We are lacking for someone to provide us a holistic picture of V.O.D . It 's going to help provide a bigger picture on who is No . 1 in V.O.D . '' Rentrak , a company based in Portland , Ore. , already provides viewer tracking for video-on-demand based on data from cable set-top boxes , but Rentrak does not receive the set-top data from all the cable companies that offer video-on-demand .