Damn this is an gamechanger, TY for you hard work!

Absolutely blew me away! I am still shocked by how much of a difference it makes. I was about to ditch my beloved Firefox because NOTHING could fix Youtube, but this saved my life. Thank you!!!!

Works great!

Really saved my life and made streaming videos so much easier. No more buffering issues and the feature to search up subtitles on the fly through the video player makes looking for subtitled videos a breeze. So far works on streaming sites outside of YouTube as well.

finally made an account just to write this, 100% recommend this extension! I tried it after reaching my breaking point of frustration with Youtube in general, and it's been absolutely wonderful. I was astonished when I turned the extension on for the first time and watched how fast it buffered, ever since I was little I thought buffering was simply perpetually locked at that snail speed youtube normally forces on you. Having it all buffer in one go is so much nicer on my sad potato of a PC. So far my only hurdles are that I would love to use the audio menu, but it's a little too overwhelming for me and I don't really know what to do with it; and that it makes using theatre mode on youtube a bit difficult. It's the way I watch all youtube videos, as it's almost fullscreen but without being too overstimulating, and allowing me to escape to the comments if a phobia comes up or there's just too much going on, but there's not a theatre mode option in the FastStream player UI, and I can't access the youtube player ui or use its hotkeys (as far as I'm aware, but I am a bit dumb), so it's a bit janky getting it to work when youtube just decides every now and then that it wants to go back to standard viewing mode. But that's just for a specific website, and this extension is still being developed and cared for. so please if you come across this in the extension store, give it a try! <3
P.S. sorry for the ramblings, my mental issues can make it a bit hard for me to come across clearly or in an organized manner

This has improved my streaming experience so much. No more stuttering, or videos playing for a minute before buffering restarts or crashes and requires a refresh. There are so many options for subtitles, resolution, playback settings (brightness slider is a personal favourite for dark videos) etc., to make your viewing experience best suited for you. Highly recommend this add-on, and thank you developer.

Has been working wonderfully on 720p and 1080p on the sites I use to watch my shows.

I appreciate that it lets you search OpenSubtitles for subs directly through the player (and you can edit the way the subs display!).

Now I'm unable to save video on Firefox Mac & Firefox Windows.

Doesn't work on 720. Might work on 480, but 480 streams fine for me.
It seems to increase the buffering speed overall of youtube, but will not complete an entire video. My video does buffer faster, but not fully.
Just tested if something might be blocking the extension:
about:config media.mediasource.enabled setting it to false will fully buffer a video that this extension only buffers around 20-40 seconds worth

This is a wonderful extension that allows unlimited buffering of video in any resolution. The settings are thorough and make the extension very customizable.

The only small issues are that it stutters when seeking in 4k, breaks sponsorblock, it's limited to 140s buffering in incognito, and downloads are all 720p for some reason. These are only nitpicks.

Overall, this extension is amazing, and I am grateful to the developer.

I miss when youtube used to let me buffer an entire video.

Luckily with this extension I don't have to miss it anymore.

Honestly probably the best extension I have installed since I have a poor connection where the video where the buffering is often MUCH longer than the video itself,
so I can just leave the video buffering for a few minutes then come back to a perfectly smooth watching experience on any website!