Claims
- 1. A method of inhibiting the making of an acceptable video recording of a video signal, the video signal including a plurality of video lines, each video line including a color burst having a predetermined phase, the method comprising the steps of:
determining a duration of the color burst; and modifying a phase of a portion of a duration of each color burst to be other than the predetermined phase, whereby making of an acceptable video recording of the video signal is inhibited.
- 2. The method of claim 1, wherein the step of modifying includes the step of shifting the predetermined phase by 180°.
- 3. The method of claim 1, wherein the step of modulating includes the step of shifting the predetermined phase by at least 20°.
- 4. The method of claim 1, wherein at least 60% of the duration of the color burst is modified.
- 5. The method of claim 1, wherein a duration of the color burst is eight to ten cycles of a color subcarrier signal, and the step of modifying includes modulating more than four of the cycles.
- 6. The method of claim 1, wherein in each video field, at least one band of video lines is subject to the step of modifying, followed by a band of video lines which are not subject to the step of modifying.
- 7. The method of claim 1, wherein an modified portion precedes an unmodified portion of the color burst.
- 8. The method of claim 1, wherein an unmodified portion precedes a modified portion of the color burst.
- 9. The method of claim 1, wherein an unmodified portion precedes and follows a modified portion.
- 10. The method of claim 1, wherein a modified portion precedes and follows an unmodified portion of the color burst.
- 11. The method of claim 1, wherein the video signal is an NTSC video signal.
- 12. The method of claim 1, where the video signal is a PAL video signal.
- 13. A method of inhibiting the making of an acceptable video recording of a video signal, the video signal including a plurality of video lines, each video line including a color burst having a predetermined phase, the method comprising the steps of:
modifying a duration of the color burst; and modifying a phase of one or more portions of a duration of each color burst to be other than the predetermined phase, whereby making of an acceptable video recording of the video signal is inhibited.
- 14. The method of claim 11, wherein the step of modifying a duration of the color burst comprises:
increasing a duration of the color burst.
- 15. The method of claim 12, wherein the step of increasing the duration of the color burst comprises beginning the color burst duration before a normal duration.
- 16. The method of claim 12, wherein the step of increasing a duration of the color burst comprises ending the color burst duration after a normal duration.
- 17. The method of claim 12, wherein the step of increasing a duration of the color burst comprises beginning a color burst duration before a normal color burst duration and ending the color burst duration after a normal duration.
- 18. The method of claim 13, wherein a modified color burst duration begins at a trailing edge of horizontal sync.
- 19. The method of claim 13, wherein a modified color burst duration begins between a leading edge of horizontal sync and a trailing edge of horizontal sync.
- 20. The method of claim 14, where in an end of a modified burst duration is at the beginning of active video.
- 21. The method of claim 11, wherein the step of modification of a duration of the color burst comprises:
increasing the duration of the color burst by adding a first portion to the color burst duration between the trailing edge of horizontal sync and the beginning of a normal duration of color burst; further increasing the duration of the color burst by adding a second portion following the normal duration of the color burst that end prior to the beginning of active video.
- 22. The method of claim 19, wherein the step of phase modulation comprises:
modifying a phase of a first portion of the modified color burst duration and retaining a normal burst phase in a second portion of the modified color duration.
- 23. The method of claim 13, wherein the video signal is an NTSC video signal.
- 24. The method of claim 13, where the video signal is a PAL video signal.
- 25. A method of inhibiting the making of an acceptable video recording of a PAL video signal, the video signal including a plurality of video lines, each video line including a color burst having a predetermined phase, the method comprising the steps of:
determining a duration of the color burst; and modifying the phase of the color burst so that the average in said plurality of lines having the phase vectors of said modified signals is nearly 180° opposite the average in said plurality of lines having the phase vectors of the proper color burst signals, whereby making of an acceptable video recording of the video signal is inhibited.
- 26. The method of claim 25, wherein the step of modifying the phase of the color burst comprises the step of:
modifying an NTSC burst by −90°.
- 27. The method of claim 25, wherein the step of modifying the phase of the color burst comprises the step of:
modifying a PAL burst by +90°.
