Abstract: Various techniques and associated embodiments are disclosed for providing defensive measures against “black boxes,” wherein the techniques utilize unconventional schemes for detecting the vertical blanking interval (VBI) of a video signal containing a copy protection signal. The unconventional schemes would be of particular interest to the black boxes, which must locate the VBI to generate a vertical rate signal in order to perform the task of illegally removing the copy protection signal. The unconventional schemes utilize the particular characteristics or peculiarities of the video signals in the VBI to detect the VBI and generate therefrom a reliable vertical or frame rate signal. The characteristics include various pulse spacings and/or pulse widths which may occur in specific lines in the VBI, and which may be detected to allow deriving the reliable vertical or frame rate signal.

Abstract: A copy protection color stripe process is defeated first by determining the location of the video lines including the color stripe process. Then some or all of the lines including the modified color bursts are modified so as to render the overall video signal recordable. The modification is accomplished in a number of ways, including phase shifting the color stripe burst into the correct phase, replacing, attenuating and or eliminating some of the color stripe bursts or at least a portion of particular color burst envelopes so that they are no longer effective, mixing the color stripe burst with color stripe signals of the correct phase so as to eliminate most or all of the phase error present or modifying the horizontal sync pulse signals immediately preceding the modified color bursts so that the modified color bursts are not detected by a VCR and hence have no effect.

Abstract: 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.

Abstract: Illegal cable decoders, i.e., black boxes, are defeated by adding, inserting and/or superimposing an added signal onto an already scrambled video signal, which added signal is capable of disrupting the operation of the illegal cable decoder. As a result of the added signal, the illegal cable decoder outputs an unstable or unviewable picture or signal and concealment is maintained. In another embodiment of an added signal, a modulated signal with a range from about blanking level to about peak white level is added, inserted and/or superimposed on the unstable scrambled video signal in the vertical blanking interval and/or its vicinity. As a result, the illegal cable decoder is caused to generate some horizontal instabilities at its output.

Abstract: 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.

Abstract: Copy protection normally included in a video signal to prevent unauthorized copying is dynamically modified, by changing an attribute of the copy protection to be added to or present in the video signal. The copy protection can include any signal that affects playability of an attenuated video signal, for example, by triggering an early or late horizontal or vertical retrace (such as caused by sync narrowing or the checker signals described in U.S. Pat. No. 5,583,936). The attribute change is related to scene content carried by the video signal, so that bright and dark scenes carry different copy protection. The attribute being changed can be, for example a checker's low level that is reduced to below the blanking level when the scene content is darker than normal, and increased to above the blanking level when the scene content is brighter than normal. Alternatively, the attribute being changed can be the width of a synchronization pulse normally present in the video signal.

Abstract: A method and apparatus is disclosed which reduces or removes the effectiveness of commercial skip systems such as presently found in VCRs, PVRs, etc. which are designed to delete commercials from signal material upon playback of a previously recorded version of the signal material. In an embodiment, the effectiveness of the commercial skip system is reduced or removed by adding a flat field of selected signal level to active line portions of video lines of the signal material. Other embodiments modify the normal fade to black signal indicative of a commercial to provide a fade to non-black signal. In further embodiments, a fade to non-black signal is inserted in an overscan area of the signal picture. Still further embodiments modify audio signals or selected signals in the horizontal blanking interval which may be used in commercial skip systems to detect the presence of commercials.

Abstract: An improved method and apparatus for maintaining concealment for a scrambled signal when frequency pre-emphasis is used to defeat the scrambling. The pre-emphasis may be synthesized with high pass or peaking circuitry. More commonly however the pre-emphasis is available in television sets with a fine tuning control. By adjusting the fine tuning control to cause purposely mistuning off center, a peaking effect is generated which is used to counter the scrambled signal. The application discloses one embodiment which uses de-emphasis to counter the peaking effect. In another embodiment, signals added in the vicinity of the horizontal blanking interval causes the peaking effect to enhance these added signals over stable edges of the video signal. Since these added signals are position modulated for example, the television's sync circuits and horizontal oscillator circuits will cause scan circuits to generate position modulation.

Abstract: A voltage controlled amplifier is improved in noise performance with nonlinear local feedback elements while maintaining low distortion for various control settings. By paralleling nonlinear elements, distortion is further improved. Preferably, these nonlinear elements consist of diode pairs connected to the emitters of a differential amplifier whereby the bases of the transistors are used to control the signal current.

Abstract: The horizontal blanking interval (HBI) of a normal video signal is modified to enhance the playability of the applied copy protected video signal while maintaining the copy protection effectiveness. As generally known, a copy protected video signal with positive-going pulses in a back porch region causes possible black level depression. The addition of a negative-going pulse and/or negative-going and positive-going pulse pair immediately prior to the H sync signal in the front porch region causes a reduction in such black level depression while resulting in enhanced playability. In other embodiments, an amplitude extending pulse is added to a latter portion of the H sync pulse or to a latter portion of a pseudo sync pulse, to increase the negative-going amplitude of the respective pulse. Various combinations of the added pulses also are possible.

Abstract: In the known color stripe process for preventing recording of video signals, the color burst present on each line of active video is modified so that any subsequent video tape recording of the video signal shows variations in the color fidelity that appear as undesirable bands or stripes of color error. This color stripe process is improved by a combination of modifying the phase of the color burst on only part of the color burst. Additional improvements were obtained by incorporating techniques of widening the normal color burst envelope towards the trailing edge of horizontal sync and towards the beginning of active video. These techniques are useful in improving the performance of the color stripe process in both the NTSC and PAL color systems. However, additional improvements are described in the PAL system whereby the phase modifications are controlled so as to avoid distubing the so-called PAL ID pulse.

