The spec says: Implementors are encouraged to return "maybe" unless the type can be confidently established as being supported or not. Generally, a user agent should never return "probably" if the type doesn't have a codecs parameter. OSX, Windows, and GTK media engines return "probably" if a type does *not* have a codecs parameter.
Created attachment 32622 [details] proposed patch
Comment on attachment 32622 [details] proposed patch r=me
http://trac.webkit.org/changeset/45758
*** Bug 27409 has been marked as a duplicate of this bug. ***