Title of Invention	METHOD AND APPARATUS FOR PROVIDING COPY PROTECTION SIGNALS IN A VIDEO SIGNAL AND FOR REDUCING THE EFFECTS OF THE COPY PROTECTION SIGNALS
Abstract	A method and apparatus for synthesizing and defeating copy protection signals is disclosed, wherein various embodiments dynamic vary the sync or pseudo sync and AGC pulse separation by applying a modulation of position shifting, trimming and/or narrowing techniques over selected time periods. Apparatus for synthesizing the copy protection signals uses timing circuitry (80-96) to identify video lines to contain the copy protection signals and the location in those video lines of the copy protection signals. There is a circuit (98-102) which is arranged to generate modulated inverted pseudo sync pulses and to generate AGC pulses which vary in width and are delayed in position relative to the modulated inverted pseudo sync pulses. The generated modulated pulses are then added to the video signal by summing amplifiers.

Title of Invention

METHOD AND APPARATUS FOR PROVIDING COPY PROTECTION SIGNALS IN A VIDEO SIGNAL AND FOR REDUCING THE EFFECTS OF THE COPY PROTECTION SIGNALS

Abstract

A method and apparatus for synthesizing and defeating copy protection signals is disclosed, wherein various embodiments dynamic vary the sync or pseudo sync and AGC pulse separation by applying a modulation of position shifting, trimming and/or narrowing techniques over selected time periods. Apparatus for synthesizing the copy protection signals uses timing circuitry (80-96) to identify video lines to contain the copy protection signals and the location in those video lines of the copy protection signals. There is a circuit (98-102) which is arranged to generate modulated inverted pseudo sync pulses and to generate AGC pulses which vary in width and are delayed in position relative to the modulated inverted pseudo sync pulses. The generated modulated pulses are then added to the video signal by summing amplifiers.

