Temasys plugin doesn't work on OS X running in Oracle Virtualbox

[magiccpp1]

We are running os x in virtualbox, looks AdapterJS doesn't work with Safari on the guest OS X.
from our test AdapterJS works fine with Safari on the host OS X, so the issue is that AdapterjS may not work well in the virtualbox.

the system description:
Host: OS X Sierra version 10.12.4
Oracle Virtualbox version: 5.1.22 r115126
Guest: OS X Sierra version 10.12.4 - used
Safari on Guest: version 10.1 (12603.1.30.0.34)
USB Webcam : Logitech C920.
Temasys Version: both of 0.8.891 and 0.8.892 don't work.

Symptom:
we used AdapterJS.webRTCReady(callback) in our webpage, and expect the function callback to be invoked.
however, when using Safari on the guest system, callback was not called.
we then used the host with same configuration and tested again, this time webRTCReady() works fine.

P.S. we have tested the camera in Facetime and the camera works fine in virtual box.