A Fast Mode Decision Algorithm for SVC Multi-Layer Encoder Control

• Main Authors: Jhe-Yong Lin, 林哲永
• Other Authors: Wen-Hsiao Peng
• Format: Others
• Language: en_US
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/11243317533392005659

碩士 === 國立交通大學 === 資訊科學與工程研究所 === 98 === This thesis addresses the problem of performing fast mode decision for SVC multi-loop encoder control. The conventional bottom-up encoder control is characterized by its uneven distribution of rate-distortion loss relative to single-layer coding. For a tradeoff between the coding efficiency of the base layer (BL) and the enhancement layer (EL), a multi-layer encoder control was proposed. The current approach, however, poses two major problems: (1) it uses the weighted Lagrangian cost as the search criterion for mode decision at the BL and (2) it adopts the single-layer decision criterion for the EL. The former amounts to solving a constrained optimization problem in which both the objective function and the constraints may vary with the choice of the weighting factor, while the latter can sometimes lead to unpredictable results at the EL. To solve these problems, we have revisited the problem formulation of multi-layer encoder control, and have proposed an improved two-stage algorithm by using the concept of dominant mode pairs and by revising the mode decision criterion at the EL. Experimental results show that our fast mode decision algorithm, on average, needs to check only 13 mode pairs, compared to 56 required for the exhaustive search. The mode set reduction leads to a considerable time saving of 84-88%, with an ignorable change in R-D performance. Besides, the results produced with the new decision criterion are more predictable and consistent with different choices of the weighting factor.