US Patent 7751587 Data production method and apparatus

A watermark information detection process prevents prolonging of time required for setup process when no watermark information can be detected from an optical disc where watermark information has been recorded. During a setup, the number of retrials is limited. Weighting of the retrial is changed so that detection of watermark information is performed when it is confirmed that watermark information is recorded. This enables detection of information for copyright protection in an appropriate processing time.