libavcodec/vc1dec.c:3478: error: Uninitialized Value
  The value read from ysub[_] was never initialized.

libavcodec/vc1dec.c:3478:28: 
3476.                     v->vc1dsp.sprite_v_double_twoscale(dst, src_h[0][0], src_h[0][1], ysub[0],
3477.                                                        src_h[1][0], src_h[1][1], ysub[1], alpha, width);
3478.                 } else if (ysub[0]) {
                                 ^
3479.                     v->vc1dsp.sprite_v_double_onescale(dst, src_h[0][0], src_h[0][1], ysub[0],
3480.                                                        src_h[1][0], alpha, width);