Full Text	METHOD AND APPARATUS FOR PROVIDING COPY PROTECTION SIGNALS IN A VIDEO SIGNAL AND FOR REDUCING THE EFFECTS OF THE COPY PROTECTION SIGNALS This invention relates to method and apparatus for providing copy protection signals in a video signal and for reducing the effects of the copy protection signals. This application is divided &om Indian Patent Application No.IN/PCT/2001/00203. CROSS REFERENCE TO RELATED APPLICATIONS This invention is related to commonly ovmed U.S. Patent No. 4,631,603 entitled "METHOD A>ro APPARATUS FOR PROCESSING A VIDEO SIGNAL SO AS TO BE ABLE TO PROHIBrr THE MAKING OF ACCEPTABLE VIDEO TAPE RECORDINGS THEREOF" which issued on December 12,1986; to U.S. Patent No. 4,695,901 entitled "METHOD AND APPARATUS FOR REMOVING PSEUDO-SYNC PULSES AND/OR AGC PULSES FROM A VIDEO SIGNAL" which issued on September 22,1987; to U.S. Patent No. 4j907,093 for METHOD AND APPARATUS FOR PREVENTING THE COPYING OF A VIDEO PROGRAM" which issued March 6, 1990; to U.S. Patent No. 4,819,098 for "METHOD AND APPARATUS FOR CLUSTEIONG MODIFICATIONS MADE TO A VIDEO SIGNAL TO INHIBIT THE , MAKING OF ACCEPTABLE VIDEO TAPE RECORDINGS" which issued on April 4, 1989; to U.S. Patent No. 5,157,510 for "METHOD AND APPARATUS FOR DISABLING ANTI-COPY PROTECTION SYSTEM IN VIDEO SIGNALS USING PULSE NARROWING which issued on October 20, 1992; to U.S. Patent No. 5,194,965 for "METHOD AND APPARATUS FOR DISABLING ANTI-CGPY PROTECTION SYSTEM IN VIDEO SIGNALS" issued on March 16, 1993; to U.S. Patent No. 5,625,691 for "METHOD AND APPARA;rUS TO DEFEAT CERTAIN COPY PROTECTION PULSES WITHIN A VIDEO SIGNAL" issued on April 29,1997; to U.S. Patent No. 5,633,927 for "VIDEO COPY PROTECTION PROCESS ENHANCEMENT TO D^TRODUCE HORIZONTAL AND VERTICAL PICTURE DISTORTIONS" issued on May 27, 1997; to U.S. Patent No. 5,748.733 for "METHOD AND APPARATUS TO REDUCE EFFECTS OF CERTAIN COPY PROTECTION PULSES WITHIN A VIDEO SIGNAL" issued on May 5, 1998; to U.S. Patent No. 5,661,801 for "METHOD AND APPARATUS FOR STABILIZ^G AND BRIGHTENING PRERECORDED TV SIGNALS ENCODED WITH COPY PROTECTION" issued on August 26, 1997; to U.S. Patent No. 4,336,554 for "CODE SIGNAL BLANKING APPARATUS" issued on June 22, 1982 and to U.S. Patent No. 5„583,936 for "VIDEO COPY PROTECTION PROCESS ENHANCEMENT TO INTRODUCE HORIZONTAL AND VERTICAL PICTURE DISTORTIONS" issued on December 10,1996, All of the above are incorporated by reference. Also related is U.S. Patent No. 4,163,253 for "METHOD APPARATUS FOR MODIFYING A VIDEO SIGNAL TO PREVENT UNAUTHORIZED RECORDING AND REPRODUCTION THEREOF" issued on July 31,1979. BACKGROUND OF INVENTION Field of the Invention The field of tiie invention is in the mechanisms and/or methods for defeating, removing, or reducing the effects of the video copy protection signals. These mechanisms are also used to synthesize and improve the performance of a video copy protection signal. Description of the Prior Art The Hollywood movie industry is very concerned about the unauthorized copying of movies and programs. As an example, on September 17, 1997 Jack Valenti, President and Chief Executive OfSce of the Motion Picture Association of America stated "If you can't protect what you own - You don't own anything." The patent by Ryan, 4,631,603, 5 incorporated by reference, discloses a way to process an ordinary program video source to have copy protection. The copy protected video is viewable on a TV set but it produces a recording lacking any entertainment value. That is, the video programs that are not recordable suffer from artifacts ranging from low contrast to synchronizing problems. The '603 patent describes a method for "confiising" or causing misoperation of the AGC system in a videocassette recorder while not causing a black depression problem in a television receiver displaying the copy protected signal. A Polish Patent Application (PL 304477 ('477)) by Tomasz Urbaniec entitled "Method and Device for Protecting Videophonic Recordings Against Authorized Copying" filed July 28,1994, hereby incorporated by reference, discloses ai Variation of the '603 patent by Ryan. Figure la of the '603 patent describes the waveform of the copy protected video signal as disclosed by Ryan and is replicated herein as Figure la. Figure 4 of the Urbaniec patent '477 describes the comparative waveform as disclosed by Urbaniec, which is replicated herein as Figure 1(b). As is well known in the art, the videocassette system has a limited luminance frequency response, less than 2 MHz. A signal as described by Ryan recorded on a videocassette duplicating, recorder with the AGC turned off (to avoid the effects of copy protection) will produce a video signal with pulse shapes modified by the limited frequency response of the duphcating recorder. Since there is no gap between the pseudo sync pulses and the AGC pulses of Ryan, the AGC system of a home duplicating recorder will respond to &e combination of the pseudo sync pulses and the AGC pulses. The limited bandwidth of the recording VCR responds slightly differently to the combination of pseudo-sync and AGC pulses separated by a time gap of 0.5 f^econds to 2.0 i^seconds. If the time gap is as low as 0.5 fiseconds, the limited bandwidth of the recording videocassette recorder distorts the time gap to effectively remove it and the effectiveness of the copy protection is essentially the same as that achieved by Ryan. As the gap widens, the effectiveness of the copy protection is reduced or removed. To defeat the copy protection process, there are a number of known ways such as attenuating, blanking, narrowing, level shifting, modifying and/or clipping the copy protection pulses as described in patents 4,695,901 ('901), 4,336,554 ('554), 5,157,510 (¦510), 5,194,965 ('965), 5,583.936 ('936), 5,633,927 ('927), 5,748,733 ('733) and 5,661,801 ('801) cited above and hereby incorporated by reference. In the patents mentioned above, the AGC and/or sync or pseudo sync pulses (see 4,695,901) are chanjged in amplitude, changed in level relative to normal sync pulses, and/or changed in pulse width, so as to allow a satisfactory recording. In particular, Patent 5,194,965 and 5,157,510 disclose narrowing of the AGC and/or pseudo sync pulses so that the record VCR does not sense these narrowed added pulses and thus, makes a satisfactory copy. SUMMARY OF THE INVENTION To defeat the anti-copy signal, the present invention discloses a method and apparatus utilizing pulse position and pulse width modulation of the AGC and/or sync or pseudo sync pulses. The invention also discloses the insertion of a sufficiently wide time gap between the AGC and/or pseudo sync pulses such that the record VCR will respond to or sense the sync or pseudo sync pulses but still will allow for a recordable copy. The copy protection defeating mechanisms of tiiis inyentipn can alaab.e.used.ia.. combination v/ith any of the defeat inventions mentioned above. For example, to defeat the copy protection process, one can sliift (delay) the AGC pulse by about 1.5 fiseconds away from the preceding pseudo sync pulse and then trim the trailing'edge of the preceding pseudo sync pulse by 0.6 (isecond. Thus a gap of about 2.1 ^.seconds exists between the trailing edge of the trimmed pseudo sync pulse and the leading edge of the delayed AGC pulse. If this gap is, for example, near blanking level for 2.1 ^seconds, then the VCR will sample the voltage in the gap instead of the added AGC