See the Pen Videogular – Buffering Plugin by Two Fucking Developers (@2fdevs) on CodePen.
Buffering plugin doesn’t have too much magic behind. It just waits until your video is prepared to play and then hides itself.
You can of course add your custom buffering because it’s 100% CSS and you can override it as you wish.
You can install with bower:
bower install videogular-buffering