code won't run, but gives no error

I have written the following code that involves multiple functions. Basically, I'm tracking a moving animal to export mobile and immobile into excel. Evidently this is wrong because the code is not running. However, I do not know what the problem is because it detects nothing wrong and gives no error message.

Here is the code:

close all
clear all
clc

% path of the folder containing the videos
videoFolder = 'currentFolder';r
videoFiles = dir(fullfile(videoFolder, '*.mp4'));
% loop through each video file and process them
for i = 1:length(videoFiles)
    % loading the video file
    video = VideoReader(fullfile(videoFolder, videoFiles(i).name));
    % parameters for motion detection
    threshold = 50; % pixel threshold for motion detection
    numFrames = video.NumFrames;
    frameRate = video.FrameRate;
    immobileTime = 0; 
    % variables to store data
    startTime = []; % start time of each mobile phase
    endTime = []; % end time of each mobile phase
    % loop through each frame of the video
    for j = 1:numFrames
        frame = read(video, j);
        grayFrame = rgb2gray(frame);
        if j > 1
            diffFrame = abs(grayFrame - prevFrame);
        else
            diffFrame = zeros(size(grayFrame));
        end
        motionMask = diffFrame > threshold;
        numPixelsWithMotion = sum(motionMask(:));
        percentPixelsWithMotion = numPixelsWithMotion / numel(motionMask);
        
        if percentPixelsWithMotion < 0.05 % rodent immobile if less than this
            immobileTime = immobileTime + (1 / frameRate); % add the duration of the immobile phase
        else % more than 0.05, its mobile
            startTime = [startTime, j]; 
            if j > 1 % if this is not the first mobile phase
                endTime = [endTime, j-1]; 
            end
        end
        prevFrame = grayFrame;
        
    end
    endTime = [endTime, numFrames];
    mobileTime = endTime - startTime;
    outputFile = fullfile(videoFolder, [videoFiles(i).name(1:end-4) '_results.csv']);
    resultsTable = table(mobileTime', immobileTime, 'VariableNames', {'MobileTime_ms', 'ImmobileTime_s'});
    writetable(resultsTable,outputFile);
    
end

Answer 1

[Walter Roberson]

Either there is no folder in the current directory that is literally named currentFolder or else the folder literally named currentFolder exists but has no .mp4 files.

Note that in your code 'currentFolder' will not be replaced by the name of the current folder: it will be treated as the character vector ['c' 'u' 'r' 'r' 'e' 'n' 't' 'F' 'o' 'l' 'd' 'e' 'r']

[Shandilya]

So I've tried 3 things:

1. Changed the directory by adding filepath --> videoFolder = '/Users/shandi/Desktop/Dr Sareesh';
2. Double checked if any of the videos were corrupted and none of them were corrupted. All the videos are in .mp4
3. Though this is a long shot, I resetted Matlab thinking it could be playing up

The end result is still the same "code won't run but doesn't give any error". Not sure what I'm missing

[Walter Roberson]

Please try this code and report back the kind of information it tells you

videoFolder = '/Users/shandi/Desktop/Dr Sareesh';

if ~exist(videoFolder, 'dir')
    error('videoFolder directory "%s" does not exist', videoFolder);
end

videoFiles = dir(fullfile(videoFolder, '*.mp4'));

numfiles = length(videoFiles);
if numfiles == 0
    error('videoFolder directory "%s" has no .mp4 files', videoFolder);
end

for i = 1 : numfiles
    thisfile = fullfile(videoFiles(i).folder, videoFiles(i).name);
    if ~exist(thisfile, 'file')
        warning(sprintf('file found in directory but reportedly does not exist: "%s"', thisfile));
    else
        created_reader = false;
        try
            video = VideoReader(thisfile);
            created_reader = true;
        catch ME:
        end
        if created_reader
            fprintf('reader okay for file "%s"\n', thisfile);
        else
            warning(sprintf('failed creating reader for file "%s"', thisfile));
        end
        clear video
    end
end

Answer 2

[Shandilya]

once i ran this code, i've had 2 errors

1. Error: File: tracking_mark4.m Line: 23 Column: 18. Invalid expression. Check for missing or extra characters. --> this would be "catch ME:" so i removed the colon to see if the code would run and this is when i got the 2nd error
2. Error using tracking_mark4 (line 4). videoFolder directory "/Users/shandi/Desktop/Dr Sareesh" does not exist --> which is really wierd so i double checked the pathname through mac terminal which also stated "file path does not exist.

This is when a lightbulb moment came about, it turns out when giving the exact pathname to terminal, it reads Dr Sareesh as 2 different folder names which is wierd so i changed the folder name to "FST" and the code you had provided worked like a charm. Thank you so much!!

Going back to my original code, changing the pathname seemed to run the code and it seems to all work fine as of now. I was able to get my immobile time in the units i require for the analysis.

Thank you so much for your help! Really appreciate it!!

[Walter Roberson]

Spaces in folder names can indeed cause problems unless you are careful with quoting or escaping the spaces.