Decompressing .s14 files

Hello guys.

Since I'm pulling graphics off of the Code Geass DS game, I figured I'd do the same thing for the audio as well.  The sound effects are in a nice audio bank, but the character voices are compressed in .s14 files.  I know it's a MPEG file in there, but I don't know how to decompress it.


Here's one of them as an example.

Thank you in advance.