libavcodec/vp3.c:850: error: Uninitialized Value
  The value read from motion_y[_] was never initialized.

libavcodec/vp3.c:850:29: 
848.                         if (s->macroblock_coding[current_macroblock] == MODE_INTER_FOURMV) {
849.                             s->motion_val[1][frag][0] = motion_x[k];
850.                             s->motion_val[1][frag][1] = motion_y[k];
                                 ^
851.                         } else {
852.                             s->motion_val[1][frag][0] = motion_x[0];
