Just a note. If a file will play in Windows Media Player (WMP) then you should have the codec installed. Some of the popular players e.g. VLC pretty much have their own built in codecs so they may play a video even though the codec isn't available for WMP. Also, some installed codecs may be output only i.e. only the decompressor part and you can't use them to encode video. There are codec 'packs' available that offer a lot of codecs, but in general it is best not to use them. Try to find only the specific codec you need or install only that one from a pack. Currently, H.264/MPEG-4 AVC is quite popular (YouTube, BluRay etc) and produces very good size/quality and (IIRC) is built into AviDemux. I have no idea whether Poser will deal with it though :-)

"Democracy is a pathetic belief in the collective wisdom of individual ignorance." - H. L. Mencken