https://bugs.winehq.org/show_bug.cgi?id=52769
--- Comment #10 from Nikolay Sivov bunglehead@gmail.com --- (In reply to Zeb Figura from comment #9)
I don't know what the mfplat considerations are, but it also strikes me as potentially reasonable to create an element wrapping GStreamer's rtspsrc, but without hooking that up directly to decodebin.
Current version of it is now at https://github.com/ValveSoftware/wine/pull/142, it doesn't share mf.dll parts now.