The invention is related to a method and a device for encoding of a bit sequence. Said method comprises generating, for each run of Ones comprised in the bit sequence, a unary representation of length of the respective run of Ones, generating a first sequence by concatenating the generated unary representations of lengths of runs of Ones, generating, for each run of Zeroes comprised in the bit sequence, a unary representation of the length of the respective run of Zeroes, generating a second sequence by concatenating the generated unary representations of lengths of runs of Zeroes, and bit plane encoding the generated first and second sequence of unary representations. In most cases, overall entropy of bit planes of unary representations of run lengths is smaller than entropy of the bit sequence. Thus, more compact encoding can be achieved.