Method and apparatus for modifying a video signal
OwnerJames A. Karlockinventor
Life of this patent
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Abstract
A standard video signal is processed by including an interval of an insertion signal whose potential varies continuously between the video sync tip level and a level substantially above blanking level during at least part of the active interval of at least one blank line in the vertical blanking interval.
Claims33
A method for processing a video signal so as to inhibit the making of acceptable videotape recordings therefrom, wherein the video signal has a blanking interval which includes a sync pulse, said method comprising the steps of:
- generating multiple cycles of a continuous anti-copying waveform which includes negative peaks and whose positive peak amplitude is greater than the voltage of said sync pulse;
- setting the negative tips of said sync and said negative peaks of said anti-copying waveform at the same voltage which includes clamping the negative tips of said synch to said same voltage;
- and
- inserting said anti-copying waveform into said video signal following said synch pulse, and within said blanking interval, such that the negative tips of said continuous anti-copying waveform are at the same voltage as said negative tips of sync whereby said added continuous anti-copying waveform confuses the automatic gain control of a videotape recorder so as to produce an unacceptable video recording.
A method of inserting an anti-copying waveform into a video signal comprising the steps of:
- generating a continuous anti-copying waveform which has negative peaks and positive peaks;
- maintaining said negative peaks of said continuous anti-copying waveform at a voltage substantially equal to the sync tip voltage of said video signal while said positive peaks are at a voltage equal to or substantially greater than the blanking level of said video signal, said negative peaks of said continuous anti-copying waveform being clamped to a voltage equal to the sync tip voltage;
- and
- inserting said continuous anti-copying waveform between the horizontal sync pulses of said video signal;
- so as to output a video signal including an inserted waveform which prevents the making of an acceptable video recording of said video signal.
A method of inserting an anti-copying waveform into a video signal comprising the steps of:
- generating a continuous anti-copying waveform which has negative peaks and positive peaks;
- maintaining said negative peaks of said continuous anti-copying waveform at a voltage substantially equal to the sync tip voltage of said video signal while said positive peaks are at a voltage equal to or substantially greater than the blanking level of said video signal;
- and
- inserting said continuous anti-copying waveform between the horizontal sync pulses of said video signal;
- so as to output a video signal including an inserted waveform which prevents the making of an acceptable video recording of said video signal;
- wherein the generating a continuous anti-copying waveform step can generate more than one insertion waveform, with at least one group of said waveforms being the same below said blanking level and differing only at amplitudes above said blanking level.
A method of inserting an anti-copying waveform into a video signal comprising the steps of:
- generating a continuous anti-copying waveform which has negative peaks and positive peaks;
- maintaining said negative peaks of said continuous anti-copying waveform at a voltage substantially equal to the sync tip voltage of said video signal while said positive peaks are at a voltage equal to or substantially greater than the blanking level of said video signal;
- and
- inserting said continuous anti-copying waveform between the horizontal sync pulses of said video signal, wherein said insertion step sums said continuous waveform with said video signal;
- so as to output a video signal including an inserted waveform which prevents the making of an acceptable video recording of said video signal.
A method of inserting an anti-copying waveform into a video signal comprising the steps of:
- generating a continuous anti-copying waveform which has negative peaks and positive peaks wherein said positive peaks are at a voltage that is varied in amplitude in response to the content of said video signal;
- maintaining said negative peaks of said continuous anti-copying waveform at a voltage substantially equal to the sync tip voltage of said video signal while said positive peaks are at a voltage equal to or substantially greater than the blanking level of said video signal;
- and
- inserting said continuous anti-copying waveform between the horizontal sync pulses of said video signal;
- so as to output a video signal including an inserted waveform which prevents the making of an acceptable video recording of said video signal.
A method of generating and inserting multiple connected cycles of an anti-copying waveform, with negative tips at a predetermined level, into a video signal between horizontal sync pulses comprising the steps of:
- generating a reset signal derived from the horizontal sync of said video signal;
- generating multiple cycles of a continuous wave, in accordance with said reset signal, at a frequency greater than the frequency of said horizontal synch and with an amplitude equal to or greater than the sync amplitude of said video signal;
- frequency dividing said continuous wave and logically combining said frequency divided outputs to provide a non-symmetrical square wave;
- and
- inserting the non-symmetrical square wave as an anti-copying waveform into said video signal between horizontal sync pulses such that the negative peaks of said waveform are at the same voltage as the negative tips of said horizontal sync;
- so as to output a video signal including an inserted waveform which prevents the making of an acceptable video recording of the video signal.
A method of inserting an anti-copying signal into a video signal between horizontal sync pulses comprising the steps of:
- providing horizontal sync in response to said video signal;
- supplying a reset signal derived from said horizontal sync;
- generating a rectangular wave at a frequency greater than the frequency of said horizontal sync, in the absence of said reset signal;
- integrating said rectangular wave to produce a waveform with at least one sloped edge;
- and
- inserting said waveform into said video signal;
- so as to produce a video signal that cannot be recorded on an ordinary video tape machine without severe degradation.
A method of producing and inserting an anti-copying signal between horizontal sync pulses of a video signal comprising the steps of:
- generating a random noise signal;
- limiting said random noise by clipping the negative peaks of the said noise, so as to supply a noise signal with negative peaks at a predetermined level;
- and
- inserting said noise signal into said video signal between horizontal sync pulses such that the negative peaks of said noise signal are at the same voltage as the negative tips of said horizontal sync;
- so as to output a video signal including an inserted waveform which prevents the making of a normal video recording of the video signal.
A method of adding an insertion signal to a video signal so as to inhibit the undesired copying thereof, comprising the steps of:
- generating an insertion waveform having negative peaks and positive peaks;
- setting the level of the sync tips of said video signal and the negative peaks of said insertion waveform to a predetermined voltage difference between said sync tips and said negative peaks;
- and
- combining said insertion waveform and said video signal in a manner such that said negative peaks of said insertion signal are at the same voltage as said sync tips and the positive peaks of said insertion waveform are at a level substantially above the blanking level of said video signal;
- so as to output a video signal which produces a recording of substandard quality when recorded by an ordinary video tape recorder.
A method of inserting an anti-copying waveform into a video signal, comprising the steps of:
- generating an anti-copying insertion signal;
- measuring at least one parameter of the picture portion of said video signal;
- varying at least one parameter of said insertion signal in response to said measurement;
- and
- inserting said parameter adjusted anti-copying signal into said video signal between the horizontal sync pulses of said video signal so as to produce an un-copyable video signal with reduced visible artifacts.
A method for processing a standard video signal in which the horizontal blanking interval includes a horizontal sync pulse having a tip at a negative potential relative to the blanking level and the vertical blanking interval includes a succession of blank lines in which the potential during the active line interval remains substantially at the blanking level, said method comprising including an insertion signal whose potential varies between a lower level that is substantially at the sync tip level and an upper level that is substantially above the blanking level in the video signal during the active line interval of at least a first blank line and a second blank line, the first blank line being earlier in its field than the second blank line, and the upper level of the insertion signal being higher in the second blank line than in the first blank line.
Dependencies are inferred from the claim text.