Fast Mode Decision Based on RDO for AVS High Definition Video Encoder

In this paper, we propose a fast and effective mode decision (MD) algorithm based on rate distortion optimization (RDO) for AVS high definition video encoder. The fast algorithm is composed of two parts. Firstly, mode preselection based on sum of absolute difference (SAD) is employed to reduce modes for candidate so as to alleviate the dramatic throughout burden. Secondly, we adopt 4-way parallel scanning technique to reduce the cycles of each mode decision based on RDO. Theoretical analysis and experimental results show that the proposed fast algorithm can meet the needs of 720P and 1080P real-time high definition AVS video encoding. Besides, the mode pre-selection algorithm provides a similar performance to the all modes enabled algorithm. And the 4-way parallel technique using negligible extra resources increases the speed of coding bits estimation by 3.4 times than traditional techniques.