Digital signal coding method and apparatus, digital signal decoding apparatus; digital signal arithmetic coding method, and digital signal arithmetic decoding method
In a bit stream syntax containing compressed video slice data for compressed video data of a slice structure, a slice header for compressed video slice data has attached thereto a slice start code, a register reset flag indicating whether a register value, which designates a status of a codeword occurring in an arithmetic coding process, should be reset in the next transmission unit, an initial register value which indicates a register value to be used to start arithmetic coding/decoding to build/decompose the next transmission unit, only when the register reset flag indicates that the register should not be reset.
1. A digital signal coding apparatus for making a compression coding by dividing a digital signal into predetermined transmission units, comprising:
an arithmetic coding unit for compressing the digital signal of said transmission unit by arithmetic coding,
the arithmetic coding unit comprising:
a context model determination unit for determining a context model to be used for each type of coding data among a plurality of context models:
a binarization unit for generating a binarization rule defined based on the type of coding data;
a probability of occurrence generation unit for providing a probability of occurrence of the context model corresponding to the binarization rule;
a coding unit for arithmetic coding the digital signal of said transmission unit based on the generated probability of occurrence;
a transmission unit generation unit for multiplexing information representing an initial state of the probability of occurrence of the context model to be used for each of said coding data, and information of initializing a register value which shows an arithmetic coding process into a bit stream as part of the coded data of said transmission unit.
2. A digital signal coding method for making a compression coding by dividing a digital signal into predetermined transmission units, when the digital signal of said transmission unit is compressed by arithmetic coding, said method comprising:
a context model determination step of determining a context model to be used for each type of coding data among a plurality of context models;
a binarization step for generating a binarization rule defined based on the type of coding data;
a probability of occurrence generation step for providing a probability of occurrence of the context model corresponding to the binarization rule;
a coding step for arithmetic coding the digital signal of said transmission unit based on the generated probability of occurrences;
a transmission unit generation step for multiplexing information representing an initial state of the probability of occurrence of the context model to be used for each of said coding data, and information of initializing a register value which shows an arithmetic coding process into a bit stream as part of the coded data of said transmission unit.