I asked a question before but I think the problem has changed enough to ask it in a new way.
I tracked some footage using the setup tracking scene button, and had issues with the rendering. I switched over to Cycles from Blender Render , and used Shadow Catcher. This seemed to work until I exported the render, which I think is placing the shadow below the tracked camera scene. When rendering, the image viewer shows the shadow background layer being rendered, but the final image doesn't have it.
OKAY! I've done some work and gotten pretty good results. I believe my issue before was that I had objects on the wrong layers.