The qtwebkit package currently depends on GStreamer 0.10. OpenSUSE has a patch to make it build against GStreamer 1: https://build.opensuse.org/package/view_file/openSUSE:Factory/libQtWebKit4/gstreamer-1.0.diff?expand=1 That patch should be applied in Rawhide.
Built for Rawhide and F21 Branched.