Texture-Based Fast CU Size Decision and Intra Mode Decision Algorithm for VVC

Abstract

Versatile Video Coding (VVC) is the next generation video coding standard. Compared with HEVC/H.265, in order to improve coding efficiency, its complexity of intra coding increases significantly. Too much encoding time makes it difficult for real-time coding and hardware implementation. To tackle this urgent problem, a texture-based fast CU size decision and intra mode decision algorithm is proposed in this paper. The contributions of the proposed algorithm include two aspects. (1) Aiming at the latest adopted QTMT block partitioning scheme in VVC, some redundant splitting tree and direction are skipped according to texture characteristics and differences between sub-parts of CU. (2) A fast intra mode decision scheme is proposed which considers complexity and texture characteristics. Some hierarchical modifications are applied including reducing the number of checked Intra Prediction Modes (IPM) and candidate modes in Rough Modes Decision (RMD) and RD check stage respectively. Compared with the latest VVC reference software VTM-4.2, the proposed algorithm can achieve approximately 46% encoding time saving on average with only 0.91% BD-RATE increase or 0.046 BD-PSNR decrease.