算术编码方法是将被编码的一则消息或符号串（序列）表示成0和1之间的一个间隔（Interval），即对一串符号直接编码成[0,1]区间上的一个浮点小数。符号序列越长，编码表示它的间隔越小，表示这一间隔所需的位数就越多。信源中的符号序列仍然要根据某种模式生成概率的大小来减少间隔。可能出现的符号概率要比不太可能出现的符号减少范围小，因此，只正加较少的比特位。-Arithmetic coding method is to be a coded message or symbol strings (sequences) that between 0 and 1 into an interval (Interval), that is directly encoded into a string of symbols [0,1] range of a floating-point decimal. The longer the symbol sequence, encoding the smaller the interval that it said that the median of this interval, the more necessary. Source is still the symbolic sequence generated according to a mode to reduce the size of the probability interval. May be less than the probability of the symbols of the symbols may be small to reduce the scope, therefore, are only plus-bit bit less.