An apparatus for generating an image signal for a display (103) comprises a receiver (105) which receives a video signal comprising three-dimensional data for a sequence of images. An image generator (107) generates display images for the sequence of images based on the three dimensional data and a rendering viewpoint. A shot transition detector (111) detects shot transitions in the sequence of images and a viewpoint controller (113) changes the rendering viewpoint in synchronization with the shot transition. A signal generator (109) generates the image signal to comprise the display images. The apparatus may further track viewer movements and adapt the rendering accordingly. In addition the system may bias the viewpoint towards a nominal viewpoint. The viewpoint changes due to tracking may be non-synchronous whereas the viewpoint changes due to bias may be synchronous with shot transitions.