pulses for its AGC amplifier. By sampling this gap voltage near blanking level, the copy protection signal is then nullified. Alternatively, the gap voltage level may be set above or below blanking level. It is important to note that by simply delaying or shifting the position of the leading edge.of Ae AGG pulse relative to the trailing edge of the pseudo sync pulse, the gap between the pseudo sync pulses and the AGC pulses will nullify or partially niillify the effects of the AGC copy protection signaL' It is also possible to create this gap in other ways su"ch as moving flxe trailing edge of pseudo sync pulse away from the leading edge of the upcoming AGC pulse, or some combination of moving the position of both the AGC pulse and pseudo sync pulse to form a gap that would defeat the copy protection process. Typical gap durations of 1.5 )j.seconds or more have proved effective in defeating the copy protection signal. Compounding the narrowing of the pseudo sync pulses and/or AGC pulses with this gap further enhances defeating the copy protection signal. It should be noted fliat the defeat method as described above can be varied and then used as a copy protection signal. By dynamically varying the gap from zero to greater than 1.5 jiseconds between the trailing edge of the pseudo sync pulse relative to the leading edge of the upcoming AGC pulse, a new copy protection signal is made to effectively mimic the Ryan '603 patent with amplitude modulated AGC pulses. By varying the gap via position modulation of &e pseudo sync pulses relative to the AGC pulse or vice versa, or dynamically narrowing or changing the pulse width of the added pulses (AGC pulse and/or sync or pseudo sync pulse), an easier copy protection implementation is possible in the digital domain and/or analog domain. Today's digital domain is the format of choice for implementing copy protection in cable systems and the like (i.e. digital versatile disc players). The range of pulse widths can be for example, between about 50% to 100% of the normal pulse widths (i.e. the pseudo sync pulse normal widths are about 2,3 j.iseconds and the AGC normal widths are about 2.3 p.seconds to 3 p-seconds depending on how many added pulses are in a television (TV) line). In general the copy protection process of the invention may start having the added pulse pairs as for example in Figure 2(a) of Ryan '603 patent, where the AGC pulse and/or pseudo sync pulse are position separated relative to time. If the gap due to position separation is insufficient to "turn off the copy protection process (i.e. position modulation amounts to only 1.0 fxsecond of gap), then the AGC pulse and/or pseudo sync pulse can be narrowed as a function of time to increase the gap sufficiently (i.e. slowly trim or narrow the AGC pulse and/or pseudo sync pulse by about 0,35 p-second each, which would add another 0.7 jasecond to the 1.0 psecond gap for a increased gap duration of 1.7 pseconds). After the gap has been extended as to "defeat" or turn off the copy protection signal, then the new copy protection signal is reactivated by reducing the separation (for example, to zero) between the AGC pulse and pseudo sync pulse and by restoring the pulse widths of the (trimmed or narrowed) AGC pulses and/or pseudo sync pulse to their full normal pulse widths. The method of using relative position modulation between the sync and AGC pulses for defeating and/or synthesizing a copy protection signal can be applied to the copy protection pulses within or around a horizontal blanking interval. The method can. also be combined with narrowing any portion of the added pulses. In order to produce a further effective copy protection signal, a variation of the 4,631,603 patent has been developed. To this end, the AGC pulses also are amplitude modulated firom full amplitude to zero and vice versa over the period of for example about 20 to 30 seconds. As a result, the illegal copy will have constantly changing brightness levels. This causes more annoyance when compared to a constant dim picture (when the AGC pulses are static and at full amplitude). BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS Figure la illustrates a the basic anticopy process consisting of AGC and pseudo sync pulses; Figure lb illustrates the Urbaniec modification to the basic anticopy process consisting of AGO and pseudo sync pulses; Figure 2 illustrates various ways to position shift the AGC pulse to defeat the copy protection signal. Figure 2 also shows a way of dynamically shifting the position of the AGC pulse to provide the copy protection process of the invention; Figure 3 illustrates a combination of position shifting and narrowing (trimming) the AGC pulses to defeat the copy protection signal. Figure 3 also shows a way of dynamically shifting the position and then narrowing the AGC pulses in accordance with the copy protection process of the invention; Figure 4 illustrates various ways to shift the relative position between AGC pulses and pseudo sync pulses while narrowing pseudo sync and/or AGC pulses to defeat the copy protection signal. If the positional shifting and narrowing of AGC pulses and/or pseudo sync pulses is done from zero to maximum, then this technique can be used as the copy protection signal of the invention; Figure 5 illustrates a block diagram of an apparatus for defeating a copy protection signal by delaying the AGC pulses; Figures 5a to 5e illustrate the waveforms generated at various points in the circuit of Figure 5; Figure 6 illustrates an apparatus for defeating a copy protection process by inserting a time gap between the pseudo sync pulses and the AGC pulses; Figures 6a to 6E illustrate several waveforms related or generated by the circuit of Figure 6 given typical copy protection signals as an input; Figure 7 illustrates copy protection apparatus of the invention that generates a dynamically variable time gap (around blanking level) between the trailing edge of pseudo sync pulses and the leading edge of AGC pulses; Figures 7a to 7e illustrate the relevant waveforms that are generated at various points in the circuit of Figure 7; Figures 8a and 8b illustrate position delay or modulation of the raised back porches as mentioned in *098.which can be used as a defeat process or as a copy protection signal. By varying the gap between the trailing edge of (horizontal) normal sync pulses and their raised back porch AGC pulses, the VCR will respond to these as if the raised back porch AGC pulses are being amplitude modulated up and down, which results in yet another dynamic copy protection process of the invention; Figure 9a illustrates a prior art copy protection signal. Figure 9b illustrates a defeating or modifying method by reversing at least portions of the pseudo sync and/or AGC pulses. Figure 9c illustrates another method for defeating or modifying the original process (Figure 9a for example) by phase sliifdng (i.e., inverting) portions of the pseudo syncs and/or AGC pulses; Figure 10 is a block diagram illustrating a circuit for reversing at least portions of the pseudo sync and/or AGC pulses by way of a memory circuit; and Figure 11 is a block diagram illustrating a circuit for inverting or phase shifting portions of the pseudo syncs and/or AGC pulses by way of an inverting or phase shifting amplifier along with a switching or dissolving amplifier. An optional level shifting and/or attenuating circuit