In this technical demonstration we show a web video search engine based on ontologies, the Sirio system, that has been developed within the EU VidiVideo project. The goal of the system is to provide a search engine for videos for both technical and non-technical users. In fact, the system has different interfaces that permit different query modalities: free-text, natural language, graphical composition of concepts using boolean and temporal relations and query by visual example. In addition, the ontology structure is exploited to encode semantic relations between concepts permitting, for example, to expand queries to synonyms and concept specializations.
