A method of operating an encoder/decoder, and a device, for encoding/decoding a digital image into/from a video bitstream, said methods/device being arranged to: determine a parameter of an entropy code associated to one or more indexes of a block for encoding a coding unit of said digital image according to a palette, said palette comprising a set of indexes associated to pixel values, said entropy code being used for the encoding of at least part of said block, wherein an index of said block is encoded using a flag to indicate one of a plurality of modes for determining the value of the index, and the parameter of the entropy code is determined in dependence of which mode was indicated by the flag to determine the value of the index; and encode/decode said digital image into/from the video bitstream by using the determined parameter to adapt the entropy code.