libavcodec/vp3.c:833: error: Uninitialized Value
  The value read from motion_x[_] was never initialized.

libavcodec/vp3.c:833:25: 
831.                         motion_y[1] = RSHIFT(motion_y[2] + motion_y[3], 1);
832.                     } else {
833.                         motion_x[1] = motion_x[0];
                             ^
834.                         motion_y[1] = motion_y[0];
835.                     }
