1. A system for video compositing, comprising: a storage device for storing a composite timeline file; a timeline manager responsive to said stored timeline file for reading rendering instructions and compositing instructions; a plurality of filter graphs, each for receiving one of a plurality of video streams and for rendering frames therefrom in response to said rendering instructions; 3D hardware responsive to said rendered frames and said compositing instructions for creating a composite image; a frame scheduler responsive to said plurality of filter graphs for controlling the frequency at which said 3D hardware creates a new composite image; and an output for displaying said composite image.