are decoded correctly.
but when coupling is in use there is a bug.
i am currently finding the root of the bug.
if anybody can help.

Originally committed as revision 9657 to svn://svn.ffmpeg.org/ffmpeg/trunk