Enhancement on the Entropy Coding of Intra Mode in VVC

The emerging Versatile Video Coding (VVC) standard introduces several intra prediction modes and intra mode coding techniques. Most Probable Mode (MPM) is derived to enable efficient signaling for the selected intra mode. We propose the modification of intra mode coding for the MPM index. The first bin of mpm_idx is adaptively coded by regular coding engine or bypass engine according to neighboring infra modes. Two versions of the VVC Test Model (VTM) 2.0 and VTM4.0 were used to verify the proposed method with different numbers of MPM. Experimental results in 3-MPMs show 0.10%, 0.11%, 0.12% BD-rate savings for Y, U, and V components, respectively, for All Infra (AI) configuration. And the other results in 6-MPM show 0.05%, 0.08%, 0.07% BD-rate gains. No noticeable changes in runtimes of both encoder and decoder are observed.