[kyleplum]

There are always going to be some subjective decisions in the lossy encoding process. Determining which bits to drop via encoder configurations/customization is far from an exact science. These decisions themselves can act as a watermark.

[aidenn0]

At sufficiently high bitrates modern lossy codecs are transparent. Even MP3, a dinosaur of a lossy codec is transparent (as in nobody can successfully ABX it) for a lot of music starting somewhere in the neighborhood of 192kbps, and at the 320kbps that commercial stores sell MP3s it is transparent for all physically generated music so far tested (some electronic music with incredibly fast attacks can have audible artifacts).

[dTal]

No, as was already explained upthread, "the watermark is supposed to survive being re-encoded, so it can’t be something just in the compression algorithm". It needs to be something that survives no matter which subjective decisions the lossy encoder makes.