Example apparatus disclosed herein include a signature collector to collect a first signature for media being presented to a plurality of households, a media creditor to credit the media when the first signature matches a reference signature in a reference signature database. The example apparatus also includes a signature thresholder to, when the first signature does not match the reference signature in the reference signature database, determine if the first signature matches an unknown signature in an unknown signature database; increase a count associated with the unknown signature when the first signature matches the unknown signature; and determine when a second signature matches the first signature, the second signature including metadata identifying the media. The example apparatus also includes a signature handler to store a reference signature for the first signature by associating the metadata identifying the media with the first signature when the count of the first signature satisfies a threshold, the reference signature to be stored in the reference signature database.

Example local devices disclosed herein include memory including a set of reference fingerprints corresponding to media, the set of reference fingerprints from a remote device different from the local device and one or more processor circuits to execute machine readable instructions to generate a monitored fingerprint of the media presented at a location and compare the monitored fingerprint to at least some of the set of reference fingerprints from the remote device. Additionally, the one or more processor circuits are to determine an amount of time that has passed since the media started and after a match between the monitored fingerprint and one or more reference fingerprints of the set of reference fingerprints, cause transmission of audience measurement information to identify the media, the audience measurement information including data indicative of the amount of time that has passed since the media started.

Example device meters disclosed herein include a signature reporter to report, to a data processor, media signatures of a first type to monitor media presented by a media device Disclosed example device meters also include a signature generator to (i) generate the media signatures of the first type, (ii) generate media signatures of a second type, different from the first type, to continue monitoring the media presented by the media device after receipt, from the data processor, of an indication that a first media signature of the first type is associated with first reference media, and (iii) in response to detection at the device meter of a change in a source of the media presented by the media device, revert to generation of the media signatures of the first type to monitor the media presented by the media device.

Methods and apparatus for determining increasing robustness of media signatures are disclosed. An example apparatus disclosed herein is to select to at least one of (A) boost a first characteristic of a media signal at a first time or (B) attenuate a second characteristic of the media signal at a second time based on an effect of the at least one of the boost of the first characteristic or the attenuation of the second characteristic on a difference between a third characteristic of the media signal at a third time and a fourth characteristic of the media signal at a fourth time. The disclosed example apparatus is also to perform the selected one of (A) the boost of the first characteristic of the media signal at the first time or (B) the attenuation of the second characteristic of the media signal at the second time to enhance the media signal.

In one aspect, a method includes (i) receiving query fingerprint data representing content transmitted by a content-distribution system on a channel; (ii) comparing the received query fingerprint data with multiple reference fingerprint data sets, wherein each of the multiple reference fingerprint data sets corresponds with a different respective content segment; (iii) based on the comparing, detecting a respective match between the received query fingerprint data and reference fingerprint data in each of the multiple reference fingerprint data sets; (iv) accessing broadcast-schedule data associated with the channel; (v) using the accessed broadcast-schedule data to identify which one of the different respective content segments is being transmitted by the content-distribution system on the channel, thereby identifying a corresponding upcoming content modification opportunity on the channel; and (vi) performing an action to facilitate performing a content modification operation related to the identified upcoming content-modification opportunity on the channel.

In one aspect, a method includes (i) accessing broadcast-schedule data associated with a channel; (ii) using the accessed broadcast-schedule data to identify an upcoming content-modification opportunity on the channel; and (iii) responsive to identifying the upcoming content-modification opportunity on the channel, performing an action to facilitate performing a content-modification operation related to the identified upcoming content-modification opportunity on the channel, wherein performing the action comprises causing in-band message data to be inserted into at least a portion of a content segment that is being transmitted by a content-distribution system on the channel.

A method and system for assigning a multimedia content element to a user. The method includes generating at least one signature to the multimedia content element; determining, based on the generated at least one signature, whether the multimedia content element exists in a database; and assigning a unique identifier of the user to the multimedia content element, when it is determined that the multimedia content element does not exist in the database.

Methods and apparatus to determine a state of a media presentation device are disclosed. Example disclosed methods include generating a first set of weighted coefficients based on first audio received by first and second microphones at a first time. Example disclosed methods include generating a second set of weighted coefficients based on second audio received by the first and second microphones at a second time after the first time. Example disclosed methods include comparing the first set of coefficients and the second set of coefficients to generate a similarity value. Example disclosed methods include, when the similarity value satisfies a threshold, determining that the media presentation device is in a first state. Example disclosed methods include, when the similarity value does not satisfy the threshold, determining that the media presentation device is in a second state.

A system and method is provided for managing visual content. In one instance, an exemplary method includes receiving a stream of video fingerprints derived in a fingerprint generator by an irreversible data reduction process, from respective temporal regions within a particular visual content stream and at a fingerprint processor that is physically separate from the fingerprint generator via a communication network. The fingerprints are processed in the fingerprint processor to generate metadata which is not directly encoded in the fingerprints. Processing of the fingerprints includes windowing the stream of fingerprints with a time window, deriving frequencies of occurrence of particular fingerprint values or ranges of fingerprint values within each time window, determining statistical moments or entropy values of said frequencies of occurrence, comparing said statistical moments or entropy values with expected values for particular types of content, and generating metadata representing the type of the visual content.

Methods and apparatus to dynamically generate audio signatures adaptive to circumstances associated with media being monitored are disclosed. An example apparatus includes a signal selector to select a first signature scheme from among a plurality of signature schemes to generate monitored signatures for media being monitored by a meter. The first signature scheme is selected based on a circumstance associated with the media. The apparatus includes a signal generator to generate a first monitored signature from the media based on the first signature scheme. The apparatus further includes a communications interface to transmit the first monitored signature to a data collection facility.