https://scholars.lib.ntu.edu.tw/handle/123456789/122247
標題: | 針對H.264/AVC標準之多重描述視訊編碼 H.264/AVC-Based Multiple Description Video Coding |
作者: | 蘇哲群 Su, Che-Chun |
關鍵字: | 多重描述編碼;影像壓縮;影像傳輸;影像切片;multiple description coding;video compression;video transmission;slice group | 公開日期: | 2006 | 摘要: | 隨著數位視訊技術的進步以及網際網路(Internet)、無線網路的快速發展,利用網路傳輸影像資訊的需求持續地在增加,影像傳輸技術也越來越受到重視;相關的應用包括:視訊會議、影像串流、數位視訊廣播等,而近年來非常熱門的P2P(peer-to-peer)網路亦整合了影像傳輸技術提供網路電視服務和大量的影音資訊分享;由於網路傳輸環境的不穩定,封包遺失和位元錯誤是不可避免的,因此,如何提供可信賴、穩定的影像傳輸成為一個亟需解決的問題。 多重描述編碼(Multiple Description Coding, MDC)技術能夠有效抵抗資料經由網路傳輸過程中產生的封包遺失,並具有優秀的錯誤更正能力。利用多重描述編碼技術,可以在易發生錯誤的封包網路上提供穩定的影像傳輸:首先,視訊信號在發送端會被壓縮並利用冗餘編碼(Redundancy Coding)成為許多條可以獨立解碼的位元流,接著利用封包網路上不同的路徑傳送至接收端,而根據傳送到的各個位元流的錯誤情形,解碼器將可重建出不同品質的影像,由於可獨立解碼的特性,只要收到某一條位元流,即能重建出可接受的畫質,而接收到越多的位元流,重建出來的影像畫質也越高;當某些位元流發生封包遺失或錯誤時,亦可利用其他完整位元流的資訊達到較好的錯誤更正。 在本論文中,我們提出了一個以H.264/AVC視訊壓縮標準為基礎之多重描述視訊編碼架構,利用H.264/AVC標準所提供的先進視訊壓縮工具:包括影像切片(Slice Group)、可變區塊大小之運動補償(Variable Block-Size Motion Compensation)、多重參考畫面(Multiple Reference Frame)等,來達到高效率的冗餘編碼,而本架構亦支援了完整的錯誤更正機制;根據實驗的結果顯示,我們所提出之多重描述視訊編碼架構的位元率-失真(Rate-Distortion)表現超越了其他同樣以H.264/AVC為基礎之架構;和一般的單一描述視訊編碼架構比較,則擁有更好的錯誤更正能力。因此,結合各種網路傳輸技術,本架構將能提供可信賴、穩定的影像傳輸服務。 With the advances of digital video technology and the rapid growth of the Internet and wireless networks, video communication has been gaining in importance. Emerging applications includes: video conferencing, digital video broadcasting, peer-to-peer video transmission, etc. Extensive works on the Internet routing algorithms as well as the video coding techniques have been conducted to provide reliable video transmis-sion over error-prone environments. Multiple description coding (MDC) has emerged as a promising approach to combat packet losses and enhance error-concealment in video transmission. By using MDC, a video sequence is encoded into multiple independently decodable descrip-tions. As more descriptions are received at the decoder, the reconstructed video with better quality is obtained. These multiple description streams are transmitted along multiple paths to provide reliable transmission over packet-networks. The efficiency of an MDC scheme depends on the way of introducing redundancy into individual descriptions. An H.264/AVC-based multiple description video coding scheme is proposed. The proposed MDC scheme utilizes the advanced video coding tools and features pro-vided in H.264/AVC, including slice groups, variable block-size motion compensation, and multiple reference frames. Slice groups are adopted to produce multiple descrip-tions. Spatial and temporal correlations between neighboring macroblocks in video frames are exploited to achieve efficient redundancy coding. From the experimental results, the proposed MDC scheme has superior rate-distortion (R-D) performance to previous slice-group based MDC scheme. A complete error-concealment mechanism is also supported by the proposed MDC scheme to handle packet losses. Combined with the current Internet routing algorithms, e.g. an over-lay network, the proposed MDC scheme is capable of providing a practical solution for video transmission. |
URI: | http://ntur.lib.ntu.edu.tw//handle/246246/58811 | 其他識別: | en-US |
顯示於: | 電信工程學研究所 |
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ntu-95-R93942044-1.pdf | 23.31 kB | Adobe PDF | 檢視/開啟 |
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