1. A method for encoding a picture, comprising: determining a single maximum allowed number of candidates for a plurality of merge candidate lists for all of a plurality of prediction units (PU) for a slice region in the picture; binarizing a merge candidate index for one of the plurality of prediction units in the slice region using a truncated unary coding in which a maximum codeword size is one less than the single maximum allowed number of candidates in the at least one slice region; encoding the single maximum allowed number of candidates in a slice header for the slice region into a bit stream; and encoding the binarized merge candidate index into the bit stream.