Code generation and allocation apparatus

Abstract

A method of generating and allocating codewords includes allocating one of two selectable codewords band bas codeword 'b' when a preceding codeword 'a' and a following codeword “b” form a code stream X, in which the codewords band bhave opposite INV values which are parameters indicating whether the number of '1s' contained in a codeword is an odd number or an even number. When the code stream of the preceding codeword “a” and the following codeword bis X, and when the code stream of the preceding codeword “a” and the following codeword bis X, the codewords are allocated such that the INV values of Xand Xare maintained to be opposite when the preceding codeword “a” or the following codeword b(b) (bor b) should be replaced by another codeword in compliance with a predetermined boundary condition given between codewords. The codewords are allocated so that a DC suppression capability of the code stream can be maintained.