In a method and apparatus for predicting and coding motion vectors in a video
compression scheme, an ordered list of segments for a reference frame is used to
create a hierarchy of segments with a plurality of levels. Motion vectors for segments
in the top level are entropy coded, and these vectors are used to predict vectors
for segments at the next level. Residual vectors are entropy coded to correct these
predictions, and the process of prediction from above and coding residuals continues
recursively down through the hierarchy of segment levels. Information about the
previous motion of segments may be exploited in the prediction process. In a complementary
method and apparatus for decoding motion vectors, the same segment hierarchy is
used to predict motion vectors by the same method used during encoding, and these
predicted vectors are added to residual motion vectors to reconstruct the actual
motion vectors.
