Video to frames converting problem

I was using code to convert video into frames, i was working but now i am using video recorded by go pro hero 10 so the size of video is high , because of that now that code is not working . if i crop and trim video n reduces the size its working.

what should i do to convert high size video into images

% import the video file
video = VideoReader('test.mp4');

% read the total number of frames
n = video.NumberOfFrames

% reading and writing the frames

for i = 1:n
    frames=read(video,i);
    %save the frames
    imwrite(frames,['images' int2str(i), '.jpg']);
    im(i)=image(frames);
    
end

[DGM]

How exactly is it not working? Are you getting an error? If so, what is the error?

Since all I can do is guess, I'll just point out everything I see. I doubt that any of these are the cause of any error, but who knows.

% import the video file
video = VideoReader('test.mp4');
% read the total number of frames
%n = video.NumberOfFrames % this isn't recommended
n = video.NumFrames

% reading and writing the frames
for i = 1:n
    frames = read(video,i);
    %save the frames
    %imwrite(frames,['images' int2str(i), '.jpg']); % these names won't sort easily
    imwrite(frames,sprintf('images_%07d.jpg',i)); % these names will sort trivially
    image(frames); % there's no point saving handles to deleted objects
end

Personally, I'd avoid the call to image(), since it's only going to slow the process and you're not going to see anything but the last frame anyway.

[Manu Gowda]

Thank you for your help.

Please check the pic attached for error information

[DGM]

Interesting... So I guess read() is failing silently. Are the other properties of the video object populated correctly?

[Walter Roberson]

See

https://www.mathworks.com/matlabcentral/answers/295962-why-is-numberofframes-different-in-os-x-and-windows-systems#answer_228816

See also the documented limitation:

• For some AVI, MOV, or MP4 files on Windows®, using the readFrame function to read all of the frames in the file can result in a different number of frames than the value returned by the NumFrames property of the VideoReader object.

[Manu Gowda]

Yes all properties of video is same.

If i crop video below certain level this code is working without any error.

[Walter Roberson]

"crop video below certain level" -- if you are referring to number of frames, then that would be consistent with the fact that NumberOfFrames and NumFrames are unreliable on Windows, and that the (now obsolete) NumberOfFrames was never known properly for variable framerate files until you finished reading the video.

Even for fixed framerate files, you need to take NumberOfFrames was an estimation, as recorded framerates are typically estimates. For example "30 frames per second" is typically NTSC, which is talked about as 29.97 frames per second but is really

format long g
30/1.001

ans = 
            29.97002997003

and due to the way that frame rates are implemented as a ratio of two integers, round off typically occurs in the representation...

[Manu Gowda]

'crop the video' means, not reducing the no of frames (trimming the video) . It means i am croping the video so that number of frames and length of video is same but i am selecting particular region of intrest by croping.