Back when I was young, we had a 180 cinema in one of our theme parks, which was amazing, but then came the 360 movie cinema, and no one looked back! Seems like the case here 
It seems like the video is being converted to 360 (so, double the size, but 50% less information), and is being displayed this way. I will see how we can make 180 work, so far the texture creation only supports 360.
Just a small hack to get it to work - https://www.babylonjs-playground.com/#SQ5UC1#25 (make sure you use the right URL ), but this is not the solution for the 5.7K, and not the real solution for general users. I will see how I manage to integrate it in the framework.
The other problem is the browser support, which we very sadly cannot help with. Chrome would not even display it, firefox told me the file is corrupt. Gonna love web standards!