I'll do my best to describe this issue.
Let's say I load up an episode of Parks and Rec, or of Downton Abbey. About 80% of my episodes work fine, but then one comes along that behaves as follows:
Video starts; immediate full screen black (audio continues). Black lasts for about 1 full second. Then video returns, approximately 1-3 full seconds, then there is black, same as described before.
It's interesting that you suspect cabling problems, but then I would expect to experience the same type of behavior when playing with VLC, MPC-HC, or any other app at least some of the time.
I did adjust the registry to display the full 256 colors, as described. Other than that, I have the video drivers updated, and the Nvidia settings all point defer to the playing software. I'm contemplating doing a complete reinstall of windows, but I'm not sure that will do anything, as my current install is only a few months old.