Scalable data arithmetic decoding method

PURPOSE: A scalable data arithmetic decoding method is provided to decode a trunked part additionally by notifying a decoding end time in a bit stream truncation state. CONSTITUTION: A symbol to be decoded is determined in an arithmetically encoded scalable bit stream(700). A probability of the determined symbol is anticipated(710). The symbol is generated by using the anticipated probability(720). The arithmetic decoding is interrupted according to generation of ambiguity(740). The symbol is decoded to 0(760). The symbol is decoded to 1(770).