This is only about your video format compatibility:
On Windows 7, neither Cyberfox nor ordinary Firefox can play the video on your web page (for me, that means). Vivaldi works as expected. The downloaded ogv file plays in VLC and SMPlayer, but MPC-HC only plays audio. The MediaInfo tool doesn’t recognize the format.
On an Ubuntu Studio 16.04/64 virtual machine, Firefox also can’t play the video, and the default Parole Media Player 0.8.1 can’t play the ogv (Could not initialise Xv output). VLC can, again.
Since Firefox can play many ogv videos properly, perhaps you could tweak some format settings, to make it more compatible.
If it is not only me, having problems.
Be well!
(edit: typo)