map image to camera.

I need to map a image to my camera in cycles so the image fits to the edge of the camera. For some camera tracked footage. I have been at this for hours. It was so easy in BI.

I need to put image in the world texture I have put in a environment texture and a image texture but can not get it to map. I have seen tuts but none have shown me how to match the image to camera view. When the camera moves the world texture (image sequence) is the same or does not move but follows the camera.