static int decode_cabac_field_decoding_flag(H264Context *h) {
    const long mbb_xy = h->mb_xy - 2L*h->mb_stride;

    unsigned long ctx = 0;

    ctx += h->mb_field_decoding_flag & !!h->mb_x; //for FMO:(s->current_picture.mb_type[mba_xy] >> 7) & (h->slice_table[mba_xy] == h->slice_num);
    ctx += (h->cur_pic.mb_type[mbb_xy] >> 7) & (h->slice_table[mbb_xy] == h->slice_num);

    return get_cabac_noinline( &h->cabac, &(h->cabac_state+70)[ctx] );
}