近年隨著寬頻網路的普及與多媒體資料編解碼技術的成熟，在網際網路中資料傳輸型態與特性，已逐漸從過去的非即時性數據資料演進至現階段的多媒體服務，然而在傳統網際網路的傳送機制下已無法滿足多媒體應用的需求，加上在視訊編碼過程中，不同型態的視訊封包具有不同重要性，若一視同仁地直接在網路上傳送，將使得視訊品質遭受嚴重影響。
基於以上的問題，本論文針對H.264視訊提出一套傳送於差異式服務網路之跨層服務品質對應機制。此機制包含三個主要部分：第一，在應用層中提出調適性視訊封包優先權訂定機制，針對每個視訊封包所位於的畫面位置與內容資訊ㄧ同進行評估，並對於不同的影像特性進行調適性優先權調整；第二，在網路層中提出一套動態跨層服務品質對應機制，利用『應用層』中視訊封包優先權等級資訊對應到『網路層』中有限的差異式服務等級，並依據目前網路狀況做動態服務品質對應調整；第三，對於封包標頭所帶來的額外負擔，提出一套同時考慮優先權等級與封包標頭負荷的視訊封包封裝策略。在整體傳輸效能評估上，本論文所提出的跨層服務品質對應機制於差異式服務網路中，可有效提升視訊接收品質，比起未支援服務品質的傳統網際網路上增加4dB。而調適性視訊封包優先權訂定機制相對於僅使用畫面位置/封包內容之優先權機制也有3dB/1.5dB提升。對於具有優先權考量的視訊封裝策略亦比一般固定大小的封裝策略，提升約1.6dB。

With the technology advances in multimedia compression and Internet, video streaming of multimedia application is full of potentials. However, the delivery mechanism of the traditional Internet can not satisfied with the demand of multimedia application. Additionally, considering the video encoding process, the property of video packet with different types has different significance. An equal error protection to all video packets in the Internet will degrade the video quality significantly.
Therefore, this thesis proposes a cross layer QoS mapping framework for H.264 video transmission over Diffserv network. Then there are three main parts in this framework; First, application layer proposes an adaptive priority of video packet mechanism. Furthermore, the mechanism can estimate each packet location and content information to adjust different video with adaptive priority. Second, network layer recommends a dynamic cross layer QoS mapping (D-CQM) mechanism. According to the current network situation, D-CQM can use the priority of video packet in application layer and it corresponds to the limited Diffserv level in network layer to regulate the dynamic QoS mapping. Third, for the extra packet header, it brings a packetization strategy that considers the priority of video packet and packet header overhead simultaneously. After evaluating the whole transmission efficiency, the cross layer QoS mapping framework over Diffserv network can improve the quality of video receiving and also better than the traditional Internet up to 4dB. Moreover, the adaptive priority of video packet is superior to the frame/packet based priority up to 3dB/1.5dB. For the strategy of priority packetization, it also increase PSNR up to 1.6dB than fixed packetization.

參考文獻
[1] A.Zibiani, J.F.Rezende, O.C.M.B.Duarte, and S. Fidia, “Improving the delivery quality of MPEG video streams by using differentiated services,” Proc. ECUMN''02, pp.107-115, Colmar, France , April 2002.
[2] H.Zhao, N.Ansari and Y.Q.Shi, “Transmission of real-time video over IP differentiated services,” Electronics Letters Volume 38, Issue 19, pp.1151-1153 , Sep. 2002.
[3] J.Magalhaes and P.Guardieiro,“A New QoS. Mapping for Streamed MPEG Video over a DiffServ Domain,” Communications, Circuits and Systems and West. Sino Expositions, IEEE 2002 International Conference on Volume 1, pp.675-679, July 2002.
[4] C.H.Ke, C.K.Shieh, W.S. Hwang, and ZIVIANI, “A Two-Markers System for Improved MPEG Video Delivery in a DiffServ Network,” IEEE Communications Letters, IEEE Press, v. 9, n. 4, pp.381-383, April 2005.
[5] H.Zhao, N.Ansari and Y.Q.Shi, “Layered MPEG video transmission over IP DiffServ,” Information Technology: Coding and Computing. ITCC 2005. International Conference on Volume 1 pp.63 - 67, April 4-6 2005.
[6] T. Ahmed, A. Mehaoua, and G. Buridant, “Implementing MPEG-4 video on demand over IP differentiated services,” Proc. IEEE Globecom, pp.2489–2493, San Antonio, TX, USA, Nov. 2001.
[7] T. Ahmed, G. Buridant and A. Mehaoua, “Encapsulation and Marking of MPEG-4. Video over IP Differentiated Services,” in IEEE ISCC 01, Tunisia, July 2001.
