Methods, apparatus, systems, and articles of manufacture to monitor media are disclosed. An example apparatus includes first means for performing a first mapping of a first media identifier and timestamp to a second media identifier in a look-up table (LUT), the first media identifier and timestamp based on media obtained from a server, the first media identifier to identify the media, means for determining a third media identifier and a second timestamp based on media monitoring information (MMI) obtained from the server, the MMI obtained from the server in response to an access of the media identified by the third media identifier by a media device, second means for performing a second mapping of the third media identifier and the second timestamp to the first media identifier and timestamp in the LUT, and means for crediting access of the media to the media device based on the second mapping.

Methods, apparatus, and machine-readable storage media to monitor media presentations are disclosed. A disclosed example apparatus includes a locator to compare a location of a mobile device with a set of reference locations at which audio monitoring is to be performed. The disclosed example apparatus further includes an audio receiver to enable a microphone of the mobile device to collect audio for media monitoring when (1) the location of the mobile device corresponds to a first one of the reference locations and (2) a media presentation monitor at the first one of the reference locations indicates a likelihood of media being presented at the first location satisfies a threshold. In some disclosed examples, the audio receiver of the example apparatus is to disable the microphone from collecting audio for media monitoring when the location of the mobile device does not correspond to any of the reference locations.

Methods, apparatus, and machine-readable storage media to monitor media presentations are disclosed. A disclosed example apparatus includes a locator to compare a location of a mobile device with a set of reference locations at which audio monitoring is to be performed. The disclosed example apparatus further includes an audio receiver to enable a microphone of the mobile device to collect audio for media monitoring when (1) the location of the mobile device corresponds to a first one of the reference locations and (2) a media presentation monitor at the first one of the reference locations indicates a likelihood of media being presented at the first location satisfies a threshold. In some disclosed examples, the audio receiver of the example apparatus is to disable the microphone from collecting audio for media monitoring when the location of the mobile device does not correspond to any of the reference locations.

Methods, apparatus, systems and articles of manufacture to determine headphone adjustment for portable people meter listening to encoded audio streams are disclosed. Example apparatus disclosed herein include a meter data analyzer to determine audience estimates for streaming media; a headphone survey analyzer to calculate a global lift factor based on a determined proportion of the audience that listens to streaming media via headphones and a determined proportion of the audience that listens to streaming media without headphones; a headphone survey adjuster to: calculate adjustment factors for a plurality of unique demographic adjustment groups; an audience adjustment calculator to apply the adjustment factors to the audience estimates for streaming media, wherein the adjustment factors are applied to audience members in the audience estimates that are associated with respective unique demographic adjustment groups; and report new audience estimates based on the audience estimates with the applied adjustment factors.

Example apparatus disclosed herein are to obtain a first hash key, a second hash key and a third hash key representative of first reference media in response to a first query of a first table, the second hash key associated with a second time preceding a first time associated with the first hash key, the third hash key associated with a third time following the first time associated with the first hash key. Disclosed example apparatus are also to prequalify the first hash key as a candidate for subsequent signature processing associated with a first site signature in response to a determination that the second hash key corresponds to a second site signature preceding the first site signature in time and that the third hash key corresponds to a third site signature following the first site signature in time.

Example apparatus disclosed herein are to obtain a first hash key, a second hash key and a third hash key representative of first reference media in response to a first query of a first table, the second hash key associated with a second time preceding a first time associated with the first hash key, the third hash key associated with a third time following the first time associated with the first hash key. Disclosed example apparatus are also to prequalify the first hash key as a candidate for subsequent signature processing associated with a first site signature in response to a determination that the second hash key corresponds to a second site signature preceding the first site signature in time and that the third hash key corresponds to a third site signature following the first site signature in time.

Methods, apparatus, systems and articles of manufacture are disclosed for source classification using HDMI audio metadata. An example apparatus includes a metadata extractor to extract values of audio encoding parameters from HDMI metadata obtained from a monitored HDMI port of a media device, the HDMI metadata corresponding to media being output from the monitored HDMI port; map the extracted values of the audio encoding parameters to a first unique encoding class (UEC) in a set of defined UECs, different ones of the set of defined UECs corresponding to different combinations of possible values of the audio encoding parameters capable of being included in the HDMI metadata; and identify a media source corresponding to the media output from the HDMI port based on one or more possible media sources mapped to the first UEC.

Methods and apparatus to perform audio watermarking and watermark detection and extraction are disclosed. Example apparatus disclosed herein are to select frequency components to be used to represent a code, different sets of frequency components to represent respectively different information, respective ones of the frequency components in the sets of frequency components located in respective code bands, there being multiple code bands and spacing between adjacent code bands being equal to or less than the spacing between adjacent frequency components in the code bands. Disclosed example apparatus are also to synthesize the frequency components to be used to represent the code, combine the synthesized frequency components with an audio block of an audio signal, and output the audio signal and a video signal associated with the audio signal.

A system and method in which a TV signal reception device (e.g., set top box) receives a broadcast signal, sends the broadcast signal to a TV, and sends an event signal to a rating statistics information server or associated user terminal when a predetermined condition occurs, to ultimately cause an associated user terminal to generate fingerprint data of audio from the TV and to provide the fingerprint data to the server so as to facilitate channel identification and generation of ratings statistics.

A system and method in which a TV signal reception device (e.g., set top box) receives a broadcast signal, sends the broadcast signal to a TV, and sends an event signal to a rating statistics information server or associated user terminal when a predetermined condition occurs, to ultimately cause an associated user terminal to generate fingerprint data of audio from the TV and to provide the fingerprint data to the server so as to facilitate channel identification and generation of ratings statistics.