Hi, In the specification page 142 1.(d). it is said : If FTYPE is non-zero (inter frame), using PF, NMBS, MBMODES, NBS, and BCODED, decode the motion vectors into MVECTS using the procedure given in Section 7.5.1. I think, there is a little mistake as the correct procedure is not in section 7.5.1 but in section 7.5.2 (?) Regards J.F.