Arithmetic coding is one of the classic information theory methods that produce essentially-optimal results. Like everywhere else in information theory, the emi

Arithmetic coding is one of the classic information theory methods that produce essentially-optimal results. Like everywhere else in information theory, the eminence of the probability distribution is fully recognised, and given it, arithmetic coding gives you an information-theoretically optimal lossless compression (to the degree that the probability distribution describes the data well) (by treating the objects in question as numbers and intuitively, like the other post says, only keeping diffs). See https://en.wikipedia.org/wiki/Arithmetic_coding https://en.wikipedia.org/wiki/Arithmetic_coding