libavcodec/vp9mvs.c:338: error: Uninitialized Value
  The value read from hp was never initialized.

libavcodec/vp9mvs.c:338:32: 
336.                 s->counts.mv_joint[j]++;
337.                 if (j >= MV_JOINT_V)
338.                     mv[1].y += read_mv_component(s, 0, hp);
                                    ^
339.                 if (j & 1)
340.                     mv[1].x += read_mv_component(s, 1, hp);
