libavcodec/vp3.c:807: error: Uninitialized Value
  The value read from motion_y[_] was never initialized.

libavcodec/vp3.c:807:25: 
805.                     if (s->macroblock_coding[current_macroblock] == MODE_INTER_FOURMV) {
806.                         s->motion_val[0][current_fragment][0] = motion_x[k];
807.                         s->motion_val[0][current_fragment][1] = motion_y[k];
                             ^
808.                     } else {
809.                         s->motion_val[0][current_fragment][0] = motion_x[0];
