施吉昇臺灣大學:資訊工程學研究所陳勇銘Chen, Yong-MingYong-MingChen2010-06-022018-07-052010-06-022018-07-052008U0001-1108200813402900http://ntur.lib.ntu.edu.tw//handle/246246/184960點對點網路的加入可使視訊串流系統減少規模化之成本。在此目標之下，用戶端及伺服器端的管理機制都是不可或缺的一環。然而，至今所提出用於伺服器端的排程演算法，若應用於點對點網路，都難以充分發揮。因此，在這篇論文中我們針對點對點可調性視訊串流，提出了基於非精確計算排程模型之即時演算法，可應用在伺服器端以充分利用其可用的頻寬。為了提升相同頻寬下的播放品質，我們的資源分配演算法依據各次要工作對播放品質的貢獻度分配其執行時間，同時考慮了次要工作之間的相依性，以符合分散式系統的特性。我們並使用經H.264 可調性視訊編碼的視訊檔案來做測試，實驗結果證實，在可用頻寬不足以使用戶端順暢播放完整視訊串流時，我們的排程演算法所提升的播放品質要優於雙優先權排程演算法的結果。P2P network can be employed in a video streaming system to improve the system scalability with lower cost. To achieve jitter-less video playback on the requesting peer, it requires both the requesting policy on the requesting peer and the scheduling policy on each sending peer. Earlier works for dedicated streaming servers, however, are not suitable for P2P streaming. In this thesis, we propose a resource management mechanism for the sending peers in P2P scalable streaming. The workload model and real-time scheduling algorithm are based on imprecise computation. The resource allocation algorithm exploits the utilization of available bandwidth by considering data dependency and maximizing the utility enhancement of optional tasks. We use test clips encoded in H.264 SVC in the experiments. The results show that our algorithm utilizes the available bandwidth and the gain in playback quality is better than dual priority scheduling algorithm when the bandwidth is insufficient to receive the whole high quality stream.List of Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viiiist of Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ixist of Algorithms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xhapter 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1hapter 2 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.1 P2P Streaming System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.2 Real-Time Scheduling for Imprecise Computation . . . . . . . . . . . . . 6.3 QoS-based Resource Allocation Model . . . . . . . . . . . . . . . . . . . . 7.4 Scalable Video Coding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.4.1 SVC Extension of H.264/AVC . . . . . . . . . . . . . . . . . . . . . 9.4.2 Real-Time Scheduling for Scalable Video . . . . . . . . . . . . . . 9.5 System Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.5.1 System Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.5.2 Requesting Peer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.5.3 Sending Peer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13hapter 3 Resource Management Mechanism for Scalable Video Streaming . 14.1 Problem Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.1.1 Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.1.2 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.1.3 Optimization Objectives . . . . . . . . . . . . . . . . . . . . . . . . 16.2 Algorithm Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18.2.1 Task Scheduling Algorithm . . . . . . . . . . . . . . . . . . . . . . 18.2.2 Resource Allocation Algorithm . . . . . . . . . . . . . . . . . . . . 19.2.3 Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21hapter 4 Performance Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . 23.1 Experimental Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23.2 Experimental Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25.3 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30hapter 5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32eferences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33application/pdf388222 bytesapplication/pdfen-US非精確計算排程模型即時系統排程資源管理點對點串流系統H.264可調性視訊編碼imprecise computingreal-time schedulingresource managementP2P streaming systemH.264 SVCthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/184960/1/ntu-97-R95922028-1.pdf