To enable video calls, install the following packages.

Transport level security:
- gst-plugins-srtp
- gst-plugins-dtls

Peer to peer connection reliability:
- gst-plugins-libnice

Video output into a window:
- gst-plugins-gtk

At least one codec is needed in common with the other end of the call, as they
are negotiated when the call begins.

Video codecs:
- gst-plugins-x264
- gst-plugins-vpx

Audio codecs:
- gst-plugins-good
- gst-plugins-speex
- gst-plugins-opus