libavcodec/mpegvideo_common.h:422: error: Uninitialized Value
  The value read from ptr[_] was never initialized.

libavcodec/mpegvideo_common.h:422:13: 
420.     for(i=0; i<5; i++){
421.         if(i && mv[i][0]==mv[MID][0] && mv[i][1]==mv[MID][1]){
422.             ptr[i]= ptr[MID];
                 ^
423.         }else{
424.             ptr[i]= s->obmc_scratchpad + 8*(i&1) + s->linesize*8*(i>>1);
