libavcodec/h264_direct.c:358: error: Uninitialized Value
  The value read from mv[_] was never initialized.

libavcodec/h264_direct.c:358:21: 
356.                 b = 0;
357.                 if (ref[0] > 0)
358.                     a = mv[0];
                         ^
359.                 if (ref[1] > 0)
360.                     b = mv[1];
