libavcodec/vc1.c:654: error: Uninitialized Value
  The value read from mvy[_] was never initialized.

libavcodec/vc1.c:654:18: 
652.         case 0x1:
653.             tx = mid_pred(mvx[1], mvx[2], mvx[3]);
654.             ty = mid_pred(mvy[1], mvy[2], mvy[3]);
                      ^
655.             break;
656.         case 0x2:
