I would love it if this extension got a sharpness filter added, was a bit disappointed it wasn't one of the filter options.
Not to mention an integer based scaling option for people with 4k displays when watching 1080p videos, though I don't know if that's even possible.
A sharpness filter would help a lot though, since Nvidia's edge enhancement doesn't work in Firefox.

Does a wonderful job in most cases but does not stop youtube from auto playing in background tabs neither in firefox, chrome or opera. I think Youtube is overriding your setting somehow being the spammy ad monster it is.

One other small issue:
Sometimes videos don't start out in my preferred quality. I set it at 480p for this silly laptop, for instance). So videos wont even start because they're trying to play at 1080 or 720p instead. I noticed the same issue in Opera.

What an absolutely fantastic extension. The key things I use this for are to block ads, stop autoplaying the next video and set the default playback speed to 1.5.

Love this addon, can't use YT without it! Would love to see an option to sync audio as on some videos the audio can be out of sync due to uploader error and it really bugs me! Other than that this is a MUST extension if you ever touch youtube.

Absolutely fantastic, I love this add-on! The only thing I'd like more from it is the option to disable scrolling down the page while fullscreen, otherwise this is perfect.

never had any problems with this addon does what it says (would recommend it) also removes ads

Have had zero issues with the tool, very useful, and never fails.