libavcodec/h264.c:1018: error: Uninitialized Value
  The value read from ref[_] was never initialized.

libavcodec/h264.c:1018:20: 
1016.         }else{
1017.             for(list=0; list<2; list++){
1018.                 if(ref[list] >= 0)
                         ^
1019.                     pred_motion(h, 0, 4, list, ref[list], &mv[list][0], &mv[list][1]);
1020.                 else
