Apparatus and method for preventing unauthorized copying of video signals

Abstract

In a digital video tape recorder (VTR) which reproduces digital video and audio signals from a magnetic tape, a copy protect bit in the reproduced digital video signal is detected, and on the basis of the copy protect bit, a code is generated and inserted into the vertical blanking interval of the reproduced video signal. When a video signal (which may be in analog or digital form) having the code in the vertical blanking interval is received in a digital VTR, the code is detected and recording of the video signal and an associated audio signal is inhibited if the code indicates that the received video signal is copy protected.

Description

BACKGROUND OF THE INVENTIONThis invention relates to a method and apparatus for preventing copying of video signals which are intended to be copy protected and more particularly is directed to prevention of unauthorized copying of video signals transmitted or received by a digital video tape recorder (VTR).There has been proposed a VTR for consumer use in which program information in the form of a video signal and an associated audio signal are recorded in digital form on a magnetic tape. Digital recording of video signals and associated audio signals make it possible for such program information to be reproduced and copied (or "dubbed") onto another tape with little or no deterioration in the quality of the signal reproduced from the copy tape. These are times, however, when it is desirable to prevent such signals from being recorded. For example, in order to protect the rights of those holding a copyright in the recorded material, copyright protection schemes have been proposed in...

AI Technical Summary

Benefits of technology

Accordingly, it is an object of the present invention to provide a method and apparatus for preventing a digital VTR from recording video signals which are designated as copy protected signals.

A further object of this invention is to prevent a digital VTR from recording copy protected video signals which are received in analog form from a digital VTR or another source of video signals.

Problems solved by technology

The previously proposed copy protection systems for digital VTRs are not effective to prevent a digital VTR from recording a signal received in analog form, and the high quality of the resulting copies makes such copies a significant threat to the interests of those owning rights in the program information, such as copyright holders.

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