1. A method for selecting a reference frame in a frame buffer for encoding a current frame in a video encoding system, the method comprising: storing in a frame buffer a plurality of reference frames, each reference frame associated with a characteristic metric vector, the characteristic metric vector representing the reference frame in a frequency domain; generating for the current frame a characteristic metric vector representing the current frame in a frequency domain; determining an interframe distance between the current frame and at least one of the reference frames, the interframe distance based upon a distance between the characteristic metric vector of the current frame the characteristic metric vector of the reference frame; and selecting for encoding the current frame at least one reference frame for which the interframe distance is below a threshold distance.