Video Mixing Renderer 9 (VMR) DirectShow graph building issue

[QuantumSquirrel]

I've been experimenting with DirectShow video playback in Windows guests (XP, Vista, 7 and 8.1) using GraphStudioNext, and I stumbled on a issue that might be cause by the VirtualBox additions display driver. (The host PC is running Windows 10 x64 and has a Nvidia Geforce GTX 750 Ti graphics card).

If you start GraphStudioNext and drag a video on to it will by default create a graph with the VMR7 and hit play then it will play fine. If you remove the VMR7 filter and then go to Graph -> Insert Video Renderer, you can try out the various other video renderers.

All of these work fine (Video Renderer, VMR7, EVR) except VMR9, which fails to build the graph, reporting a cannot connect pins error. This error is not normal and doesn't occur on non-virtualized versions of Windows.