[8] X.Zhu, M.Chen and Y.YU “Video Transmission Based on Diffserv Over IP Network,” Communication Technology Proceedings, ICCT 2003. International Conference on Volume: 2, pp. 1754- 1757 vol.2, April 2003 .
[9] J. Shin, J. Kim, and C.-C.J.Kuo “Quality-of-Service Mapping Mechanism for Packet Video in Differentiated Services Network,” IEEE Transactions on Multimedia, Vol. 3, No. 2 pp. 219-231, June 2003.
[10] G.Hwang, J.Shin, and J.W.Kim, “Dynamic Class Mapping Scheme for Prioritized Video Transmission in Differentiated Services Network,” IEICE Trans, Vol. E89-B, No. 2, pp. 393-400, Feb. 2006.
[11] G.Hwang, J.Shin, and J.W.Kim, “Scalable and Adaptive QoS Mapping Control Framework for Packet Video Delivery,” Springer-Verlag LNCS (PCM2005), Nov. 2005.
[12] J.C. De Martin, D.Quaglia, “Distortion-Based Packet Marking for MPEG Video Transmission. over Diffserv Networks,” IEEE International Conference on Multimedia and Expo, Tokyo, pp. 521-524 , Aug. 2001.
[13] F.D.Agostino, E.Masala, L. Farinetti, J.C. De Martin “A Simulative Study of Analysis-By-Synthesis Perceptual Video Classification and Transmission over DiffServ IP Networks,” Proceedings of IEEE Int. Conf. on Communications (ICC), Anchorage, Alaska, vol. 1, pp. 572-576, May 2003.
[14] UCB/LBNL/VIANT. (1998) Network Simulator – NS (version 2).
[15] D.E.Wrege, E.W.Knightly, H.Zhang, and J.Liebeherr, “Deterministic Delay Bounds for VBR Video in Packet-Switching Networks: Fundamental Limits and Practical Trade-Offs,”IEEE/ACM Transactions on Networking, vol. 4, no. 3, pp. 352-362, Jun. 1996.
[16] E. W. Knightly and H. Zhang, “D-BIND: An Accurate Traffic Model for Providing QoS Guarantees to VBR Traffic,” IEEE/ACM Transactions on Networking, vol. 5, no. 2, pp. 219-231, April 1997.
[17] R. Braden, D. Clark, and S. Shenker, “Integrated Services in the Internet Architecture: an Overview,” RFC 1633, June 1994.
[18] J. Wroclawski, “The Use of RSVP with IETF Integrated Services,” RFC 2210,Sep. 1997.
[19] S. Blake, D.Black, E.Davies , “An Architecture for Differentiated Services,” RFC2475, Dec. 1998.
[20] K. Nichols, V. Jacobson, L. Zhang, “A Two-bit Differentiated service architecture for the internet,” RFC 2638, July 1999.
[21] T. Wiegand, G. J. Sullivan, G. Bjontegaard, and A. Luthra, “Overview of the H.264/AVC video coding standard,” IEEE Trans. Circuits Syst. Video Technol., vol. 13, July 2003.
[22] S. Wenger, “H.264/AVC over IP,” IEEE Trans. Circuits Syst. Video Technol, vol. 13, July 2003.
[23] T. Stockhammer, M. Hannuksela, and T. Wiegand, “H.264/AVC in wireless environments,” IEEE Trans. Circuits Syst. Video Technol., vol. 13, pp. 657–673, July 2003.
[24] R. Braden, L.Zhang, Berson, S. Herzog, and S. Jamin, “Resource ReSerVation Protocol (RSVP),” RFC 2205, Sep. 1997.
[25] S.Shenker, C.Partidge, and R. Guerin, “Specification of Guaranteed Quality of Service,” RFC 2212, Sep. 1997.
[26] V. Jacobson, K.Nichols, K.Poduri , “An Expedited Forwarding PHB,” RFC2598, June 1999.
[27] J.Heinanen, F.Baker, W.Weiss, “Assured Forwarding PHB Group,” RFC2597, June 1999.
[28] K. Nichols, S. Blake, F. Baker, and D. Black, “Definition of the differentiated services field (DS field) in the IPv4 and IPv6 headers,” RFC2474, IETF, Dec. 1998.
[29] H. Schulzrinne, S. Casner, R. Frederick, V. Jacobson, “RTP: A Transport Protocol for Real-Time Applications,” RFC 1889, Jan. 1996.
[30] B. G. Haskell , A. Puri, and A. N. Netravali, “Digital Video: An Introduction to MPEG-2,” New York: Chapman & Hall, 1997.
