> I have some videos from lectures (e.g. Dan, Alan, Elliot Miranda) that
> are encoded with strange audio codecs.
>
> The files are .asf, video codec is "Microsoft MPEG-4 Video Codec V2",
> audio codecs used is either
> "Voxware MetaSound AC16V1" or "ACELP.net", both of which seem to be
> proprietary and only
> available on Windows.
>
> Is there a way to convert these videos to some format working on the
> Mac?

I think that you could use the VLC (VideoLan) player (perhaps on Windows or 
Linux with the original codecs) to stream a different representation.

-- Ned Konz

Following on from what Ned said, you might also want to look at mplayer

http://www.mplayerhq.hu/homepage/design7/dload.html

which you can compile with a bunch of windows native codecs on x86 Linux.  The 
configure script has a number of options to determine the support for streaming 
style protocols.  I'm pretty sure that I have watched the various lectures that 
you are probably referring to on Linux but I might have had to fiddle with the 
url where the .asf file is concerned.

I have never tried them

http://www.mplayerhq.hu/homepage/design7/projects.html

but there are a number of related projects that talk about transcoding and 
other platform support.

As for working on the Mac, I think you can build mplayer for the Mac but I 
don't know whether there are wrappers for the x86 dlls or another scheme to 
decode windows files.
--
Audacity is cross platform, opensource, and good for transcoding.

http://audacity.sourceforge.net/