Method and apparatus for video tag signal recovery using various techniques to regenerate and re-record the tag signal

• US 6,594,441 B1
• Filed: 12/01/1999
• Issued: 07/15/2003
• Est. Priority Date: 12/01/1999
• Status: Expired due to Term

• Current Assignee: Marking Object Virtualization Intelligence, LLC
• Original Assignee: Macrovision Corporation (Adeia Inc.)
• Inventors: Holzgrafe, James R.
• Primary Examiner(s): Boccio, Vincent
• Assistant Examiner(s): Fletcher, James A.
• Application Number:
  US09/452,354
• Time in Patent Office: 1,322 Days
• Field of Search: 386/94, 386/95, 386/102, 386/108, 380/203, 380/201, 380/217, 380/239
• US Class Current: 386/260
• CPC Class Codes: H04N 2005/91328 the copy protection signal being a copy management signal, e.g. a copy generation management signal [CGMS]
• CPC Class Codes: H04N 2005/91335 the copy protection signal being a watermark
• CPC Class Codes: H04N 2005/91357 by modifying the video signal
• CPC Class Codes: H04N 5/913 for scrambling ; for copy protection
• CPC Class Codes: H04N 5/9201 involving the multiplexing of an additional signal and the video signal

Abstract

In typical prior art generational copy protection processes, a video tag signal is added to a watermarked and/or copy protected video signal to prevent the production of unauthorized second generation copies and the playback of illicit second generation copies. This application discloses a means for defeating the tag signal/watermark copy protection process. To this end, various embodiments are disclosed by which the tag signal is recovered, converted to a selected tag representation and is carried or stored in some manner, concurrently with the recording of a first generation copy of the video signal, which may or may not be tagless. The first generation copy is played back and the tag representation is converted to a regenerated tag signal which is selectively re-inserted in the reproduction of the first generation copy prior to recording a second generation copy, which now is playable.

Claims

1. A method of restoring a tag signal in a video signal containing the tag signal and a watermark for copy protection, wherein the tag signal is removed from its location in a first generation copy to prevent unauthorized second generation copies and playback of the copies, comprising the steps of:

recovering the tag signal from the copy protected video signal;

recording the first generation copy of the video signal which includes the watermark;

concurrently saving by some suitable means the recovered tag signal; and

inserting the saved tag signal into a reproduction of the first generation copy to enable the recording of a second generation copy of the video signal which is playable.

2. The method of claim 1 wherein the steps of recovering and saving include:

reading the tag signal in the copy protected video signal;

converting the recovered tag signal to a tag representation of selected format; and

storing the converted tag representation for subsequent readout.

3. The method of claim 2 wherein the tag representation is an in-frame signal, a video signal, a digital data signal or an audio signal.

4. The method of claim 2 wherein the step of inserting includes:

synthesizing the stored converted tag representation to provide a regenerated tag signal; and

adding the regenerated tag signal to the reproduction of the first generation copy prior to recording the second generation copy.

5. The method of claim 4 wherein the tag signal is one or more pulses in a specific location or locations in the video signal, and the step of adding restores the regenerated tag signal into the corresponding specific location or locations in the second generation copy of the video signal.

6. The method of claim 5 wherein the tag signal location or locations is in-frame or out-of-frame.

7. The method of claim 1 wherein the video signal includes blanking intervals and said tag signal is located out-of-frame and thus in a portion of the blanking intervals, and wherein:

the step of recovering includes converting the out-of-frame tag signal to an in-frame video component;

wherein the in-frame video component is added to the video signal prior to recording the first generation copy; and

the step of inserting includes synthesizing a regenerated tag signal from the in-frame video component and adding the regenerated tag signal back into the reproduction of the first generation copy in the original out-of-frame location prior to recording the playable second generation copy.

8. The method of claim 7 wherein the in-frame video component location is any portion of the video signal which is actually recorded, and reproduced rather than synthesized.

