ATM and broadcast quality video

ATM technology has become increasingly interesting for the transmission of video material between remote studios. Two main reasons for this are that ATM can offer flexible bandwidth and “dial-up” services. In the radio broadcasting industry ISDN in combination with compression algorithms such as MPEG-1 Layer II has offered these features for a long time, and ATM is expected to offer some of the same flexibility for video services. However, one of the problems associated with video transmission over ATM is the variable transport delay, introduced by the cell switches, which can impair the strict timing required for real-time broadcast video signals. This paper examines the timing issues related to ATM and their influence on video signals. Different methods of obtaining synchronisation are described, and the results from experimental testing of two of them on an ATM field trial network carrying compressed video and other traffic are presented