Patent ID: 8023370

Claim:
An apparatus for converting a groove/land polarity upon a groove/land track change on an optical medium, comprising: a physical identification (PID) detector detecting a first sector from the optical medium into a first PID value; a sector information unit providing an information relative to the optical medium, including a second PID value indicative of either a second sector or at least one reference groove/land changing point laid on the optical medium; a sector counter counting a first value, wherein an initiation of the first value to be counted is set by the sector information unit based on the information and/or the PID detector based on the first PID value; and a comparing unit determining at least one oncoming groove/land changing point allocated on the optical medium for performing the groove/land polarity conversion, based on when the first value approaches a second value either predetermined in or generated by the sector information unit according to the information.