AtomicParsley is a freeware commandline tool for Mac OS X as well as for Linux and Windows (cygwin). It allows to manipulate the metadata in mpeg4 files (m4a, m4b, m4p, m4v & mp4) and in 3GPP files.

It’s very handy if you like to generate or manipulate the metadata in movie files to provide iTunes-like metadata automatically on a server. It even can turn your selfmade movies into “video podcasts” or “movies” inside your iTunes library like the movies you downloaded from the iTunes Music Store.