Black screen video

Hi

I have integrated playkit into my react-native app following the steps shown over here.

Specifically, I have created a java class which is an exact copy of the following class:

I am testing on a Android 8.0+ device.
When the video loads, there is only audio. The video is just a black screen. I am linking to a mp4 file - in fact to the same file gleaned in the java class link above. I have tried a different mp4 file and encountered the same problem

Can someone please help on where I can start looking to fix this?

There are no errors shown anywhere.

Cheers
Vinod