how to make transformation in mp4 vedio

i have two vedio of mp4.i want to apply some tranformation on it and run the tranform vedio.i have wriiten the code but contently facing the error.i even tried "NumberOfFrames" but it is unrecongnized in my matlab

code is here

% read videos
vid1 = VideoReader('video1.mp4');
vid2 = VideoReader('vedio2.mp4');

% read first frame from each video
frame1 = readFrame(vid1);
frame2 = readFrame(vid2);

% create a figure
fig = figure;

while hasFrame(vid1) && hasFrame(vid2)
    % read frames from each video
    frame1 = readFrame(vid1);
    frame2 = readFrame(vid2);
    
    % perform geometric transformations
    frame1_scaled = imresize(frame1, 0.5);
    frame1_sheared = imresize(frame1, [size(frame1,1) size(frame1,2)*0.8]);
    frame1_rotated = imrotate(frame1, 30, 'crop');
    
    frame2_scaled = imresize(frame2, 0.5);
    frame2_sheared = imresize(frame2, [size(frame2,1) size(frame2,2)*0.8]);
    frame2_rotated = imrotate(frame2, -30, 'crop');
    
    % concatenate frames
    combined_frame = cat(2, cat(1, frame1, frame1_scaled, frame1_sheared, frame1_rotated), ...
                          cat(1, frame2, frame2_scaled, frame2_sheared, frame2_rotated));
    
    % display frames
    imshow(combined_frame, 'Parent', fig);
    drawnow;
end

error that i facing is

Error using cat 
Dimensions 
of
arrays 
being
concatenated
are
not
consistent.

Error in untitled (line 27)
    combined_frame = cat(2, cat(1, frame1, frame1_scaled, frame1_sheared, frame1_rotated), ...

Answer 1

[Hitesh]

Hi Muhammad,

The error indicates that frames concatenated are not having consistent dimensions which leads to error. Kindly ensure that all frames have the same dimensions before concatenation. Follow the below steps to ensure the consistent dimension across all frames

• Padding: Each frame is padded to ensure consistent dimensions across all frames being concatenated.
• Dynamic Sizing: The maximum height and width are calculated dynamically to accommodate the largest transformation result.

The "fig" variable is also used incorrectly as an axes handle. In MATLAB, "imshow" requires a valid axes handle, not a figure handle. You need to create an axes object within the figure and then use that axes handle with "imshow".

Kindly refer to the revised code and mentioned comments for better understanding:

% Read videos
vid1 = VideoReader('video1.mp4');
vid2 = VideoReader('video2.mp4');

% Create a figure
fig = figure;
ax = axes('Parent', fig);

while hasFrame(vid1) && hasFrame(vid2)
    % Check if the figure is still open
    if ~isvalid(fig)
        break; % Exit the loop if the figure is closed
    end

    % Read frames from each video
    frame1 = readFrame(vid1);
    frame2 = readFrame(vid2);
    
    % Perform geometric transformations
    frame1_scaled = imresize(frame1, 0.5);
    frame1_sheared = imresize(frame1, [size(frame1,1) size(frame1,2)*0.8]);
    frame1_rotated = imrotate(frame1, 30, 'crop');
    
    frame2_scaled = imresize(frame2, 0.5);
    frame2_sheared = imresize(frame2, [size(frame2,1) size(frame2,2)*0.8]);
    frame2_rotated = imrotate(frame2, -30, 'crop');
    
    % Find the maximum height and width for consistent dimensions
    max_height = max([size(frame1, 1), size(frame1_scaled, 1), size(frame1_sheared, 1), size(frame1_rotated, 1), ...
                      size(frame2, 1), size(frame2_scaled, 1), size(frame2_sheared, 1), size(frame2_rotated, 1)]);
    max_width = max([size(frame1, 2), size(frame1_scaled, 2), size(frame1_sheared, 2), size(frame1_rotated, 2), ...
                     size(frame2, 2), size(frame2_scaled, 2), size(frame2_sheared, 2), size(frame2_rotated, 2)]);
    
    % Pad frames to make them the same size
    frame1 = padarray(frame1, [max_height - size(frame1, 1), max_width - size(frame1, 2)], 'post');
    frame1_scaled = padarray(frame1_scaled, [max_height - size(frame1_scaled, 1), max_width - size(frame1_scaled, 2)], 'post');
    frame1_sheared = padarray(frame1_sheared, [max_height - size(frame1_sheared, 1), max_width - size(frame1_sheared, 2)], 'post');
    frame1_rotated = padarray(frame1_rotated, [max_height - size(frame1_rotated, 1), max_width - size(frame1_rotated, 2)], 'post');
    
    frame2 = padarray(frame2, [max_height - size(frame2, 1), max_width - size(frame2, 2)], 'post');
    frame2_scaled = padarray(frame2_scaled, [max_height - size(frame2_scaled, 1), max_width - size(frame2_scaled, 2)], 'post');
    frame2_sheared = padarray(frame2_sheared, [max_height - size(frame2_sheared, 1), max_width - size(frame2_sheared, 2)], 'post');
    frame2_rotated = padarray(frame2_rotated, [max_height - size(frame2_rotated, 1), max_width - size(frame2_rotated, 2)], 'post');
    
    % Concatenate frames
    combined_frame = cat(2, cat(1, frame1, frame1_scaled, frame1_sheared, frame1_rotated), ...
                          cat(1, frame2, frame2_scaled, frame2_sheared, frame2_rotated));
    
    % Display frames
    imshow(combined_frame, 'Parent', ax);
    drawnow;
end