This project focused on two supportive information techniques for virtual TV studio environments using a back projected screen and real time video composition on the GPU. In traditional TV, studios use blue or green background chroma-key for video composition. Therefore the actors cannot see the final composite without a preview monitor. Pointing at objects on the background image is especially difficult, requiring experience and rehearsal. In this system, the actors can see and point at supportive information displays such as computer-generated backgrounds, virtual actors, reading scripts and/or final composites behind them. To compose the computer graphics into the free area on the screen, a special real-time GPU-based video rendering program has been developed. (http://akihiko.shirai.as/projects/LuminaStudio/)