How to record a clip for the right and left eye and convert it into a frame

Hello, I am trying to record a video clip for each eye and turn them into pictures, but I am stuck in the issues of reversing directions during filming, and I tried a lot to add a detection code, but there is still an error, how can I modify the code so that I can at least record clips for all eyes only

%% Take a video from the camera

detector = vision.CascadeObjectDetector(); % Create a detector for face using Viola-Jones

detector1 = vision.CascadeObjectDetector('EyePairSmall'); %create detector for eyepair

video_source = videoinput('winvideo',1,"MJPG_640x480");

set(video_source,'ReturnedColorSpace','gray');

%Code to display the dimensions of the camera in real time

preview(video_source);

%img = flip(vid, 2);

% Create an subjectect to write a file

writer = VideoWriter(subject,'Motion JPEG AVI');

% of the movie duration is calculated by the number of frames per second

% over the total of the frames, but does not specify a duration camera

% recording, but determines the duration of the video clip

% writer.FrameRate/length FR/totalF or FR/L

%T=L/FR RTR=2T

writer.FrameRate = 5.0; length = 150;

% video file in MATLAB is actually a composite structure that has two

% parts, These two parts, one is the gradient colormap, the other is the

% video data content

file.colormap=[];

% Open the subjectect and start recording

open(writer);

% video_source=flip(video_source,2);

for i=1:length

frame = getsnapshot(video_source1);

file.cdata = frame;

writeVideo(writer,file);

end

% It is a good habit to stop all things at hand

close(writer);

closepreview;

delete(video_source);