OK, a couple fun things. I finally got an output from SABR yay! The bug was really stupid, and it took me wayyy to long to figure out. I get the ustreamerconfig as base64, HOWEVER, this isn’t standard base64, it’s URL safe base64… for some reason. To send it in SABR, I have to turn it into bytes, specifically an NSData. These old iOS versions don’t have a standard base64 library, so I import one. The base64 library does not accept the - & _ type, and instead of like throwing any sort of error or even a log, it just… ignores them! So the error was actually accurate, it was a malformed config, specifically ustreamer config.

I also did some stuff on POTokens. It appears that youtube did an update, and the POToken engine does more checks to see if it’s on youtube.com, or something like that. It seems it now specifically refuses POTokens were minted on not youtube.com, and only for the video id case, and only sometimes, specifically if fexp in the URL is 51973818, if it’s 51973819 it works. Also for some reason on my end using the visitorData works, which it doesn’t for other people in the youtube.js discord. Oh I should mention it also affects the library BgUtils, which my thing (and yt-dlp, and literally everything) is based on/uses. For now, i’m going to ignore the POToken issue, since I’m honestly not that great at debugging the youtube’s JS (i spent like a couple hours trying, if you search for function Vr in the base.js you’ll find something in the POToken minter as of right now). However according to Luan (the author of the BgUtils thingy), nothing changed in the player code, so idk, Idk how I could really debug the potoken engine.

Oh also, something… interesting, someone else in the BgUtils discord decided to uhh fork my thing and using the power of AI, implement POToken gen using QuickJS. I initally tried this for POToken gen but got stuck with me missing polyfills. I’m considering taking parts of the forked code (specifically the polyfills), and some of my older QuickJS code and having two POToken systems you can switch between in case one breaks (ES6 issues for example), but idk if I should.

I guess for now, I get to go actually write an implementation reading SABR data/UMP now. Maybe i’ll be doing this on a plane again :D (return flight)