a method to insert or splice new pictures into an existing video stream is provided where the video stream is compressed according to the mpeg - 2 video compression standard . the method assures that the new pictures will fit into the encoded stream in the space allotted without running over or under their given bit allocation . the method comprises of steps by which a number of new pictures may be encoded to a precise bit target given the number of free bits in the buffer at the start and end of the splicing , while preventing buffer overruns and under runs .