The description states it works for html5 video, so I hope you can change your review to reflect that this extension is working as stated.
Sorry, it probably uses webrtc and I don’t think I have a method to inject in such APIs.
Most things that interface with call audio causes many glitches since its live two way communication and that requires such low latency.
I have never used whatsapp but it is a service that requires phone linking etc? So I don't have a way to test it.