Bilateral anti-copying device for video systems
First Claim
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1. A method of preventing incoming video information from being recorded by a video tape recorder, comprising the following steps:
- monitoring the luminance portion of said incoming video information for presence of a leading code sequence which is in a predetermined format;
upon detection of such a leading code sequence, monitoring the luminance portion of said incoming video information for a trailing code sequence which is in a predetermined format;
upon detection of such a trailing code sequence, comparing said leading code sequence with said trailing code sequence; and
inhibiting recording circuitry in said video tape recorder when said leading and trailing code sequences bear a predetermined relationship to each other.
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Abstract
A video system anti-copying device in which leading and trailing code sequences are inserted into the luminance portion of a video signal. These code sequences are visually manifested as dropouts on a video monitor. When the sequences match, operation of record circuitry in a video recorder is inhibited.
177 Citations
21 Claims
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1. A method of preventing incoming video information from being recorded by a video tape recorder, comprising the following steps:
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monitoring the luminance portion of said incoming video information for presence of a leading code sequence which is in a predetermined format; upon detection of such a leading code sequence, monitoring the luminance portion of said incoming video information for a trailing code sequence which is in a predetermined format; upon detection of such a trailing code sequence, comparing said leading code sequence with said trailing code sequence; and inhibiting recording circuitry in said video tape recorder when said leading and trailing code sequences bear a predetermined relationship to each other. - View Dependent Claims (2, 3, 4, 5)
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6. A method for processing a video signal to embed therein information which, when detected by a video recorder, will inhibit recordation of such video signal by such recorder, comprising the following steps:
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establishing first and second lines of video information which are spaced one field apart from each other; recording, in the luminance portion of said first line of video information, a leading code sequence; and recording, in the luminance portion of said second line of video information, a trailing code sequence which bears a predetermined relationship with said leading code sequence. - View Dependent Claims (7, 8, 9, 10, 11, 12)
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13. A circuit for use with a video recorder to inhibit recording operation thereof when recording a video signal which contains corresponding leading and trailing code sequences which are one field apart from each other, comprising:
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means for monitoring the luminance portion of said video signal for digital code sequences; first means for storing a digital code sequence which is detected by said monitoring means; second means for storing another digital code sequence which is detected by said monitoring means; means for comparing said digital code sequences which have been stored in said first and second storing means; and means for inhibiting recording operation of the video tape recorder when said comparing means indicates that said digital code sequences have a predetermined relationship with each other. - View Dependent Claims (14, 15, 16)
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17. A circuit for inserting leading and trailing digital code sequences into a video signal, said sequences being spaced one field apart from each other, comprising:
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means for DC-restoring said video signal;
)means for monitoring the luminance portion of said video signal after it has been DC-restored; means for determining when said luminance portion satisfies predetermined luminance criteria for a predetermined time; first means for inserting into said DC-restored video signal at the line immediately following a line in which said luminance portion satisfies said criteria for said time, a digital leading code sequence inserted at a level between a predetermined IRE level and the luminance level of said DC-restored video signal; means for identifying, in said DC-restored video signal, a line which is one field later than said line in which said digital leading code sequence has been inserted; and second means for inserting into said DC-restored video signal at said later line a digital trailing code sequence between said predetermined IRE level and the luminance level of said DC-restored video signal. - View Dependent Claims (18)
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19. A method of preventing a video signal from being recorded by a video recorder, comprising the following steps:
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encoding the luminance portion of said video signal in such a manner that, after said encoding, said video signal appears visually acceptable to a user who displays said video signal on a video monitor; monitoring said video signal to detect said encoding; and inhibiting recording of said video signal by said recorder upon detection of said encoding.
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20. A method of transmitting digital information within an analog signal comprising the steps of
generating leading and trailing digital code sequences containing digital information and inserting said code sequences in said analog signal to thereby produce a combined signal, transmitting the combined signal, detecting the leading and trailing code sequences in the transmitted combined signal and comparing the leading and trailing code sequences, extracting said digital information when the leading and trailing code sequences bear a predetermined relationship, and repeating the foregoing steps.
Specification