libavcodec/vp9dsp.c:1600: error: Uninitialized Value
  The value read from flat8out was never initialized.

libavcodec/vp9dsp.c:1600:25: 
1598.                       FFABS(q2 - q0) <= 1 && FFABS(q3 - q0) <= 1;
1599. 
1600.         if (wd >= 16 && flat8out && flat8in) {
                              ^
1601.             dst[strideb * -7] = (p7 + p7 + p7 + p7 + p7 + p7 + p7 + p6 * 2 +
1602.                                  p5 + p4 + p3 + p2 + p1 + p0 + q0 + 8) >> 4;