- 28. An apparatus for inhibiting the making of an acceptable video recording of a video signal, the video signal including a plurality of video lines, each video line including a color burst having a predetermined phase, comprising:
a burst gate generator to produce a burst gate signal which is coupled to a subcarrier processor; a line generator to produce a line count to the subcarrier processor; the subcarrier processor produces modified color burst signals so as produce a copy protection video signal, whereby making of an acceptable video recording of the video signal is inhibited.
- 29. An apparatus for inhibiting the making of an acceptable video recording of a video signal, the video signal including a plurality of video lines, each video line including a color burst having a predetermined phase, comprising:
an input amplifier coupled to a sync separator and a chroma separator; the sync separator provides a separated sync to a burst gate generator, a burst blanker and a line counter; the chroma separator separates the chroma from the video signal and couples the burst gate generator produces a burst gate signal which is coupled to a subcarrier processor; a line generator to produce a line count to the subcarrier processor; the subcarrier processor produces modified color burst signals so as produce a copy protection video signal, whereby making of an acceptable video recording of the video signal is inhibited.
- 30. In order to restrict recording when a digital video signal is pre-recorded and a digital video signal is played back by playback equipment and output as an analog video signal, a recording medium features pre-recorded information that indicates the placements of copy-prevention signals whose phases are controlled so that the average of the phase vectors of the proper color burst signals that are originally placed on said plurality of lines is nearly 180° opposite the average in said plurality of lines having the phase vectors of the modified color burst signals for a plurality of consecutive lines of said analog video signal.
Priority Claims (1)
Number |
Date |
Country |
Kind |
PCT/US96/17719 |
Nov 1996 |
US |
|
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation-in-part application of Ser. No. 08/438,155, filed May 9, 1995 entitled METHOD AND APPARATUS FOR DEFEATING EFFECTS OF COLOR BURST MODIFICATIONS TO A VIDEO SIGNAL BY Ronald Quan and John O. Ryan.
[0002] This application claims the benefit of U.S. Provisional Application Numbers: Ser. No. 60/010015, entitled AN IMPROVED METHOD AND APPARATUS FOR MODIFYING THE COLOR BURST TO PROHIBIT VIDEOTAPE RECORDING by William J. Wrobleski; filed Jan. 16, 1996.; Ser. No. 60/010,779 entitled AN ADVANCED COLOR BURST AND APPARATUS FOR MODIFYING THE COLOR BURST TO PROHIBIT VIDEO TAPE RECORDING by William J. Wrobleski., filed Jan. 29, 1996; Ser. No. 60/014,246 entitled A SYSTEM AND METHOD FOR COPY PROTECTION OF VIDEO RECORDING USING AN ADVANCED AND SPLIT COLOR BURST SYSTEM by William J. Wrobleski filed Mar. 26, 1996; Ser. No. 60/024,393 entitled METHOD OF COPY PROTECTION OF A PAL COLOR VIDEO SIGNAL by William J. Wrobleski filed Jun. 28, 1996; and Ser. No. 60/021,645 entitled METHOD OF IMPROVED COPY PROTECTION OF A PAL COLOR VIDEO SIGNAL by William J. Wrobleski filed Jul. 12, 1996. All of the above co-pending applications are incorporated by reference.
Provisional Applications (5)
|
Number |
Date |
Country |
|
60010015 |
Jan 1996 |
US |
|
60010779 |
Jan 1996 |
US |
|
60014246 |
Mar 1996 |
US |
|
60024393 |
Jun 1996 |
US |
|
60021645 |
Jul 1996 |
US |
Divisions (1)
|
Number |
Date |
Country |
Parent |
09091661 |
Jun 1998 |
US |
Child |
10174706 |
Jun 2002 |
US |
Continuations (1)
|
Number |
Date |
Country |
Parent |
08438155 |
May 1995 |
US |
Child |
08897132 |
Jul 1997 |
US |
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
08897132 |
Jul 1997 |
US |
Child |
09091661 |
Jun 1998 |
US |