https://bugs.winehq.org/show_bug.cgi?id=45988
--- Comment #15 from Julian RĂ¼ger jr98@gmx.net --- What he linked in comment #10 is not a gstreamer plugin. Far from it.
The github repo does not exist any longer but there are forks of it. It ships a bunch of native dlls and sets overrides for them via .reg files.
So technically it is a valid Wine bug, since that should definitely be supported by Wine's builtin media foundation instead of relying on native dlls.