支援多種視訊壓縮標準之AVS編碼器設計

Abstract

本論文提出了一個能支援多種視訊壓縮標準之數字音視頻編解碼技術標準 (AVS) 編碼器設計，此設計可令一既有MPEG-4 ASP編碼器支援數字音視頻編解碼技術標準第二部份 (AVS Part-2)，並能以同一架構支援先進視訊編碼 (Advanced video coding/H.264)。 MPEG-4乃一視訊壓縮標準，此標準訂定了許多規範 (profile) 針對不同應用像是影像串流 (streaming video)、光學碟片 (CD distribution)、影像會議 (video conversation) 及廣播電視 (broadcast television)。在這許多規範中，先進簡易規範 (ASP) 最廣為業界應用。數字音視頻編解碼技術標準是由中國大陸AVS工作小組所開發的，其效能與國際知名標準H.264相當，但運算複雜度較低而更適合硬體開發。 第四章針對Transform Coding以及Entropy Coding提供了有效的硬體架構設計而第三章則分析了Sub-Pel Motion Estimation及Variable-Block-Size Motion Compensation此二種壓縮工具對高解析度視訊之壓縮效率。

In this thesis, a practical solution for enabling an existing MPEG-4 ASP encoder to support AVS Part-2 is proposed. MPEG-4 is a video coding standard that defines many profiles to targets on streaming video, CD distribution, video conversation, and broadcast television. Among those profiles, MPEG-4 ASP is the most commonly employed one in industry. On the other side, the second generation video coding standard recently developed in China is AVS Part-2, which provides similar coding efficiency to H.264/AVC with lower computation complexity. Therefore, AVS Part-2 seems a better choice when implementing a multi-standard video coding system based on MPEG-4. Before designing architectures, comparisons of coding tools between the two standards are listed in order to find out the hardware components that needs re-design. Besides, sub-pel ME, variable-block-size motion compensation, and intra prediction, are analyzed to evaluate their coding efficiency. According to the comparison and analyses, transform coding, intra prediction, and entropy coding are the three most important coding tools which has the highest priority when implementing the multi-standard system.