When I try to play a webm/vp8 video in our player, I see a blank screen with audio only. There is no video. It works fine in both Chrome and Safari but not FireFox. I m using the newest release of Firefox Quantum(57.0.1 (64-bit)) on a mac OS. I tried disabling 'Hardware Acceleration' but that did nothing. I also played around with different configurations, but nothing seems to work. I'd need some assistance with this. Thanks for the help.

Video codec: vp8 Audio codec: opus Container: webm