A system and method for contextually enriching a concept database. The method includes determining, based on at least one signature of a first multimedia data element (MMDE) and signatures of a plurality of third concepts stored in the concept database, at least one matching first concept among the plurality of third concepts; generating a reduced representation of the first MMDE; comparing the reduced representation of the first MMDE to signatures representing a plurality of second MMDEs to determine a plurality of matching MMDEs among the plurality of second MMDEs; generating, based on the reduced representation of the first MMDE and the signatures representing the plurality of matching MMDEs, a second concept; and generating at least one context based on the second concept and the plurality of third concepts, wherein each context includes at least one common pattern among the second concept and at least one of the plurality of third concepts.

Disclosed are methods and systems involving location-based disambiguation of media channel identification, in a scenario where a fingerprint of media content being rendered by a media presentation device matches multiple reference fingerprints corresponding respectively with multiple different media channels. Upon detecting such a multi-match situation, a server or other entity will use a location of the media presentation device as a basis to disambiguate between the matching reference fingerprints and thus to determine the channel on which the media content being rendered by the media presentation device is arriving.

A method for generating a signature is disclosed. As part of the method, a first number of bits are identified in respective rows of an audio signature matrix that are determined to be the strongest bits in the row, bits of the audio signature matrix are replaced with respective cells having values depending on whether the respective bits are included in the first number of bits, a set of uniformly distributed numbers are generated within a range of numbered locations corresponding to cells of the audio signature matrix; numerical distances are determined, from respective numbers in the set of uniformly distributed numbers, to the numbered locations of the matrix, associated with nearest occurrences of a first value. A set of integers is generated based on the distances.

A computing system receives from a media presentation device a query fingerprint stream representing media content being presented by the media presentation device, where the query fingerprint stream has been determined to represent a first channel. The computing system then detects that a threshold mismatch exists between the received query fingerprint stream and a reference fingerprint stream representing the first channel, thus indicating a likelihood that the media presentation device has transitioned from presenting the first channel to presenting a second channel. Responsive to detecting the threshold mismatch, the system thus discontinues channel-specific action with respect to the first channel. For instance, the system could discontinue superimposing of first-channel-specific content on the presented media content and perhaps start superimposing of second-channel-specific content instead.

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.

Real-time latency of audio/video streams is identified. Signatures of a reference audio/video stream and signatures of a test audio/video stream are buffered. A needle is constructed as a vector including a set of signatures of the reference audio/video stream. Correlations of the needle to successive vectors of sets of signatures of the test audio/video stream are computed using a correlation function that calculates relatedness of the needle vector to each of the successive vectors of the test audio/video stream. A synchronization offset is identified between the test stream and the reference stream according to a maximum correlation point of the correlations of the needle to the successive sets of signatures of the test audio/video stream. The reference audio/video stream and the test audio/video stream are aligned according to the synchronization offset.

Example apparatus disclosed herein to implement signature matching with meter data aggregation for use in media identification applications include a match job aggregator to aggregate batches of meter data from a meter to form aggregated meter data associated with the meter, and a hash matcher to identify a valid hash key match between meter hash keys generated from meter signatures in the aggregated meter data and reference hash keys corresponding to a collection of media assets. Disclosed example apparatus also include a signature matcher to align, based on the valid hash key match, a sequence of reference signatures corresponding to a first media asset associated with the valid hash key match and a corresponding sequence of the meter signatures, and compare the sequence of reference signatures and the corresponding sequence of meter signatures to identify media represented by at least a portion of the sequence of the meter signatures.

Example apparatus disclosed herein include means for processing media signatures of a first type to monitor media presented by a media device, the processing of the media signatures of the first type to be performed until a first media signature of the first type is determined to match a reference signature of the first type. Disclosed example apparatus also include means for processing media signatures of a second type associated with the first reference media to monitor the media presented by the media device, the processing of the media signatures of the second type to begin after the first media signature of the first type is determined to match the reference signature of the first type, the processing of the media signatures of the second type to end when a number of media signatures of the second type is determined not to match corresponding reference signatures of the second type.

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.

Methods and apparatus for determining increasing robustness of media signatures are disclosed. An example apparatus includes a characteristic analyzer to determine a first difference between (A) a first characteristic of an audio signal at a first time and (B) a second characteristic of the audio signal at a second time. The apparatus further includes a characteristic enhancer to compare the first difference to a first threshold; at least one of (A) boost the first characteristic of the audio signal at the first time or (B) attenuate the second characteristic of the audio signal at the second time when the first difference does not satisfy the threshold to create an enhanced audio signal; and determine whether a second difference between a third characteristic of the enhanced audio signal at the first time and a fourth characteristic of the enhanced audio signal at the second time satisfies the threshold, the third characteristic corresponding to the first characteristic, the fourth characteristic corresponding to the second characteristic.