Sample adaptive offset in AVS2 video standard

AVS2 video standard is the next-generation video coding standard under the development of Audio Video coding Standard (AVS) workgroup of China. In this paper, the design of Sample Adaptive Offset (SAO) in AVS2 is presented. Considering the implementation issues, a shifted structure in which the SAO parameter region is shifted from the Largest Coding Unit (LCU) to the upper-left is adopted to make the SAO parameter region consistent with the processing region in implementation. Moreover, the category dependent offset is introduced in the edge type based on the statistical results to improve the offset coding and non-consecutive offset bands are adopted in the band type to optimize offset bands. The test results show that SAO achieves on average 0.3% to 1.4% luma coding gain in AVS2 common test conditions.