線上視訊於IP網路可變延遲環境下之訊務平順化研究摘要
在本篇論文中,針對線上視訊服務提出一套有效訊務平順化之整合方案,其中包含視訊訊務預測以及因應可變延遲網路之智慧型線上平順調整機制。有別於其他相關文獻,本論文突破線上訊務平順化技術的瓶頸,具有更低的傳輸率變動與保有低峰值頻寬需求的優點,更重要地,具有對抗網路延遲之能力。實驗結果顯示,傳輸率變動造成的協商次數大幅降低最多可達80%,改善之傳輸率規劃可有效地因應網路的延遲,使得畫面丟棄率大幅降低約20%以上,進而有效提升使用者播放的視訊品質。 |
On-line Video Traffic Smoothing for IP Networkswith Variable DelayAbstractThe
technique of on-line video traffic smoothing is a significant method
to improve the network BW utilization and reduce the burstiness
characteristic of live video data. An efficient traffic smoothing
scheme should not only consider the characteristics of video coding,
but also consider the QoS capacity of IP network and the limitation
of server and client buffer space. Regarding the methods of
delivering video data used by current video coding standards, a
constant transmission rate and a fixed network delay are assumed
whether the Hypothetical Reference Decoder (HRD) in H.263 or the
video buffering verifier in MPEG is considered. These assumptions
are quite rigid and unrealistic due to the variety of current
network environments, especially for live on-line video
applications. Therefore, this paper proposes an Integrated On-line traffic Smoothing (IOS) system that consists of the Long-Span Prediction (LSP) scheme, the Smart Hopping (SH) approach, the Middle Tracking (MT) method, and the Dynamic Bound Adjustment with network Delay Tracking (DBA-DT) strategy. Compared with traditional schemes, the proposed IOS can provide more efficient smoothing performances with low variance of transmission rates and low peak rate requirement. More importantly, IOS provide the robust capability against the dynamic network delay. Simulation results reveal that IOS can effectively reduce the number of negotiations with network up to 80% and low the frame loss rate up to 20%. |