Early Skip Mode Decision for HEVC Encoder With Emphasis on Coding Quality

Abstract

Although High Efficiency Video Coding (HEVC) is suitable for high definition (HD) and ultra-HD video services due to its high compression efficiency and excellent coded picture quality, its high encoding complexity is an obstacle for wide-spread practical applications. Although many fast coding schemes can alleviate the complexity problem, their coding quality suffers much. In this paper, an early skip mode decision is proposed to reduce the encoding complexity of HEVC while not sacrificing its coding quality much. The proposed method determines the skip mode by utilizing its distortion characteristics just after calculating rate-distortion cost of 2N × 2N merge mode, and those prediction units decided as the skip mode do not undergo remaining mode decision processes. The threshold for the early decision is estimated directly from the video data themselves. Experimental results show that the proposed method achieves encoding complexity reduction of 30.1% in random access main condition and 26.4% in low-delay main condition on average with virtually no coding loss compared to the HEVC full rate-distortion optimized decision.