Syntax-based arithmetic video coding for very low bit rate visual telephony

A syntax-based arithmetic coding (SAC) is introduced for applications in very low bit rate visual telephony. An upper bound of SAC on encoding bit rates for finite homogeneous Markov chains is derived and is the source entropy plus a vanishing term depending only on the actual implementation precision. The SAC video coder is implemented in a layered structure; the states of symbol output of video coder are chosen for an efficient performance