how do sprate audio and vidio from a vidio file plese help me with this

if true
  % code
hmfr = video.MultimediaFileReader('D:\Wildlife.wmv','AudioOutputPort',true,'VideoOutputPort',true);
> hmfw = video.MultimediaFileWriter('D:\123.wmv','AudioInputPort',true,'VideoInputPort',true);
> while ~isDone(hmfr)
> [v,a] = step(hmfr);
> step(hmfw,v,a);
> end
> msgbox('Completed');
> release(hmfw);
> release(hmfr);
>
> ??? Undefined function or method 'release' for input arguments of
> type 'video.MultimediaFileWriter'.
>
> Error in ==> videowriter at 8
> release(hmfw);