libavcodec/motionpixels.c:249: error: Uninitialized Value
  The value read from p.u was never initialized.

libavcodec/motionpixels.c:249:17: 
247.                 p.v += mp_gradient(mp, 1, mp_get_vlc(mp, gb));
248.                 p.v = av_clip_intp2(p.v, 5);
249.                 p.u += mp_gradient(mp, 2, mp_get_vlc(mp, gb));
                     ^
250.                 p.u = av_clip_intp2(p.u, 5);
251.             }
