| 摘要 |
PROBLEM TO BE SOLVED: To suppress an effect of a nonstationary property of a digital signal from an information source on a coding rate even if the digital signal is a highly nonstationary digital signal.SOLUTION: A codeword ψ(X(U)) generated in a coding apparatus 14 by lossless compression coding on a series X(U) produced by the division of a series Xof a digital signal into X(U) and X(V) is decoded to X(U) in a decoding apparatus 16. An entropy calculation section 36 calculates a conditional entropy H(X(U)|X(U')) based on X(U') produced by the division of a series Xstored in an encrypted data storage section 32 having the same length of a temporal interval as X, and decides a matrix size of an LDPC matrix on the basis of the minimum value of H(X(U)|X(U')). A second decoding section 38 decodes a codeword &phgr;(X(V)) to X(V) by the use of the LDPC matrix and auxiliary information. |
