How to extract a frame every 10 s from the video ?

Hi,

I have a video which runs for 30 minutes at the rate of 60 fps. I need to extract the frame every 10 second. For example: 10s(600th frame),20s(1200th frame),30s(1800th frame) so on..... I looked through the internet I can get the info about how to read, write video and extract frame but did not get the info about exactly what I am looking for. Your help will be appreciated!

Thanks

Answer 1

[Stephan]

https://de.mathworks.com/help/matlab/ref/videoreader.read.html#busxibt-2

In your case the interval to take the first frame after 10 seconds would be:

v = VideoReader('YOUR_FILENAME.mp4');
frames = read(v,[600:600:end]);

The result is a 4D-Array which is the first 3 dimensions having the video frame and the 4th dimension is the time - here 10 seconds

[muhammad choudhry]

Link is very useful, but I am getting this error using the code above,

Error:

The end operator must be used within an array index expression.

Error in Spec_Frame (line 3)

frame = read(v,[600:600:end]);

Also would like to know how would I then save that data into the separate folder, for example I read the info and it shows me into the workspace, how would i save images showing into the work space into the folder for further processing.

[Stephan]

v = VideoReader('YOUR_FILENAME.mp4');
frames = read(v);
frames = frames(:,:,:,600:600:end);

for k = 1:size(frames,4)
    imwrite(frames(:,:,:,k),['C:\YOUR_FOLDER\MyImage_', num2str(k), '.jpg'])
end

[muhammad choudhry]

Hi, thansk for the quick reply. 2 questions, why did end operator not work for the previous code? and second is the error I am getting this time is that mean data is too big ?

Error:

Error using Movie_Frame (line 38)

Requested 720x1280x3x20259 (52.2GB) array exceeds maximum array size preference. Creation of arrays greater

than this limit may take a long time and cause MATLAB to become unresponsive.

[Stephan]

wanted_frames = 600:600:20259;
v = VideoReader('YOUR_FILENAME.mp4');

for k = 1:numel(wanted_frames)
    frame = read(v, wanted_frames(k));
    imwrite(frame,['C:\YOUR_FOLDER\MyImage_', num2str(k), '.jpg'])
end

[muhammad choudhry]

Thanks alot!

[B Sarath]

Sir could you please help me the writing the code for to divide video into frames for every 2 seconds.The file properties are length:1:46 Frame rate: 29.92 fs Storage:16.7mb

[Image Analyst]

I don't know what this means. Do you want to split up a single video into multiple videos, each having a run time of 2 seconds? Do you want to take the frames for each 2 second long segment and write them out to a folder (with a name that is the start time of that segment)?