is also shown in Figure 11. DESCRIPTION-OF THE PREFERRED EMBODIMENTS As previously discussed, Figures la and lb illustrate prior art copy protection and copy protection defeating signals, respectively. Figure 2 illustrates various waveforins corresponding to ways that AGC pulses can be delayed to provide the copy protection defeating technique of the invention. First, the waveform D in Figure 2 illustrates'the AGC pulse and pseudo sync pulse at the normal position previously shown in Figure la which causes copy protection. Waveforms A to C show various delays or gaps between the trailing edge of pseudo sync pulse and the leading edge of the respective AGC pulse. Waveforms A and B are effective in turning off the copy protection signal while waveform C causes partial reduction or turn off of the copy protection signal. For effective defeat of the copy protection signal it follows that waveforms A and B are preferable. For a new copy protection signal that is dynamically varied from on to off, one technique of the invention starts for example, with several seconds of the waveform D of Figure 2 (copy protection on) then transitions to the waveform C of Figure 2 (copy protection partially on) and then transitions to the waveform B of the Figure 2 (copy protection turned off). The gap, or separation T4, in Figure 2 is preferably continuously or discretely changing from zero to greater than about 1.5 jiseconds. Waveform A is used to turn copy protection off. In Figure 2 (as well as Figures 3, 4) the time interval Tl defines the normal s)mc to the first piseudo sync pulse period, T2 defines the repetition rate of added pseudo sync pulses, T3 defines the pseudo sync pulses' width and T4 defines the gap duration. T6 designates the width of a white reference pulse which may be included as an option. Figure 3 illustrates a variation of the embodiment of Figure 2 with AGC pulse narrowing, although the pseudo sync pulses can be narrowed as well. In the waveform H of Figure 3, the pulse resembles a narrowed AGC pulse in the patents '510 and '965 of previous mention. While waveform H of Figure 3 can be used for defeating copy protection signals, it can again also be used as part of a copy protection signal. The waveform D of Figure 2 represents a normal copy protection signal which can transition to the waveform H of Figure 3, a signal with a narrowed AGC pulse,-and then transition to waveform F of Figure 3, a signal.with a gap and narrowed AGC pulse. Finally the cdpy protection signal can be turned off by a transition to the waveform G of Figure 3, where the gap is larger with a narrowed AGC pulse. Waveform E of Figure 3 is equivalent to waveform A of Figure 2 and is used to defeat copy protection. Figure 4 illustrates pseudo sync pulse narrowing combined with position delay or modulation of varying pulse widths of the AGC pulses to defeat the copy protection process, or form a dynamic copy protection signal. The waveform D' of Figure 4 illustrates a defeat process not illustrated in the patents of previous mention by Quan et al -510 and '965. In waveform D' of Figure 4 the pseudo sync pulse's trailing edge is advanced to provide a narrowed pseudo S3aic followed by a delayed AGC pulse leading edge to provide a narrowed AGC pulse. The waveform C of Figure .4 illustrates a further gap increase in duration between the AGC pulse by position delaying the AGC pulse using an advanced trailing edge to narrow the pseudo sync pulse. The waveform B' of Figure 4 illustrates a combination of position separation between the AGC pulse and the pseudo sync pulse with narrowed AGC and pseudo sync pulse. Thus, the waveform B' can be used as a method to defeat the copy protection. WE CLAIM : 1.A method of providing copy protection signals in a video signal, employing sync, pseudo sync and respective automatic gain control (AGC) pulses, comprising: dynamically modulating the pulse width of the AGC pulses or of the sync and respective AGC pulses, wherein one or more AGC and/or sync and respective AGC pulse is modulated at a time. 2.The method as claimed in claim 1, wherein the step of dynamically modulating comprises: modulating over one or more video lines the position and/or pulse width of the sync or pseudo sync pulses and/or the respective AGC pulses. 3.The method as claimed in claim 2, wherein only the AGC pulses are shifted in position continuously or discretely. 4.The method as claimed in claim 2, comprising: dynamically amplitude modulating the sync, pseudo sync and/or the AGC pulses. 5.The method as claimed in claim 2, comprising: dynamically narrowing and expanding any portion of the sync, pseudo sync and/or AGC pulses. 6.The method as claimed in claim 2, wherein the AGC pulses are shifted in position or are narrowed continuously or discretely to dynamically enable and disable the copy protection signals. 7.The method as claimed in claim 2, wherein the sync or pseudo sync pulses have a small position separation, which can be zero, from the respective AGC pulses to maintain the copy protection effect, and wherein the position separation or gap between the sync or pseudo sync pulse and the respective AGC pulse is gap width modulated. 8.The method as claimed in claim 2, wherein the sync or pseudo sync pulses have a small position separation, which can be zero, from the respective AGC pulses to maintain the copy protection effect, and wherein: the dynamic modulating of the position separation comprises position and/or pulse width modulating the sync or pseudo sync and/or the AGC pulses; and amplitude modulating the position and/or pulse width modulated sync or pseudo sync and/or AGC pulses. 9.The method as claimed in claim 2, employing raised back porch AGC pulses, which involves: dynamic modulating at least one or a selected combination of a position, gap width, pulse width or amplitude or one or more of selected pulses of the sync, pseudo sync, AGC and/or raised back porch AGC pulses so as to synthesize the copy protection signals. 10.The method as claimed in claim 9, wherein only the AGC or raised back porch AGC pulses are position and/or pulse width modulated. 11.The method as claimed in claim 8, wherein only the sync and/or pseudo sync pulses are position and/or pulse width modulated. a circuit for providing a gap between the sync or pseudo sync pulse and the respective AGC pulse by shifting any combination of the trailing edge of the sync or pseudo sync pulse and/or of the leading edge of the respective AGC pulse, wherein the gap is sufficiently wide to cause the defeat or reduction in the effects of the copy protection signal. A method and apparatus for synthesizing and defeating copy protection signals is disclosed, wherein various embodiments dynamic vary the sync or pseudo sync and AGC pulse separation by applying a modulation of position shifting, trimming and/or narrowing techniques over selected time periods. Apparatus for synthesizing the copy protection signals uses timing circuitry (80-96) to identify video lines to contain the copy protection signals and the location in those video lines of the copy protection signals. There is a circuit (98-102) which is arranged to generate modulated inverted pseudo sync pulses and to generate AGC pulses which vary in width and are delayed in position relative to the modulated inverted pseudo sync pulses. The generated modulated pulses are then added to the video signal by summing amplifiers.

