In this paper we describe a proposal for multimedia and e-learning content description based on standards interoperability within a digital library environment integrated in a virtual campus. In any virtual e-learning environment, a complex scenario which usually includes a digital library or, at least, a repository of learning resources, different levels of description are needed for all the elements: learning resources, multimedia content, activities, roles, etc. These elements can be described using library, e-learning and multimedia standards, depending on the specific needs of each particular scenario of use, but this might lead to an undesirable duplication of metadata, and to inefficient content queries and maintenance. Furthermore, there is a lack of semantic descriptions which makes all these contents merely become digital objects in the digital library, without exploiting all the possibilities in a e-learning virtual environment. Due to its flexibility and completeness, we propose to use the MPEG-7 standard for describing all the learning resources in the digital library, combined with the use of an ontology for a formal description of the learning process. The equivalences of Dublin Core, LOM and MPEG-7 standards are outlined, and the requirements of a proposal for a MPEG-7 based representation for all the contents in the digital library and the virtual classroom are described. The intellectual property policies for content sharing both within and among organizations are also addressed. With such proposal, it would be possible to build complex multimedia courses from a repository of learning objects using the digital library as the core repository.