A DMAP structure is a binary record used in Apple's DAAP protocol. A DMAP structure may contain other DMAP structures. Fields in a DMAP structure are identified by a short name ("msdc"). The short name is what's in the binary record, but a content codes list gives a long name ("dmap.databasescount") and a data type for the record (32-bit integer). . http://search.cpan.org/dist/Net-DAAP-DMAP