Full Text

METHOD AND APPARATUS FOR PROVIDING COPY
PROTECTION SIGNALS IN A VIDEO SIGNAL AND FOR
REDUCING THE EFFECTS OF THE COPY PROTECTION
SIGNALS
This invention relates to method and apparatus for providing copy protection signals in a
video signal and for reducing the effects of the copy protection signals.
This application is divided &om Indian Patent Application No.IN/PCT/2001/00203.
CROSS REFERENCE TO RELATED APPLICATIONS
This invention is related to commonly ovmed U.S. Patent No. 4,631,603 entitled
"METHOD A>ro APPARATUS FOR PROCESSING A VIDEO SIGNAL SO AS TO BE
ABLE TO PROHIBrr THE MAKING OF ACCEPTABLE VIDEO TAPE
RECORDINGS THEREOF" which issued on December 12,1986; to U.S. Patent No.
4,695,901 entitled "METHOD AND APPARATUS FOR REMOVING PSEUDO-SYNC
PULSES AND/OR AGC PULSES FROM A VIDEO SIGNAL" which issued on
September 22,1987; to U.S. Patent No. 4j907,093 for METHOD AND APPARATUS
FOR PREVENTING THE COPYING OF A VIDEO PROGRAM" which issued March 6,
1990; to U.S. Patent No. 4,819,098 for "METHOD AND APPARATUS FOR
CLUSTEIONG MODIFICATIONS MADE TO A VIDEO SIGNAL TO INHIBIT THE
, MAKING OF ACCEPTABLE VIDEO TAPE RECORDINGS" which issued on April 4,
1989; to U.S. Patent No. 5,157,510 for "METHOD AND APPARATUS FOR
DISABLING ANTI-COPY PROTECTION SYSTEM IN VIDEO SIGNALS USING
PULSE NARROWING which issued on October 20, 1992; to U.S. Patent No. 5,194,965
for "METHOD AND APPARATUS FOR DISABLING ANTI-CGPY PROTECTION
SYSTEM IN VIDEO SIGNALS" issued on March 16, 1993; to U.S. Patent No. 5,625,691
for "METHOD AND APPARA;rUS TO DEFEAT CERTAIN COPY PROTECTION
PULSES WITHIN A VIDEO SIGNAL" issued on April 29,1997; to U.S. Patent No.
5,633,927 for "VIDEO COPY PROTECTION PROCESS ENHANCEMENT TO
D^TRODUCE HORIZONTAL AND VERTICAL PICTURE DISTORTIONS" issued on
May 27, 1997; to U.S. Patent No. 5,748.733 for "METHOD AND APPARATUS TO

REDUCE EFFECTS OF CERTAIN COPY PROTECTION PULSES WITHIN A VIDEO
SIGNAL" issued on May 5, 1998; to U.S. Patent No. 5,661,801 for "METHOD AND
APPARATUS FOR STABILIZ^G AND BRIGHTENING PRERECORDED TV
SIGNALS ENCODED WITH COPY PROTECTION" issued on August 26, 1997; to U.S.
Patent No. 4,336,554 for "CODE SIGNAL BLANKING APPARATUS" issued on June
22, 1982 and to U.S. Patent No. 5„583,936 for "VIDEO COPY PROTECTION PROCESS
ENHANCEMENT TO INTRODUCE HORIZONTAL AND VERTICAL PICTURE
DISTORTIONS" issued on December 10,1996, All of the above are incorporated by
reference.
Also related is U.S. Patent No. 4,163,253 for "METHOD APPARATUS FOR
MODIFYING A VIDEO SIGNAL TO PREVENT UNAUTHORIZED RECORDING
AND REPRODUCTION THEREOF" issued on July 31,1979.
BACKGROUND OF INVENTION
Field of the Invention
The field of tiie invention is in the mechanisms and/or methods for defeating,
removing, or reducing the effects of the video copy protection signals. These mechanisms
are also used to synthesize and improve the performance of a video copy protection signal.
Description of the Prior Art
The Hollywood movie industry is very concerned about the unauthorized copying
of movies and programs. As an example, on September 17, 1997 Jack Valenti, President
and Chief Executive OfSce of the Motion Picture Association of America stated "If you
can't protect what you own - You don't own anything." The patent by Ryan, 4,631,603,
5 incorporated by reference, discloses a way to process an ordinary program video source to

have copy protection. The copy protected video is viewable on a TV set but it produces a
recording lacking any entertainment value. That is, the video programs that are not
recordable suffer from artifacts ranging from low contrast to synchronizing problems. The
'603 patent describes a method for "confiising" or causing misoperation of the AGC
system in a videocassette recorder while not causing a black depression problem in a
television receiver displaying the copy protected signal.
A Polish Patent Application (PL 304477 ('477)) by Tomasz Urbaniec entitled
"Method and Device for Protecting Videophonic Recordings Against Authorized
Copying" filed July 28,1994, hereby incorporated by reference, discloses ai Variation of
the '603 patent by Ryan. Figure la of the '603 patent describes the waveform of the copy
protected video signal as disclosed by Ryan and is replicated herein as Figure la. Figure 4
of the Urbaniec patent '477 describes the comparative waveform as disclosed by Urbaniec,
which is replicated herein as Figure 1(b).
As is well known in the art, the videocassette system has a limited luminance
frequency response, less than 2 MHz. A signal as described by Ryan recorded on a
videocassette duplicating, recorder with the AGC turned off (to avoid the effects of copy
protection) will produce a video signal with pulse shapes modified by the limited
frequency response of the duphcating recorder. Since there is no gap between the pseudo
sync pulses and the AGC pulses of Ryan, the AGC system of a home duplicating recorder
will respond to &e combination of the pseudo sync pulses and the AGC pulses.
The limited bandwidth of the recording VCR responds slightly differently to the
combination of pseudo-sync and AGC pulses separated by a time gap of 0.5 f^econds to
2.0 i^seconds. If the time gap is as low as 0.5 fiseconds, the limited bandwidth of the
recording videocassette recorder distorts the time gap to effectively remove it and the

