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Have a vague memory of some old HN discussion about how known fluctuations in light because of slightly varying electricity frequency have been used already to

by 3036e4 1y ago

Have a vague memory of some old HN discussion about how known fluctuations in light because of slightly varying electricity frequency have been used already to detect fake video and that databases exist with information about frequencies by location and time for this purpose?

_neil 1y ago
Might have been audio? https://phys.org/news/2018-02-power-grid-fluctuations-hidden-audio.amp https://phys.org/news/2018-02-power-grid-fluctuations-hidden...
- 3036e4 1y ago
  Sibling comment and article mentioning "Electric network frequency (ENF)" lead to further reading mentioning both audio and visual fluctuations being used.
  - _neil 1y ago
    Ah you’re right. Pretty cool.
tantalor 1y ago
https://pmc.ncbi.nlm.nih.gov/articles/PMC9304164/ https://pmc.ncbi.nlm.nih.gov/articles/PMC9304164/ > Electric network frequency is a signal unique over time and thus can be used in time estimation for videos.