Chandrasekhar - what errors are you observing? Please copy and paste the full error message to your question.
One problem may be how you are reading your frames from the original video. Initially, you use
video = read(vidobj);
and then in the for loop you use
F(i)=getframe;
Why not just use read (this all depends on which version of MATLAB that you are using) in your for loop as
for k=1:n
kthImg = read(vidob,k); % no need to convert from frame since already image
% now convert to double, CYG etc.
end
In the above, on each iteration of the loop we read each image from the video and then do the conversion.
