When looking into the problem I found out that the audio format identification functionality doesn't play well with the ID3v2 metadata format that we use at Voxbiblia. The ID3 tag enables users to organize our MP3 files into whole books or even whole Bibles on their computers or portable MP3 players, and it even enables them to read the actual Bible text of the passage recorded in a specific audio segment. As you might imagine the ID3 functionality is quite useful, and also close to universally used and accepted in popular playback products such as iTunes and Windows Media Player, so I think that it's kind of strange that Sun's MP3 plugin doesn't at least support it by skipping over the tag is kind of surprising.

However, it is not impossible to do just that yourself. If you open the MP3 file yourself and skip forward to after the end of the tag before you hand over the InputStream to the AudioSystem framework it can identify and decode the MP3 stream correctly.

So, I wrote some code that did just that. It's a little bit more tricky to than you might think, because the ID3 format encodes the tag length information in an unusual format, but other than that the strategy is quite straightforward.

The class can be downloaded here: MP3Identifier.java. Enjoy.

Anyway, I'm really happy to be able to give back to the free software community, small pieces of software that I have written. My dream is to some day write a piece of software that grows it's own community around it, with other people contributing new functionality and fixes to problems. I hope that some day that dream will come true. For now it's just me publishing small parts of the software I write. Not all that bad.

For interested parties the information about my library, named id3j, is found at Voxbiblia's Free software page.

Update:
Changed the name of the released package, because of a naming collision.