libavcodec/h264_direct.c:389: error: Uninitialized Value
  The value read from ref[_] was never initialized.

libavcodec/h264_direct.c:389:17: 
387.             if (ref[0] > 0)
388.                 a = mv[0];
389.             if (ref[1] > 0)
                     ^
390.                 b = mv[1];
391.         } else {
