I finally fixed my problem. turns out arch is retarded and their repo is very old so i had to install the latest version of yt-dlp and reinstall the addon using the install.sh

works great, easy to customize.with this addon, it's no longer needed to deal with the problem of the html5 player in firefox. hope it to be maintained for a long time.

Install instructions worked perfectly for antiX-23b3

Much better on 15 year old Laptop for watching videos than trying to watch them in Firefox

Simple, no ridiculous permissions needed, works great.

Let me randomly mention SponsorBlock script for MPV :) https://github.com/po5/mpv_sponsorblock

An excellent extension. I like using my old 2009 eeebox PC, and this extension allows me to painlessly watch YouTube vids on it! Linux + MPV + yt-dlp + this add-on = old computer's grace saved. Thank you!

This is the greatest Addons EVER!

Simple, beautiful code, and works perfectly.

It's a great extension, but I realized I don't need it because its functionality is implemented by ;v keystroke in Tridactyl.

Seems a really nice addon, unfortunately this doesn't work on my machine.
It seemed weird at the beginning so tried to produce a video on mpv just dropping the link to it, and didn't work, checked some forum and saw I missed the update of youtube-dl. I updated it so it now work dropping link to it.
Tried to check this addon again, but wasn't that lucky, doesn't work anyway :/
Checked the comment, followed the instruction on github and finally works.
github.com/woodruffw/ff2mpv

Works great.

Works as advertised! If I may make a request for future updates, would it be possible to choose h264 and limit the playback to 1080p. I'm using the add-on on a very old computer that struggles with videos over 1080p and doesn't hardware-accelerate VP9.