I don't know what you're referring to, but so far we are using libsndfile which handles all the formats that we want (and also some that we don't need).
But due to its license, it will soon (2.2 or 2.3) be replaced with lower level libraries (libogg, libvorbis, libflac, ...) and we'll support WAV, OGG/Vorbis and FLAC. This new system will also make it very easy to write extensions to handle other formats. In the end, people will probably be able to use plugins written by the community to extend the set of formats (including MP3, if they can handle the license).