1. A method for decoding a video bitstream, comprising: determining, for a current block of the video bitstream, a reference motion vector from a number of candidate reference motion vectors, wherein the reference motion vector is associated with a reference block and includes a predicted portion and a residual portion; selecting a probability context model for the current block by evaluating the residual portion of the reference motion vector with one or more thresholds, wherein the selecting comprises: comparing a magnitude of the residual portion of the reference motion vector with the one or more thresholds to determine an indication of likelihood of motion intensity for the current block; and selecting the probability context model from a plurality of probability context models based on the indication of likelihood of motion intensity for the current block; and entropy decoding, for the current block using a processor, a motion vector residual associated with the current block using the probability context model, wherein the motion vector residual is determined as a difference between a motion vector determined for the current block and the reference motion vector.