We currently ship the ktp-call-ui for QtGStreamer 0.10, which depends on GStreamer 0.10. There's a branch for QtGStreamer 1.0 for GStreamer 1.x: https://projects.kde.org/projects/extragear/network/telepathy/ktp-call-ui/repository/show?rev=gst-1.0-port We should upgrade Rawhide's ktp-call-ui to a snapshot from that branch (or a release if it happens soon).
See also, http://community.kde.org/KTp/Tasks/NewCallUI
I added the changes from the gst-1.0-port branch as a conditionally applied patchset.
Built for Rawhide and F21 Branched.