Validating MPEG-21 encapsulated functional metadata

We describe the validation process of a functional metadata document encapsulated in an MPEG-21 digital item. The validation starts with an MPEG-21 digital item containing the functional metadata and ends with a valid functional metadata document or with a list of error codes. Since the W3C schema language does not suffice to validate all relationships within a functional metadata document, a set of extra rules is defined. These rules are implemented through the use of transformations on functional metadata documents. These transformations are implemented using XSLT.