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I have read that we can use audio watermarks to "identify the original produces of the material or the consumers of the media."

How consumers of the media is measured by audio watermarks?

Lets say in TV we play an video which has audio watermark in it and 100's of people are watching it. How do we capture the audio watermark that got played in viewers TV?

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  • $\begingroup$ usually by correlating Signal+Watermark with the specific watermark that you're trying to detect. now in this case consider the Watermark to be the "signal" and the Signal to be the "noise". so you'll have a very low S/N ratio. it's why watermarks need a lot of signal with the tiny watermark embedded to be detected. $\endgroup$
    – robert bristow-johnson
    Jan 2, 2017 at 18:25
  • $\begingroup$ @robertbristow-johnson can you give any link / reference / tutorial for capturing the watermarked audio signal? It will be very helpful for me :) $\endgroup$
    – sravis
    Jan 3, 2017 at 16:49

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In the U.S., a company called Nielsen has its watermarking technology encoded into broadcast content (Radio/TV/etc), while some 65k individuals called "panelists" wear a small pager-like meter called a portable people meter (PPM) which "listens" for and reports the watermarks that it "hears" (as the individuals go about their daily life). The "panelists" are essentially a statistically significant sample of the larger population of Radio/TV consumers.

Nielsen’s watermarking involves codes, and each PPM transmits both complete and partial codes back to Nielsen. In situations where partial codes exist, Nielsen has edit rules that “fill in the blanks” by validating against nearby complete codes. Broadcasters are currently updating their station’s encoders with the Enhanced CBET (Critical Band Encoding Technology) technology. Prior testing and preliminary results from the roll-out show that there is an increase in the quality of the code detection and an increase in average quarter hour audience estimates.

Here are some links for you:

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