Just found this interesting site:
http://okejl.dk/dunstan/
It has x64 codecs for AC3 audio (=Dolby) and a couple of video formats
(XVid, x264, etc.).
I have only tested the Xvid one with VirtualDub 1.6.11 x64 and works Ok.
Have not tested the others.
This is the full page contents:
DGDecode64.zip 16-Oct-2005 12:43 46k
Decomb.zip 16-Oct-2005 12:45 82k
UnDot64.zip 16-Oct-2005 12:43 4k
UnDot64src.zip 16-Oct-2005 12:43 21k
ac3acm64.zip 16-Oct-2005 12:45 24k
ac3acm64src.zip 16-Oct-2005 12:45 69k
avisynth64.zip 16-Oct-2005 12:45 196k
decomb64src.zip 16-Oct-2005 12:45 70k
dgdecode64src.zip 16-Oct-2005 12:43 175k
huffyuv64.zip 16-Oct-2005 12:43 24k
x264cli_x64.zip 14-Dec-2005 08:07 323k
x264cli_x64src.zip 19-Oct-2005 11:08 832k
x264vfw64.zip 16-Oct-2005 12:44 131k
xvid64.zip 16-Oct-2005 12:44 258k
xvid64src.zip 16-Oct-2005 12:45 1.1M
Use at YOUR OWN risk!!!
Carlos