libavcodec/vc1.c:674: error: Uninitialized Value
  The value read from mvy[_] was never initialized.

libavcodec/vc1.c:674:9: 
672.         for(i= t1+1; i<4; i++)if(!intra[i]) {t2 = i; break;}
673.         tx = (mvx[t1] + mvx[t2]) / 2;
674.         ty = (mvy[t1] + mvy[t2]) / 2;
             ^
675.     } else {
676.         s->current_picture.motion_val[1][s->block_index[0]][0] = 0;
