A highly efficient mode decision algorithm and architecture for AVS HD Video Encoder

In Advanced Audio Video coding Standard (AVS), the utilization of variable block size ranging from 16×16 to 8×8 in inter frame encoding improves the coding efficiency significantly compared with a fixed MB partition. Rate distortion optimization (RDO) is the best known mode decision method, but the corresponding extremely high computational complexity limits its application. This paper proposes an algorithm based on the visual perception model and Sobel operator edge detection model to quickly select the best inter mode from 16×16, 16×8, 8×16 and 8×8 just by using the original pixels. We further analyze and redesign the MB level pipeline structure, and give the optimized hardware structure of the encoder. We tested different sequences including cif, 720p and 1080p, and the experimental results show that the coding efficiency is comparable with the traditional RDO method. The proposed hardware structure saves fractional motion estimation (FME) by 60% in areas and reduces the processing time by 200 cycles. Our proposed mode decision architecture can support the real time processing of 1080P@30fps.