Sure - happy to discuss further! But Iām about as knowledgeable as you on this topic since I only found out about it the other day myself.
Hereās another page with more detail about the technical process and links to academic papers:
Wouldnāt watermark checking apply to modern digital sources obtained online?
I suspect that the technology has been available for some time, however Iām not sure how widespread the use is. From what I can understand, itās embedded data in the audio itself, so any recording / playback medium could hold an audio signal which contains a watermark, not just online sources or digital files.
Does that mean that, in theory, anything pre-adoption of the process wouldnāt contain any watermark messages?
I would think that if the physical recording medium itself is older than the process, then sure - it wonāt have a watermark on it. But just because a piece of music is older than the the process doesnāt mean it wonāt have been watermarked because they can obviously be added after the music had been recorded.
What if a producer creates their own watermark to mask the pre-existing watermark?
See link above for more detail about how it works - possible I suppose, but youād need to know the technology used to imprint the watermark, and have access to similar technology to āover-writeā an existing one (I guess!).
Iām really not an expert on this at all - Iām just using the web and my brain so donāt quote me on any of this stuff!