libavcodec/h264_refs.c:511: error: Uninitialized Value
  The value read from i was never initialized.

libavcodec/h264_refs.c:511:9: 
509.                (mmco_index != h->mmco_index ||
510.                 (i = check_opcodes(h->mmco, mmco_temp, mmco_index)))) {
511.         av_log(h->avctx, AV_LOG_ERROR,
             ^
512.                "Inconsistent MMCO state between slices [%d, %d, %d]\n",
513.                mmco_index, h->mmco_index, i);
