libavcodec/vp9mvs.c:307: error: Uninitialized Value
  The value read from hp was never initialized.

libavcodec/vp9mvs.c:307:28: 
305.             s->counts.mv_joint[j]++;
306.             if (j >= MV_JOINT_V)
307.                 mv[0].y += read_mv_component(s, 0, hp);
                                ^
308.             if (j & 1)
309.                 mv[0].x += read_mv_component(s, 1, hp);
