[StainlessS]

My expierence is that AVS+ is much more efficient using the available memory.

Mine too.

Is it possible to have an AVSValue with an ArraySize() of 0?

Yes.

FrameSel plugin, 2nd arg is array of frame numbers,

env->AddFunction("FrameSel", "ci*[SCmd]s[Cmd]s[Show]b[Ver]b[Reject]b[Ordered]b[Debug]b[Extract]i", Create_FrameSel, 0);,

AVSValue __cdecl Create_FrameSel(AVSValue args, void* user_data, IScriptEnvironment* env) {
PClip		_child	= args[0].AsClip();						// Source Clip, No Default
AVSValue	_Frames	= args[1];								// Frames, Array of frame numbers as filter arguments
const char *_SCmd	= args[2].AsString(NULL);				// SCmd, Frames in string, defaults to NULL
const char *_Cmd	= args[3].AsString(NULL);				// Cmd, Frames Cmd File, defaults to NULL
bool		_show	= args[4].AsBool(false);				// show, show frame numbers
bool		_ver	= args[5].AsBool(false);				// ver, show version
bool		_reject = args[6].AsBool(false);				// Reject Mode
bool		_ordered= args[7].AsBool(true);					// ordered Mode
bool		_debug  = args[8].AsBool(false);				// debug
int 		_extract = args[9].AsInt(1);					// extract

	if(_SCmd && *_SCmd == '\0')		_SCmd=NULL;				// Convert user supplied "" to NULL
	if(_Cmd  && *_Cmd  == '\0')		_Cmd=NULL;				// Convert user supplied "" to NULL

//	if(_Cmd==NULL && _SCmd==NULL && _Frames.ArraySize()==0)
//		return _child;										// No frames specified at all, return orig clip as if no filter.

	return new FrameSel(_child,_Frames,_SCmd,_Cmd,_show,_ver,_reject,_ordered,_debug,_extract,env);
}

Above, is actually switched off (commented out), but still shows that you can have ArraySize==0 when no frames specified.