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Comment by adrianN | Hacker News Reader

If the listener doesn't know the "true" information, it is sufficient if the watermarked version sounds plausibly like a real sound. I think it's too strong to require the watermark to be completely inaudible. It is sufficient if given two recordings of unknown sounds a listener can't tell which one is watermarked and which one isn't.

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As a musician; no. That is not sufficient. Any audible watermark -- and as the grandparent comment correctly points out, that is any that is going to do its job -- is unacceptable. It is modifying what the artist intended you to hear in a destructive way. It is destroying the original performances. This is a terrible practice.

Are you against all lossy compression methods as well? The watermark can simply be a slight tweak of the compression algorithm that could as well have been done for non-watermarking reasons.

I think the point is that the watermark is supposed to survive being re-encoded, so it can’t be something just in the compression algorithm.

There is a discussion to be had around watermarks surviving transcoding but I was mostly trying to understand whether the opinion

> It is modifying what the artist intended you to hear in a destructive way. It is destroying the original performances.

also applies to lossy encoding.

The whole point of lossy compression is that it tries to be inaudible, as a primary concern.

The whole point of audio watermarking is that it survives lossy compression. Inaudibility is merely a secondary concern.

This is an adversarial relationship, and one that the audio watermarking is doomed to lose. By and large, lossy codecs succeed in transparency, and therefore as an inevitable consequence, watermarking fails at it. After decades of development, lossy codecs are just too good - there's nowhere left to hide information.

(It's also worth noting that the consumer benefits from the quality tradeoff that compression makes, in the form of decreased storage and bandwidth. They don't benefit from the audio watermarking at all.)

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.

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).

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.

Graphical watermarks also destroy the original image, and I think are much more intrusive than what an audible one would be.

I'm unable to load the article and haven't heard one in real life, but in theory it could be done in a way that is imperceptible to human ears but detectable by a program. E.g. imagine masking specific frequencies within a noisy section of the video.

There should be less destructive ways for studios to do this, but unless it's in the video or audio signal it doesn't stand a chance of working reliably.

If a signal is imperceptible to human ears but detectable by a program, it's a prime candidate for being thrown away by lossy compression to save space. All the low hanging fruit there has long since been grabbed. The whole point of an audio watermark is that it must survive re-encoding, but it's a race that cannot be won.

The difference is that the graphical watermark on e.g. a photograph usually isn't there when you've paid for it. These audio watermarks are very obvious to me and frankly make instruments sounds out of tune -- it's like the beating you can hear when tuning strings. I basically only listen to classical music and will not tolerate this.

Right, but it's a problem with this specific implementation, not something that couldn't be addressed by user friendlier versions.

To be clear, I'm also against any kind of watermark, but I'd rather it be done with an imperceptible (to me) audio signal than with a constant graphical watermark as is usually the case. Actually, graphical watermarks could be smarter and less obtrusive as well.

> The difference is that the graphical watermark on e.g. a photograph usually isn't there when you've paid for it.

The same could be the case for these audio ones. It's user hostile if this is done on already paid content (but again, I can't read the original article to confirm).

You are thinking about blatant watermarks on stock imagery and the like. Movies at the theater[1] and streaming videos[2] absolutely contain subtle visible watermarks even though you are paying to see them, which is directly analogous to having audible watermarks on Spotify. In the case of movie theaters we are somewhat desensitized to them, as old projection technologies used similar flashing dots for other reasons, like a cue to the projectionist to get the next reel ready[3].

[1] https://creativepro.com/major-movie-studios-specify-digital-...

[2] https://partnerhelp.netflixstudios.com/hc/en-us/articles/440...

[3]https://en.wikipedia.org/wiki/Cue_mark

Oops, that second link is about another type of watermarking, not the anti-piracy kind. Unfortunately, I won't have time to dig up a more appropriate link today.

All kinds of things between the bits on my harddrive and my brain modify what the artist intended me to hear. Is it also unacceptable to listen to songs on headphones, or in rooms with a different geometry than where the song was recorded?

That bar is far too low - reductio ad absurdem, you could go as far as changing lyrics - or substituting an entirely different song - and if you'd never heard the song before you'd never know the difference.

As for more subtle changes, what constitutes a "plausible sound" in any given context is an AI-complete problem. Sure on a particular song, you might get away with e.g. tinkering with the reverb a bit, or changing the tempo by 0.5% - but how can you possibly do that in the general case?

Remember - all such changes have to be audibly salient to humans, because that's the only thing guaranteed to survive.

The connections made between artist expression and listeners are precious, rare, vital.

You’re saying it’s ok to decimate it - as long it’s replaced with some “plausible” proxy? Plausible decided by who, the artist or business requirements?

The argument is that this exists on a spectrum. The best way to get the artists true intention is to watch a film in a well-calibrated theater. Then a high-quality Blu-ray. Web streaming involves even more compromise.

We tolerate Netflix releasing films in less than 4k. They do that because of a practical business benefit (cost). Similarly, Universal is making a compromise in the artist's vision to meet a business requirement. I think if the compromise is sufficiently small and the business benefit is sufficiently large, it's ok to do this.

As a former orchestra player, and a listener who likes to sit in front of a Hi-Fi system, and listen to music intently, this is not OK.

When you're passive listening, you're only perceiving the "outlines" of the music, but listening actively reveals a lot of details, and this kind of wobbling becomes both more noticeable and disturbing.

When listening the music actively, anyone can distinguish between natural and unnatural sounds, and this will bother many people if they listen more actively.

If I piss in your cereal, and dont tell you, is it still ok if it tastes semi ok?

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