effectiveness of the copy protection is essentially the same as that achieved by Ryan. As
the gap widens, the effectiveness of the copy protection is reduced or removed.
To defeat the copy protection process, there are a number of known ways such as
attenuating, blanking, narrowing, level shifting, modifying and/or clipping the copy
protection pulses as described in patents 4,695,901 ('901), 4,336,554 ('554), 5,157,510
(¦510), 5,194,965 ('965), 5,583.936 ('936), 5,633,927 ('927), 5,748,733 ('733) and
5,661,801 ('801) cited above and hereby incorporated by reference.
In the patents mentioned above, the AGC and/or sync or pseudo sync pulses (see
4,695,901) are chanjged in amplitude, changed in level relative to normal sync pulses,
and/or changed in pulse width, so as to allow a satisfactory recording.
In particular, Patent 5,194,965 and 5,157,510 disclose narrowing of the AGC
and/or pseudo sync pulses so that the record VCR does not sense these narrowed added
pulses and thus, makes a satisfactory copy.
SUMMARY OF THE INVENTION
To defeat the anti-copy signal, the present invention discloses a method and
apparatus utilizing pulse position and pulse width modulation of the AGC and/or sync or
pseudo sync pulses. The invention also discloses the insertion of a sufficiently wide time
gap between the AGC and/or pseudo sync pulses such that the record VCR will respond to
or sense the sync or pseudo sync pulses but still will allow for a recordable copy.
The copy protection defeating mechanisms of tiiis inyentipn can alaab.e.used.ia..
combination v/ith any of the defeat inventions mentioned above. For example, to defeat
the copy protection process, one can sliift (delay) the AGC pulse by about 1.5 fiseconds
away from the preceding pseudo sync pulse and then trim the trailing'edge of the
preceding pseudo sync pulse by 0.6 (isecond. Thus a gap of about 2.1 ^.seconds exists

between the trailing edge of the trimmed pseudo sync pulse and the leading edge of the
delayed AGC pulse. If this gap is, for example, near blanking level for 2.1 ^seconds, then
the VCR will sample the voltage in the gap instead of the added AGC pulses for its AGC
amplifier. By sampling this gap voltage near blanking level, the copy protection signal is
then nullified. Alternatively, the gap voltage level may be set above or below blanking
level. It is important to note that by simply delaying or shifting the position of the leading
edge.of Ae AGG pulse relative to the trailing edge of the pseudo sync pulse, the gap
between the pseudo sync pulses and the AGC pulses will nullify or partially niillify the
effects of the AGC copy protection signaL' It is also possible to create this gap in other
ways su"ch as moving flxe trailing edge of pseudo sync pulse away from the leading edge of
the upcoming AGC pulse, or some combination of moving the position of both the AGC
pulse and pseudo sync pulse to form a gap that would defeat the copy protection process.
Typical gap durations of 1.5 )j.seconds or more have proved effective in defeating the copy
protection signal. Compounding the narrowing of the pseudo sync pulses and/or AGC
pulses with this gap further enhances defeating the copy protection signal.
It should be noted fliat the defeat method as described above can be varied and then
used as a copy protection signal. By dynamically varying the gap from zero to greater
than 1.5 jiseconds between the trailing edge of the pseudo sync pulse relative to the
leading edge of the upcoming AGC pulse, a new copy protection signal is made to
effectively mimic the Ryan '603 patent with amplitude modulated AGC pulses. By
varying the gap via position modulation of &e pseudo sync pulses relative to the AGC
pulse or vice versa, or dynamically narrowing or changing the pulse width of the added
pulses (AGC pulse and/or sync or pseudo sync pulse), an easier copy protection
implementation is possible in the digital domain and/or analog domain. Today's digital
domain is the format of choice for implementing copy protection in cable systems and the

like (i.e. digital versatile disc players). The range of pulse widths can be for example,
between about 50% to 100% of the normal pulse widths (i.e. the pseudo sync pulse normal
widths are about 2,3 j.iseconds and the AGC normal widths are about 2.3 p.seconds to 3
p-seconds depending on how many added pulses are in a television (TV) line).
In general the copy protection process of the invention may start having the added
pulse pairs as for example in Figure 2(a) of Ryan '603 patent, where the AGC pulse and/or
pseudo sync pulse are position separated relative to time. If the gap due to position
separation is insufficient to "turn off the copy protection process (i.e. position modulation
amounts to only 1.0 fxsecond of gap), then the AGC pulse and/or pseudo sync pulse can be
narrowed as a function of time to increase the gap sufficiently (i.e. slowly trim or narrow
the AGC pulse and/or pseudo sync pulse by about 0,35 p-second each, which would add
another 0.7 jasecond to the 1.0 psecond gap for a increased gap duration of 1.7 pseconds).
After the gap has been extended as to "defeat" or turn off the copy protection signal, then
the new copy protection signal is reactivated by reducing the separation (for example, to
zero) between the AGC pulse and pseudo sync pulse and by restoring the pulse widths of
the (trimmed or narrowed) AGC pulses and/or pseudo sync pulse to their full normal pulse
widths.
The method of using relative position modulation between the sync and AGC
pulses for defeating and/or synthesizing a copy protection signal can be applied to the
copy protection pulses within or around a horizontal blanking interval. The method can.
also be combined with narrowing any portion of the added pulses.
In order to produce a further effective copy protection signal, a variation of the
4,631,603 patent has been developed. To this end, the AGC pulses also are amplitude
modulated firom full amplitude to zero and vice versa over the period of for example about
20 to 30 seconds. As a result, the illegal copy will have constantly changing brightness