9. The method of claim 7 wherein the in-frame video component includes configurations such as an amplitude modulated colored pulse, a position modulated pulse, a colored patch with tag information color modulation, and/or an audio signal.

10. The method of claim 1 wherein the tag signal comprises one or more pulses at a specific time location or locations in the video signal, wherein:

the step of recovering includes converting the tag signal to a video signal component;

the step of saving includes storing the video signal component corresponding to the tag signal in a separate storage means in synchronism with the first generation copy; and

the step of inserting includes recovering the video signal component from the separate storage means, synthesizing a regenerated tag signal from the video signal component, and adding in real time the regenerated tag signal back into the reproduction of the first generation copy in the original time location or locations prior to the recording of the playable second generation copy.

11. The method of claim 10 wherein the step of converting includes:

providing amplitude or position modulation of the pulse or pulses, frequency or phase modulation of a chroma/subcarrier signal, and/or an audio signal employing any suitable modulation process and recorded on one or more audio channels of the separate storage means.

12. The method of claim 1 wherein the tag signal comprises one or more pulses at a specific time location or locations in the video signal, wherein:

the step of recovering includes converting the tag signal into a tag representation commensurate with the pulse or pulses;

the step of saving includes storing the tag representation as digital data in a storage medium in any convenient format; and

the step of inserting includes reading the stored digital data, synthesizing a regenerated tag signal from the digital data in real time and adding the regenerated tag signal into the reproduced first generation copy in synchronism therewith prior to the recording of the playable second generation copy.

13. The method of claim 12 wherein the digital data is stored in a computer file or other non-volatile memory, or retained in a volatile memory.

14. The method of claim 12 wherein the steps of converting and storing are performed in a computer, wherein the video signal is first converted from analog to digital format and is stored along with the digital data in the computer'"'"'s memory.

15. The method of claim 14 wherein the steps of reading, synthesizing and adding are performed in the computer.

16. The method of claim 12 wherein the steps of converting and storing are performed in a computer, wherein the video signal is first converted from analog to digital format and is stored along with the digital data in a non-volatile or volatile storage medium.

17. The method of claim 12 wherein:

the step of storing includes;

determining the exact length of an actual digital tag sequence; and

storing the exact length of the actual digital tag sequence; and

the step of inserting includes;

playing back the first generation copy;

simultaneously and repetitively reading the stored actual digital tag sequence to synthesize the regenerated tag signal in real time; and

adding the regenerated tag signal to the reproduced first generation copy in synchronism therewith.

18. The method of claim 17 wherein the length of the actual digital tag sequence is stored in non-volatile or volatile storage medium.

19. The method of claim 17 wherein the step of determining includes:

storing a number of bits well in excess of any reasonable actual digital tag sequence length; and

performing an autocorrelation process on the stored excessive number of bits to determine the actual digital tag sequence length.

20. The method of claim 17 wherein the step of determining is performed by a hardware autocorrelator.

21. The method of claim 12 wherein:

the step of storing includes;

applying the digital data to an input shift register of a hardware autocorrelator, the shift register being of length sufficient to store a sequence of bits well in excess of the expected actual digital tag sequence length;

determining the exact length of the actual digital tag sequence;

storing the exact length of the actual digital tag sequence in convenient form; and

the step of inserting includes;

simultaneously and repetitively reading the stored actual digital tag sequence to synthesize the regenerated tag signal in real time; and

adding the regenerated tag signal at the specific time location or locations to the reproduced first generation copy.

22. The method of claim 21 wherein the shift register is non-volatile and is configured as a circular shift register which clocks out a continuous repetition of the actual digital tag sequence.

23. A method of restoring a tag signal in a second generation and beyond playable copy of copy protected program material, wherein the tag signal is removed from its location in a first generation copy of the copy protected program material, comprising the steps of:

recovering the tag signal from the copy protected program material;

storing the recovered tag signal in a suitable manner for subsequent readout; and

adding the stored tag signal, upon readout, back into a reproduced first generation copy of the program material, to allow the production of the second generation and beyond playable copy or copies.

