After a longish break, released a new AudioFormat when I noticed how aggravating the current version was :-)
The new version, 0.4, allows you to add files to the list of files to convert via a file selector or by dragging. It also should handle and report errors a bit better. And maybe it'll even recognize Vorbis files? Although I suspect it'll get very confused if it encounters something like Ogg Tarkin files. Will have to work on that a bit more.