U.S. Philips Corporation

Technicolor Videocassette, Inc.

Eidak Corporation

William J Buynak

Graham S Stubbs

Eugene Leonard

Karoly Budai

Michael A Sterling

Anti-copying protection for video material is provided wherein at least one high-amplitude pulse is inserted into various lines of the video signal, in and immediately preceding the vertical interval associated with each field, during the process of preparing a master recording for use in the high-speed duplication of legitimate recordings of the video material. A preferred embodiment of the present system and method is directed to videotape-to-videotape anti-copying protection. A high-amplitude pulse is inserted in the back porch region of horizontal sync pulses, and immediately following certain equalizing and vertical sync pulses, at an intermediate stage in the mastering process, whereby the pulse is inserted into a separated luminance component of the video signal, which is later recombined with the chromenance signal. Such method allows for the insertion of an higher amplitude pulse than would otherwise be possible, and yields a pulse of the desired final width, without the occurrence of such undesirable effects as loss of color lock or darkening of the picture with respect to legitimate recordings. The resulting modified video material may be viewed properly on a TV receiver or other display, but when coping from the legitimate source is attempted, the copy will yield a video signal which is too distorted for proper viewing. A further modification of the value of negative-going horizontal sync pulses provides additional synchronization error in recorded copies of legitimately recorded video material so as to further render such materials effectively non-copiable.

Videotape anti-copying encryption scheme

Augmenting pulses are added to the horizontal sync pulse intervals of a video signal to prevent a copy of the thus modified video signal from being satisfactorily displayed. The magnitude of the augmenting pulses is chosen so that the modified signal containing these pulses can be displayed without distortion. When the modified video signal is recorded and then reproduced by a typical VCR (i.e., when the modified video signal is copied), attenuation of the augmenting pulses and the remaining portions of the horizontal sync pulse occurs so that a television receiver cannot properly detect horizontal sync in the copied modified video signal, resulting in an unsatisfactory display.

Horizontal pulse augmentation of a video signal

An editing display system using a CRT display, with variable margin and tabulation facilities. Dual cursors are provided on the display: the first indicating the row and column in the display selected by the user, the second 'shadow' cursor appearing in the same column but on the rule indice line of the display. The dual cursor function is implemented by providing a random access memory which is partitioned into data sets in which the first character represents the location of a cursor on a given line, and the remaining characters identify the actual characters on that line. Direct memory access including fixed format information is used for transferring the data in memory to a shift register in the video control portion of the system.

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Bayville, NY, United States of America

William J Buynak