Digital entroping for digital audio reproductions

• US 7,177,430 B2
• Filed: 10/31/2001
• Issued: 02/13/2007
• Est. Priority Date: 10/31/2001
• Status: Active Grant

• Current Assignee: NVIDIA Corporation
• Original Assignee: PortalPlayer USA, Inc. (NVIDIA Corporation)
• Inventors: Kim, Jason Seung-Min
• Primary Examiner(s): Moazzami; Nasser
• Assistant Examiner(s): Sherkat; Arezoo
• Application Number:
  US10/000,700
• Publication Number:
  US 20030081780A1
• Time in Patent Office: 1,931 Days
• Field of Search: 380/252, 380/269, 713/200, 704/200.1
• US Class Current: 380/252
• CPC Class Codes: G11B 20/00086 Circuits for prevention of unauthorised reproduction or copying, e.g. piracy indicating unauthorised use of record carriers in general G11B23/28; scrambling for television signal recording H04N5/913; network architectures or network protocols for network security H04L63/00; cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00
• CPC Class Codes: G11B 20/00826 wherein a spoiler signal is added to degrade the signal quality
• CPC Class Codes: H04K 1/02 by adding a second signal to make the desired signal unintelligible

Abstract

The present invention provides a system and method for introducing white noises into a digital audio signal so that there is progressive and cumulative degradation in audio quality after each successive reproduction of the audio sound signal in a fashion analogous to analog audio reproduction. The invention provides a white noise generator, and a digital entroping unit. In a preferred embodiment, the white noise generator is implemented by a hardware random number generator. The digital entroping unit controls the magnitude of white noise desired based on a random number generated by the random number generator, and adds the white noise to the input audio sound signal to produce a degraded audio sound signal. The magnitude of white noise can be controlled by using various masking and formatting of random number data.

Claims

1. A method for progressive degradation of a digital audio signal to prevent unauthorized reproduction of said digital audio signal comprising:

generating white noise; and

degrading said digital audio signal using said white noise to produce a degraded digital audio signal, so that a cumulative degradation effect is obtained during a successive reproduction of said digital audio signal.

2. The method of claim 1 wherein said white noise is a random number comprising a plurality of digital bits.

3. The method of claim 2 wherein said degrading comprises adding a predetermined number of said plurality of digital bits to said digital audio signal.

4. The method of claim 3 wherein said predetermined number is one (1).

5. The method of claim 4 wherein said adding said predetermined number of said plurality of digital bits comprises adding a least significant bit of said random number.

6. The method of claim 4 wherein said adding said predetermined number of said plurality of digital bits comprises adding a most significant bit of said random number.

7. The method of claim 3 wherein said predetermined number is two (2).

8. The method of claim 7 wherein said adding said predetermined number of said plurality of digital bits comprises adding two (2) least significant bits of said random number.

9. The method of claim 7 wherein said adding said predetermined number of said plurality of digital bits comprises adding two (2) most significant bits of said random number.

10. A computer program product for use in conjunction with a computer system, the computer program product comprising a computer readable storage medium and a computer program mechanism embedded therein, the computer program mechanism comprising:

instructions for generating white noise, and

instructions for degrading a digital audio signal using said white noise to produce a degraded digital audio signal so that a cumulative degradation effect is obtained during a successive reproduction of said digital audio signal.

11. The computer program product of claim 10 wherein said white noise is a random number comprising a plurality of digital bits.

12. The computer program product of claim 11 wherein said degrading comprises adding a predetermined number of said plurality of digital bits to said digital audio signal.

13. The computer program product of claim 12 wherein said predetermined number is one (1).

14. The computer program product of claim 13 wherein said adding said predetermined number of said plurality of digital bits comprises adding a least significant bit of said random number.

15. The computer program product of claim 12 wherein said predetermined number is two (2).

16. The computer program product of claim 15 wherein said adding said predetermined number of said plurality of digital bits comprises adding a least significant bit of said random number.

17. A method for progressive degradation of a digital audio signal, comprising:

generating a random number;

selecting a predetermined number of bits of said random number;

adding said predetermined number of bits to said digital audio signal to produce a degraded digital audio signal, and

wherein said predetermined number of bits of said random number is selected so that said degraded digital audio signal represents approximately 3 dB difference from said digital audio signal and,

wherein the adding said predetermined number of bits provides cumulative degradation in successive reproductions of said digital audio signal.

18. The method of claim 17 wherein said predetermined number of bits comprises a least significant bit of said random number.

19. The method of claim 17 wherein said predetermined number of bits comprises a most significant bit of said random number.

20. A computer program product for use in conjunction with a computer system, the computer program product comprising a computer readable storage medium and a computer program mechanism embedded therein, the computer program mechanism comprising:

instructions for obtaining a random number;

instructions for selecting a predetermined number of bits of said random number; and

instructions for adding said predetermined number of bits to said digital audio signal to produce a degraded digital audio signal, wherein said predetermined number is selected so that said degraded digital audio signal represents approximately 3 dB difference from said digital audio signal and,

wherein the adding said predetermined number of bits provides cumulative degradation in successive reproductions of said digital audio signal.

21. The computer program product of claim 20 wherein said predetermined number of bits comprises a least significant bit of said random number.

22. The computer program product of claim 20 wherein said predetermined number of bits comprises a most significant bit of said random number.

