Motion vectors are obtained by using a Least Square Error
method to estimate the motion of enclosed vertices. In the octree
approach, tri-linear interpolation of corner representational
motion vectors over space is used for the estimation of the motion
of the enclosed vertices. The vertex motion Δv for the target
point is computed using tri-linear interpolation of the eight motion
vectors of the cell, as shown in Figure 4 and illustrated in
Equation 3. Where w is the weight of each motion vector. For
detail implementation, please refer to the paper [25].