ogg detection

I should parse the $1 parameter ([example](http://stackoverflow.com/questions/965053/extract-filename-and-extension-in-bash)) to make sure that the movie _needs_ to be transcoded.  If it's in an [ogg container](https://en.wikipedia.org/wiki/Ogg), oggfwd and Icecast can already stream that without transcoding and thus lowering perceived quality.
