I am using motion tracking in Blender 2.61 and can render fine in Blender internal, but do not know how to set it up in cycles. I tried using the video as an environment texture but I really do not know what I’m doing. Is this possible, I like cycles much better?
Thank You
I’m not sure exactly what you mean, but if you want to ‘composite’ with Cycles (not had chance to look into it yet with cycles - there’s no info on it) - Render Layers aren’t available in 2.61 - 2.62 I think is out this week, this should have render layers for cycles (I hope I’m right). Or if you want to check it out now, head over to www.graphicall.org and download an svn version. 
At the moment, I think that cycles will only render with the CPU, not GPU. (see Blender Bug Tracker)
If that works for you, then…
First, render your scene with cycles using a transparent background, which is found in the Integrator panel.
Go into the compositor, type shift+a to add a new node, and choose input–>movie clip. Follow this up with an alpha over node: color–>alpha over. Plug them together like this:
To be honest, I have not had to do a scene yet that also used shadows- but this can’t be that much harder. If you can do the above, then you’ll probably be able to mess around and get the shadows pass in there as well. Best of luck!
sorry about the double images. Was trying to figure out the best one…
Thanks samiboy I will try this method. 
