You may find the following pseudocode useful.
videoCell = {'a.mp4','b.mp4','c.mp4'};
for i = 1:numel(videoCell) % go through each video
v = VideoReader(videoCell{i});
while hasFrame(v) % read each frame
frame = readFrame(v);
if frameLightConditionMet(frame)
% Proceed to the next video once obtain a frame that meets
% specific light condition;
% Store that frame
break;
end
end
end
