Great it works! at first i was confused about what the ./install script was going to do... I still im , i have to admit, but im learning.

Works great.

Kind of bummed it wasn't working for me. On Win 10 here with Firefox 76. I got the native client working and when on a youtube video, the toolbar icon for Send to MPV player would first start playing audio from the video, then a few seconds later the video (MPV) would finally open, then it just stops playing sound or video. :( ~ MPV player works just fine playing a youtube video by dragging the url into the player. Oh well :\
https://addons.mozilla.org/en-US/firefox/addon/play-with/ works flawlessly and doesn't require the native client.
https://addons.mozilla.org/en-US/firefox/addon/ff2mpv/ is another option, though I haven't tried it.

After configuring for half an hour it wouldn't play a single Dailymotion video.
It just always gives a HTTP 403 error message.

Almost perfect but having issues with not opening some videos. Months have passed but https://addons.mozilla.org/en-US/firefox/addon/open-with still better in opening links.

I like this app a lot. It allows me to get gpu acceleration for videos with an easy button instead of a copy paste to terminal.

To perfect this app, they need to fix the issue of the "one more step" dialog appearing after closing an mpv session. The configuration is established correctly already.

Самое то для нищих железом.

Any way to make this work for youtube playlists?
Works for me for a single video.

It has a bug where it opens the "One last step" page after every video closes, even though the extension is already working fine.

the toolbar button works fine but the right click context-menu has a weird behaviour and somtimes crashes.

Due to the WeEX transition, I tried this addon as a replacement for openwith, only to find out it even works more reliable than the former.
My only complaint is the the unnecessary "one last step" pop-up which randomly occurs despite the installed native-client.
But since this is deactivatable in the options, a 5/5 is due.

working as mpv-youtube-dl, except one additional install. damn web extensions and bless those who find out how to make this work :)

Вроде работает. Хотя сначала были сбои в работе, то проигрывал видео, то отказывался.

Works great, good replacement for mpv-youtube-dl-binding
, which won't work in Firefox 57 anymore. @dinko_dimitrov This is also the reason why the native client is needed, the new Extensions based on WebExtension technology has no OS level access.