A fast CU size decision algorithm based on adaptive depth selection for HEVC encoder

HEVC adopt a flexible coding unit partition technology to exploit more coding efficiency compare to previous standard H.264/AVC. In HEVC test model (HM), the encoder tries all possible depth levels to find out partition structure with least rate distortion cost for each coding tree block. This may achieve highest coding efficiency, but also bring huge computation complexity. In this paper, we proposed a fast coding unit (CU) size decision algorithm based on adaptive depth selection for HEVC. Since there is strong temporal correlation between encoding picture and previous encoded picture, we can derivate an adaptive CU depth set for the encoding CU with prediction from previous encoded picture. Simulation results show that the proposed algorithm can reduce the encoding time by 35.7%, 35.6% and 30.7% on average in all intra, low delay B and random access configuration, compared to HM 12.0.