An old memory just popped up
> The Wadsworth Constant is the idea (and 2011 meme) that one can safely skip past the first 30 percent of any YouTube video without missing any important content.
https://www.dictionary.com/e/pop-culture/the-wadsworth-const...
The funniest part of that meme is that YouTube implemented a (now obviously removed) "wadsworth" query parameter that skipped the first 30% of a video.
Might make a good browser plugin. Binary search, but for video. Tweaking the exact ratios might be an interesting problem. I'm thinking (no evidence!) that 30% for a forward jump and 15% for a backward jump might work better. Large jumps forward until you hit something interesting, then small jumps back to find the start.