For those of you pulling from bitbucket: I did some more investigation into the issue relating to libgstvideo, and it turns out that since the gstreamer binary libraries were last updated in the repository, the gstreamer headers (which you have to install separately for development at this point) changed slightly so that what was once a macro got changed to a function. If you installed gstreamer 1.6 or newer on Windows, you'll run into this problem and you'll get a pop-up window telling you about a DLL problem. Note that you don't get any benefit from having newer gstreamer libraries installed; when you run RetroFE as packaged in the Artifacts directory, it uses the version from the repo rather than the one you built against the headers of. Until the libraries in the repo are updated, or some other solution is put in place, I'd recommend installing and building against gstreamer 1.4 if you hit the problem.
On Linux and Mac, there aren't any binary libraries in the repo, so this mismatch doesn't occur. You'll build with the same headers that your version of the installed libraries were built with, so it will all match up and be happy.