VeriLook : Livestreaming from 2 USB cameras

[ppp123]

I am trying to use two USB cameras to display two separate live stream on UI.
I am using two threads to read frames from the hDevice and display it on UI.
But at a time only one thread is able to work as other thread gives following error on NDeviceStartCapturing(hDevice) function,
Libv412 : device or resource busy.

In thread I have used start and stop capturing function. then also it is giving device busy error.

I have gone through ImageCapture tutorial and in that only one camera is capturing images at a time.

How can I use two USB cameas without any error for live streaming?