Fast intra mode decision of HEVC based on hierarchical structure

In this paper, we propose a fast intra mode decision for high efficiency video coding (HEVC) to reduce its encoding complexity. It proposes an early termination method under its hierarchical structure that uses the intra prediction mode (IPM) of corresponding previous-depth prediction unit (PU) and block size of current-depth transform unit (TU). To reduce even more complexity, the number of candidates of the rough mode decision (RMD) is further reduced for RD optimization, and the IPM of corresponding previous-depth PU is always included in the list of candidates for intra mode decision. Experimental results show that the encoding complexity can be reduced by up to 22.99% in high efficiency (HE) condition and 26.16% in low complexity (LC) condition with only a little bit-rate increment compared to the full intra mode decision of HM 3.0.