For those in the class who may be:

1) Burning the midnight oil tonight to complete your project, and

2) Still not satisfied with the procedure for converting media using Video Downloader

Take a look at Damnvid (via Lifehacker).  It is cross-platform and apparently does lots of conversion work for you.  This might become especially useful as you begin to think about your Mashup project, as that will also entail a fair bit of download and conversion of found media from the web.