Improvement of Deblocking Filter for AVS3

AVS3 is the third generation audio video coding standard (AVS). And the performance of AVS3 base profile is improved by 20% compared to the H.265. This paper proposes improvements to the deblocking scheme of AVS3, which has been adopted in the AVS3 baseline profile. The deblocking scheme in AVS2 has defects, including unreasonable filtering conditions and filtering coefficients. The deblocking filter in AVS3 also has the same drawback because it inherits the deblocking scheme from AVS2. These defects lead to unsatisfactory subjective quality of the AVS3 deblocking filter. Hence this paper improves the subjective quality of the AVS3 deblocking filter by reasonably modifying the filtering conditions and filter operation. In addition, to reduce the complexity of deblocking filter in AVS3, the proposed method simplifies the filtering operation of chroma deblocking. We implement the method on top of the AVS3 reference software (HPM-2.1), and the experimental result shows that subjective quality is significantly improved. The proposed method achieves 0.28% BD-rate reduction under Random Access (RA) configuration and 0.21% BD-rate reduction under ALL INTRA (AI) configuration.