A Networked Frame Buffer with Window Management Support

When processing multimedia data streams in a distributed system it is often advantageous if data, in particular, continuous data such as video and audio data, can be sent directly from the source to the sink device. An example is a video conferencing application with source devices (cameras, microphones) transmitting directly to sink devices (frame buffers, speakers) without involving an intermediate processor. This approach saves communication bandwidth and processor cycles. Further, it reduces latency and also latency jitter. Unfortunately, systems in use today do not support this kind of direct communication. Even worse, current systems do not provide real-time or quality of service (QoS) guarantees making it impossible to process or transfer continuous data within specified latency times. This paper presents the design and implementation of a networked frame buffer with window management support. The frame buffer is implemented as an independent node of a proprietary desk area network (DAN) which offers scalability and QoS guarantees. As an independent node, the frame buffer is connected directly to the network and can be accessed by any other node. Further, the core functions of window management are implemented directly on the frame buffer. This avoids processor intervention during the transmission and display of video data. Thus, the frame buffer is an ideal output device for distributed multimedia applications such as desktop video conferencing.