Optical disc, recording apparatus and method, and reproduction apparatus and method

A reproduction apparatus for an optical disc that has a sector including a plurality of frames, the reproduction apparatus comprising:

• a reading unit operable to optically read, from the plurality of frames, a first channel bit value and a second channel bit value that constitute main information, and generate a channel signal, the channel signal being composed of High sections and Low sections, both of which correspond to run lengths of the first channel bit value in the main information, and each transition point between a High section and a Low section corresponds to the second channel bit in the main information;
• a first judgment unit operable to judge whether leading and lagging errors appearing at transition points in the channel signal are arranged according to a predetermined rule;
• and
• a bit setting unit operable to set a predetermined bit value of sub information when the first judgment unit judges that the leading and lagging errors are arranged according to the predetermined rule.

A reproduction method for an optical disc that has a sector including a plurality of frames, the reproduction method comprising:

• a reading step for optically reading, from the plurality of frames, a first channel bit value and a second channel bit value that constitute main information, and generate a channel signal, the channel signal being composed of High sections and Low sections, both of which correspond to run lengths of the first channel bit value in the main information, and each transition point between a High section and a Low section corresponds to the second channel bit in the main information;
• a first judgment step for judging whether leading and lagging errors appearing at transition points in the channel signal are arranged according to a predetermined rule;
• and
• a bit setting step for setting a predetermined bit value of sub information when the first judgment unit judges that the leading and lagging errors are arranged according to the predetermined rule.