Alibaba Group Holding Limited
Palette size constraint in palette mode for video compression system

Abstract:

Systems and methods are provided for improving efficiency of an encoder performance in the HEVC palette mode by limiting the number of colors to be used in the current palette to be no more than the size of coding unit or the prediction unit, and by avoiding duplicate colors in the current palette. The encoder may signal a binary vector indicating previous elements from a palette predictor list to be reused in a current palette, determine a number of the previous elements based on the binary vector, determine a sample size of the current palette, determine a maximum number of new elements to be used in the current palette based on the number of the previous elements and the sample size, determine a set of new elements corresponding to the maximum number of new elements, and signal the set of new elements.