User Data Atom

Dear All

I need to retrieve user defined information like movie album, movie title, movie author, copyright. I think
these informations should be available under user data atom under the movie atom and  within the user
data atom these information should be available in  the form of atoms. If that be the case what should be
the format of each atom structure, e.g. what should be its type, its content etc.

Thanks In Advance
Ranjeet