libavcodec/vc1dec.c:1003: error: Uninitialized Value
  The value read from uvmy_field[_] was never initialized.

libavcodec/vc1dec.c:1003:9: 
1001.         }
1002.         uvmx_field[i] = (uvmx_field[i] & 3) << 1;
1003.         uvmy_field[i] = (uvmy_field[i] & 3) << 1;
              ^
1004. 
1005.         if (fieldmv && !(uvsrc_y & 1))