[31] T. Sikora, “The MPEG-4 video standard verification,” IEEE Trans. Circuits and Systems for Video Technology, Vol.7, Iss. 1, pp. 19-31, Feb. 1997.
[32] K. Rijkse,“H.263: video coding for low-bit-rate communication,” IEEE Communications Magazine, Dec. 1996.
[33] F.Zhang,M.R.Pickering, M.R.Frater, and J.F.Arnold, “Streaming MPEG-4 Video over Differentiated Services Network,” Workshop on Internet, Telecommunication and Signal Processing, Wollongong, Dec. 2002.
[34] F.Zhang, M.R.Pickering, M.R.Frater, and J.F.Arnold, “Optimal QoS mapping for streaming video over Differentiated Services networks,” Acoustics, Speech, and Signal Processing, 2003. Proceedings.2003 IEEE International Conference on Volume 5 vol.5, 2003.
[35] S.Aign and K.Fazel, “Temporal and spatial error concealment techniques for hierarchical MPEG-2 video codec,” Proceeding of Inform, pp. 1778-1783, 1995.
[36] S. Kaiser, K.Fazel, “Comparison of error concealment techniques for an MPEG-2 video decoder in terrestrial TV-broadcasting,” Signal Processing: Image Communication, Vol.14, No.6-8, pp. 655-676, May 1999.
[37] G.Cote and F.Kossentini, “Optimal Intra Coding of Blocks for Robust Video Communication over The Internet,” Signal Processing: Image Communication, pp.25-34, Sep. 1999.
[38] T.L.Su, M.Y.Huang, H.C.Chuang, C.-N. Wang, and T. Chiang, “A Robust MPEG-21 Media Delivery Video Streaming System,” 8th World Multi conference on Systemics, Cybernetics and Informatics, July 18-21 2004.
[39] J. Y. Liao and J.Vilasenor, “Adaptive intra block update for robust transmission of H.263,” IEEE Transactions on Circuits and Systems for Video Technology, vol. 10, pp.30 -35, Feb. 2000.
[40] P. Haskell and D. Messerschmitt, “Resynchronization of motion compensated video affected by ATM cell loss,” Proceeding IEEE Conference Acoustic Speech SignalProcessing, Vol.3, pp.545-548, March 1992.
[41] L. Ducla Soares, S. Adachi, F. Pereira, “Influence of Encoder Parameters on the Decoded Video Quality for MPEG-4 over W-CDMA Mobile Networks,” Proc. of the IEEE International Conference on Image Processing (ICIP''2000), Vol. 2, pp. 148-151, Vancouver, Canada, Sep. 2000.
[42] J. Widmer, “Equation-based Congestion Control,” Diploma Thesis , Feb. 2000.
[43] M.Buchli, D.D.Vleeschauwer, J.Janssen, A.V.Moffaert, G.H.Petit “Resource allocation and management in DiffServ networks for IP telephony,” International Workshop on Network and Operating System Support for Digital Audio and Video,PP.33-39, 2001.
[44] M.Krunz and H.Hughes, “A traffic model for MPEG-coded VBR streams,” Proceedings of the ACM SIGMETRICS ''95 Conference, pp. 47-55, 1995.
[45] R. Ben Ali, S. Pierre, Y. Lemieux, “ UMTS to IP QoS Mapping for Voice and Video-telephony Services,” IEEE Network Magazine, March 2005.
[46] 黃能富著, “區域網路與高速網路,” 維科出版社, 中華民國八十七年六月.
[47] 陳紹偉著, “視訊封包封裝與調適性自動重送於無線區域網路之研究,” 國立中央大學通訊工程研究所碩士論文, 中華民國九十二年六月.
[48] S. Wenger, “RTP Payload Format for H.264 Video,” RFC 3984, Internet Engineering Task Force, Feb. 2005.
[49] F.L. Leannec and G.M. Guillemot, “Error resilient video transmission over the Internet,” in SPIE Proceeding Visual Communications and Image Processing, Jan. 1999.
[50] T. Turletti and C. Huitema, “RTP payload format for H.261 video streams,” RFC 2032, Internet Engineering Task Force, Oct. 1996.
[51] B. Hong and A. Nosratinia, “Analysis of packet header effects in rate allocation for packet video,” International Conference on Image Processing (ICIP), Rochester, New York, pp. 177-180, vol. 2, Sept. 2002.
[52] B. Hong and A. Nosratinia, “Overhead-constrained rate-allocation for scalable video transmission over networks,” Data Compression Conference, Snowbird, Utah, pp.455, April 2-4 2002.