libavcodec/vc1dec.c:5077: error: Uninitialized Value
  The value read from xadv[_] was never initialized.

libavcodec/vc1dec.c:5077:49: 
5075.                     iline  = s->last_picture.f.linesize[plane];
5076.                 }
5077.                 if (!(xoff[sprite] & 0xFFFF) && xadv[sprite] == 1 << 16) {
                                                      ^
5078.                         src_h[sprite][0] = iplane + (xoff[sprite] >> 16) +  yline      * iline;
5079.                     if (ysub[sprite])
