標題: 可調視訊編碼位元流擷取之最佳化
Optimized Extraction for SVC Bit-streams
作者: 黃淩軒
Lin-Shung Huang
邵家健
彭文孝
John Kar-Kin Zao
Wen-Hsiao Peng
資訊科學與工程研究所
關鍵字: 可調視訊編碼;位元流擷取;Scalable Video Coding;Bit-stream extraction
公開日期: 2007
摘要: 我們的研究目的是提出一個最佳化的可調視訊編碼的位元流擷取方法,主要是能夠針對不同的播放設備以及網路頻寬調整擷取的位元流內容,使不同頻寬之下仍能提供最理想的播放畫質。 我們分析可調視訊編碼的位元流之編碼相依性限制,進而提出兩種方法來產生的擷取路徑:一、Convex Sets限制每一步擷取必須包含所有編碼相依的資料,使位元流可以完整的解碼;二、Wavefront Sets容許每一步擷取可以包含仍無法解碼的資料,但擷取路徑仍不違反編碼相依性。另外,針對異質接收端的各種播放設備的畫面大小與畫率可能不盡相同,我們提出一個模擬不同播放設備的方法,使量測到的失真值能夠較接近真實播放畫面的失真。 為了得到最佳化的播放畫質,我們提出兩種方法來選擇最佳擷取路徑:一、Global Optimal;二、Local Optimal。我們實作出一個位元流擷取路徑的測試平台,並針對不同的視訊內容、不同的播放設備、和不同的擷取路徑進行測試與分析。我們從實驗結果得到幾項結論:一、不同的擷取路徑確實會造成不同的播放品質;二、最佳化的擷取路徑因視訊內容與播放設備而異;三、利用Convex Set測試時,Local Optimal與Global Optimal可得到相同結果;四、利用Wavefront Sets與Convex Sets所選擇的Global Optimal結果是吻合的。 最後,我們將最佳化之位元流擷取方法運用於異質網路中的視訊傳輸。我們提出一個分散式視訊群播的系統架構,並探討如何在伺服端以及接收端進行資源分配。
Our research goal is to propose an optimized extraction scheme for SVC bit-streams for different device types. The basic principle of extraction path optimization is to minimize the distortion of the reconstructed frames while the rate increases. We presented two methods for extracting path permutations: (1) through the use of Wavefront Sets that allow incomplete bit-streams, as long as not violating the coding dependencies; and (2) through the use of Convex Sets that extract completely decodable bit-streams. We also introduced two path optimization methods: (1) via global optimization and (2) local optimization. We evaluate the possible extraction paths and choose the optimal according to their device-specific rate-distortion performances. From experimental results, we conclude that: (1) Different device types result in different optimal extraction paths; (2) Different content types result in different optimal extraction paths; (3) Global optimal provides the same results as local method when using the convex method. (4) Convex sets provides the same results as wavefront sets when finding the global optimal. We propose a SVC-based multisource streaming scheme, applying optimized extraction. We present bandwidth request/allocation algorithms for servers and clients using heuristic solutions.
URI: http://140.113.39.130/cdrfb3/record/nctu/#GT009455514
http://hdl.handle.net/11536/82041
Appears in Collections:Thesis


Files in This Item:

  1. 551401.pdf