VLC is a media player and converter that is cross platform and often installed on user's computers, due to it's being both free and supporting most common video and audio formats. One downside is that many of it's codecs are low quality, and have been stated by VLC developers as not good for use in transcoding. Might be good to implement when we have some sort of ranking system for converters.
Forgot to add that what needs to be done is to have an XML file written. Documentation is available on VLC's wiki at http://wiki.videolan.org/