Simplified rate-distortion optimized quantization for transform skip mode in VVC screen content coding
Jeeyoon Park, Jeehwan Lee, Byeungwoo Jeon · 2023
Rate-distortion optimized quantization for transform skip (RDOQ-TS) is shown to provide positive coding gain in VVC. This paper reduces encoding time-complexity of the RDOQ-TS scheme in VVC by adaptively skipping its level estimation (LE) process without sacrificing coding efficiency much. At first, the characteristics of each quantized level by RDOQ-TS are analyzed statistically. Subsequently, based on the statistical analysis, the LE process in the RDOQ-TS process is simplified by removing the case where the SQ (Scalar Quantization) value and the finally determined value are highly expected to be the same. For 4:2:0 screen content videos and 4:4:4 screen content videos, our proposed simplified rate-distortion optimization for transform skip reduces total encoding time respectively by 0.77% and 1.83% with no BDBR change under all intra configuration. In the case of the random access configuration, it achieves bit rate saving by -0.01 % and -0.03 % with total encoding time reduced 0.94% and 0.52% respectively.