libavcodec/vp3.c:822: error: Uninitialized Value
  The value read from motion_y[_] was never initialized.

libavcodec/vp3.c:822:21: 
820.                     }
821.                     motion_x[0] = (motion_x[0] >> 1) | (motion_x[0] & 1);
822.                     motion_y[0] = (motion_y[0] >> 1) | (motion_y[0] & 1);
                         ^
823.                     frag = mb_y * s->fragment_width[1] + mb_x;
824.                     s->motion_val[1][frag][0] = motion_x[0];
