libavcodec/vp3.c:754: error: Uninitialized Value
  The value read from motion_y[_] was never initialized.

libavcodec/vp3.c:754:17: 
752.                 }
753.                 motion_x[0] = (motion_x[0]>>1) | (motion_x[0]&1);
754.                 motion_y[0] = (motion_y[0]>>1) | (motion_y[0]&1);
                     ^
755.                 frag = s->all_fragments + mb_y*s->fragment_width[1] + mb_x;
756.                 SET_CHROMA_MV(motion_x[0], motion_y[0]);
