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\");