Can Audacity place a copyright notice in the form of a watermark in a recording.

Can Audacity place a copyright notice in the form of a watermark in a recording of original material, and be in place when exported as an mp3. In addition, that same watermark, be detectable when the mp3 is drawn back into Audacity for analysis.

Please don’t confuse this with putting a copyright notice in the meta data. I mean putting it in the very fabric of the recording, but remain undetectable when played.

I don’t want use third party software.

I have had a lot of success with doing the same thing with my imaging work, by putting my copyright watermarks in jpeg’s (or any other format, come to that). They are undetectable, and It doesn’t matter if they are worked on, re-cropped or even saved in a different format - the watermark remains.

Can add an ultrasonic watermark which is inaudible, but shows up on a spectrogram

However it won’t survive encoding to <128kbps mp3 as that removes ultrasound.

Cheers - that’s exactly what I mean.

Bear in mind such a watermark can easily be erased by a low-pass filter at ~16kHz.

MP3 (and most lossy compression) works by throwing-away details that you can’t hear so I would expect re-encoding to loose (or damage) the watermark.

How are you doing that? (There may be an equivalent process for audio)

Extract from PM:

Map makers used to put minute additions in their work that were undetectable, except for the cartographer who drew it. Examples: town plans - a mews or an ally the are non-existent, navigation charts - an extra small island in a archipelago.
This is was to protect their work against someone copying it and publishing it as their own, because the deliberate mistake would be copied as well.

There’s many ways that you can do similar things with audio. The problem is that MP3 tends to discard information that is not audible, so you will need to experiment to see if your “watermark” survives MP3 encoding.

Example, you could mix in a low frequency tone. In this example, I have mixed in a 1 Hz tone, which is completely inaudible:

However the “watermark” is clearly visible when you look at the waveform.