In this technical demonstration we show an integrated web system for video search and annotation based on ontologies. The system is composed by three components: the Orione1 ontology-based search engine, the Sirio2 search interface, and the Pan3 web-based video annotation tool. The system is currently being developed within the EU IM3I4 project. The goal of the system is to provide an integrated environment for video annotation and retrieval of videos, for both technical and non-technical users. In fact, the search engine 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. The annotation tool can be used to create ground-truth annotations to train automatic annotations ...