libavcodec/h264_direct.c:393: error: Uninitialized Value
  The value read from mv[_] was never initialized.

libavcodec/h264_direct.c:393:13: 
391.         } else {
392.             a = mv[0];
393.             b = mv[1];
                 ^
394.         }
395.         fill_rectangle(&h->mv_cache[0][scan8[0]], 4, 4, 8, a, 4);
