I have a bunch of PNG files, generated from a script. They represent consecutive frames of a video sequence and I'd like to encode them into a single AVI file (or some other video format) using mencoder. What parameters should I use to ensure that the video can be viewed on a vanilla Windows XP using Windows Media Player with no extra codecs installed apart from the default ones? So far I've tried -ovc lavc -lavcopts vcodec=wmv2 and -ovc lavc -lavcopts vcodec=msmpeg4 with no success.

(Background story: some of the people I'm collaborating with on a scientific project cannot install any codecs on their university computers without the help of the local sysadmins, who are of course not very willing to install anything. I'd like to ensure that they can also view the video files I am creating).