| 摘要 |
Access to an audiovisual product such as DVD video is controlled by dividing the data into cells 420 of an original sequence A,B,C and creating one correct sequence instruction 410a that reproduces the sequence A,B,C and a plurality of incorrect sequence instructions 410b each of which replays the sequence in the wrong order, e.g A,C,B; B,A,C etc. Sequences 410 may comprise program chains (PGC) and the correct sequence 410a may be obscured among many incorrect sequences 410b which be permutations of the correct sequence 410a. Cells 420 may be re-arranged in a scrambled order and have distorted data cells or erroneous cells added. The structure location of the correct sequence 410a may be derived from an access code or password. The cells 420 may be divided between two or more video streams (fig 20) and a switch instruction (fig 20, 2011, 2021) switches between them on reproduction. One stream may contain erroneous cell data (fig 20 C2) while another holds correct cell data (fig 20, C1). |
