There are a couple of approaches to do what you intend: to use GStreamer and to use LibRealsense.
To get the preview output of the depth camera, you should run the following command:
gst-launch-1.0 v4l2src device=/dev/video11 ! xvimagesink
You may also be interested in checking this couple of links that use the LibRealSense library to access the depth data from the camera:
Please let me know if you find this information useful.
Have a nice day,