Programmable transitions for video stream editing

Video editing applications provide a facility to transition from one video stream to another, or to filter a video stream in some way. New transitions are usually developed using a custom API for the particular package. In this article we present a shading language for specifying transitions and filters on video streams. Video editing is performed by constructing a tree based on the transitions. The shading language is compiled to a virtual machine, but can still be executed efficiently. We provide several examples of transitions which have been successfully applied using our video stream editing software.