libavcodec/vc1dec.c:3776: error: Uninitialized Value
  The value read from is_coded[_] was never initialized.

libavcodec/vc1dec.c:3776:28: 
3774.                     block_cbp   |= 0xF << (i << 2);
3775.                     block_intra |= 1 << i;
3776.                 } else if (is_coded[i]) {
                                 ^
3777.                     pat = vc1_decode_p_block(v, s->block[i], i, mquant, ttmb,
3778.                                              first_block, s->dest[dst_idx] + off,
