libavcodec/h264_direct.c:390: error: Uninitialized Value
  The value read from mv[_] was never initialized.

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