A Progressive Fast CU Split Decision Scheme for AVS3

AVS3 is the newest video coding standard developed by AVS (Audio Video coding Standard) group. AVS3 adopted QTBT(Quad-tree and Binary-tree) plus EQT(Extended quad-tree) block partition scheme, which makes the split process more flexible. The CU split structure is determined by a brute-force rate-distortion optimization (RDO) search. After the whole RDO search, the CU partition with minimum RD cost is selected. The flexible block partition and thorough RDO search bring promising coding gain while extremely complicate the encoder. To reduce the computational complexity of the CU split decision process in AVS3, this paper proposed a spatial information based fast split decision algorithm. In the proposed algorithm, the predicted value of split complexity was calculated firstly according to the information of spatial neighboring blocks. Then the predicted value was used to decide whether to split current CU or not. The experimental results show that the proposed algorithm resulted in average 31.03% encoding time saving with average 0.54% BD-BR loss for Random Access (RA) configuration. The proposed algorithm can greatly reduce the computational complexity of the CU split decision process with negligible performance loss.