libavcodec/motion_est.c:596: error: Uninitialized Value
  The value read from xmin was never initialized.

libavcodec/motion_est.c:596:9: 
594.     dminh = dmin;
595. 
596.     if (mx > xmin && mx < xmax &&
             ^
597.         my > ymin && my < ymax) {
598.         int dx=0, dy=0;
