How can I get a loop to process all ".avi" files in a folder, then produce the corresponding ".txt" and ".png" file?

I am creating a deep learning CNN with Python and Tensorflow, but the information that will be used in the network will be processed in MATLAB, and so my task is as follows:

I am to use MathWorks' sample code for MotionBasedMultiObjectTracking, but modify it in such a way that as it tracks a moving object, such as a person, in a supplied '.avi' file, it retrieves the (x,y) coordinates of the centroid of the bounding box as it moves in each frame, and writes that information to a '.txt' file. While it does this, it should also print a pattern of white dots onto an all black image, which represents the centroid/(x,y) coordinates as they change across each frame, and save the resulting image as a '.png' file.

I already have this part but that information was supplied just to provide a better understanding of what I'm trying to accomplish overall. Now my problem is that I can't figure out how to write a function or script that can go through all of my .avi files and produce the corresponding x,y coord .txt file and dot pattern .png file. Here is some code:

function MotionBasedMultiObjectTrackingExample()

% create a white image
imageTraj = 255 * ones(480, 640, 'uint8');
blackTraj = 0 * imageTraj;

% create a file to save trajectory data
fileID = fopen('Pattern 1-1.txt','w+');

%imshow(image);

% Create System objects used for reading video, detecting moving objects,
% and displaying the results.
obj = setupSystemObjects();

tracks = initializeTracks(); % Create an empty array of tracks.

nextId = 1; % ID of the next track

% Detect moving objects, and track them across video frames.
while ~isDone(obj.reader)
    frame = readFrame();
    [centroids, bboxes, mask] = detectObjects(frame);
    predictNewLocationsOfTracks();
    [assignments, unassignedTracks, unassignedDetections] = ...
        detectionToTrackAssignment();

      updateAssignedTracks();
      updateUnassignedTracks();
      deleteLostTracks();
      createNewTracks();

      displayTrackingResults();
  end % end of while

fclose(fileID);
saveas(gcf,'Pattern 1-1.png');
%open the generated image for dilation
BW = imread('Pattern 1-1.png')

%dilation function(strel('dilation type', dilation_strength))
SE = strel('square', 8);
%actually perform the dilation and show the new dilation image
BW2 = imdilate(BW,SE);
figure,imshow(BW2), title('Dilated')
%resize the dilated image
BW3 = imresize(BW2, [64 64]);
figure, imshow(BW3), title('Resized and dilated')
saveas(BW3,'resizedBW3.png');

%%Create System Objects
% Create System objects used for reading the video frames, detecting
% foreground objects, and displaying results.

      function obj = setupSystemObjects()
          % Initialize Video I/O
          % Create objects for reading a video from a file, drawing the tracked
          % objects in each frame, and playing the video.

          % Create a video file reader.
          %obj.reader = vision.VideoFileReader('udcvideo.mp4.mp4');
          obj.reader = vision.VideoFileReader('Scenario 1-1.avi');

          % Create two video players, one to display the video,
          % and one to display the foreground mask.
          obj.maskPlayer = vision.VideoPlayer('Position', [740, 400, 700, 400]);
          obj.videoPlayer = vision.VideoPlayer('Position', [20, 400, 700, 400]);

          % Create System objects for foreground detection and blob analysis

          % The foreground detector is used to segment moving objects from
          % the background. It outputs a binary mask, where the pixel value
          % of 1 corresponds to the foreground and the value of 0 corresponds
          % to the background. 

          obj.detector = vision.ForegroundDetector('NumGaussians', 3, ...
              'NumTrainingFrames', 40, 'MinimumBackgroundRatio', 0.7);

          % Connected groups of foreground pixels are likely to correspond to moving
          % objects.  The blob analysis System object is used to find such groups
          % (called 'blobs' or 'connected components'), and compute their
          % characteristics, such as area, centroid, and the bounding box.

          obj.blobAnalyser = vision.BlobAnalysis('BoundingBoxOutputPort', true, ...
              'AreaOutputPort', true, 'CentroidOutputPort', true, ...
              'MinimumBlobArea', 400);
      end % end of setupSystemObjects()

My videos are named in the folder as follows: Scenario 1-1 to 1-10, Scenario 2-1 to 2-10.... Scenario 10-1 to 10-10. So there's 100 '.avi' files in the folder. In the setupSystemObjects() function, I supply the video file reader with 'Scenario 1-1.avi'. When I run the program, it runs the process on Scenario 1-1.avi, produces Pattern 1-1.txt, and Pattern 1-1.png, just like I want. The big question is how can I loop it, updating the file name each time so that every time the function is called, it will move to the next file, let's say 'Scenario 1-2.avi' for example, and produce the respective .txt and .png files, all the way until it has finished with the 100 videos in the folder.

I have developed this loop but I'm not sure how to proceed from here: (The comments on the inside below 'code would go here' was just me trying different things.

function FileExample()
d = uigetdir('','Select Input-folder'); %select the input-folder that contains the subfolders
cd(d);
list = dir;
list = list([list.isdir]); 
list = list(~ismember({list.name},{'.' '..'}));
l=length(list);

for i=1:l
      oldfolder = cd(list(i).name);
      % Perform your operation on the files, e.g., if you are working with avi files
      files = dir('*.avi');

        numberOfFiles = length(files);
        for k = 1:numberOfFiles

            % code would go here
            % 
            % file name files(k)
            % MotionBasedMultiObjectTrackingExample( files(k) )
        end
        cd(oldfolder); 
  end
  end

Answer 1

[LO]

clear;
close all;
[logfname, pathname] = uigetfile('*.mat','Pick any AVI file'); 
cd(pathname);
%make list of AVI files in the folder 
file_list = dir ('*.AVI') ; %create a list of AVI files based on folder content

[Jan]

Disabling all warnings by warning off is a very bad idea. The warnings are very important to detect problems.

Using uigetfile only to get a folder, is not the direct way. Prefer uigetdir.

The "conversions" are not efficient here. Easier:

pathname  = uigetdir(); 
file_list = dir(fullfile(pathname, '*.AVI'));
aviFiles  = {file_list.name};

[LO]

thanks Jan, I just copy-pasted from a script of mine without cleaning

Answer 2

[Jan]

function FileExample()
Folder = uigetdir('','Select Input-folder');
FileList = dir(fullfile(Folder, '**', '*.avi'));  % Select all AVI in folder and subfolders
for iFile = 1:numel(FileList)
    file = fullfile(FileList(iFile).folder, FileList(iFile).name);
    
    % code would go here
    MotionBasedMultiObjectTrackingExample(file);
end

Now the funtion MotionBasedMultiObjectTrackingExample must accept the file name as input and imprt this file.