A. Applying Metadata Extractors (step A) An extractor applied on a multimedia content must try to identify information about this content, such as the occurrence of persons, vehicles, discussion topics, etc. For example, an automatic license plate recognition system is one kind of extractor. Extractors are the key feature of system as they produce the semantic meaning of multimedia contents. Moreover, when several extractors are applied on a multimedia content, it enriches considerably its description. We propose to illustrate in the RDF descriptions can be combined when manipulating several extractors.