libavcodec/h264_refs.c:135: error: Uninitialized Value
  The value read from lens[_] was never initialized.

libavcodec/h264_refs.c:135:12: 
133.         }
134. 
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])

int ff_h264_fill_default_ref_list(H264Context *h){
    MpegEncContext * const s = &h->s;
    int i, len;
    if(h->slice_type_nos==AV_PICTURE_TYPE_B){
        Picture *sorted[32];
        int cur_poc, list;
        int lens[2];
        if(FIELD_PICTURE)
            cur_poc= s->current_picture_ptr->field_poc[ s->picture_structure == PICT_BOTTOM_FIELD ];
        else
            cur_poc= s->current_picture_ptr->poc;
        for(list= 0; list<2; list++){
            len= add_sorted(sorted    , h->short_ref, h->short_ref_count, cur_poc, 1^list);
            len+=add_sorted(sorted+len, h->short_ref, h->short_ref_count, cur_poc, 0^list);
            assert(len<=32);
            len= build_def_list(h->default_ref_list[list]    , sorted     , len, 0, s->picture_structure);
            len+=build_def_list(h->default_ref_list[list]+len, h->long_ref, 16 , 1, s->picture_structure);
            assert(len<=32);
            if(len < h->ref_count[list])
                memset(&h->default_ref_list[list][len], 0, sizeof(Picture)*(h->ref_count[list] - len));
            lens[list]= len;
        }
        if(lens[0] == lens[1] && lens[1] > 1){
            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++);
            if(i == lens[0])
                FFSWAP(Picture, h->default_ref_list[1][0], h->default_ref_list[1][1]);
        }
    }else{
        len = build_def_list(h->default_ref_list[0]    , h->short_ref, h->short_ref_count, 0, s->picture_structure);
        len+= build_def_list(h->default_ref_list[0]+len, h-> long_ref, 16                , 1, s->picture_structure);
        assert(len <= 32);
        if(len < h->ref_count[0])
            memset(&h->default_ref_list[0][len], 0, sizeof(Picture)*(h->ref_count[0] - len));
    }
#ifdef TRACE
    for (i=0; i<h->ref_count[0]; i++) {
        tprintf(h->s.avctx, "List0: %s fn:%d 0x%p\n", (h->default_ref_list[0][i].long_ref ? "LT" : "ST"), h->default_ref_list[0][i].pic_id, h->default_ref_list[0][i].data[0]);
    }
    if(h->slice_type_nos==AV_PICTURE_TYPE_B){
        for (i=0; i<h->ref_count[1]; i++) {
            tprintf(h->s.avctx, "List1: %s fn:%d 0x%p\n", (h->default_ref_list[1][i].long_ref ? "LT" : "ST"), h->default_ref_list[1][i].pic_id, h->default_ref_list[1][i].data[0]);
        }
    }
#endif
    return 0;
}
['int ff_h264_fill_default_ref_list(H264Context *h){\n    MpegEncContext * const s = &h->s;\n    int i, len;\n    if(h->slice_type_nos==AV_PICTURE_TYPE_B){\n        Picture *sorted[32];\n        int cur_poc, list;\n        int lens[2];\n        if(FIELD_PICTURE)\n            cur_poc= s->current_picture_ptr->field_poc[ s->picture_structure == PICT_BOTTOM_FIELD ];\n        else\n            cur_poc= s->current_picture_ptr->poc;\n        for(list= 0; list<2; list++){\n            len= add_sorted(sorted    , h->short_ref, h->short_ref_count, cur_poc, 1^list);\n            len+=add_sorted(sorted+len, h->short_ref, h->short_ref_count, cur_poc, 0^list);\n            assert(len<=32);\n            len= build_def_list(h->default_ref_list[list]    , sorted     , len, 0, s->picture_structure);\n            len+=build_def_list(h->default_ref_list[list]+len, h->long_ref, 16 , 1, s->picture_structure);\n            assert(len<=32);\n            if(len < h->ref_count[list])\n                memset(&h->default_ref_list[list][len], 0, sizeof(Picture)*(h->ref_count[list] - len));\n            lens[list]= len;\n        }\n        if(lens[0] == lens[1] && lens[1] > 1){\n            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++);\n            if(i == lens[0])\n                FFSWAP(Picture, h->default_ref_list[1][0], h->default_ref_list[1][1]);\n        }\n    }else{\n        len = build_def_list(h->default_ref_list[0]    , h->short_ref, h->short_ref_count, 0, s->picture_structure);\n        len+= build_def_list(h->default_ref_list[0]+len, h-> long_ref, 16                , 1, s->picture_structure);\n        assert(len <= 32);\n        if(len < h->ref_count[0])\n            memset(&h->default_ref_list[0][len], 0, sizeof(Picture)*(h->ref_count[0] - len));\n    }\n#ifdef TRACE\n    for (i=0; i<h->ref_count[0]; i++) {\n        tprintf(h->s.avctx, "List0: %s fn:%d 0x%p\\n", (h->default_ref_list[0][i].long_ref ? "LT" : "ST"), h->default_ref_list[0][i].pic_id, h->default_ref_list[0][i].data[0]);\n    }\n    if(h->slice_type_nos==AV_PICTURE_TYPE_B){\n        for (i=0; i<h->ref_count[1]; i++) {\n            tprintf(h->s.avctx, "List1: %s fn:%d 0x%p\\n", (h->default_ref_list[1][i].long_ref ? "LT" : "ST"), h->default_ref_list[1][i].pic_id, h->default_ref_list[1][i].data[0]);\n        }\n    }\n#endif\n    return 0;\n}']