Improving clock synchronization for MPEG-2 services over ATM networks

Abstract

A stable clock indication is needed for the processing and playout of MPEG-2 streams. ATM networks can support the transfer of such streams but contribute significantly (as well as other system operations) to delay and delay variation. The MPEG-2 standard specifies strong temporal constraints for processing and presentation. MPEG-2 is also based on the assumption of a common time base shared among sender and receiver. Clock synchronization covers this requirement and is traditionally performed using PLLs. Unfortunately, their linear nature cannot simultaneously guarantee rapidity and good clock reconstruction. The non-linear technique we propose in this paper is able to offer such guarantees and also can handle higher amounts of delay variations. Such technique is not restricted to the scope of MPEG-2 clock synchronization and can also succeed in the reconstruction of time bases for generic distributed applications. It does not require any specific device, like very precise oscillators or filters.