摘要:
A codeword (102) for use in error correction of digital optical media, the codeword (102) having a plurality of data symbols and a plurality of parity symbols (PA1, PA2, PB3, PB4), and includes an augmented channel word (DAB) which can be read as either a first value (DA) or a second alternate value (DB). The augmented channel word is one of the plurality of data and parity symbols, wherein the augmented channel word retains its value irrespective of any error correction performed.