Seems that way. Probably because I'm using Maximum delta of the difference as the metric. Using some intergral-like function (e.g. average amplitude of all samples) would probably yield better results, but I have a hard time getting any useful data out of this script on my home computer. Weird.

I'll possibly work more on this topic, maybe I'll make a HN post.

That sounds right. It should go from all small steps to all big steps. Every step past the real bitrate is shucking data humans can't hear well, more and more aggressively. Every step before the real bitrate is looking for data to shuck but not finding it.

I just realized, social media sites may do something similar to save space. I've noticed whenever I upscale my video resolution, they aren't fooled. At first the video will be hosted in 4k, but later that option disappears, and only the 1080P and lower resolutions are left. But sharp footage from my real 4k camera stays hosted at 4k. I figured they must take a screenshot and determine the blurriness, but now I think they might just look at those re-encoding stats they already have.