libavcodec/vc1dec.c:3718: error: Uninitialized Value
  The value read from is_intra[_] was never initialized.

libavcodec/vc1dec.c:3718:17: 
3716.                 if (i == 4)
3717.                     vc1_mc_4mv_chroma(v, 0);
3718.                 v->mb_type[0][s->block_index[i]] = is_intra[i];
                      ^
3719.                 if (!coded_inter)
3720.                     coded_inter = !is_intra[i] & is_coded[i];
