Since 2025-05-03, With this add-on, Amazon Prime Video can't work. I.e. Sound is OK. but Image keep black screen.
This problem happens on Chrome too.
And it looks that other speed control add-ons don't have this problem.

Please solve this problem.

Suddenly on 4th May it stopped working on Amazon Prime. Whenever the extension is enabled, prime video shows black screen

to anyone saying the extension Is sketchy because It requests your data, this Is a basic permission even the most reputable addons ask for and need to function.

worked very nice. But in recent days firefox keeps telling me "video speed conroller is slowing down firefox"

not showing up

Request access to all data of all websites (wich includes passwords) for changing the speed of a video?. Not on my computer my friend.

Seems like this extension has access to all websites on Firefox unlike on Edge and Chrome, and I don't like this. I am not sure if this is something to be blamed on Firefox or the extension, but it should not have access to all data on all websites since these types of extensions will be ran on a handful of websites. Uninstalling it now.

Firefox port of one of the most useful Chrome plugins.

Rating 1 star because this one is abandoned, up-to-date and maintained version here:

https://addons.mozilla.org/en-US/firefox/addon/video-speed-controller-new/

no sound is played at under 0.1 speed

deosnt' wrok

quick find pop up when i press shortcut keys like s d z x etc in fireforx on my ubuntu desktop
please fix it

The addon stopped working entirely today without any reason. I have already tried re-installing, but it still does not work.

Does not work. When I click + it only increases the speed by +0.1x. Clicking + again DECREASES the speed by 0.2x!!!!!! infuriating. USED to work, not anymore.

Doesn't work, videos won't play and ad shows after page refresh.

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.

Please add an option to go back to the old design

Used to work fine but now makes a deflating sound when speeding up a video

Does not work

I had to disable it since it was causing serious issues to some websites that had nothing to do with youtube. The developer kindly replied saying the issues would be addressed, but I wonder if I can now trust it won't do the same again, with some other website/web app.
EDIT May 2022: still causing issues, and preventing checkout via PayPal to work at all. Such a pity I have to delete this extension permanently because it's a real disaster.