It did what it said and worked well for a few years. Unfortunately, it now somehow breaks Cloudflare verification, which left me unable to log into many web sites.

Causes problems with Google Recaptha v3

I've used it for years without problem, but recently I have been unable to complete "verify you are human" challenges on Cloudflare-protected sites, I kept getting stuck in an infinite verification loop.
After disabling/enabling all my extensions one by one, I figured out this the problem is caused by this add-on. I'm hoping that problem can be fixed by the developer, than I will happily go back to using it again and give a better rating.

Breaks CNN video playback. Built-in autoplay off feature is sufficient. Removed plugin.

worked pretty well until it prevented www.spectrum.net page from loading. Cannot find an option to whitelist.

Works on some sites, but I can't get it to save the list of sites I want it disabled on. Removing this. Please update this add-on!

Doesn't seem to work in my case

Doesn't work on tumblr and causes huge ram leaks on know your meme.

This plugin works where the built in firefox html 5 blocker does not (no matter how I configure it) which would normally mean 5 stars.

However it also for some reason blocks web fonts. As a developer that is a big issue for me and as a developer I have no idea why this html5 blocker would prevent webfonts from loading.

Because it works well 5 stars because it breaks websites fonts -3 stars

Doesn't seem to allow manually adding domains. Having to visit every domain individually is a pain. Not for me.

The extension works inconsistently.

Doesn't work for me. It's a shame there is only one app to choose from. Opera/Chrome offer several.

This add-on only half works. It works for other sites that use HTML5 video but NOT YouTube.

NOT WORKING AFTER UPDATE.PLEASE FIX

It is (was) a nice app, but it does not work now.

Used to work fairly well. Now not at all as far as I can tell. Not even YouTube where the videos keeps on rolling.

Worked fine until October when youtube videos started autoplaying again.

Nefunguje na YouTube-Videá sa naďalej automaticky prehrávajú!Prosím o opravu...

Only works if I disable preload. I want it to preload I just do not want it to auto run. So it's partially broken and unusable for me.

On vimeo, this app prevented me from seeing or playing any videos. I like the idea, but I do need to see the videos to play them.

The white list doesn't work correctly. Doesn't block autoplay videos on NFL.com which was the whole reason I installed it.