Getting device-fd form playbin

[Mohammad-AL.Gmail]

Hi, 

I have created a playbin2 and able to play pipeline.

Now I wish to set some characteristics of display. I need device-fd of the
display.

I am trying to use gst_child_proxy_get((GstObject*)pipeline,
videosink::device-fd, & device_fd, NULL);
But during runtime, the error is returned:

No property in object player

Can anybody help me to hint at what is wrong?

Kindest Rgds,
Salim