libavcodec/vc1dec.c:1620: error: Uninitialized Value
  The value read from oppfield_predB[_] was never initialized.

libavcodec/vc1dec.c:1620:9: 
1618.         samefield_pred[1] = samefield_predB[1];
1619.         oppfield_pred[0]  = oppfield_predB[0];
1620.         oppfield_pred[1]  = oppfield_predB[1];
              ^
1621.     } else {
1622.         samefield_pred[0] = samefield_pred[1] = 0;
