1. A method for recovering a motion vector to perform error concealment on received video stream, comprising: a first step selecting a first motion vector from a first slice that is above a lost slice, and selecting a second motion vector from a second slice that is below the lost slice; a second step determining at least one first orthogonal motion vector that is orthogonal to the first motion vector, and determining at least one second orthogonal motion vector that is orthogonal to the second motion vector; and a third step computing a lost motion vector, comprised in the lost slice, using a weighted average of valid motion vectors, wherein the valid motion vectors include at least one of the first motion vector, the second motion vector, the first orthogonal motion vector, and the second orthogonal motion vector.