static int mov_write_ilst_tag(AVIOContext *pb, MOVMuxContext *mov,
                              AVFormatContext *s)
{
    int64_t pos = avio_tell(pb);
    avio_wb32(pb, 0); /* size */
    ffio_wfourcc(pb, "ilst");
    mov_write_string_metadata(s, pb, "\251nam", "title"    , 1);
    mov_write_string_metadata(s, pb, "\251ART", "artist"   , 1);
    mov_write_string_metadata(s, pb, "aART", "album_artist", 1);
    mov_write_string_metadata(s, pb, "\251wrt", "composer" , 1);
    mov_write_string_metadata(s, pb, "\251alb", "album"    , 1);
    mov_write_string_metadata(s, pb, "\251day", "date"     , 1);
    if (!mov_write_string_metadata(s, pb, "\251too", "encoding_tool", 1)) {
        if (!(s->flags & AVFMT_FLAG_BITEXACT))
            mov_write_string_tag(pb, "\251too", LIBAVFORMAT_IDENT, 0, 1);
    }
    mov_write_string_metadata(s, pb, "\251cmt", "comment"  , 1);
    mov_write_string_metadata(s, pb, "\251gen", "genre"    , 1);
    mov_write_string_metadata(s, pb, "cprt",    "copyright", 1);
    mov_write_string_metadata(s, pb, "\251grp", "grouping" , 1);
    mov_write_string_metadata(s, pb, "\251lyr", "lyrics"   , 1);
    mov_write_string_metadata(s, pb, "desc",    "description",1);
    mov_write_string_metadata(s, pb, "ldes",    "synopsis" , 1);
    mov_write_string_metadata(s, pb, "tvsh",    "show"     , 1);
    mov_write_string_metadata(s, pb, "tven",    "episode_id",1);
    mov_write_string_metadata(s, pb, "tvnn",    "network"  , 1);
    mov_write_string_metadata(s, pb, "keyw",    "keywords"  , 1);
    mov_write_int8_metadata  (s, pb, "tves",    "episode_sort",4);
    mov_write_int8_metadata  (s, pb, "tvsn",    "season_number",4);
    mov_write_int8_metadata  (s, pb, "stik",    "media_type",1);
    mov_write_int8_metadata  (s, pb, "hdvd",    "hd_video",  1);
    mov_write_int8_metadata  (s, pb, "pgap",    "gapless_playback",1);
    mov_write_int8_metadata  (s, pb, "cpil",    "compilation", 1);
    mov_write_covr(pb, s);
    mov_write_trkn_tag(pb, mov, s, 0); // track number
    mov_write_trkn_tag(pb, mov, s, 1); // disc number
    mov_write_tmpo_tag(pb, s);
    return update_size(pb, pos);
}

The product divides a value by zero.