Advanced screen content coding using color table and index map

This paper presents an advanced screen content coding solution using color table and index map method. It is implemented on top of the High-Efficiency Video Coding (HEVC) Range Extension (RExt) standard draft version 5 [1], fully harmonized with the HEVC recursive quad-tree structure and also one of the promising tool under investigation for emerging HEVC based screen content coding extension. For each coding unit, a number of major colors will be selected to form the color table, then the original pixel block is translated to the corresponding index map accordingly. A 1-D string match scheme is introduced for lossless index map coding. Experiments show the significant coding efficiency improvement of proposed solution for typical screen contents, resulting in up to 49%, 46%, 45% bit rate reduction at lossless case and averaged 11.4%, 8.3%, 6.7% BD-Rate reduction at lossy scenario for respective All Intra (AI), Random Access (RA), and Low-delay using B picture (LB) structures.