FIELD: digital copy protection.
SUBSTANCE: user can use his disk drive for reading data from disk and recording these to computer file, after which procedure data may be copied further. Therefore, to prevent copying, errors are intentionally made in data on a CD, but these errors are such, that sound reproduction device in common case misses them, but they pose an obstacle for reading sound data using data reading device. Synchronous groups S0 and S1 of sub-code are positioned one frame later then in standard variant, and data inside each frame remain the same. Device for sound reproduction separates data bytes from each frame, present in sector, on selections and continues reproduction of disk despite non-precise indication of time.
EFFECT: higher efficiency, broader functional capabilities.
2 cl, 7 dwg
