Blank video with NVIDA Optimus enabled machines when using DirectShow with VMR9

Hi all,

I use DirectShow to playback video in a multimedia training application, which works well on pretty much all machines, the exception being those that use NVIDIA Optimus.

On Optimus enabled machines, the video driver senses the Direct3D surface created by the VMR9 video renderer and takes over control from the iGPU. However when it does this something goes wrong and you are left with a situation where the video plays, but with sound only.

As we do not have access to any machines with Optimus, so we have been unable to figure out what is going on by debugging, inspecting DirectShow messages, etc.

Does anyone know anything more about this issue and/or how to avoid/workaround it (as at the moment when ever we get a customer with this issue, we have to guide them through forcing the system to use the iGPU in the NVIDIA control panel)?

Thanks in advance,