1. A method for dynamically determining frames required to build a complete picture in an MPEG video stream comprising: decoding an order of frames in the MPEG video stream according to a dependency vector model, the dependency vector model being configured for determining a dependency vector as a function of the decode order video stream for seamless operation over several types of MPEG streams, wherein the dependency vector model determines the dependency vector by reviewing frames of a decode order video stream in a reverse direction until a complete intracoded picture can be derived and in which a given frame of the dependency vector is identified as an absolute dependency of a frame to be displayed, the dependency vector model further comprising (i) determining a relative cost of displaying frames in the MPEG video stream in display order, wherein the relative cost is determined as a function of a number of bytes from the start of a frame to the absolute dependency for that frame, (ii) using a difference filter for modifying the relative cost of displaying frames in the MPEG video stream in display order, and (iii) selecting a splice point as a function of a frame having a modified relative cost exceeding a threshold amount; and performing frame accurate representations of the MPEG stream in a bidirectional fashion as a function of the dependency vector determined according to the dependency vector model.