libavcodec/h264_slice.c:1668: error: Uninitialized Value
  The value read from id_list[_] was never initialized.

libavcodec/h264_slice.c:1668:13: 
1666.         ref2frm[18 + 1] = -1;
1667.         for (i = 16; i < 48; i++)
1668.             ref2frm[i + 4] = 4 * id_list[(i - 16) >> 1] +
                  ^
1669.                              (sl->ref_list[j][i].reference & 3);
1670.     }
