TYPEMAP
const char *    T_PV
MP4FILE *       T_OBJECT
u_int32_t       T_UV
u_int16_t       T_UV
u_int8_t        T_UV
MP4TrackId      T_UV
OUTPUT
T_OBJECT
        sv_setref_pv($arg, CLASS, (void*)$var);
INPUT
T_OBJECT
        if (sv_isobject($arg) && SvTYPE(SvRV($arg)) == SVt_PVMG)
          $var = INT2PTR($type, SvIVX((SV *) SvRV($arg)));
        else                     
          Perl_croak(aTHX_ \"${Package}::$func_name(): $var is not a blessed SV reference\");