Novel flexible size scheme for basic unit-level rate control

Abstract

Rate control algorithm is very important for controlling video to achieve a target bitrate with high visual quality. In this paper, a basic unit (BU)-level rate control with flexible BU size for achieving a higher coding performance. The novel scheme harnesses a criterion derived from rate–quantisation scale (R–Q) model for partitioning pictures into BUs with flexible sizes. The target bits are adaptively allocated for each BUs according to the complexity of BU’s content. The rate control algorithm of the H.264/AVC is applied to each of BUs for achieving the target bitrate. The proposed scheme is implemented in H.264/AVC reference software JM76 for performance evaluation. The experimental results show that the proposed method effectively improves the performance of rate control in respect to the rate control method in H.264/AVC reference software in low bit rate.

Keywords:

• Video coding
• BU-level rate control
• H.264/AVC

Acknowledgements

The authors would like to thank the anonymous reviewers for their careful reading and valuable comments on this paper.

This work was supported in part by National Basic Research Program of China (973 Program): 2012CB316400, in part by National Natural Science Foundation of China: 61379100, 61472388, and in part by open fund of Guangxi key laboratory of hybrid computation and IC design analysis.