Coding method of dividing information block serving as conversion unit into a plurality of sub-blocks to perform coding for each sub-block, and coding apparatus

摘要

The information block that is sequentially extracted from an information sequence and that serves as a conversion unit is divided into a plurality of sub-blocks, Then, counting is performed of the information items number of at least one of "0" and "1" that is contained in each sub- block for each sub-block of a plurality of the thus-divided sub-blocks. Then, there is performed, according to the counted result that has been thus obtained, inversion yes/no determination of whether the original information contained in each sub- block should be inverted under the consideration of minimizing the difference between the number of codes "0", and the number of codes "1", contained in the code block as a whole. Then, there is performed, regarding the sub-block, with respect to which a determination of that the original information should be inverted has been made, coding of inverting the original information contained in this sub-block and there is added, with respect to this sub-block, an inversion identification code that represents the effect that the original information has been inverted, while, regarding the sub-block, with respect to which a determination of that the original information should not be inverted has been made, there is performed coding of leaving intact the original information contained in this sub-block without inverting the same and, with respect to this sub-block there is added a maintenance identification code that represents the effect that the original information has been left intact. And by unifying a plurality of code sub-blocks, each of which has had either one of the inversion identification code or maintenance identification code added thereto, the information block is converted into a code block.