Broadcast signatures (fingerprints) from different sources are compared to distinguish between a known base media item and unknown versions of the known base media item, without prior storage of the unknown altered versions of the known base media item. Field recorders collect and store in buffers signatures found within portions of sequential broadcast content. Mobile devices (users) collect unknown signatures while recording broadcast content. Using a cloud callout routine, the mobile device requests a comparison between the collected unknown signatures and the field recorded signatures. Potential matches can be loose matches, strict matches or comparisons between failed loose comparisons.

Methods and apparatus to verify and/or correct media lineup information are disclosed. Disclosed example apparatus include a signature comparator to, when media presentation data representative of media output by a media device does not correspond to reference data associated with first reference media corresponding to a first station: identify a plurality of first signatures in a database that matches a plurality of second signatures included in the media presentation data, the plurality of first signatures including at least one of first audio signatures or first video signatures, the plurality of second signatures including at least one of second audio signatures or second video signatures generated from the media output by the media device; and determine second reference media corresponding to the plurality of first signatures; and memory to store the media presentation data.

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) 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 computing system compares various reference fingerprints each representing a reference media stream broadcast on a different respective known channel, and the computing system determines that a plurality of the reference fingerprints match each other, thus defining a multi-match group of the matching reference fingerprints. In response, the computing system identifies a fingerprint feature that could define a distinction between the reference fingerprints, and the computing system resolves the multi-match based on the identified feature, thereby determining the channel carrying the media stream being rendered by the media presentation device. And the computing system could then take channel-specific action based on the determined channel.

A computing system compares various reference fingerprints each representing a reference media stream broadcast on a different respective known channel, and the computing system determines that a plurality of the reference fingerprints match each other, thus defining a multi-match group of the matching reference fingerprints. In response, the computing system identifies a fingerprint feature that could define a distinction between the reference fingerprints, and the computing system resolves the multi-match based on the identified feature, thereby determining the channel carrying the media stream being rendered by the media presentation device. And the server then takes channel-specific action based on the determined channel.

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.

Apparatus, systems, articles of manufacture, and methods to identify media using watermarks and signatures are disclosed. An example apparatus includes a watermark evaluator to determine a category indicated by a watermark detected in the media. The example apparatus also includes a signature comparator to compare a query signature with a subset of reference signatures associated with the category to identify the media, the query signature generated from the media, the reference signatures generated from reference media associated with the category.

Methods, apparatus, systems and articles of manufacture to reduce false positive signature matches due to similar media segments in different reference media assets are disclosed. Example apparatus disclosed herein include a signature matcher to compare monitored media signatures with a library of reference media signatures, the monitored media signatures associated with monitored media, the library of reference media signatures including sequences of reference signatures associated with respective reference media assets. Disclosed example apparatus also include a match information identifier to identify a number of different matched reference media assets associated with ones of the sequences of reference media signatures that match a sequence of matched monitored media signatures. Disclosed example apparatus further include a false positive identifier to, in response to the number of different matched reference media assets satisfying a threshold number, eliminate one or more of the matched reference media assets from being credited to the monitored media.

Methods and apparatus for identifying media content using temporal signal characteristics are disclosed. An example apparatus includes at least one memory, computer readable instructions, and at least one processor to execute the instructions to identify intervals in a media signal; generate interval sums for respective ones of the intervals, a first interval sum of the interval sums based on a sum of magnitudes of first peaks of the media signal that occur between zero crossings of a first interval of the intervals of the media signal; identify second peaks based on the interval sums; and generate a signature representative of the media signal based on the second peaks.