Palette mode — A new coding tool in screen content coding extensions of HEVC

Palette mode, as a new coding tool, is adopted in the Screen Content Coding Extensions of High Efficiency Video Coding (HEVC SCC) that is being defined by the Joint Collaborative Team on Video Coding (JCT-VC). In the palette mode, pixels in a coding unit (CU) are represented by selected representative colours according to the characteristics of screen contents in which pixel values usually concentrate on few colour values. This paper introduces the palette mode in HEVC SCC, and our contributions to the palette mode are also presented. Experimental results show that disabling the palette mode suffers 20.3%, 13.0%, and 7.5% BD-rate increases for “YUV, text & graphics with motion, 1080p & 720p sequences” under all intra (AI), random access (RA), and low-delay B (LB) common test conditions, respectively.