libavcodec/vc1.c:646: error: Uninitialized Value
  The value read from intra[_] was never initialized.

libavcodec/vc1.c:646:5: 
644. 
645.     /* calculate chroma MV vector from four luma MVs */
646.     idx = (intra[3] << 3) | (intra[2] << 2) | (intra[1] << 1) | intra[0];
         ^
647.     if(!idx) { // all blocks are inter
648.         tx = median4(mvx[0], mvx[1], mvx[2], mvx[3]);
