Macrovision Corporation

Ampex Corporation

Other

Rovi Solutions Corporation

James R Holzgrafe

John O Ryan

Ronald Quan

Peter J Wonfor

Mark A Hollar

Patrice J Capitant

Kordian Jacek Kurowski

Johan Cornelis Talstra

Antonius Adrianus Cornelis Maria Kalker

David C Collier

Clayton L Davidson

William J Wrobleski

Gerow D Brill

Derek T Nelson

Joseph L Corkery

Tony Forrest Rodriquez

Andrew Mellows

Edward P Sudyka

Anne M Reagan

Method and apparatus for scrambling a high definition television signal to discourage unauthorized recording of same. While recording per se is not prevented, the resulting recorded signal is rendered unusable due to an induced 'wobble' between the active video and the associated sync pulses. The scrambled television signal is readily viewable on a compliant high definition television set which descrambles the HDTV signal using an encoded indication of the amount of wobble accompanying the HDTV signal. Also provided is a special interface to prevent unauthorized persons from using the indication of the amount of wobble so as to defeat the scrambling. Also provided are method and apparatus for defeating the scrambling method and hence allowing recording of the scrambled video signal.

Scrambling and descrambling a high definition TV signal

A method and apparatus for modifying a video signal to allow it to carry encoded data which is detectable at a suitably compliant receiver but is not recorded by a conventional video recorder. One application is to carry a descrambling key to prevent useful recording (but not viewing) of a scrambled television signal since the key will not be recorded. This encoded 'hidden' data is not recorded by the conventional video recorders because, for instance, it is located in the vertical or horizontal blanking intervals of the video signal, or is carried by a high frequency carrier signal, or is expressed by phase modulation of the video signal's synchronization pulses.

Method and apparatus for carrying data in a video signal so that the data is not recorded

Method and apparatus for providing generational copy control of a video signal. A digital video signal contains content information, first supplemental information and second supplemental information. The first supplemental information is represented by a watermark pattern, the second by a control pattern. Copying of the content information is only permitted if a predetermined combination of the first and second supplemental information is present. Pseudo-sync pulses are added to a blanking interval of an analog video signal converted from a digital video signal, the pulses representing the second supplemental information.

Generational copy control of a video signal

In typical prior art generational copy protection processes, a video tag signal is added to a watermarked and/or copy protected video signal to prevent the production of unauthorized second generation copies and the playback of illicit second generation copies. This application discloses a means for defeating the tag signal/watermark copy protection process. To this end, various embodiments are disclosed by which the tag signal is recovered, converted to a selected tag representation and is carried or stored in some manner, concurrently with the recording of a first generation copy of the video signal, which may or may not be tagless. The first generation copy is played back and the tag representation is converted to a regenerated tag signal which is selectively re-inserted in the reproduction of the first generation copy prior to recording a second generation copy, which now is playable.

Method and apparatus for video tag signal recovery using various techniques to regenerate and re-record the tag signal

Method and apparatus for scrambling a high definition television signal to discourage unauthorized recording of same. While recording per se is not prevented, the resulting recorded signal is rendered unusable due to an induced &ldquo;wobble&rdquo; between the active video and the associated sync pulses. The scrambled television signal is readily viewable on a compliant high definition television set which descrambles the HDTV signal using an encoded indication of the amount of wobble accompanying the HDTV signal. Also provided is a special interface to prevent unauthorized persons from using the indication of the amount of wobble so as to defeat the scrambling. Also provided are method and apparatus for defeating the scrambling method and hence allowing recording of the scrambled video signal.

Method and apparatus for scrambling a high definition television signal

Method and apparatus for &ldquo;copy-once&rdquo; of a digital video signal uses a watermark in the video signal. The embedded watermark has two versions: one indicates copy-never and a second indicates copy-once, the difference being a single watermark bit. The watermark carries additional bits representing a digitized attribute (image characteristic) of a particular video frame of the video signal, for instance an average value of the amplitude of a video field. The frame whose attribute is carried in the watermark has a field (or frame) marker, which is a special signal located in the overscan portion of the frame. A compliant video recorder verifies the watermark and the copy-once bit, extracts the associated attribute from the watermark, and compares it to the measured attribute of the marked video frame. Only if the extracted attribute value and the measured attribute value match is recording enabled. During the recording process, the frame markers are stripped, preventing second generation copies of the recorded video signal, and the copy-once bit is set to copy-never.

Method and apparatus for copy-once watermark for video recording

A video-scrambling system induces a random wobble i.e., time shifting, in the location of active portion of the video frame, without affecting the horizontal sync signal and colorburst in each video line, thus providing both security and concealment. The security is enhanced by filling in the gap between the nominal beginning of active video and the actual beginning of active video with a synthesized video signal which replicates the adjacent active video using a digitally generated filling pattern. Also, a random noise overlay further conceals the location of the gap. Additional concealment is provided by wiggling in time the location of the horizontal sync signal using one or two frequencies and also by randomly altering the location of the vertical sync signal. The NTSC digital encoding in accordance with the invention is simplified by using only two channels, chrominance and luminance, and by a heterodyne circuit for chrominance stability. NTSC encoding is enhanced by providing detail normally lost, by use of the chroma channel. Additionally, a non-standard video signal may be provided with a portion of the colorburst on the front porch of the horizontal blanking, thus allowing use of a relatively simple decoder.

Method and apparatus for scrambling and descrambling of video signal

Method and apparatus for scrambling and descrambling of video signals

Method and apparatus for vertically scrambling and descrambling of video

Method and apparatus for scrambling and descrambling

Vertical-rate and horizontal-rate sawtooth generators are coupled at a common input to a conventional focus control voltage and then to the centering circuits of an image tube via respective potentiometers. The amplitudes and polarities of the generator outputs are selected such that when driven simultaneously by the electrical focus control voltage supplied to an image tube, generates an image rotation which just cancels any image rotational error inherently induced by an electrical focus adjustment.

Rotation-free electrical focussing circuit for television image tubes

A vertical-rate sawtooth waveform amplitude modulates a train of horizontal-rate pulses. Positive and negative pulse clippers receive the pulse train. One generates a clipped waveform during the last half and a zero output for the first half, of a television field. The other generates a clipped waveform during the first half and a zero output the last half of the field. A pair of AC coupled integrators, driven by respective clipped waveforms, generate horizontal-rate sawtooths which are linearly modulated, one from a maximum at the beginning of the field to zero at the center thereof, and one from zero at the center to a maximum at the end of the field. Two pairs of clippers separate the two sawtooths into four half-sawtooths, wherein each is active in a time interval corresponding to respective quadrants of the picture raster. Potentiometers are used to vary the respective waveforms to allow independent correction of the scan in any corner.

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Morgan Hill, CA, United States of America

James R Holzgrafe