ATM based video and audio codecs

This paper presents the ATM-related technical features of the range of ATM based video and audio hardware codecs manufactured by FORE Systems. These devices are stand-alone and attach directly to the ATM network and are thus completely decoupled from any particular hardware and operating systems platform. The devices are managed from a remote workstation or PC. Video and audio sourced from the hardware codecs can be displayed on workstations and PCs. There are separate unidirectional codecs: the AVA-300 for encode, the ATV-300 for decode. Proxy signalling enables the construction of simple, cheap devices which still support full network signalling. The use of native ATM AALS transport provides high performance and low latency data transfer. ATM multicast and QoS support allow video and audio to co-exist with data applications. Motion-JPEG provides TV-quality video at medium data rates. M-JPEG combined with variable-Q allows maximum use to be made to be made of the available bandwidth. Finally, the CellChain reduces costs by allowing multiple devices to share a single switch port.