Encrypting webcam-video using caesar cipher - Matlab Tutorial

clc;        vid = videoinput('winvideo',1,'YUY2_160x120');        set(vid, 'ReturnedColorSpace', 'rgb');        %vid.LoggingMode = 'disk&memory';        vid.TriggerRepeat = Inf;        set(vid,'FramesPerTrigger', 1);        start(vid);        i=0;        auto_compress_count=0;        j=0;        frame=zeros();        %// Will open an avi file name test.avi in local folder        aviobj = avifile('encrypted.avi');        %// the quality of this video file         aviobj.Quality = 80;        %// compression method. See matlab manual for details.        aviobj.COMPRESSION ='None';%%color image        try        % here condition specifies how many frames to encrypt        while j<200                     i=i+1;                    img=getsnapshot(vid);                    img_size=size(img);                    %disp(temp);                    image(img);                    img1=zeros(img_size(1),img_size(2),3);                    for a =1:img_size(1)                        for b=1:img_size(2)                            for c=1:img_size(3)                                img1(a,b,c)= img(a,b,c);                            end;                        end;                    end;                    %disp(img1);                    %disp(img1);                    for a =1:img_size(1)                        for b=1:img_size(2)                            for c=1:img_size(3)                                        %disp(img1(a,b,c)+350);                                    img1(a,b,c)= img1(a,b,c) + 200;                                    if(img1(a,b,c)>255)                                    img1(a,b,c)=img1(a,b,c)-255;                                    end;                                    img(a,b,c)=img1(a,b,c);                            end;                        end;                    end;                    %disp(img1);                    image(img);                     i=i+1;                      aviobj = addframe(aviobj,img);        %managing memory       % out = imaqmem;        %mem_left = out.FrameMemoryLimit - out.FrameMemoryUsed;       % half_of_memlimit=(out.FrameMemoryLimit/2);        %if mem_left < half_of_memlimit         %   flushdata(vid,'triggers'); %each flushes only 50 frames          %  flushdata(vid,'triggers');        %end        % clear all variables from memory except some variables        %clearvars -except vid outputFolder i j auto_compress_count        j=j+1;        end  catch exception        delete(vid);        aviobj = close(aviobj);  enddelete(vid);aviobj = close(aviobj);disp('Video encrypted successfully');

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