Error-correction code for digital data on video disc

Abstract

Data for recordation on a video disc is given multi-redundancy at block, field and group levels. Raw data is filled typically serially row by indexed row of 8-bit words with at least one and preferably 3 words being auxiliary check words derived from the remainder of the data field of the block. Block filling is completed with the addition of preferred Reed/Solomon error-correction redundancy filling two rows for column error detection and correction and two columns for row error detection and correction. Thirty blocks, so prepared, are processed to obtain two redundant blocks, completing a 32-block data field. Writing the data onto the video disc occurs with a three-dimensional diagonal interleave at the field level. After interleave each field is additionally XORd with 62 other fields to create a redundant field. This redundant field plus the 63 data fields comprise a group. The group of fields is written to the video disk so as to maximally spatially separate adjacent fields. Recording occurs via an optical master disc. Stamped replications (video discs) are made from the master disc. Data from the video discs is decoded accordingly.