用於以區塊為主的分散式視訊編碼的模式決策與位元率控制技術

Mode Decision and Encoder Rate Control for Block-based Distributed Video Coding

周起如(Chou, Chiju)

指導教授 ： 江瑞秋

國立中正大學/工學院/電機工程學系/碩士(2012年)

摘要

分散式視訊編碼是一種有著低編碼複雜度的視訊編碼方式。其將視訊序列分成 intra 模式與 WZ (Wyner Ziv) 模式進行編碼。然而在大部分的分散式視訊編碼研究中，均需使用反饋通道以控制所需傳送的 parity bits 數量，然而此機制並不適用於部分無法提供反饋通道的應用環境。
本論文針對以區塊為基礎之分散式視訊編碼架構進行研究，將著重於模式選擇和編碼端的位元率估測。在模式選擇中，我們提供了一個以位元率失真成本為基礎的模式選擇架構，並針對Lagrange multiplier 進行修正，使其更符合實際編碼需求。在位元率估測上，我們提出了兩種位元率估測方法，並對此兩種方法的位元率估測結果與有反饋通道情況下的位元率使用狀況進行比較。
實驗結果顯示，新的模式選擇方法可明顯提升編碼效率。而在位元率估測方面，一方面可以維持不錯的畫面品質，同時達到較低的傳送資料量。

關鍵字

分散式視訊編碼 ； 模式選擇 ； 位元率估測 ； 位元率失真成本 ； 分類器 ； 熵

並列摘要

Distributed video coding is a coding method with low complexity encoder.It separates sequence into intra mode and Wyner-Ziv mode. Most of the distributed video coding methods need the feedback channel to control the number of transmitted parity bits. However, the feedback channel is not suitable for some application.
This paper focuses on the mode decision and encoder rate control for block-based distributed video coding. We propose a mode decision method by using the rate-distortion cost and adjust the Lagrange multiplier. We also propose two method for rate estimation, and compared the experimental results with the case with feedback channel.
The experimental results show the new mode decision can increase the coding efficiency obviously. The rate control can increase the accuracy in high QP case and keep good video quality.

並列關鍵字

Lagrange multiplier

參考文獻

[5] G. Pertazzuoli, M. Cagnazzo, F. Dufaux, B. Pesquet-Popescu, "Wyner-Ziv Coding for Depth Maps in Multiview Video-Plus-Depth," Proc. of IEEE Int'l Conf. on Image Processing (ICIP), Brussels, Belgium, September 2011.

[7] Guo gang Hua, Chang Wen Chen, “Distributed Video Coding with Zero Motion Skip and Efficient DCT Coefficient Encoding,” Proc. of IEEE Int'l Conf. on Multimedia and Expo (ICME), Hannover, Germany, June 2008.

[9] Jui-Chiu Chiang, Kuan-Liang Chen, Chi-Ju Chou, Chang-Ming Lee, Wen-Nung Lie, “Block-based Distributed Video Coding with Variable Block Modes,” Proc. of IEEE Int'l Symposium on Circuits and Systems (ISCAS), Paris, France, May 2010.

[10] C. Brites, F. Pereira, “Encoder Rate Control for Transform Domain Wyner-Ziv Video Coding,” Proc. of IEEE Int'l Conf. on Image Processing (ICIP), San Antonio, Texas, U.S.A, September 2007.

[12] M. Badem, W.A.C. Fernando, A.M. Kondoz, “Unidirectional Distributed Video Coding using Dynamic Parity Allocation and Improved Reconstruction,” Proc. of IEEE Int'l Conf. on Information and Automation for Sustainability (ICIAFs), Colombo, Sri Lanka, December 2010.