Macrovision Corporation

Ampex Corporation

Gerow D Brill

John O Ryan

Ronald Quan

James R Holzgrafe

William J Wrobleski

Joseph L Corkery

Anne M Reagan

Andrew B Mellows

Edward P Sudyka

A method and apparatus for defeating copy protection signals in a video signal, and also for providing copy protection signals for a video signal, is disclosed. The defeat technique generally utilizes a particular pulse position shifting, modulation, etc., of AGC, normal sync and/or pseudo sync pulses to increase the separation between the pulses. Various embodiments are disclosed including selective shifting of the relative positions of either the sync/pseudo sync or AGC pulses, trimming portions of the sync/pseudo sync and/or the AGC pulses and narrowing of either the sync/pseudo sync and/or the AGC pulses, all to provide the selective position separation between the sync/pseudo sync and AGC pulses. The copy protection technique includes various embodiments for dynamically varying the sync/pseudo sync and AGC pulse separation by applying a modulation of the above position shifting, trimming and/or narrowing techniques over selected time periods to cycle from the copy protection condition to the copy protection defeat condition, back to the copy protection condition.

Method and apparatus for synthesizing and reducing the effects of video copy protection signals

A video signal is modified so that a television receiver will provide a normal color picture but a video tape recorder will detect the modification and prohibit the video signal from being recorded. The color burst phase of the video signal is modified so as to make inferior quality pictures in the event that the resulting modified video signal is recorded. A disabling circuit ( ) associated with the recorder ( ) detects the presence of the modified video signal. This detection is done by determining the presence of modified color burst phase signals in even a single television line of the video signal. A control signal ( ) is produced when the modified color burst phase signal is detected, which disables the recorder ( ). If no modified color burst phase signal is detected, the recorder ( ) is enabled to allow an acceptable recording of the video signal.

Method and apparatus for detecting modified color burst signals to prevent the copying of a video program

A technique is disclosed for preventing unauthorized playback of scrambled video/audio signals recorded on, for example, a video tape cassette, which technique includes several cooperating processes and apparatus which further prevent the playback of recorded video/audio when the playback apparatus is in a still or pause mode of operation. The technique includes selected combinations of processes of inverting and re-clamping the luminance component of the video signal just prior to FM modulation; blanking an overscan portion, or portions, of the video signal and adding a video retrace signal to the overscan portion(s); inverting the normal control track signal and position modulating the normally unused edge; and selectively scrambling the audio signal and recording the scrambled audio signal in an audio track or in a Hi-Fi track. A selected user specific authorization code is recording in and recovered from the audio track. The recorded scrambled video/audio signal is recovered via a modified combo VCR/TV unit with no external video/audio jacks, which reverses the scrambling processes mentioned above, but only if the descrambling apparatus is authorized by having the proper recovered authorization code.

Method and apparatus for recording scrambled video audio signals and

In a television camera, the variable gain control is adjusted to provide a corresponding change in the camera output video signal level. The iris control simultaneously is changed to maintain the preset video signal level. This varies the iris setting and provides a corresponding change in the depth of focus to allow focussing on different objects in a scene.

Continuous depth of focus control

Precise, point-by-point correction of spatial and shading errors in a camera television picture are performed manually. The errors to be corrected are determined by visually examining a picture on a video monitor, by selecting an area for error correction which area corresponds to the type and extent of the specific error selected for correction. A position command increments or decrements an address by preselected steps to locate a movable 'cursor' which, in turn, identifies the area being corrected. A correction command retrieves the data from the area identified, and which contains the error, selectively increments or decrements the data in preselected steps, and stores the new data back in memory. The process continues until the operator is satisfied with the correction results. Correction thus may be made point-by-point, along horizontal or vertical lines or areas, in selected corner areas, etc., of the picture.

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Danbury, CT, United States of America

Gerow D Brill