How to append the frames into a object that contains video?

   avi=mmreader('r2.avi');    
 % Display the probability image.
    I = rgb2hsv(R);
    S = [];
    S(:,:,1) = I(:,:,1);
    S(:,:,2) = I(:,:,1);   
    S(:,:,3) = I(:,:,1);
 % Extract the hue information
     avi = addframe(avi, S);

Im getting error in the last line of my code because of the mmreader function. Kindly solve this error problem for me