Composition Center specific components To run StreamStudio Composition Center, you need a web content repository in addition to the basic StreamStudio components. Figure 3 StreamStudio Composition Center components The web content repository is used by the Composition Center web application for storing document definitions, resources, and rules during the document design phase. When a document definition is approved, the document definition together with its resources and rules is copied from the web content repository to the runtime repository, where it is available to the StreamServer application that produces the document.