Im using farnebacks method to estimate the motion vectors of a video, but how can i find the mean value of vectors over the entire video?

What i want is to find the medium value of the velocity vectors for every orientation and i want to do this over the entire video. so i have to take 2 frames each time and calculate the medium velocity on these two and then continue to take 2 vectors until the end.. like this 1-2, 2-3,3-4....n-1-n. i wrote the code for the calculation of medium value and it works fine but how can i apply it over the entire video? i mean using 1st-2nd,2nd-3rd..etc frame each time? the result must be a matrix with number of columns=frames and rows=0-361 for the degrees. i guess by applying a loop before the code for the calculation of medium value?

[abbxucy11]

farneback's method has outputs the velocity and the orientation for the last two frames if i dont modify it otherwise.

[Walter Roberson]

http://www.mathworks.co.uk/matlabcentral/answers/43073-a-guide-to-tags