The design and implementation of a real-time multimedia synchronization control system over high-speed communications networks.

Abstract

Sychronization is considered as a key issue in distributed multimedia systems. In a real-time multimedia presentation, data objects of different media types or coding formats are delivered from distributed media-storing servers to the remote client simultaneously over high-speed networks. The multiple streams need to be synchronized so that the multimedia document can be presented in the way specified by its creator. The synchronization research involves issues such as temporal relationship modeling, extending network protocols and supporting the implementation of applications where the synchronization control mechanisms integrate with other system functionality, such as the ATM network transmissions. The video coding/decoding and the distributed database management. In this thesis, we investigate a software synchronization control system for a target presentational application, i.e., a Multimedia News-on-demand service. Relying on the Quality of Services (QoS) supported by the ATM-based virtual connections, the system prevents major multi-stream mismatches through a delivery scheduling operation. Moreover, the synchronization errors brought by the inevitable network delay variations are recovered through a Stream Synchronization Protocol (SSP) in order to preserve the presentation quality. We apply the Time Flow Graph (TFG) to model the temporal relationships among the media components so that the scheduling and recovering operations can be efficient. Synchronization QoS parameters are employed in the SSP control. In addition, the differences between the characterization of coded and uncoded data streams are taken into account. We present a priority-based synchronization control for coded data, e.g., the MPEG-2 video stream. For the implementation of such a control system, we elaborate a set of data structure specifications and algorithms. As well, we develop the software modules to implement the synchronization control prototype.