I mean, I think that in the long run, trying to fight an arms race against Google on ad visibility is a losing proposition, but this isn’t really all that hard to defeat from a technical standpoint. You just identify ads relative to timestamp offsets from a given matched frame. Use some kind of fuzzy (needs to?be fuzzy because lossy compression will alter frames a bit) hash to identify that frame, and use an identifier where it’s computationally-cheap to reject most frames.

So, like, “ad ranging from frame hash 18037gb5028de882 + .53 sec lasting 30 seconds”.

I dunno how Sponsorblock works – I don’t use it – but I assume that it has some human manually identify a time. In picking a frame to use for the offset, the software needs to hash each frame in the video. Then when someone flags a frame as starting an ad sequence, search backwards from the identified time, and pick a frame to match against, look for a frame with a unique hash in the video.

There’d be some preprocessing time, but I imagine that the human interface would basically be the same. Some overhead to playback software, because it has to generate the hash for each frame while playing. If there’s no Sponsorblock information for a given video, don’t need to generate the hashes, though.