| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to discriminate an illegally copied optical disk and to provide a reproducing device having functions of canceling, etc., reproduction of the illegal disk. SOLUTION: Such a small pit (IT) is recorded on a predetermined region of an optical disk beforehand as cannot correctly be transcribed by an ordinarily used method for illegal copy and can give different signal from a normal disk detected when the disk cannot be correctly transcribed. A normal disk is discriminated based on whether or not this small pit is normally detected. Based on the discrimination result, cancellation, etc., of the reproduction is performed. |
