ViCRO: An Interactive and Cooperative VideoRecording on-demand System over MBone

This paper presents an interactive and cooperative VideoConference Recording On-demand system (ViCRO) designed for remote playback, recording and browsing multimedia sessions over the Internet MBone. It consists of Media Servers, possibly cluster-based, and Media Clients. The interaction multiclient/multi-server is based on the RTSP protocol for streaming control, on the RTP protocol for multimedia data streaming, on the LRMP protocol for reliable messaging and on the SAP protocol for group rendezvous. The time-critical and continuous components of the media clients and media servers are built by using Java and Actor based Framework (JAF), i.e., a variant of the Actor model specialized to multimedia requirements. JAF centres on timing predictability, customizable scheduling and a modular specification of QoS constraints. The main goal is to integrate MBone and WWW technologies towards media-on-demand and virtual collaborative work in heterogeneous environments. The paper introduces the Java-enabled ViCRO system and describes its application in several scenarios ranging from teleteaching to videoconferencing.