I wrote a little piece on this once that is still mostly accurate . In OS X, ffmpegX is your best bet. it reads avi and asf with wma and wmv, but for some reason it thinks they all have a video framerate of 100. You can fix this in the end with sync-hole . On system 9 Divx Doctor and Divx player have helped me convert weird file formats. They also have Divx software for osX. Hope this helps. My only real complaint with mac is its inability to have quicktime deal with strange video compressions. I have also had a bit of success with vcd players for OSX. You need lots of patience- and the thing that really annoys me is they play fine on ibms. I have been tempted to compromise and buy an ibm to run these sort of files But I would prefer it if Mac could improve quicktimes capabilities. Phil