Arithmetic decoding method and arithmetic coding method
An arithmetic decoding method is a method in which a context variable specifying a probability of a possible value of each of elements included in a binary string corresponding to a value of a given variable is initialized and arithmetic decoding is performed, using the context variable. The method includes: determining, from among a plurality of initialization methods as a method of initializing the context variable, an initialization method corresponding to the given variable or a group which includes the given variable; and initializing the context variable using the determined initialization method.
1. An arithmetic decoding method comprising:
initializing a context variable, the context variable specifying a probability of a possible value of each of elements included in a binary string; and
arithmetic decoding, using the context variable as an initial value, on the binary string which corresponds to a value of a given variable,
wherein a group to which the given variable belongs is dynamically changeable, and
wherein in the initializing, (i) in a case where the given variable belongs to a first group, the context variable is initialized by a first initializing method selected from among a plurality of initializing methods, and (ii) in a case where the given variable belongs to a second group, the context variable is initialized by a second initializing method different from the first initializing method.
2. An arithmetic coding method comprising:
initializing a context variable, the context variable specifying a probability of a possible value of each of elements included in a binary string; and
arithmetic coding, using the context variable as an initial value, on the binary string which corresponds to a value of a given variable,
wherein a group to which the given variable belongs is dynamically changeable, and
wherein in the initializing, (i) in a case where the given variable belongs to a first group, the context variable is initialized by a first initializing method selected from among a plurality of initializing methods, and (ii) in a case where the given variable belongs to a second group, the context variable is initialized by a second initializing method different from the first initializing method.