levels. This causes more annoyance when compared to a constant dim picture (when the
AGC pulses are static and at full amplitude).
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure la illustrates a the basic anticopy process consisting of AGC and pseudo
sync pulses;
Figure lb illustrates the Urbaniec modification to the basic anticopy process
consisting of AGO and pseudo sync pulses;
Figure 2 illustrates various ways to position shift the AGC pulse to defeat the copy
protection signal. Figure 2 also shows a way of dynamically shifting the position of the
AGC pulse to provide the copy protection process of the invention;
Figure 3 illustrates a combination of position shifting and narrowing (trimming)
the AGC pulses to defeat the copy protection signal. Figure 3 also shows a way of
dynamically shifting the position and then narrowing the AGC pulses in accordance with
the copy protection process of the invention;
Figure 4 illustrates various ways to shift the relative position between AGC pulses
and pseudo sync pulses while narrowing pseudo sync and/or AGC pulses to defeat the
copy protection signal. If the positional shifting and narrowing of AGC pulses and/or
pseudo sync pulses is done from zero to maximum, then this technique can be used as the
copy protection signal of the invention;
Figure 5 illustrates a block diagram of an apparatus for defeating a copy protection
signal by delaying the AGC pulses;
Figures 5a to 5e illustrate the waveforms generated at various points in the circuit
of Figure 5;

Figure 6 illustrates an apparatus for defeating a copy protection process by
inserting a time gap between the pseudo sync pulses and the AGC pulses;
Figures 6a to 6E illustrate several waveforms related or generated by the circuit of
Figure 6 given typical copy protection signals as an input;
Figure 7 illustrates copy protection apparatus of the invention that generates a
dynamically variable time gap (around blanking level) between the trailing edge of pseudo
sync pulses and the leading edge of AGC pulses;
Figures 7a to 7e illustrate the relevant waveforms that are generated at various
points in the circuit of Figure 7;
Figures 8a and 8b illustrate position delay or modulation of the raised back porches
as mentioned in *098.which can be used as a defeat process or as a copy protection signal.
By varying the gap between the trailing edge of (horizontal) normal sync pulses and their
raised back porch AGC pulses, the VCR will respond to these as if the raised back porch
AGC pulses are being amplitude modulated up and down, which results in yet another
dynamic copy protection process of the invention;
Figure 9a illustrates a prior art copy protection signal. Figure 9b illustrates a
defeating or modifying method by reversing at least portions of the pseudo sync and/or
AGC pulses. Figure 9c illustrates another method for defeating or modifying the original
process (Figure 9a for example) by phase sliifdng (i.e., inverting) portions of the pseudo
syncs and/or AGC pulses;
Figure 10 is a block diagram illustrating a circuit for reversing at least portions of
the pseudo sync and/or AGC pulses by way of a memory circuit; and
Figure 11 is a block diagram illustrating a circuit for inverting or phase shifting
portions of the pseudo syncs and/or AGC pulses by way of an inverting or phase shifting

amplifier along with a switching or dissolving amplifier. An optional level shifting and/or
attenuating circuit is also shown in Figure 11.
DESCRIPTION-OF THE PREFERRED EMBODIMENTS
As previously discussed, Figures la and lb illustrate prior art copy protection and
copy protection defeating signals, respectively.
Figure 2 illustrates various waveforins corresponding to ways that AGC pulses can
be delayed to provide the copy protection defeating technique of the invention. First, the
waveform D in Figure 2 illustrates'the AGC pulse and pseudo sync pulse at the normal
position previously shown in Figure la which causes copy protection. Waveforms A to C
show various delays or gaps between the trailing edge of pseudo sync pulse and the
leading edge of the respective AGC pulse. Waveforms A and B are effective in turning off
the copy protection signal while waveform C causes partial reduction or turn off of the
copy protection signal. For effective defeat of the copy protection signal it follows that
waveforms A and B are preferable.
For a new copy protection signal that is dynamically varied from on to off, one
technique of the invention starts for example, with several seconds of the waveform D of
Figure 2 (copy protection on) then transitions to the waveform C of Figure 2 (copy
protection partially on) and then transitions to the waveform B of the Figure 2 (copy
protection turned off). The gap, or separation T4, in Figure 2 is preferably continuously or
discretely changing from zero to greater than about 1.5 jiseconds. Waveform A is used to
turn copy protection off.
In Figure 2 (as well as Figures 3, 4) the time interval Tl defines the normal s)mc to
the first piseudo sync pulse period, T2 defines the repetition rate of added pseudo sync

pulses, T3 defines the pseudo sync pulses' width and T4 defines the gap duration. T6
designates the width of a white reference pulse which may be included as an option.
Figure 3 illustrates a variation of the embodiment of Figure 2 with AGC pulse
narrowing, although the pseudo sync pulses can be narrowed as well. In the waveform H
of Figure 3, the pulse resembles a narrowed AGC pulse in the patents '510 and '965 of
previous mention. While waveform H of Figure 3 can be used for defeating copy
protection signals, it can again also be used as part of a copy protection signal. The
waveform D of Figure 2 represents a normal copy protection signal which can transition to
the waveform H of Figure 3, a signal with a narrowed AGC pulse,-and then transition to
waveform F of Figure 3, a signal.with a gap and narrowed AGC pulse. Finally the cdpy
protection signal can be turned off by a transition to the waveform G of Figure 3, where
the gap is larger with a narrowed AGC pulse. Waveform E of Figure 3 is equivalent to
waveform A of Figure 2 and is used to defeat copy protection.
Figure 4 illustrates pseudo sync pulse narrowing combined with position delay or
modulation of varying pulse widths of the AGC pulses to defeat the copy protection
process, or form a dynamic copy protection signal.
The waveform D' of Figure 4 illustrates a defeat process not illustrated in the
patents of previous mention by Quan et al -510 and '965. In waveform D' of Figure 4 the
pseudo sync pulse's trailing edge is advanced to provide a narrowed pseudo S3aic followed
by a delayed AGC pulse leading edge to provide a narrowed AGC pulse. The waveform
C of Figure .4 illustrates a further gap increase in duration between the AGC pulse by
position delaying the AGC pulse using an advanced trailing edge to narrow the pseudo
sync pulse. The waveform B' of Figure 4 illustrates a combination of position separation
between the AGC pulse and the pseudo sync pulse with narrowed AGC and pseudo sync
pulse. Thus, the waveform B' can be used as a method to defeat the copy protection.