Abstract: A voltage controlled amplifier is improved in noise performance with nonlinear local feedback elements while maintaining low distortion for various control settings. By paralleling nonlinear elements, distortion is further improved. Preferably, these nonlinear elements consist of diode pairs connected to the emitters of a differential amplifier whereby the bases of the transistors are used to control the signal current.

Abstract: In the known color stripe process for preventing recording of video signals, the color burst present on each line of active video is modified so that any subsequent video tape recording of the video signal shows variations in the color fidelity that appear as undesirable bands or stripes of color error. This color stripe process is improved by a combination of modifying the phase of the color burst on only part of the color burst. Additional improvements were obtained by incorporating techniques of widening the normal color burst envelope towards the trailing edge of horizontal sync and towards the beginning of active video. These techniques are useful in improving the performance of the color stripe process in both the NTSC and PAL color systems. However, additional improvements are described in the PAL system whereby the phase modifications are controlled so as to avoid disturbing the so-called PAL ID pulse.

Abstract: Method and apparatus for modifying or reducing effects of signals added to a video signal to permit more unhampered copying and/or viewing thereof. In one version the method and apparatus replace or level shift portions of a video signal to overcome effects caused by these pulses. Typically these pulses are added for copy protection purposes. Modification of the video signal allows for more unhampered viewing and/or copying of the video signal.

Abstract: An improved television scrambling signal is achieved by adding erroneous clamp pulses into a television signal after the signal may have been previously scrambled, for example, by prior art position modulated horizontal sync pulses. Prior art scrambling systems such as those using position modulated sync pulses cause tearing in an unauthorized displayed television picture. The addition of the erroneous clamp pulses of the present invention causes both tearing and darkening of the picture. This darkening can completely shut off the display on some TV sets, thus yielding complete concealment of the television signal. In an alternative embodiment, an erroneous color “rainbow” effect is provided by modifying a portion of a color burst signal, to cause the color subcarrier system in a TV set to unlock.

Abstract: Video signals are scrambled by position modulating or switching between two types of modified horizontal sync pulses. These modified horizontal pulses are modulated or switched at a rate that causes a non-interlaced tearing pattern when viewed by an unauthorized viewer, whereby greater concealment is achieved by the invention when compared to the prior art. The modified scrambling process also is adapted to achieve lower tuner AGC artifacts. With added fake vertical sync signals and strategic use of double or multiple horizontal sync pulses per TV line, modern TV sets using count down circuits are also affected vertically to enhance the concealment effects.

Abstract: In a known copy protection process for preventing recording of video signals, pseudo sync and AGC pulses are present on predetermined lines within the blanking intervals of the video signal so that any subsequent video tape recording of the video signal shows a picture of very low entertainment quality. This copy protection process is defeated first by determining the location of the video lines containing the copy protection using the color burst signal or chroma in the horizontal blanking interval to determine on-line detection. Then some or all of the lines including copy protection signals are modified so as to render the overall video signal recordable. The modification is accomplished in a number of ways, including gain shifting portions of the video signal, level shifting portions of the video signal, bandwidth limiting certain portions of the video signal or replacing certain portions of the video signal with other video elements.

Abstract: Various techniques and associated embodiments are disclosed for providing defensive measures against “black boxes,” wherein the techniques utilize unconventional schemes for detecting the vertical blanking interval (VBI) of a video signal containing a copy protection signal. The unconventional schemes would be of particular interest to the black boxes, which must locate the VBI to generate a vertical rate signal in order to perform the task of illegally removing the copy protection signal. The unconventional schemes utilize the particular characteristics or peculiarities of the video signals in the VBI to detect the VBI and generate therefrom a reliable vertical or frame rate signal. The characteristics include various pulse spacings and/or pulse widths which may occur in specific lines in the VBI, and which may be detected to allow deriving the reliable vertical or frame rate signal.

Abstract: A VGA (or other component video signal) output, e.g. from a computer or DVD player, is protected so it is viewable on a VGA monitor. However, if the component video signal is converted to composite video (e.g. television) the resulting television picture is of substantially degraded quality, thereby inhibiting viewing and/or copying. This protects for instance copyrighted material in the VGA format from unauthorized use. The protection involves modifying the horizontal or vertical synchronization signals in the VGA video in such a way that there is no adverse affect on a typical VGA monitor. However, most or all VGA to television converters and/or television sets and VCR's suffer from loss of synchronization, resulting in an unviewable picture. Also, methods and circuits for defeating the copy protection are provided.

Abstract: In the known color stripe process for preventing recording of video signals, the color burst present on each line of active video is modified so that any subsequent video tape recording of the video signal shows variations in the color fidelity that appear as undesirable bands or stripes of color error. This color stripe process is defeated first by determining the location of the video lines including the color stripe process, either by prior experimentation or by on-line detection. Then some or all of the lines including the modified color bursts are modified so as to render the overall video signal recordable. The modification is accomplished in a number of ways, including phase shifting the color stripe burst into the correct phase, replacing some of the color stripe bursts or a portion of particular color stripe bursts so that they are no longer effective, and mixing the color stripe burst with color stripe signals of the correct phase so as to eliminate most or all of the phase error present.