A principled design for scalable internet visual communications with rich media, interactivity, and structured archives

In contrast to video conferencing, webcasting supports scaleable Internet visual communications, yet it is typically viewed as an ephemeral one-way broadcast medium. We present a principled design for interactive webcasts that are accessible both in real-time and retrospectively. We derive system architecture and functionality from project goals, results from the video communications literature, and observations of prototype implementations in real webcasts. The ePresence system is scalable, interactive, and able to support presenters and engage remote audiences with rich media. It also provides automatically derived, structured, navigable, and searchable archives for the retrospective use of webcasts.