針對點對點網路的使用者可選擇性之即時視訊串流

在這篇論文中，我們針對即時視訊串流提出了一個新的方法，此方法建構在點對點網路(peer-to-peer network)上，而最大的特點是使用者可以依據自己的需求，自由地選擇其所想要的影像品質，可達到更好的網路適應性(adaptive)。由於在此方法中，節點(peers)之間的溝通方法都是由接收端的要求訊息(requesting message)所組成，也不需要任何複雜的演算法去得到影像的傳送次序和傳送對象，所以其方法是較為簡易了解而容易實行的。在此即時視訊串流系統中，我們針對於實作方面在封包中加上了標籤，也使得封包可被分類成數種種類，而且使封包的種類可以被辨識出來，並對於不同的網路狀況給予其種類不同的優先權，如此一來便可以針對其視訊串流設計一些管理上的機制。對於視訊串流管理的方面，我們設計了一些方法，藉由捨棄低優先權的封包，而只讓高優先權的封包通過，隨著不同的狀況有不同的優先權分配，會有以下的結果：當網路壅塞時，讓其串流可以適應網路隨時變動的頻寬，當網路暢通時，其串流便更能達到即時的功能。對於伺服器(server)來說，除了提供連結的資訊給所有peers，更扮演著提供補救通道(patching channel)的角色，讓整個即時的視訊串流的傳輸可以更穩定。在此論文的最後，我們選擇NS-2來當作為我們的模擬工具，模擬結果顯示封包漏失率可以被降低到百分之十左右，而封包延遲時間的標準差也降低於十五毫秒，除此之外，我們也顯示了最大的佇列的大小變化和其視訊串流的適應網路頻寬的能力。

關鍵字

點對點傳輸技術；即時視訊串流；多畫質視訊服務

並列摘要

In this thesis, a new approach for real-time video streaming on a peer-to-peer network is proposed. It provides the ability to control the quality of service of networks from end systems. This scheme makes use of the layer video coding techniques and extends them to the peers such that users can select the quality of video by themselves. The communication of the protocol is simply constructed by the request of receiving peers. Our system is adaptive to network bandwidth since users can choose different levels of video depending on the traffic conditions. We inserted two types of tags, the timing tag and layer tag, into the video packets for implementation. With the proposed management of the tags, the timing tag is used to reduce the display delay while the layer tag is used in a congested network. When serious congestion happens, the higher layers of video data will be sacrificed to get more bandwidth for lower layers of data. Therefore, our system is adaptive to the bandwidth. These functions provide the real-time ability and are adaptive to non-congestion and congestion conditions. Moreover, the server can provide real-time patching channels to stabilize the video quality of peers. We simulate this system by ns-2 with the proposed scheme, and show that the packet loss rate is reduced to around 10% with 1000 peers. The standard deviation of delay time is below 15ms. Besides, we also show the reduction of the maximum queue size and the adaptive ability of the video stream in this system.

並列關鍵字

peer-to-peer ； real-time video streaming ； multi-quality service

參考文獻

[4] S. Banerjee, B. Bhattacharjee, and C. Kommareddy, “Scalable application layer multicast,” in Proceeding of ACM SIGCOMM, 2002.

[5] D. A. Tran, K. A. Hua, and T. Do, “Zigzag: An efficient peer-to-peer scheme for media streaming”, Proc. of the IEEE INFOCOM 2003, 30 March-3 April 2003, pp.1283 - 1292 vol.2

[6] M. Castro, P. Druschel, A.-M. Kermarrec, “SplitStream: high-bandwidth multicast in cooperative environments,” in Proc. ACM SOSP’03, Oct. 2003.

[7] G.J. Lee, C. K. Choi, C. Y. Choi, H. K. Choi, “P2Proxy: peer-to-peer proxy caching scheme for VOD service”, Proc. of the International Conference on Computational Intelligence and Multimedia Applications (ICCIMA’05), 16-18 Aug. 2005 pp. 272 - 277

[8] Yang G., Kyoungwon S., Jim K., and Don T., “P2Cast: Peer to peer Patching Scheme for VoD Service”, WWW2003, May 20–24, 2003.

國際替代計量

針對點對點網路的使用者可選擇性之即時視訊串流

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