Gst, OpenCv and user(not root) access problems


I have app that uses gst via OpenCV on Ubuntu. When service worked under root everything was fine. when I’ve changed user, service stopped working. I’ve used solution given here, namely

sudo chmod u+s /usr/bin/gst-launch-1.0 
sudo chmod a+x /usr/bin/gst-launch-1.0

but still no luck.

1)Is it possbile to use gst without root on Ubuntu, is it possbile with gst and OpenCV? What should I do to achieve this?
2) How OpenCV uses gst, accroding to src it doesn’t call gst-launch but why then there is access problems with no root?

Thanks in advance.