WE CLAIM :
1.A method of providing copy protection signals in a video signal,
employing sync, pseudo sync and respective automatic gain control (AGC)
pulses, comprising:
dynamically modulating the pulse width of the AGC pulses or of the
sync and respective AGC pulses, wherein one or more AGC and/or sync and
respective AGC pulse is modulated at a time.
2.The method as claimed in claim 1, wherein the step of dynamically
modulating comprises:
modulating over one or more video lines the position and/or pulse
width of the sync or pseudo sync pulses and/or the respective AGC pulses.
3.The method as claimed in claim 2, wherein only the AGC pulses are
shifted in position continuously or discretely.
4.The method as claimed in claim 2, comprising:
dynamically amplitude modulating the sync, pseudo sync and/or the
AGC pulses.
5.The method as claimed in claim 2, comprising:
dynamically narrowing and expanding any portion of the sync, pseudo
sync and/or AGC pulses.
6.The method as claimed in claim 2, wherein the AGC pulses are shifted
in position or are narrowed continuously or discretely to dynamically enable
and disable the copy protection signals.
7.The method as claimed in claim 2, wherein the sync or pseudo sync
pulses have a small position separation, which can be zero, from the
respective AGC pulses to maintain the copy protection effect, and wherein
the position separation or gap between the sync or pseudo sync pulse and
the respective AGC pulse is gap width modulated.

8.The method as claimed in claim 2, wherein the sync or pseudo sync
pulses have a small position separation, which can be zero, from the
respective AGC pulses to maintain the copy protection effect, and wherein:
the dynamic modulating of the position separation comprises position
and/or pulse width modulating the sync or pseudo sync and/or the AGC
pulses; and
amplitude modulating the position and/or pulse width modulated sync
or pseudo sync and/or AGC pulses.
9.The method as claimed in claim 2, employing raised back porch AGC
pulses, which involves:
dynamic modulating at least one or a selected combination of a
position, gap width, pulse width or amplitude or one or more of selected
pulses of the sync, pseudo sync, AGC and/or raised back porch AGC pulses
so as to synthesize the copy protection signals.
10.The method as claimed in claim 9, wherein only the AGC or raised
back porch AGC pulses are position and/or pulse width modulated.
11.The method as claimed in claim 8, wherein only the sync and/or
pseudo sync pulses are position and/or pulse width modulated.

a circuit for providing a gap between the sync or pseudo sync pulse
and the respective AGC pulse by shifting any combination of the trailing edge
of the sync or pseudo sync pulse and/or of the leading edge of the respective
AGC pulse, wherein the gap is sufficiently wide to cause the defeat or
reduction in the effects of the copy protection signal.

A method and apparatus for synthesizing and defeating copy protection signals is disclosed, wherein various embodiments dynamic vary the sync or pseudo sync and AGC pulse separation by applying a modulation of position shifting, trimming and/or narrowing techniques over selected time periods. Apparatus for synthesizing the copy protection signals uses timing circuitry (80-96) to identify video lines to contain the copy protection signals and the location in those video lines of the copy protection signals. There is a circuit (98-102) which is arranged to generate modulated inverted pseudo sync pulses and to generate AGC pulses which vary in width and are delayed in position relative to the modulated inverted pseudo sync pulses. The generated modulated pulses are then added to the video signal by summing amplifiers.

Documents:

69-KOL-2005-FORM-27.pdf

69-kol-2005-granted-abstract.pdf

69-kol-2005-granted-claims.pdf

69-kol-2005-granted-correspondence.pdf

69-kol-2005-granted-description (complete).pdf

69-kol-2005-granted-drawings.pdf

69-kol-2005-granted-examination report.pdf

69-kol-2005-granted-form 1.pdf

69-kol-2005-granted-form 18.pdf

69-kol-2005-granted-form 3.pdf

69-kol-2005-granted-gpa.pdf

69-kol-2005-granted-reply to examination report.pdf

69-kol-2005-granted-specification.pdf

69-kol-2005-granted-translated copy of priority document.pdf

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Patent Number

242761

Indian Patent Application Number

69/KOL/2005

PG Journal Number

37/2010

Publication Date

10-Sep-2010

Grant Date

09-Sep-2010

Date of Filing

03-Feb-2005

Name of Patentee

MACROVISION CORPORATION

Applicant Address

1341 ORLEANS DRIVE, SUNNYVALE, CA

Inventors:

#	Inventor's Name	Inventor's Address
1	BRILL GEROW D	113 DEER HILL AVENUE DANBURY, CT 06810
2	QUAN RONALD	10910 WUNDERLICH DRIVE CUPERTINO, CA 95014

PCT International Classification Number

H04N 7/167

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	60/098,804	1998-09-02	U.S.A.