I have a very weird bug that I just can't understand.
I am currently using the WPFMediaKit library in one of my programs. When using the library in a near empty new "demo" wpf solution, the image from the USB Camera source is rendered perfectly to the MediaCaptureElement class. However, using a more complex solution, the same library (without changes), the frame gets rendered black. I can see there is connection to the camera and everything goes well, DirectShow graph is built normally and everything just looks fine, besides the black frames. I can even open the camera properties and see it pushing out frames as usual.
Also, this only happens on Dell E6540 (With an AMD and Intel HD gpu) if it's Windows 7. Windows 8/10 work fine. Have tried a lot of drivers nothing seems to change the output.
I have no clue what to do or what to try.
After many hours and just after deciding to post this question, I found the answer.
The more complex solution, under the AMD Settings application was set to use "High Performance" mode, this mode was automatically enabled on Windows 7 for some reason. Disabling that and setting it to "none" or "lower power" fixed the issue.
Doesn't change the fact that there is an issue with laptops with dedicated AMD GPUs, probably something to do with DirectX/Direct3D which is used to render the frames.