Have you tried to get a thumbnail from a video stored on your phone?! It ain't easy ...
This guy figured it out. Took a lot of digging into the raw API.
Videos Android App (Android Code Monkey)
He has an awesome blog with tutorials on Android App Development. How-to setup the Eclipse, JDK and Eclipse Android Plugin. Has a sample Hello Android app as well as how to add Base64 Encoding back into the API. The documentation says its in there, but it's not Got check. Anyway, worth a read ...
My favorite (!!!) Applying themes to Eclipse to get rid of the bright white background!
Android Code Monkey