On linux we currently only search for gstreamer libraries and tries to use that directly. QtMultimedia does however also work and could be used when gstreamer can not be used directly.
Created attachment 192194 [details] Patch
Created attachment 192195 [details] Patch Fix wrong indent
Created attachment 192197 [details] Patch Fix typo as well
Committed r148422: <http://trac.webkit.org/changeset/148422>