Enhanced Cu Partitioning Search Method for Intra Coding in HEVC

Most encoders in High Efficiency Video Coding (HEVC) standard determine the coding unit (CU) partitions in a depth-first full search manner. For intra coding, this method ignores the impact of partitioning on the subsequent blocks, which incurs less accurate prediction and worsens encoding efficiency performance. In this paper, we present an enhanced CU partitioning search method, where the various partitioning types are examined to effectively mitigate such impact. To reduce the additional complexity, we further refine the search candidates, early terminate the search process, and reuse encoding information. Experimental results show that compared with the unmodified HM software, the proposed method achieves a bit rate saving of 0.34% on average and 0.67% at most. Since our method doesn't modify the original definition of HEVC, the encoded bitstreams can be uncompressed by a standard HEVC decoder with no complexity increase.