libavcodec/h264_refs.c:137: error: Uninitialized Value
  The value read from lens[_] was never initialized.

libavcodec/h264_refs.c:137:16: 
135.         if(lens[0] == lens[1] && lens[1] > 1){
136.             for (i = 0; h->default_ref_list[0][i].f.data[0] == h->default_ref_list[1][i].f.data[0] && i < lens[0]; i++);
137.             if(i == lens[0])
                    ^
138.                 FFSWAP(Picture, h->default_ref_list[1][0], h->default_ref_list[1][1]);
139.         }
