Abstract: The present invention relates to a system and method of inserting a secondary stream of digital frames into a primary stream of digital frames without transcoding any of the streams, where the primary stream is encoded according to a first format and the secondary stream is encoded according to a second format where each frame is independent of a succeeding frame. The approach comprises receiving a requested splice-out point in the primary stream; determining an optimal splice-out point in the primary stream in dependence upon the requested splice-out point; receiving a requested splice-in point in the primary stream; determining an optimal splice-in point in the primary stream in dependence upon the requested splice-out point; and replacing the section of the primary stream between the optimal splice-out point and the optimal splice-in point with the secondary stream.