libavcodec/vp3.c:764: error: Uninitialized Value
  The value read from motion_x[_] was never initialized.

libavcodec/vp3.c:764:21: 
762.                     motion_y[1] = RSHIFT(motion_y[2] + motion_y[3], 1);
763.                 } else {
764.                     motion_x[1] = motion_x[0];
                         ^
765.                     motion_y[1] = motion_y[0];
766.                 }
