SAO Filter in HEVC: A survey

High Efficiency Video Coding (HEVC) otherwise called as H.265 uses half of the bitrate when it is compared with its previous video coding standard namely Advanced Video Coding (AVC) otherwise called as H.264. This can be achieved with the help of SAO Filter. SAO filter reduces the bitrate by 50% when compared with H.264 video compression technique which uses macro block where in H.265 uses SAO filter. SAO filter calculates the offset in which data must be processed in the Codec. In this paper, a comprehensively survey the existing algorithm, model and architecture for SAO filter in HEVC. First, a compression on AVC and HEVC is given. Meanwhile, function of CTU and SAO filter is briefly explained. Second, function of SAO filter is reviewed which includes various offset calculations, statistical collection phase and parameter determination. Third, various proposed models over time on SAO filter are reviewed. Finally, this survey concluded the current status of SAO filter in HEVC and deliver insightful discussions and prospects for future work. This survey can serve as a reference for researchers on SAO filter in HEVC and related fields.