Simulcast resolution in content matching systems

1. A method to identify media sources, the method comprising:

comparing monitored signatures generated from monitored media with reference signatures generated from reference media provided by a plurality of reference sources;

determining tracking segments associated with respective ones of the reference sources, each tracking segment representing sequences of matches between the monitored signatures and respective reference signatures for a respective one of the reference sources; and

evaluating time lengths of the tracking segments to identify which reference source in the plurality of reference sources provided the monitored media.

2. A method as defined in claim 1 wherein the monitored signatures and the reference signatures include respective timestamps, and comparing the monitored signatures with the reference signatures comprises:

comparing the monitored signatures with a first group of the reference signatures having a range of times within a first time tolerance when the monitored media has been determined to be associated with live media; and

comparing the monitored signatures with a second group of the reference signatures having a range of times within a second time tolerance greater than the first tolerance when the monitored media has been determined to not be associated with live media.

3. A method as defined in claim 1 wherein the monitored signatures and the reference signatures include respective timestamps, and determining the tracking segments comprises:

determining whether a first time difference between a first monitored signature and a second monitored signature is substantially similar to a second time difference between a first reference signature determined to match the first monitored signature and a second reference signature determined to match the second monitored signature, the first reference signature and the second reference signature associated with a first reference source; and

if the first time difference and the second time difference are substantially similar, augmenting a respective tracking segment associated with first reference source to indicate that the second reference signature matched the second monitored signature.

4. A method as defined in claim 3 wherein augmenting the respective tracking segment comprises storing the second reference signature in the respective tracking segment.

5. A method as defined in claim 1 further comprising discarding ones of the tracking segments having respective time lengths that are less than a threshold.

6. A method as defined in claim 5 further comprising configuring the threshold to achieve a particular average simulcast resolution factor.

7. A method as defined in claim 1 wherein evaluating the time lengths of the tracking segments comprises:

determining whether one tracking segment has a longest time length among the tracking segments; and

when one tracking segment has the longest time length, associating the monitored media with a particular one of the reference sources corresponding to the one tracking segment having the longest time length.

8. A method as defined in claim 7 further comprising indicating that source identification for the monitored media was unsuccessful when multiple tracking segments are determined to have the longest time length.

9. A machine readable storage medium comprising machine readable instructions which, when executed, cause a machine to at least:

compare monitored signatures generated from monitored media with reference signatures generated from reference media provided by a plurality of reference sources;

determine tracking segments associated with respective ones of the reference sources, each tracking segment representing sequences of matches between the monitored signatures and respective reference signatures for a respective one of the reference sources; and

evaluate time lengths of the tracking segments to identify which reference source in the plurality of reference sources provided the monitored media.

10. A storage medium as defined in claim 9 wherein the monitored signatures and the reference signatures include respective timestamps, and the machine readable instructions, when executed, cause the machine to compare the monitored signatures with the reference signatures by:

comparing the monitored signatures with a first group of the reference signatures having a range of times within a first time tolerance when the monitored media has been determined to be associated with live media; and

comparing the monitored signatures with a second group of the reference signatures having a range of times within a second time tolerance greater than the first tolerance when the monitored media has been determined to not be associated with live media.

11. A storage medium as defined in claim 9 wherein the monitored signatures and the reference signatures include respective timestamps, and the machine readable instructions, when executed, cause the machine to determine the tracking segments by:

determining whether a first time difference between a first monitored signature and a second monitored signature is substantially similar to a second time difference between a first reference signature determined to match the first monitored signature and a second reference signature determined to match the second monitored signature, the first reference signature and the second reference signature associated with a first reference source; and

if the first time difference and the second time difference are substantially similar, augmenting a respective tracking segment associated with first reference source to indicate that the second reference signature matched the second monitored signature.

12. A storage medium as defined in claim 11 wherein the machine readable instructions, when executed, further cause the machine to store the second reference signature in the respective tracking segment to augment the respective tracking segment.

13. A storage medium as defined in claim 9 wherein the machine readable instructions, when executed, further cause the machine to discard ones of the tracking segments having respective time lengths that are less than a threshold.

14. A storage medium as defined in claim 9 wherein the machine readable instructions, when executed, cause the machine to evaluate the time lengths of the tracking segments by:

determining whether one tracking segment has a longest time length among the tracking segments; and

when one tracking segment has the longest time length, associating the monitored media with a particular one of the reference sources corresponding to the one tracking segment having the longest time length.

15. A storage medium as defined in claim 14 wherein the machine readable instructions, when executed, further cause the machine to indicate that source identification for the monitored media was unsuccessful when multiple tracking segments are determined to have the longest time length.

16. An apparatus to identify media sources, the apparatus comprising:

a scanning engine to:

compare monitored signatures generated from monitored media with reference signatures generated from reference media provided by a plurality of reference sources;

determine tracking segments associated with respective ones of the reference sources, each tracking segment representing sequences of matches between the monitored signatures and respective reference signatures for a respective one of the reference sources; and

evaluate time lengths of the tracking segments to identify which reference source in the plurality of reference sources provided the monitored media; and

a memory to store the reference signatures.

17. An apparatus as defined in claim 16 wherein the monitored signatures and the reference signatures include respective timestamps, and to compare the monitored signatures with the reference signatures, the scanning engine is to:

compare the monitored signatures with a first group of the reference signatures having a range of times within a first time tolerance when the monitored media has been determined to be associated with live media; and

compare the monitored signatures with a second group of the reference signatures having a range of times within a second time tolerance greater than the first tolerance when the monitored media has been determined to not be associated with live media.

18. An apparatus as defined in claim 16 wherein the monitored signatures and the reference signatures include respective timestamps, and to determine the tracking segments, the scanning engine is to:

determine whether a first time difference between a first monitored signature and a second monitored signature is substantially similar to a second time difference between a first reference signature determined to match the first monitored signature and a second reference signature determined to match the second monitored signature, the first reference signature and the second reference signature associated with a first reference source; and

if the first time difference and the second time difference are substantially similar, augment a respective tracking segment associated with first reference source to indicate that the second reference signature matched the second monitored signature.

19. An apparatus as defined in claim 18 wherein the scanning engine is to store the second reference signature in the respective tracking segment to augment the respective tracking segment.

20. An apparatus as defined in claim 16 wherein the scanning engine is to discard ones of the tracking segments having respective time lengths that are less than a threshold.

21. An apparatus as defined in claim 16 wherein to evaluate the time lengths of the tracking segments, the scanning engine is to:

determine whether one tracking segment has a longest time length among the tracking segments; and

when a first tracking segment has the longest time length, associate the monitored media with a particular one of the reference sources corresponding to the first tracking segment having the longest time length.

22. An apparatus as defined in claim 21 wherein the scanning engine is further to indicate that source identification for the monitored media was unsuccessful when multiple tracking segments are determined to have the longest time length.