libavcodec/vp3.c:806: error: Uninitialized Value
  The value read from motion_x[_] was never initialized.

libavcodec/vp3.c:806:25: 
804.                         BLOCK_Y * s->fragment_width[0] + BLOCK_X;
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 {
