近幾年來，隨著網際網路的快速發展，以及多媒體技術的日益精進，利用IP廣域網路來展現多媒體資料已經變得可行。然而，多媒體資訊太耗費頻寬，面對網路不佳時播放品質也跟著不佳。使用者對於資訊的需求也跟著網路發展，而迫切的需要即時的資訊。
在本文中，我們提出在IP網路上透過即時的RTP/RTCP傳輸協定，進行現場多媒體群播展現的系統，這個系統除了聲音影像資訊之外、也將送端的網頁瀏覽事件同步再現於各個收端，使得送端的情境能與收端分享。另一方面連續型態的串流媒體與分散型態的事件資訊在經過網路傳送之後，必定會發生時序不同步的問題，如何在不使用額外的展示與應用機制下，仍能保持時序關係的同步展現，也是我們討論的重點。此外，我們也針對除了網路延遲之外，可能會發生在實作上的另一個同步問題，也就是取樣時戳的對應偏差，探討其發生的原因，並提出解決之道。
本系統的特性包括：

The Internet and multimedia technology has improved significantly in the recent years, thus it is workable now to present multimedia information using IP on wide area network. The main problem of multimedia on network is the cost of communication bandwidth however, it consumes too much bandwidth. The quality of network deteriorates rapidly with heavily traffic load, so does the effect of multimedia presentation. On the other hand, users need real-time information urgently now by information high way to adapt global communication. Under such circumstance, the multimedia presentation we found today can hardly work across IP network with real-time characteristic.
In the thesis, we propose a Live Telepresentation System using real-time RTP/RTCP protocol on IP network. Besides using audio and video media in Telepresentation, the system also transports the events of web browsing to end clients replay the browsing activity simultaneously with audio and video presentation. We also discuss the synchronization methodologies that maintain the temporal relations among discrete event data and continuous stream after network transmission. The features of our system are as follows:

[1] Tim Berners-Lee, “World Wide Web”, W3 Consortium.
[2] ISO/IEC 14496-1：1999, Information technology — Very-low bitrate audio-visual coding — Part I: Systems.
[3] D. James Gemmell and C. Gordon Bell, “Noncollaborative Telepresentations Come of Age”, Communication of ACM, Vol. 40, No. 4, pp. 79-89, April 1997.
[4] Y. Ishibashi and S. Tasaka and E. Minami, “Performance measurement of a stored media synchronization mechanism: quick recovery scheme”, in Conf. Rec. GLOBECOM’95, pp. 811-817, Nov. 1995.
[5] Wanjiun Liao and Victor O. K. Li, “Synchronization of distributed multimedia systems with user interactions”, ACM Press Multimedia System, Vol. 6, pp. 196-205, May 1998.
[6] R. Steinmetz, “Human perception of jitter and media synchronization”, IEEE Journal on selected Areas in Communication, Vol. 14, No. 1, pp.61-72, Jan. 1996.
[7] HTTP/1.1：R. Fielding, J. Gettys, J. Mogul, H. Frystyk and T. Berners-Lee, “ Hypertext Transfer Protocol — HTTP/1.1”, RFC2068, Internet Engineering Task Force, January 1997.
[8] Jourdan, M. Layaida, N. and Sabry-Ismail, L. “Madeus: an Authoring Environment for Interactive Multimedia Documents”, Multimedia Computing and Systems ''97. Proceedings, IEEE International Conference, pp. 644—645, 1997.
[9] Allen J. F., “Maintaining Knowledge about Temporal Intervals”, CACM, Vol. 26, No. 11, pp. 832-843, Nov. 1983.
[10] Synchronized Multimedia Integrated Language (SMIL) 1.0 Specification, http://www.w3.org/TR/1998/REC-smil-19980615
[1] RTSP：H.Schulzrinne, A. Rao, R. Lanpjier. “Real Time Streaming Protocol （RTSP）”, RFC 1326, April 1998.
[12] Franck Rousseau and Andrzej Duda, “synchronized multimedia for WWW”, Computer Networks and ISDN Systems, Vol. 30, pp. 417-429, 1998.
[13] Shuji Tasaka and Yutaka Ishibashi, “Single-Stream versus Multi-Stream for Live Media Synchronization”, IEEE ICC 98. Conference Record, Vol. 1, pp. 470-476, 1998.
[14] ISO/IEC 11172-1: “Information technology — Coding of moving pictures and associated audio for digital storage media at up to about 1.5 Mbps, Part I: Systems”, International Standard, 1993.
[15] ISP/IEC 13818-1: “Information technology — Generic coding of moving pictures and associated audio information: Systems”, International Standard, Nov. 1994.
[16] ITU-T Recommendation H.223: “Multiplexing protocol for low bit rate multimedia communication”, March 1996.
[17] V. Jacobson and S. McGanne, “Visual Audio Tool”, Lawrence Berkeley Laboratory. Software on-line.
[18] S. McGanne and V. Jacobson, “vic: A flexible framework for packet video”, in Proc. ACM Multimedia’95, pp. 511-522, Nov. 1995.
[19] Chung-Ming Huang, Chian Wang and Cheng-Yi Kuo, “A Master-Medium-based Interactive Synchronization Control Scheme for Distributed Multimedia Systems”, Proceedings of Euromicro98- Euromicro Workshop on Multimedia and Telecommunications, pp. 506-513, 1998.
[20] 翁志達, “支援非同步加入及事件驅動錄製功能之網路教學系統”, 國立中央大學資訊工程研究所碩士論文, June 1998.
[21] RFC1889: RTP：A Transport Protocol for Real-Time Applications. Audio-video Transport Working Group, H. Schulzrinne, S. Casner, R. Frederick and V. Jacobson, January 1996.
[22] Scott Roberts, “Keeping an Eye on Your Browser by Monitoring Internet Explorer” 4.0 Events”, Microsoft Systems Journal, Vol. 13, No. 6, pp. 69-82, June 1998.