This is actually similar to how it works for traditional TV and Radio Broadcast in copyright societies:
(Total revenue of license period x peak/non peak weighting x duration of song played) / total music duration for license period.
This is something YouTube vehemently fought against. At least in the original 2014 contract with PRS for music.
IIRC YouTube would never send cue sheets (list of included tracks per video) in the usage reporting data. It was just the video title. That was the old deal though - I left before the new deal was signed with ICE services.
Edit: oh, and sampling has its own process. The content creator has to negotiate with each individual rights holder as to the splits when the song is registered.
I don't think it's fair if copyright holders can just inject their audio by having it played in the background somewhere as you are recording (like recording in the vicinity of a bar, which is what one of the commenters talked about), and then get to monetize that.
Which is exactly what these corporations are doing when they buy air time on the radio: part of it is definitely marketing strategy to have that audio be in the background or present in as much places as possible, purely for exposure.
It's something they are actively injecting in our shared/public spaces, basically making ambient sounds "copyrighted", and it's kinda ridiculous they expect to be paid when successful.
I know, this is how copyrights works. But it's a relatively new thing they actually take action when something is recorded that has unwanted background sounds, that the video maker unwittingly recorded, while the copyright holder is explicitly paying to have that sound be playing in the background of as many venues as possible, with the purpose to expose it t as many people as possible.
Also this crazy idea is unheard of (haha pun) in other kinds of media: If one of my graphic designs would be shortly visible in the background of a camera pan ... can you imagine trying to claim even 0.1% monetisation?
Having recently been enlightened as to the incompetence of record labels when it comes to handling revenue splits in the simple model (e.g. they can't even get them right for Tier 1 artists with a simple split between authors), I'd not hold out much hope they'd be able to cope with a more complex model like this. And that's before you get to antiquated places like the PRS who would also need to be involved.
30-minute (1800s) video plays an 18s of a somg? Mechanical right by song's author to 1% of monetisation.
Used in samling or simultaneously with other copyrighted works? Mechanical split among works.
The percentage might be tweaked -- vieo holder splits 50-50, so songwriter gets 0.5% rather than 1%, in this hypo.