Early termination of coding unit splitting for HEVC

The emerging high-efficiency video coding (HEVC) standard employs a new coding structure characterized by coding unit (CU), prediction unit (PU) and transform unit (TU). It improves the coding efficiency significantly, but also introduces great computation complexity on the decision of optimal CU, PU and TU sizes. To reduce the encoding complexity, we propose a CU splitting early termination scheme for inter frame coding. In the proposed scheme, the characteristics of prediction residuals are utilized to early terminate the CU splitting. Specifically, the Mean Square Error (MSE) between the prediction block and the origin block for each CU level is obtained and then compared with an adaptive threshold. The recursive CU splitting process is early terminated according to the threshold. Experimental results demonstrate that, the proposed algorithm achieves up to 34.83% total encoding time reduction with less than 0.25% BD-rate increase on average.