How to convert Image frame into video ?

clc;

output_folder = 'D:\Matlab book and files\SLT\frames'

location = dir('D:\Matlab book and files\SLT\frames\*.tiff');

vidObj = VideoReader('akiyo2_grayscale2.mp4');

numFrames = 0;

frame = cell(1,300) ;

frame2image = cell(1,300);

image2frame = cell(1,300);

rgbtogray = cell(1,300);

graytorgb = cell(1,300);

entrpopygray= cell(1,300);

while hasFrame(vidObj)

F = readFrame(vidObj);

numFrames = numFrames + 1;

frame{numFrames} = F ;

[r,c,n]=size(F)

end

numFrames

for i= 1:300

imshow(frame{1,i});

frame{1,i}=getframe;

rgbtogray{1,i} = rgb2gray(frame2im(frame{1,i}));

outputFileName = fullfile(output_folder, ['frame' num2str(i) '.tiff']);

imwrite(rgbtogray{1,i},outputFileName);

entrpopygray{1,i}= entropy(rgbtogray{1,i}); % calculate a entropy of each image

end

video = VideoWriter('yourvideo.avi'); %create the video object

video.FrameRate= vidObj.FrameRate;

open(video); %open the file for writing

for ii=1:300

img = location(ii).name ;

I = imread(img); % the problem i am facing to concatenate a frames into video

F= getframe(gcf);

writeVideo(video,F); %write the image to file

end

close(video); %close the file

Answer 1

[Anusha]

Hi,

I understand that you are trying to convert a video into image frames, calculating the entropy of each frame/image and then recombining the image sequence into a video.

I found two issues with the code posted.

• The ‘location’ variable is declared and accessed at the start of the code. At this point, the video frames are not extracted and the ‘frames’ folder is empty.
• To access the folder containing the individual video frames in .tiff format, the location variable should be declared after the frames are extracted from the video sequence.
• VideoWriter function was unable to find the output path to store the video object.
• The correct path for the video object should be updated. Note that the individual frames and the final video sequence will be stored in the “output_folder = 'D:\Matlab book and files\SLT\frames' “.

The working code with the modifications is shown below:

clc;
output_folder = 'D:\Matlab book and files\SLT\frames'; 
vidObj = VideoReader('akiyo2_grayscale2.mp4');
numFrames = 0;
frame = cell(1,300) ;
frame2image = cell(1,300);
image2frame = cell(1,300);
rgbtogray = cell(1,300);
graytorgb = cell(1,300);
entrpopygray= cell(1,300);
while hasFrame(vidObj)
    F = readFrame(vidObj);    
    numFrames = numFrames + 1;
    frame{numFrames} = F ;
    [r,c,n]=size(F)
end
numFrames
for i= 1:300    
    imshow(frame{1,i});
    frame{1,i}=getframe;
    rgbtogray{1,i} = rgb2gray(frame2im(frame{1,i}));
    outputFileName = fullfile(output_folder, ['frame' num2str(i) '.tiff']);
    imwrite(rgbtogray{1,i},outputFileName);
    entrpopygray{1,i}= entropy(rgbtogray{1,i}); % calculate a entropy of each image
end
% Access the frames folder with individual frames
location = dir('D:\Matlab book and files\SLT\frames\*.tiff'); 
imageNames = {location.name}';
% Define the correct folder path to store the combined video sequence
video = VideoWriter(fullfile(output_folder,'yourvideo.avi')); 
%create the video object
video.FrameRate= vidObj.FrameRate;
open(video)
for ii = 1:length(imageNames)
    img = imread(fullfile(output_folder,imageNames{ii}));
    writeVideo(video,img)
end
close(video)  

Please refer to the following documentation for more details regarding ‘image to video sequence conversion’ : Convert Between Image Sequences and Video - MATLAB & Simulink (mathworks.com)

Thanks,

Anusha

[Mohd Shaliyar]

Thanks anusha for your valuable support.

Thanks a lot.