+ // change inter to intra blocks if no reference frames are available
+ if (!s->last_picture.data[0] && !s->next_picture.data[0])
+ for(i=0; i<s->mb_num; i++){
+ const int mb_xy= s->mb_index2xy[i];
+ if(!IS_INTRA(s->current_picture.mb_type[mb_xy]))
+ s->current_picture.mb_type[mb_xy]= MB_TYPE_INTRA4x4;
+ }
+