MPEG-4形狀編碼核心單元設計與實現

Abstract

本篇論文介紹了如何設計並且實現一個MPEG-4形狀編碼核心單元: CAE，此單元可適用於MPEG-4 Core Profile的規格。此外，在輸入輸出的介面上我們亦採用了VSI Alliance 所制定的BVCI標準，如此可增強介面溝通的相容性與硬體的再利用能力。 論文中首先分析MPEG-4的動態影像編碼流程並藉由測試所得的統計資料來瞭解各個演算法的計算複雜度。本論文接著提出了BVCI及CAE單元的詳細分析及硬體架構設計。在BVCI的設計上，我們使用了參數化的設計概念，對於控制訊號的時序以及BVCI內的特殊功能都可透過參數來改變設定。至於在CAE的設計上，我們也提出了MUX-based context computation,及快速renormalization的硬體架構。此外，本論文也針對低功率MUX的架構設計，以及整個BVCI-CAE的stall分析和緩衝器的容量做了詳盡的探討。 我們的BVCI-CAE已通過了詳盡的驗證流程並經post-layout模擬後證實可成功地使用在62.5MHz的速度，其功率消耗是66mW。

This thesis provides the design and implementation issues of the shape encoding core: CAE (Context-based Arithmetic Encoding) for the MPEG-4 video encoder (Core Profile). This CAE unit is encapsulated by the interface protocol: VSI Alliance- BVCI (Basic Virtual Component Interface) standard, so as to enhance the compatibility and re-usability. This thesis first presents the profiling and functional analysis in order to find out the computational load of each algorithm in MPEG-4 video encoder and realize the relationship of encoding tools. In order to encapsulate an accelerating unit with the BVCI protocol rapidly, a BVCI unit is implemented with the parameterized design concept. The handshake timing and certain optional functionality are configurable. Besides the BVCI interface, we also implement the CAE unit, which includes a multiplexer-based architecture for the context computation and the arithmetic encoding scheme with fast renormalization. Low power multiplexer design, stall analysis and buffer size decision are also explored in this thesis. Finally, this BVCI-CAE runs through the overall verification flow and function works at 62.5MHz (power dissipation: 66mW) according to the results of post-layout simulations.