Frame-based adaptive selection of ALF for fast HEVC decoding

Adaptive loop filter (ALF) is a newly introduced technique in high efficiency video coding (HEVC) that minimizes the distortion between the original frame and the coded frame. While ALF improves a coding efficiency as well as a visual quality in the video coding standard, the use of ALF increases the computational complexity at the decoder side substantially (e.g., 25 percent). This should be overcome for the implementation of fast decoder. In this paper, we propose an adaptive selection method that determines the use of ALF in a frame-level to reduce the decoding time. The proposed method exploits the fact that ALF is more effective in the frames with high RD cost values than in those with low RD cost values by determining the ALF-skip frame with the RD cost values of the current and previous frames. Through experimental results, the decoding time using the proposed method is reduced to about 93 percent of that of the HEVC test model (i.e. HM 3.0) with a 0.4 percent BD-rate increase.