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.