In r5407 the spec clarified the rules for canPlayType: The canPlayType(type) method must return the empty string if type is a type that the user agent knows it cannot render or is the type "application/octet-stream"
Created attachment 66108 [details] Proposed patch
http://trac.webkit.org/changeset/66541
Revision r66541 cherry-picked into qtwebkit-2.2 with commit 92301c0 <http://gitorious.org/webkit/qtwebkit/commit/92301c0>