| 摘要 |
PROBLEM TO BE SOLVED: To bury desired data such as a watermark in the compression process of information data without reducing an information amount and to prevent illegal copying by simple constitution by burying input data in coefficient data obtained by orthogonal transformation. SOLUTION: At the time of recording digital audio signals DA1 from satellite broadcasting or the like in a mini disk or the like, the prescribed bit of prescribed coefficient data among the plural coefficient data obtained by performing an orthogonal transformation processing by an orthogonal transformation part 12 in a data compression process is set to a logical value corresponding to the data DC of a user watermark and buried in an encoding part 13. Then, after performing an encoding processing and compressing the data by a signal compression part 14, a recording processing is performed. Thus in a data expansion process at the time of reproduction, the data of the user watermark are decoded, the illegal copying is detected, secondary duplication is inhibited and further illegal copying is prevented. |
