Signature-based program identification apparatus and methods for use with digital broadcast systems

1. A method comprising:

receiving a digital data stream at a consumer site;

storing the digital data stream until playback;

generating digital signatures from the digital data stream during playback of the digital data stream at the consumer site by:

extracting a first non-payload portion from a first data packet of the digital data stream, the first data packet including the first non-payload portion and a first payload portion;

extracting a second non-payload portion from a second data packet of the digital data stream, the first data packet and the second data packet included in a first block of consecutive data packets;

concatenating the first non-payload portion and the second non-payload portion to form a first digital signature;

extracting a third non-payload portion from a third data packet, the third data packet including the third non-payload portion and a second payload portion;

extracting a fourth non-payload portion from a fourth data packet of the digital data stream, wherein the third data packet and the fourth data packet are included in a second block of consecutive data packets; and

concatenating the third non-payload portion and the fourth non-payload portion to form a second digital signature;

comparing the first digital signature and the second digital signature to one or more reference signatures in a reference signature database; and

identifying the digital data stream based on the comparison.

2. A method as described in claim 1 , further comprising:

associating a first time value with the digital data stream indicating when the digital data stream was received at the consumer site; and

associating the first time value with the first digital signature when the first digital signature is generated during playback.

3. A method as described in claim 2 , further comprising:

associating a second time value with each reference signature in the reference signature database;

calculating a delay window for the second time value associated with each reference signature; and

comparing the first digital signature to one or more of the reference signatures when the first time value associated with the first digital signature falls within the delay window of the second time value of one or more of the reference signatures.

4. A method as described in claim 1 , further comprising developing the reference signature database based on one or more digital data streams received at a reference site, the reference signature database including a reference signature for each digital data stream received, and wherein the reference signature database is generated at the reference site.

5. A method as described in claim 1 , wherein the digital data stream is delivered via a local device.

6. A method as described in claim 5 , wherein the local device is a digital video recorder.

7. An apparatus comprising:

a signal processor to:

receive a digital data stream at a consumer site; and

store the digital data stream until playback;

a signature generator to generate digital signatures from the digital data stream during playback of the digital data stream at the consumer site by:

extracting a first non-payload portion from a first data packet of the digital data stream, the first data packet including the first non-payload portion and a first payload portion;

extracting a second non-payload portion from a second data packet of the digital data stream, the first data packet and the second data packet included in a first block of consecutive data packets;

concatenating the first non-payload portion and the second non-payload portion to form a first digital signature;

extracting a third non-payload portion from a third data packet, the third data packet including the third non-payload portion and a second payload portion;

extracting a fourth non-payload portion from a fourth data packet of the digital data stream, wherein the third data packet and the fourth data packet are included in a second block of consecutive data packets; and

concatenating the third non-payload portion and the fourth non-payload portion to form a second digital signature; and

a program consumption analyzer to compare the first digital signature and the second digital signature to one or more reference signatures in a reference signature database.

8. An apparatus as defined in claim 7 , wherein the program consumption analyzer is to identify the digital data stream based on the comparison.

9. An apparatus as defined in claim 7 , further comprising:

a time stamper to associate a first time value with the first digital signature based on when the first digital signature is generated during playback; and

wherein the program consumption analyzer is to:

calculate a delay window for a second time value associated with each reference signature in the reference signature database; and

compare the first digital signature to one or more of the reference signatures in the reference signature database when the first time value associated with the first digital signature falls within the delay window of the second time value of one or more of the reference signatures.

10. An apparatus as defined in claim 7 , wherein the reference signature database is to store one or more reference signatures, wherein each reference signature corresponds to a digital data stream received at a reference site, and wherein the reference signature database is generated at the reference site.

11. An apparatus as defined in claim 7 , wherein the digital data stream is delivered via a local device.

12. An apparatus as defined in claim 11 , wherein the local device is a digital video recorder.

13. A machine readable storage device or storage disc comprising instructions that, when executed, cause a machine to at least:

receive a digital data stream at a consumer site;

store the digital data stream until playback;

generate digital signatures from the digital data stream during playback of the digital data stream at the consumer site by:

extracting a first non-payload portion from a first data packet of the digital data stream, the first data packet including the first non-payload portion and a first payload portion;

extracting a second non-payload portion from a second data packet of the digital data stream, the first data packet and the second data packet included in a first block of consecutive data packets;

concatenating the first non-payload portion and the second non-payload portion to form a first digital signature;

extracting a third non-payload portion from a third data packet, the third data packet including the third non-payload portion and a second payload portion;

extracting a fourth non-payload portion from a fourth data packet of the digital data stream, wherein the third data packet and the fourth data packet are included in a second block of consecutive data packets; and

concatenating the third non-payload portion and the fourth non-payload portion to form a second digital signature; and

compare the first digital signature and the second digital signature to one or more reference signatures in a reference signature database.

14. A machine readable storage device or storage disc as defined in claim 13 , wherein the instructions further cause the machine to identify the digital data stream based on the comparison.

15. A machine readable storage device or storage disc as defined in claim 13 , wherein the instructions further cause the machine to:

associate a first time value with the digital data stream based on when the digital data stream is received;

associate the first time value with the first digital signature when the first digital signature is generated during playback;

associate a second time value with each reference signature in the reference signature database;

calculate a delay window for the second time value associated with each reference signature; and

compare the first digital signature to one or more of the reference signatures in the reference signature database when the first time value associated with the digital signature falls within the delay window of the second time value of one or more of the reference signatures.

16. A machine readable storage device or storage disc as defined in claim 13 , wherein the instructions further cause the machine to store one or more reference signatures, wherein each reference signature corresponds to a digital data stream received at a reference site, and wherein the reference signature database is generated at the reference site.

17. A machine readable storage device or storage disc as defined in claim 13 , wherein the digital data stream is delivered via a local device.

18. A machine readable storage device or storage disc as defined in claim 17 , wherein the local device is a digital video recorder.

19. A method as defined in claim 1 , wherein the non-payload portions of the data packets are offset a predetermined number of bits from a header portion of the data packets.

20. An apparatus as defined in claim 7 , wherein the signature generator is to form the digital signatures by:

identifying portions of the data packets offset a predetermined number of bits from the header portion of the data packets, and

concatenating the identified portions of the data packets.

21. A method as defined in claim 1 , wherein the non-payload portion of the digital data stream includes a cyclical redundancy check.

22. A method as defined in claim 1 , wherein the first data packet and the second data packet are consecutive data packets in the digital data stream.

23. A method as defined in claim 1 , wherein the first data packet and the second data packet are at least two data packets apart in the digital data stream.

24. A method as defined in claim 1 , wherein the first block of consecutive data packets and the second block of consecutive data packets are separated by a time delay.

25. A method as defined in claim 1 , wherein the first block of consecutive data packets and the second block of consecutive data packets are separated by a third block of consecutive data packets.

26. A method as defined in claim 1 , wherein identifying the digital data stream further comprises:

comparing the first digital signature and the second digital signature to the one or more reference signatures in the reference signature database; and

identifying the digital data stream based on the comparison.

27. A method as defined in claim 1 , wherein the first data packet includes the first non-payload portion, the payload portion and a fifth non-payload portion.

28. A method as defined in claim 1 , further comprising extracting a first subset of the first non-payload portion and a second subset of the second non-payload portion to form the first digital signature.