Fast CU Partitioning for HEVC Combining Rate-Distortion Cost Estimation

In order to reduce the high encoding complexity of high efficiency video coding (HEVC), a fast coding unit (CU) partitioning scheme is proposed. Firstly, based on the Lagrange rate-distortion optimization theory and the experimental observation, the linearly relationships of the encoding bits and distortion between adjacent CU depths were achieved. Secondly, the rate-distortion (RD) cost estimation model of adjacent CU depth was proposed. Finally, the RD cost of next CU depth was predicted after encoding the current CU depth according to the RD cost estimation model. The predicted RD cost was used for judging whether the current CU needs to be spitted. Compared with the method in the reference software model of HEVC, i.e., HM12.0, experimental results reveal that the proposed algorithm can save about 33.2% and 38.9% coding complexity on average whereas the average bit-rate increment are 0.2% and 0.6% for low-delay and random-access coding structures, respectively.