A lossless coding scheme for encoding color-indexed video sequences

A new lossless video compression scheme for coding sequences of color-indexed frames is proposed. This scheme handles the frames sequentially. It reduces both the zero-order entropy and the energy of the index map of a specific frame by turning the index map into a new index map each element of which serves as an index to a pixel-dependently reordered version of the palette. Accordingly, a matching coding scheme can be exploited to encode the new index map effectively. A technique similar to the one used in animated GIF is also used to remove the inter-frame redundancy. Simulation results show that the proposed method is superior (in terms of compression ratio) to other state-of-art lossless compression algorithms in coding color-indexed video sequences.