Fast Mode Selection Algorithm for H.266/VCC Screen Content Using Joint Features

For screen content video coding, new prediction modes, such as Intra Block Copy (IBC) and Palette mode (PLT) are introduced into the new generation video coding standard H.266/VCC. Though improves the coding efficiency, the computational complexity increases a lot. To reduce the cost of intra mode prediction, features of corner, horizontal/vertical activity and mean luminance gap are jointly considered to classify the screen content video frame into low-contrast and high-contrast screen videos; and current coding unit (CU) are divided into natural content background CU, screen content background CU, screen content foreground CU. For each sort of CU, some intra prediction modes are selectively skipped to reduce the best mode decision cost. Experimental results show that compared with H.266/VVC VTM-7.3 standard with IBC and PLT enabled, the proposed algorithm saves 26.41% of coding time with only 1.21% bitrate increasement under the configuration of all-intra (AI), which reduces the coding complexity effectively.