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.

Example apparatus to determine a state of a media presentation device are disclosed. A disclosed example apparatus is to determine contribution values from at least one of a signal measured from a sensing device or an output signal accessed from the presentation device, the contribution values indicative of a state of a presentation device. The disclosed example apparatus is also to sum a first plurality of the contribution values corresponding to a first measurement cycle to generate a first intermediate fuzzy score for the first measurement cycle, store the first intermediate fuzzy score in a buffer, the buffer including a plurality of intermediate fuzzy scores corresponding to respective measurement cycles, combine the intermediate fuzzy scores corresponding to a first time period to form a final fuzzy score, and when the final fuzzy score satisfies a threshold, set the state of the presentation device as on and enable crediting of media.

Example methods, apparatus, and articles of manufacture for media metering are disclosed. An example apparatus disclosed herein includes at least one memory, instructions in the apparatus, and at least one processor installed in a media presentation device to execute the instructions to at least: cause a video decoder to generate video display rasterizing information, present the video display rasterizing information via an output device of the media presentation device, and in response to monitoring being enabled, generate metering information corresponding to media presented in association with the video display rasterizing information presented via the output device.

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 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.

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.

Apparatus, systems, articles of manufacture, and methods to identify and credit media using ratios of media characteristics are disclosed herein. Example apparatus to identify media include at least one memory, instructions, and at least one processor to execute the instructions to: determine a first ratio based on a first time interval and a second time interval of a monitored media signal; determine a second ratio based on the second time interval and a third time interval of the monitored media signal; generate a first ratio signature based on the first and second ratios; and initiate transmission of the first ratio signature to a recipient that is to compare the first signature with a second ratio signature to identify the media.

Methods and apparatus for determining whether a media presentation device is in an on state or an off state are disclosed. A disclosed example method comprises determining contribution values from at least one of a signal measured from a sensing device or an output signal accessed from the presentation device, wherein the contribution values are indicative of a state of a presentation device. Summing, via a logic circuit, a first plurality of the contribution values corresponding to a first measurement cycle to generate a first intermediate fuzzy score for the first measurement cycle. Storing the first intermediate fuzzy score in a buffer including a plurality of intermediate fuzzy scores corresponding to respective measurement cycles. Combining, via the logic circuit, the intermediate fuzzy scores corresponding to a first time period to form a final fuzzy score. When the final fuzzy score satisfies a threshold, setting the state of the presentation device as on and enabling crediting of media presented by the presentation device.

Example methods, apparatus, and articles of manufacture for media metering are disclosed. An example machine readable storage device disclosed herein includes instructions that, when executed, cause a processor to at least cause a video decoder to generate video display rasterizing information, present the video display rasterizing information via an output device of a media presentation device, and in response to monitoring being enabled, generate metering information corresponding to media presented in association with the video display rasterizing information presented via the output device.

First fingerprint data is accumulated in a first fingerprint buffer of a channel identification server in parallel with accumulation of second fingerprint data in a second fingerprint buffer of the channel identification server. The first and second fingerprint data include multiple fingerprints representing broadcast content broadcast by corresponding broadcast sources during contiguous time periods, and accumulating the fingerprints includes appending newly received first fingerprints to previously received first fingerprints to generate continuous fingerprints. The channel identification server also receives an unmatched fingerprint representing broadcast content received from an unknown broadcast source by the end-user device. The unmatched fingerprint into probes, which are scrubbed against both first and second continuous fingerprints in an attempt to determine a match between the unmatched fingerprint and either the first or second continuous fingerprint. The unknown broadcast source is identified based on that determination.