隨著科技的進步，影音壓縮技術從MPEG-1、MPEG-2、MPEG-4發展到H.264(MPEG-4第十部分)，其中H.264/AVC則是首度使用視訊編碼層(Video Coding Layer；VCL)和網路提取層(Network Abstraction Layer；NAL)，透過網路提取層能把視訊編碼層壓縮好的影片使用在任何的網路架構上傳輸到網路上。 可調性視訊編碼(scalable video extensions)：SVC(Scalable Video Coding)是H.264/AVC的延伸架構，H.264/AVC及H.264/SVC的設計有別於以往影像壓縮技術，考慮到網路傳輸的特性，使影片在網路上傳輸能有更佳的表現能力，提供更適合的影像品質，H.264/AVC及H.264/SVC所提出的網路提取層及分層編碼架構的視訊壓縮技術都是試圖提升影片在網路傳輸的特性，藉由分層編碼過後的位元流能把影片同時傳輸到網路上，並隨著頻寬的變動和使用者不同的視訊品質要求，解碼出不同品質的影音串流資料。本文也將利用其優點實作出H.264/SVC影音壓縮技術的多層傳輸服務，並設計出能因應各種網路狀況而能快速擴充的平台。According to the advance in technology, the video compression technology has grown up from MPEG-1, MPEG-2, MPEG-4 and then to H.264 (MPEG-4 Part 10) which is the first one to use video coding layer and network abstraction layer. The compressed video can be transferred to any network structure with network abstraction layer. Scalable Video Coding (SVC) is an extended architecture of H.264/AVC. The design of H.264/AVC and H.264/SVC are different from the previous video compression technology. H.264/AVC and H.264/SVC will take the network transmission into account to improve the performance of the network capacity and to provide the better image quality. H.264/SVC and H.264/AVC are the layered coding structure, the bitstream of the compressed video with layered coding structure can separate into many layers, and then the layers can simultaneously transmit in the network, and the user can receive the best suitable combination of these layers representations according to the radio channel condition and the capacity of the terminal station dynamically. Here, we propose a multi-layer mechanism for the video compression technology of H.264/SVC, and design a platform to extend features quickly depending on any the network condition.
