Firefox 55.X - How to block automatic video playback on websites

Is there any Firefox 55.X plugin that would effectively block video playback on various sites?
A plugin that blocks audio and video in various formats is welcome.

Kolobos wrote:

Check https://addons.mozilla.org/en/firefox/addon/flashstopper/

FlashStopper can handle most popular sites.
With the introduction of the HTML5 standard and the tag, Flash technology is slowly beginning to depart. Even Adobe has declared that it will continue working on Flash until 2020.
To disable automatic playback on HTML5 based pages in Firefox you do not need to install add-ons, you can enter "about: config" in the address bar and Because websites use different methods of playing multimedia, it may not be enough. You need to combine several methods.
See this thread. https://support.mozilla.org/pl/questions/1150702

Kolobos wrote:

FlashStopper also blocks html5.

That is correct, but the name of this plugin does not suggest anything.

It doesn't hurt to type in the address bar " about: config "and
change the parameter setting media.autoplay.enabled on false .
It should help in most cases, when despite the installed FlashStopper some sites still play movies automatically.

Quote:

FlashStopper for Firefox

Make video players (flash & html5) show video thumbnail instead of autoplaying ...
...
Known issues:
* Isolated media elements will not stop (use media.autoplay.enabled = false)

"Isolated media" refers in this case to media played by additional plugins installed for the browser. There are a few, though less popular than Flash, but still used. Even Silverlight or QuickTime.

Together with the HTML5 standard and the "audio" and "video" tags, it is possible to embed and play video and audio material on websites without the need to install add-ons ... all you need is the latest version of the browser.