I've seen many conflicting answers online so:
When reading an optical disk, which one of these is true:
A 'pit' represents 1 and a 'land' represents 0
A 'pit' represents 0 and a 'land' represents 1
C. None of the above.
The frames of channel data are finally written to disc physically in the form of pits and lands, with each pit or land representing a series of zeroes, and with the transition points—the edge of each pit—representing 1.
A change from pit to land (or land to pit) is a 1.
Consecutive pits (or consecutive lands) is a 0.
There's no yes/no answer. The usual optical disk data representation is NOT in one-to-one correspondence with the data recorded, rather a CD (for instance) eight-bit chunk of input is translated into a fourteen-bit group, and that fourteen-bit group is burned onto the disk. What convention you use for the fourteen-bit group is irrelevant to the user (who only gets the eight-bit decoded data back).
So, a single bit of input/output data doesn't correspond to a single feature on the disk in any one-to-one correspondence.