I wonder if it can be filtered out, on the other hand. Does anybody have knowledge on audio fingerprinting/watermarking? Or is it perhaps security theater?
here's some old (ugly) code - quite short as you can see:
- encoding: https://github.com/jcelerier/libaudiotool/blob/master/src/li...
- decoding: https://github.com/jcelerier/libaudiotool/blob/master/src/li...
It would be interesting if they found a way to watermark the audio in such a way that removing the mark makes the audio unusable.
AFAIK these are just used to identify the streaming / download source (e.g. Spotify / TIDAL / Qobuz etc.), rather than the individual user as will be the case with Zoom. It'll be interesting to see what, if anything, has changed with the technology.
A common technique is to add pseudo noise to encode data over the whole audio spectrum. It's related to the spread spectrum techniques used for radio communications resistant to signal degradation (natural or jamming), common in many radio protocols, like your GPS receiver in your phone.