Recent Firefox v87.0 update broke this extension's ability to show GUI. Addon works invisibly, just without buttons.

Controller no longer shows (yes, I checked for HTML5), although it re-appears sometimes for no reason

It continually slows down websites that don't even have videos on them. e.g. google docs continuously has problems running when I had this extension installed. Removing this extension solved the problem. Why is it even running on the page?

Yes

helps remove blurring of videos in HTML5 by increasing speed to 2x, 3x or 4x as it blows away blurring by pushing speed

Works like a charm.

great extesnion

Working great, but would recommend you include in the settings window guidance that the shortcuts are case-sensitive - I found that info on the readme in github, but until I did, I thought the shortcuts weren't working. Thanks much!

very useful extension for all videos. inclusion of keyboard shortcuts means no more fiddling with speed settings on every video

Works as intended and (usually) without any problems at all.

This is fantastic

Why did you change the design? HORROR!
Now the control panel is just HUGE and it gets in the way of your viewing! It used to be tiny and inconspicuous ...
It would be better to add the Reset Speed button.

-RU-
Зачем изменили дизайн? УЖАС! Теперь панель управления просто ОГРОМНА, и мешает просмотру! Раньше была крохотная и не приметная...
Лучше бы добавил кнопку Ресет Спид.

add a shortcut to go back to the beginning of video 。

This is the best speed controller extension I've used so far. Ever since I found it, I've never bothered testing new ones. New browser? Look for this extension, done.