STORAGE MEDIUM FOR CARRYING INFORMATION ENCODED IN TWO DIMENSIONS

A storage medium carries physically distinct blocks of symbols representing digital information. The symbols are arranged in the blocks such that the digital information represented by the symbols can be determined from only the two-dimensional position of the symbols relative to one another and any other differentiable characteristic intrinsic to the symbols. A method and apparatus recovers the symbols using oversampling in two dimensions and derives the information represented by the symbols. Blocks having two or more two-dimensional alignment patterns with good auto-correlation properties are used in some embodiments to facilitate recovery of the digital information. In one embodiment, motion picture film carries a conventional analog soundtrack and a digital soundtrack for a plurality of channels; the digital soundtrack is represented by symbols carried on the film in the areas between sprocket hole perforations.