Enhanced Hash-based Intra Block Copy for HEVC Screen Content Coding using Sucessive Elimination Algorithm

Abstract

An efficient algorithm is proposed not only to reduce the computation cost of the hash-based intra block copy (IBC), but also to achieve the Bjontegaard delta bit rate (BDBR) gain for High Efficiency Video Coding standard (HEVC) screen content coding(SCC). Recently, the HEVC Screen Content Coding Draft 6 was published including several new tools. Among those, hash-based intra block copy shows the high coding gain but it has a massive computational complexity even though it is adopted as a fast algorithm for global block search for IBC mode. The proposed algorithm suggests the effective way to calculate the lower bound for rate-distortion (RD) cost when performing the hash-based IBC process and to eliminate the impossible candidates earlier. Experimental results show that about 50% on the average and up to 86.80% of the search points can be early terminated as well as 0.21% on the average BDBR saving can be achieved compared to HM-16.8+SCM-6.1.