+- [libfaad and mp4ff](http://www.audiocoding.com/). For aac files
+(m4a) you need libfaad and libmp4ff (package: `libfaad-dev`). Note
+that for some distributions, e.g. Ubuntu, mp4ff is not part of the
+libfaad package. Install the faad library from sources (available
+through the above link) to get the mp4ff library and header files.