It has bothered me for a while, but the fullscreen button has been, and is still disabled with video from youtube embedded into posts. Anyone know why? It only ever happens on this site.

I am using the HTML 5 player, and Safari 9.1.2.

...but it's definitely not just DBO - happens all over the place. We're just using the standard embed code over here.

FWIW, I've had videos embedded on other sites refuse to go fullscreen. Oddly, it seems to be specific to the individual videos and not the site they're embedded on.

Yeah, I'm pretty sure it's based on the video.

I always just assumed it was an option they gave YouTubers to try and force people to actually go to YouTube instead of watching an embedded video.

I believe it's a query param you can pass in:

?fs=1 would allow fullscreen (which is the default setting) or ?fs=0 would disable it.

https://developers.google.com/youtube/player_parameters#fs

Possibly, although it's possible to just disable embedded playback entirely (music videos tend to do that a lot). Maybe they consider disabling fullscreen to be an in-between option.