23. A method for progressive degradation of digital audio signal comprising a plurality of pulse code modulated audio data, wherein said pulse code modulated audio data each comprises a plurality of bits, said method comprising:

(a) generating a random number comprising sixteen (16) bits,

(b) selecting a predetermined number of bits of said random number;

(c) adding said predetermined number of bits to a first pulse code modulated audio data of said digital audio signal; and

(d) repeating (a)–

(c) until said plurality of pulse code modulated audio data are processed to produce degraded digital audio signal,

whereby said degraded digital audio signal is degraded approximately 3 dB from said digital audio signal, wherein

said digital audio signal is degraded by said approximately 3 dB for each successive reproduction of said digital audio signal.

24. The method of claim 23 wherein said predetermined number of bits comprise a least significant bit (LSB).

25. The method of claim 24 wherein said predetermined number of bits comprise a most significant bit (MSB).

26. A computer program product for use in conjunction with a computer system, the computer program product comprising a computer readable storage medium and a computer program mechanism embedded therein, the computer program mechanism comprising:

(a) instructions for obtaining a random number comprising sixteen (16) bits;

(b) instructions for selecting a predetermined number of bits of said random number;

(c) instructions for adding said predetermined number of bits to a first pulse code modulated audio data of said digital audio signal; and

(d) instructions for repeating (a)–

(c) until said plurality of pulse code modulated audio data are processed to produce degraded digital audio signal, whereby said degraded digital audio signal is degraded approximately 3 dB from said digital audio signal, wherein

said digital audio signal is degraded by said approximately 3 dB for each successive reproduction of said digital audio signal.

27. The computer program product of claim 26 wherein said random number is generated by a random number generator comprising linear feedback shift registers (LFSR).

28. The computer program product of claim 27 wherein said predetermined number of bits comprise a least significant bit (LSB).

29. The computer program product of claim 28 wherein said predetermined number of bits comprise a most significant bit (MSB).

30. A system for progressive quality degradation in reproduction of digital audio signal comprising a plurality of pulse code modulated audio data, said system comprising:

a white noise generator to generate white noise;

means for degrading said digital audio signal using said white noise, and

whereby said degrading cumulatively affects reproduction of said digital audio signal so that repeated applications of said white noise to said digital audio signal progressively degrade said digital audio signal.

31. The system of claim 30 wherein said white noise comprises a random number generated by a random number generator comprising linear feedback shift registers (LFSR).

32. The system of claim 31 wherein said means for degrading said digital audio signal comprises means for adding said random number to said digital audio signal.

33. A system for progressive quality degradation in reproduction of digital audio signal comprising a plurality of pulse code modulated audio data, said system comprising:

a random number generator to generate a random number; and

a digital entroping unit for adding said random number to a pulse code modulated audio data, whereby wherein said random number is added during each reproduction of said digital audio signal and a cumulative degradation effect is obtained during successive reproductions of said digital audio signal.

34. The system of claim 33 wherein said random number generator comprises linear feedback shift registers (LFSR).

35. The system of claim 34 wherein said digital entroping unit further comprising means for adding a predetermined number of bits of said random number to said pulse code modulated audio data.

36. A method for degrading a digital audio signal input to prevent unauthorized reproduction of said digital audio signal comprising:

generating white noise; and

adding said white noise to said digital audio signal input to produce a digital audio signal output, wherein said white noise is added during each unauthorized reproduction of said digital audio signal and a cumulative degradation effect is obtained during successive reproductions of said digital audio signal.

37. The method of claim 36 wherein said white noise is a random number comprising a plurality of digital bits.

38. The method of claim 37 wherein a predetermined number of said plurality of digital bits is added to said digital audio signal input.

39. The method of claim 38 wherein said predetermined number is an integer or fixed number.

40. The method of claim 39 wherein said adding said predetermined number of said plurality of digital bits comprises adding a least significant bit of said random number.

41. The method of claim 40 wherein said adding said predetermined number of said plurality of digital bits comprises adding a most significant bit of said random number.

42. A method for progressive degradation of a plurality of digital audio data, comprising:

generating a number;

selecting a predetermined number of bits of said number;

randomly selecting a subset of said plurality of digital audio data to which to add said predetermined number of bits; and

adding said predetermined number of bits to a digital audio data to progressively produce a degraded digital audio data, wherein said predetermined number of bits is added during a successive reproduction of said digital audio data.

43. The method of claim 42 wherein said selecting comprises:

generating a random number; and

determining whether to add said predetermined number of bits based upon said random number.

44. The method of claim 43 wherein said predetermined number of bits of said number is selected so that said degraded digital audio data represents approximately 3 dB difference from said digital audio data.

45. The method of claim 44 wherein said predetermined number of bits comprises a least significant bit of said number.

46. The method of claim 44 wherein said predetermined number of bits comprises a most significant bit of said number.

47. A computer program product for progressive degradation of a plurality of digital audio data, the computer program product comprising a computer readable storage medium and a computer program mechanism embedded therein, the computer program mechanism comprising:

instructions for obtaining a number;

instructions for selecting a predetermined number of bits of said number;

instructions for randomly selecting a subset of said plurality of digital audio data to which to add said predetermined number of bits; and

instructions for adding said predetermined number of bits to a digital audio data to progressively produce a degraded digital audio data, wherein said predetermined number of bits is added during a successive reproduction of said digital audio data.

48. The computer program product of claim 47 wherein said instructions for selecting comprises:

instructions for generating a random number; and

instructions for determining whether to add said predetermined number of bits based upon said random number.

49. The computer program product of claim 48 wherein said predetermined number is selected so that said degraded digital audio data represents approximately 3 dB difference from said digital audio data.

50. The computer program product of claim 49 wherein said predetermined number of bits comprises a least significant bit of said number.

51. The computer program product of claim 50 wherein said predetermined number of bits comprises a most significant bit of said number.