Reproducing method and apparatus for reproducing highly efficiently encoded data from a record medium composed of spectrum data and scale factor data determines if address of changed highly efficient encoded data and stores it. The method and apparatus determines whether or not the address of highly efficient encoded data whose scale factor data is changed corresponding to the operating mechanism and stores it in a memory store apart from the write address by a predetermined distance. By partly changing the scale factor values and filtering process is accomplished.
A phase-change optical disc formatting device which formats a phase-change optical disc so that signal characteristics of an area in which at least one of a file structure and application data is to be recorded are substantially equal to signal characteristics of a format area. A phase-change optical disc formatting method including: formatting a phase-change optical disc so that signal characteristics of an area in which at least one of a file structure and application data is to be recorded are substantially equal to signal characteristics of a format area. A phase-change optical disc formatted such that signal characteristics of an area of the phase-change optical disc in which at least one of a file structure and application data is to be recorded are substantially equal to signal characteristics of a format area of the phase-change optical disc.