Tried a few different extensions for setting video speed on the current page and this is the only one that does everything I want. Click on the toolbar icon, click on the speed you want, done.

As a bonus, you can completely customize the menu and add a button for any particular speed you want. Really convenient.

Please add another 'Big Rewind / Big Fast forward' buttons for 60 seconds steps.

Easily usable and configurable. Works on all sites, not only YT.

Perfeito, funcionou em todos os sites que eu tentei usar.

Лучшее дополнение из всех, которые пробовал. Максимально гибкое в настройках + может ускорять даже в тех плеерах, в которых не ускоряли другие дополнения.

I love how configurable this addon is. Also, the user interface is easy to understand, and fits right in with the look and feel of Firefox. Thanks!

hotkeys are not working when video are on full screen (increase and decrease speed). If you can implement it, it would be super helpful!

Works on WhatsApp for Audio and Video. Excellent. I wonder how to choose a default speed. e.g.: all videos and audio automatically play in speed 2.0

This add-on has saved me hundreds of hours.

extremely well though addon. I love the little icon constantly showing the actual speed. This is attention to details. Thank you. I cant find a Paypal to donate

Dont bother with any other speed control extension. This is the only one that works on browsers with various video source content. Great job guys.

SOOOO USEFUL!

Does it's Job perfectly

---BIG PROBLEM. SUGGESTION TO THE DEVELOPER:
For the loop button or any button, when you click on it, it stays exactly the same and you have no possibility of knowing if the button has been activated or not!! THAT IS A BIG PROBLEM!!
It would be simple to make the button of another color when it is enabled and keep it the same color of the other buttons when it is not enabled.
Or when I move the cursor over a button that I use, it would indicate enabled or not enabled for example.
I will change to 5 stars when a change to correct this problem has been made.
This addon works well, even the loop button works well too.

---Update on 08/11/2021: thanks to the developer to have fully corrected the problem I had stated just above. Back to 5 stars.

Thanks for sharing this addon. Dearly needed on youtube where I tested it.

I find the add on to be wonderful and have been using it for years. I am very much appreciating the update the former updates for keyboard shortcuts (e.g. Alt+Shift+Right for faster speed).

However, since the last update, the new keyboard shortcuts conflict with FireFox's default "Ctrl+Shift+Left" as well as "Ctrl+Shift+Right" (e.g.a for the address bar as well as find bar). This sadly reduces the workflow and everyday use. I guess it's easy to fix and want to Thank You in advance! Since I think it's the #1 Playback Speed service, it's worth 5 stars even now. (For more details, there is already a thread form another user on github.) Thank you!