On Stage operations are generally pretty straightforward and involve the following steps.

  • Set up various video and data cables between the camera and the Previzion computer. This includes genlock for data synchronization and timecode data inputs for Previzion, and the feeding of the HDSDI composited output signal to recorders, HD capable camera viewfinders, and on set monitors.
  • The set and camera calibration files are loaded, and key offset parameters are recorded for the Intersense camera to focal plane offset. The keyer levels are set and color balance can be adjusted for the best match between the foreground and background.
  • After the lighting has been set on the green screen the operator would then set up the keyer levels, adjust the matted density and background mix, then add in any garbage mattes if necessary. If the output is going to be a final in camera composite, the operator then sets up color matching between the foreground (green screen player) and the 3D backgrounds or plates.
  • When the camera is rolling the operator records all camera tracking data through the Previzion take system including shot, take, show as well as any changes that have been made to the 3D environment. This is recorded into a Collada text file for post processing, as well as capturing a jpg image every 10 seconds for reference.



The Previzion system continually displays tracking data and a visual lineup, so you can verify that everything is working properly. The UI has a series of status lights to indicate any errors or broken connections to the camera.

We strongly recommend providing a Previzion composited output to the camera operator as it makes a huge difference is setting up a shot when you can see it all together. This also is a big help in adjusting lighting to match between the green screen and synthetic elements.