상위깊이의 Sub-CU 부호화 정보를 이용한 HEVC의 고속 PU 결정 기법

Abstract

HEVC(High Efficiency Video Coding)-'./012345678(CU: Coding Unit)9:CU; ?@8(PU: Prediction Unit) A !, B-CD$EFG)/CU 45679PU H1 # IFGJKLMBNONPQ-ERSTUV WXYZA- ZQ=. [ ;<-$STU \]^_$`  =abZ PU H1!# $%N c =. def% LCUsub-CBF(Coded Block Flag)  Agh'CU;<PU H1 7$# AgPU ijN! =. kef% LRl(Intra) ?@! AgCUsub-Intra B-CDm N Agh';<Rl?@Nno =. p q% FG-Rl?@! Agh'CUsub-CBF Irs AgA;<Rl?@Nno =. tu#v c% LHM 14.0 wm::1.2%, 0.11%, 0.9%BD-rate YZ;31.4%, 2.5%, 23.4%^x\]Mv ONPQy=. cz3Z % LRx{Rl?@;/ |-}FG#~Ag/ PQF€, ‚1.9%BD-rate YZ;34.2%^x\] Oy=.AbstractHEVC (High Efficiency Video Coding) achieves high coding efficiency by employing a quadtree-based coding unit (CU) block partitioning structure and various prediction units (PUs), and the determination of the best CU partition structure and the best PU mode based on rate-distortion (R-D) cost. However, the computation complexity of encoding also dramatically increases. In this paper, to reduce such encoding computational complexity, we propose three fast PU mode decision methods based on encoding information of upper depth as follows. In the first method, the search of PU mode of the current CU is early terminated based on the sub-CBF (Coded Block Flag) of upper depth. In the second method, the search of intra prediction modes of PU in the current CU is skipped based on the sub-Intra R-D cost of upper depth. In the last method, the search of intra prediction modes of PU in the lower depth’s CUs is skipped based on the sub-CBF of the current depth’s CU. Experimental results show that the three proposed methods reduce the computational complexity of HM 14.0 to 31.4%, 2.5%, and 23.4% with BD-rate increase of 1.2%, 0.11%, and 0.9%, respectively. The three methods can be applied in a combined way to be applied to both of inter prediction and intra prediction, which results in the complexity reduction of 34.2% with 1.9% BD-rate increase. Keywords : HEVC, fast encoding, CU, PU, fast mode decision, sub-CBF ( (Regular Paper) 20 2, 20153(JBE Vol. 20, No. 2, March 2015)http://dx.doi.org/10.5909/JBE.2015.20.2.340ISSN 2287-9137 (Online) ISSN 1226-7953 (Print)