24. The method of claim 23 including the steps of:

converting the recovered tag signal into a selected format signal;

wherein the step of storing includes storing the selected format signal; and

synthesizing a regenerated tag signal from the stored selected format signal, said regenerated tag signal being added to the reproduced first generation copy.

25. The method of claim 24 wherein the selected format signal comprises an actual tag sequence of exact length, which sequence is repeated for the duration of the program material, and wherein one or more actual tag sequence(s) of exact length are stored, and read synchronously and repetitively during the step of adding.

26. The method of claim 24 wherein the program material includes out-of-frame intervals in which said tag signal is located, and wherein:

the step of converting includes converting the out-of-frame tag signal to an in-frame component; and

the in-frame component is added to the copy protected program material; and

the method includes the steps of;

recording the first generation copy of the program material with the added in-frame component;

synthesizing a regenerated tag signal from the in-frame component of the reproduced first generation copy; and

wherein the step of adding includes adding the regenerated tag signal into the reproduced first generation copy at the original out-of-frame location.

27. The method of claim 24 wherein the tag signal comprises one or more pulses at a specific time location or locations in the program material, wherein:

the step of converting includes converting the tag signal to a video signal component; and

the video signal component is stored in a separate storage means in synchronism with the first generation copy; and

the step of synthesizing includes reading the video signal component from the separate storage means in synchronism with the reproduced first generation copy, and synthesizing the regenerated tag signal therefrom.

28. A method of restoring a tag signal in a video signal containing the tag signal and a watermark for copy protection, wherein the tag signal is removed in a first generation copy of the video signal, comprising the steps of:

recovering the tag signal from an out-of-frame location;

converting the out-of-frame tag signal to an in-frame video component;

adding the in-frame video component to the video signal prior to recording the first generation copy;

recording the first generation copy with the in-frame video component and the watermark;

synthesizing an out-of-frame tag signal from the recorded in-frame video component; and

adding the out-of-frame tag signal back into a reproduction of the first generation copy prior to recording a second generation copy thereof which is playable.

29. The method of claim 28 wherein the synthesized out-of-frame tag signal is added to the reproduction of the first generation copy in the original out-of-frame location in the video signal.

30. A method of restoring a tag signal in a video signal containing the tag signal and a watermark for copy protection, wherein the tag signal is removed in a first generation copy of the video signal, comprising the steps of:

recovering the tag signal from the video signal;

converting the tag signal into a tag representation of the tag signal;

storing the tag representation in a storage medium in any convenient format;

recording the first generation copy with or without the tag signal;

synthesizing a regenerated tag signal from the stored tag representation;

adding the regenerated tag signal into a reproduction of the first generation copy prior to recording a second generation copy thereof which is playable.

31. The method of claim 30 wherein the tag signal comprises one or more pulses at a specific time location in the video signal, and the regenerated tag signal is added into the reproduction of the first generation copy in the original location in the video signal.

32. A method of restoring a tag signal in a video signal containing the tag signal and a watermark for copy protection, wherein the tag signal is removed from its location in a first generation copy to prevent unauthorized second generation copies and playback of the copies, comprising the steps of:

saving a version of the tag signal from the copy protected video signal;

recording the first generation copy which is not copiable;

reproducing the uncopiable first generation copy;

synthesizing a regenerated tag signal from the saved version of the tag signal; and

providing the first generation copy with the synthesized regenerated tag signal to enable producing a second generation copy.

33. The method of claim 32 wherein:

the step of saving includes recovering the tag signal and converting the recovered tag signal to said version thereof; and

the step of providing includes inserting the regenerated tag signal in the first generation copy prior to producing the second generation copy.

34. The method of claim 33 wherein the tag signal is an out-of-frame tag, wherein:

the step of converting includes converting the out-of-frame tag to an in-frame tag representation;

adding the in-frame tag representation to the video signal prior to recording the first generation copy;

synthesizing the regenerated tag signal from the in-frame tag representation; and

adding the synthesized regenerated tag signal to the reproduced first generation copy in the out-of-frame location.

