Fast mode decision method for all intra spatial scalability in SHVC

Scalable high efficiency video coding (SHVC) is now being developed by the Joint Collaborative Team on Video Coding (JCT-VC). In SHVC, the enhancement layer (EL) employs the same tree structured coding unit (CU) and 35 intra prediction modes as the base layer (BL), which results in heavy computation load. To speed up the mode decision process in the EL, the correlations of the CU depth and intra prediction modes between the BL and the EL are exploited in this paper. Based on the correlations an EL CU depth early skip algorithm and a fast intra prediction mode decision algorithm are proposed for all intra spatial scalability. Experimental results show that 45.3% and 42.3% coding time of the EL can be saved in AH Intra 1.5× spatial scalability and 2× spatial scalability respectively. In the meantime, the R-D performance degraded less than 0.05% compared with SHVC Test Model (SHM) 5.0.