Digital Watermarking

Hello

Just a question which is from a technical point of view interesting to me. Maybe somebody has knowledge on this topic:

I own a lot of sample libraries.
Some of them say “Please be fair, do not distribute it to others”. That’s absolutely acceptable and I won’t do this with all my purchased libraries of course.

On the other hand, some manufacturers say that their samples are watermarked. What does this mean?

  1. Is the piece of sample recognizable when distributed? And how do they do it? Tag the file? Add some inaudible frequencies?
    and despite of what method:
    Is the watermark still recognizable in the mixdown (after applying also lots of compressor, EQ, etc.) of my song when loaded up to the internet or played in the radio?
    or
  2. Does this mean that the samples have my S/N inside and the manufacturer can protect his copyright by coming back on me if I would share the samples?
    or
  3. Is such watermarking just impossible or useless for audio and the manufaturer just says that it is marked?

Again, I’m not involved in any pirating of software or so. I just questioned myself.

Thanks and regards,

Ralph

https://en.m.wikipedia.org/wiki/Audio_watermark

This is a good read… http://www.kvraudio.com/forum/viewtopic.php?f=6&t=322995&start=45

Thank you guys!

Now it’s a bit clearer. Especially that link on the KVR site gave me a good understanding of how it could work:
http://audiowatermarking.info/products_comparison.php

Cheers, Ralph