35. The method of claim 33 wherein:

said version is a tag representation which is stored in a suitable storage medium concurrently with recording the first generation copy; and

the regenerated tag signal is synthesized from the stored tag representation and is added to the reproduced first generation copy.

36. The method of claim 32 wherein the tag version is stored in the video signal.

37. The method of claim 32 wherein the tag version is stored in a suitable storage medium.

38. Apparatus for restoring a tag signal in a second generation copy of a video signal containing the tag signal and a watermark for copy protection, wherein the tag signal is removed from its location in a first generation copy of the copy protected video signal, comprising:

means for saving a version of the tag signal concurrently with recording the first generation copy;

means for reproducing the recorded first generation copy;

means for synthesizing a regenerated tag signal from the saved version of the tag signal; and

inserter means for adding the regenerated tag signal to the reproduced first generation copy prior to producing the second generation copy which now is playable.

39. The apparatus of claim 38 wherein the saving means includes:

autocorrelator means for determining the exact length of an actual digital tag sequence forming the version of the tag signal; and

wherein the synthesizing means repetitively and synchronously provides the actual digital tag sequence to generate the regenerated tag signal added via the inserter means.

40. The apparatus of claim 39 wherein the autocorrelator means is a hardware autocorrelator.

41. The apparatus of claim 40 wherein the hardware correlator includes:

a shift register of length sufficient to store a sequence of bits well in excess of the actual digital tag sequence length;

an array of logic gates coupled to the shift register; and

a decision unit including accumulator means coupled to the array of logic gates for indicating the exact length of the actual digital tag sequence.

42. The apparatus of claim 38 wherein:

the means for saving include a tag recovery circuit, a conversion circuit for converting the recovered tag signal to a tag representation corresponding to the version, and a storage means for saving the tag representation.

43. The apparatus of claim 42 wherein the tag representation is saved in the video signal concurrently with recording the first generation copy.

44. The apparatus of claim 42 wherein the tag representation is stored in a suitable storage means concurrently with recording the first generation copy.

45. The apparatus of claim 42 wherein the tag signal is one or more pulses in a specific location or locations in the copy protected video signal, and the inserter means adds the regenerated tag signal into the corresponding specific location or locations in the reproduced first generation copy prior to recording the second generation copy.

46. The apparatus of claim 42 including:

a recorder/reproducer for recording and reproducing the first generation copy; and

a synthesis circuit coupled to the recorder/reproducer for generating the regenerated tag signal in synchronism with the reproduced first generation copy.

47. The apparatus of claim 42 wherein the tag signal is located out-of-frame in the copy protected video signal, wherein:

the conversion circuit converts the out-of-frame signal to an in-frame video component;

the storage means saves the in-frame video component in the copy protected video signal concurrently with recording the first generation copy thereof;

the synthesizing means generates the regenerated tag signal in the form of the original out-of-frame tag signal; and

the inserter means adds the regenerated out-of-frame tag signal to the reproduced first generation copy in its original location.

48. The apparatus of claim 42 wherein the storage means comprises a computer file or other non-volatile memory, or a volatile memory which is not turned off during the storage period.

49. The apparatus of claim 42 wherein the means for saving, the means for synthesizing and the inserter means comprise a computer.

50. The apparatus of claim 42 wherein:

the tag recovery and conversion circuits determine the exact length of an actual digital tag sequence;

the storage means store the actual digital tag sequence; and

the synthesizing means repetitively and synchronously read the stored actual digital tag sequence from the storage means to generate the regenerated tag signal which is added via the inserter means.

51. The apparatus of claim 50 wherein the tag recovery and conversion circuits include:

means for storing a number of bits well in excess of any reasonable number of bits forming the actual digital tag sequence length; and

means for performing an autocorrelation process on the stored excessive number of bits to determine the actual digital tag sequence length.