Hello sonnyboy1,

this problem is likely not caused by Firefox, instead it is a problem with the ad blocker. Please contact the developer of the ad blocker to solve the problem.

By "floating videos" do you mean picture in picture. You can switch that off in Settings > General > Browsing > Enable picture-in ....

https://support.mozilla.org/en-US/kb/turn-picture-picture-mode

Your content blocker may enable you to get rid of the warning about an "ad blocker".

Opening a fixed mini player automatically is a feature offered by the website and is created via JavaScript if the main player is scrolled out of view. A lot of websites now have a fixed (pop-up) mini player in one the corners once you start playing a video that stays visible if you scroll the page. This website mini player shouldn't be confused with the Firefox PiP (picture-in-picture) feature (you likely see the Firefox PiP icon if you hover the mini player).

You would need to use a content blocking extensions to block such a player.

You can look at these prefs on the about:config page to see what settings work for you to block autoplay.

• media.autoplay.default = 5 [0:allow;1:blockAudible;5:blockAll]
• media.autoplay.blocking_policy = 2
• media.autoplay.allow-extension-background-pages = false
• media.autoplay.block-event.enabled = true
• media.block-autoplay-until-in-foreground

You can open the about:config page via the location/address bar. You can accept the warning and click "I accept the risk!" to continue.

• https://support.mozilla.org/en-US/kb/about-config-editor-firefox