Hello Paul, I use Syntheyes regularly with Carrara. There are a couple or reasons that this is happening. Carrara is not a video playback device so it's not optimized for real-time video playback within the Assembly Room. (even playing an animation in the Assembly Room without a movie backdrop is in slow-motion because of all the 3D resources that Carrara has to process) The best work-around is to use the Quad view in Carrara to minimize the screen redraw area of your movie backdrop. Additionally, you can click zoom out to make it smaller still. Everything does render just as it should with great results but getting streaming video probably isn't going to happen anytime soon. :-/ Mark