Inter-Palette Coding in Screen Content Coding

The joint collaborative team on video coding has been developing an emerging standard for screen content coding (SCC) as an extension of HEVC known as HEVC-SCC. Intrablock copy (IBC) and palette coding are the two powerful coding tools adopted into HEVC-SCC. In this paper, a novel coding tool named inter-palette coding is proposed, which takes the advantages of both IBC and palette coding. With the inter-palette method, a new palette copy mode COPY_INTER can be applied, which enables the index samples to copy the pixels in the prediction block fetched by IBC or motion compensation. Experimental results show that the proposed scheme can achieve 3.15% BD-rate savings under all intra conditions on typical sequences containing "text and graphics with motion" averagely, with almost no complexity penalty.