Vectorized and Optimized Dependent Quantization for Practical VVC Encoding

Versatile Video Coding (VVC) introduces dependent quantization (DQ) as a key coding tool, but it also has a high computational complexity. Therefore, optimizing DQ is crucial for practical VVC encoder implementations. In this paper, we propose optimization techniques for reducing the complexity of the DQ process, including efficient structure initialization, vectorized state update, rate distortion (RD) cost calculation, and last nonzero (LNZ) coefficient identification. The proposed optimizations are incorporated into the uvg266 practical VVC encoder. According to our evaluations, these optimization techniques accelerate the DQ process by over 1.7× and the entire VVC intra encoder by 1.4×, without any coding efficiency degradation. The proposed optimizations achieve more than twice the speedup over the existing techniques.