An apparatus for entropy coding a sequence of bits obtains, using a first probability distribution, a first conditional probability for coding a bit at a position within the sequence of bits, the first conditional probability being a conditional probability of the bit having a certain value given that a sub-sequence of the sequence of bits has first respective values; obtains, using a second probability distribution that is different from the first probability distribution, a second conditional probability for coding the bit, the second conditional probability being a conditional probability of the bit having the certain value given that the sub-sequence has second respective values; obtains, using the first conditional probability and the second conditional probability, a mixed probability for coding the bit; and codes the bit using the mixed probability.