A Networked Frame Buffer with Window Management Support

Michaela Blott, Hans Eberle
Institute for Computer Systems, Swiss Federal Institute of Technology
CH-8092 Zurich, Switzerland

Abstract

When processing multimedia data streams in a distrib-uted system it is often 
advantageous if data, in particu-lar, 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 commu-nication 
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 sup-port. The frame buffer is implemented as an 
independent node of a proprietary desk area network (DAN) which offers 
scalability and QoS guarantees. As an in-dependent 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 dis-play of video data. Thus, the frame buffer is an ideal output device 
for distributed multimedia applications such as desktop video conferencing.