Transparent background exported as .WEBM format

[elleh15988724]

I'm trying to export a green screen clip with a transparent background in WEBM format in Premiere Pro, and I followed this tutorial: HOW TO EXPORT WEBM FROM PREMIERE PRO (WITH ALPHA/TRANSPARENCY) - Premiere Pro Tutorial - YouTube and many others to the latter, but when I upload it into VLC Media Player or back into Premiere, the black background is still there but with some white fuzzy areas in the back. I'm not really sure what else I can do. 

Here is what the end result looks like:

Any help would be greatly appreciated. Thanks.

 

[elleh15988724]

Also, is QuickTime the only way to get a transparent background, or is there another way?