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rafef
0

how save frames that exit from video in a specific folder

Asked by rafef
on 1 Mar 2012
Latest activity Answered by Hasti Hayati on 6 Dec 2016
hi * i have this function that do extract video into frames,*
function [] = intoframe(inpath)
inpath=('clock.avi')
myVid= mmreader(inpath);
numFrames= myVid.NumberOfFrames;
i= 1;
while i<= numFrames
currentFrame= read(myVid,i);
combinedString=strcat(int2str(i-1),'.jpg');
imwrite(currentFrame,combinedString);
i=i+1;
end
end
how can save these frames into a specific folder

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3 Answers

Answer by Image Analyst
on 1 Mar 2012

See my demo:
Pay particular attention to these lines:
folder = pwd; % Make it a subfolder of the folder where this m-file lives.
outputFolder = sprintf('%s/Movie Frames from %s', folder, baseFileName);
% Create the folder if it doesn't exist already.
if ~exist(outputFolder, 'dir')
mkdir(outputFolder);
end
OK, now here's the demo:
% Demo macro to extract frames and get frame means from an avi movie
% and save individual frames to separate image files.
% Also computes the mean gray value of the color channels.
clc; % Clear the command window.
close all; % Close all figures (except those of imtool.)
imtool close all; % Close all imtool figures.
clear; % Erase all existing variables.
workspace; % Make sure the workspace panel is showing.
fontSize = 14;
% Change the current folder to the folder of this m-file.
% (The line of code below is from Brett Shoelson of The Mathworks.)
if(~isdeployed)
cd(fileparts(which(mfilename)));
end
% Open the rhino.avi demo movie that ships with MATLAB.
folder = fullfile(matlabroot, '\toolbox\images\imdemos');
movieFullFileName = fullfile(folder, 'rhinos.avi');
% Check to see that it exists.
if ~exist(movieFullFileName, 'file')
strErrorMessage = sprintf('File not found:\n%s\nYou can choose a new one, or cancel', movieFullFileName);
response = questdlg(strErrorMessage, 'File not found', 'OK - choose a new movie.', 'Cancel', 'OK - choose a new movie.');
if strcmpi(response, 'OK - choose a new movie.')
[baseFileName, folderName, FilterIndex] = uigetfile('*.avi');
if ~isequal(baseFileName, 0)
movieFullFileName = fullfile(folderName, baseFileName);
else
return;
end
else
return;
end
end
try
movieInfo = aviinfo(movieFullFileName)
mov = aviread(movieFullFileName);
% movie(mov);
% Determine how many frames there are.
numberOfFrames = size(mov, 2);
numberOfFramesWritten = 0;
% Prepare a figure to show the images in the upper half of the screen.
figure;
screenSize = get(0, 'ScreenSize');
newWindowPosition = [1 screenSize(4)/2 - 70 screenSize(3) screenSize(4)/2];
set(gcf, 'Position', newWindowPosition); % Maximize figure.
% set(gcf, 'Position', get(0,'Screensize')); % Maximize figure.
% Ask user if they want to write the individual frames out to disk.
promptMessage = sprintf('Do you want to save the individual frames out to individual disk files?');
button = questdlg(promptMessage, 'Save individual frames?', 'Yes', 'No', 'Yes');
if strcmp(button, 'Yes')
writeToDisk = true;
% Extract out the various parts of the filename.
[folder, baseFileName, extentions] = fileparts(movieFullFileName);
% Make up a special new output subfolder for all the separate
% movie frames that we're going to extract and save to disk.
% (Don't worry - windows can handle forward slashes in the folder name.)
folder = pwd; % Make it a subfolder of the folder where this m-file lives.
outputFolder = sprintf('%s/Movie Frames from %s', folder, baseFileName);
% Create the folder if it doesn't exist already.
if ~exist(outputFolder, 'dir')
mkdir(outputFolder);
end
else
writeToDisk = false;
end
% Loop through the movie, writing all frames out.
% Each frame will be in a separate file with unique name.
meanGrayLevels = zeros(numberOfFrames, 1);
meanRedLevels = zeros(numberOfFrames, 1);
meanGreenLevels = zeros(numberOfFrames, 1);
meanBlueLevels = zeros(numberOfFrames, 1);
for frame = 1 : numberOfFrames
% Extract the frame from the movie structure.
thisFrame = mov(frame).cdata;
% Display it
hImage = subplot(1,2,1);
image(thisFrame);
axis square;
caption = sprintf('Frame %4d of %d.', frame, numberOfFrames);
title(caption, 'FontSize', fontSize);
drawnow; % Force it to refresh the window.
% Write the image array to the output file, if requested.
if writeToDisk
% Construct an output image file name.
outputBaseFileName = sprintf('Frame %4.4d.png', frame);
outputFullFileName = fullfile(outputFolder, outputBaseFileName);
% Stamp the name and frame number onto the image.
% At this point it's just going into the overlay,
% not actually getting written into the pixel values.
text(5, 15, outputBaseFileName, 'FontSize', 20);
% Extract the image with the text "burned into" it.
frameWithText = getframe(gca);
% frameWithText.cdata is the image with the text
% actually written into the pixel values.
% Write it out to disk.
imwrite(frameWithText.cdata, outputFullFileName, 'png');
end
% Calculate the mean gray level.
grayImage = rgb2gray(thisFrame);
meanGrayLevels(frame) = mean(grayImage(:));
% Calculate the mean R, G, and B levels.
meanRedLevels(frame) = mean(mean(thisFrame(:, :, 1)));
meanGreenLevels(frame) = mean(mean(thisFrame(:, :, 2)));
meanBlueLevels(frame) = mean(mean(thisFrame(:, :, 3)));
% Plot the mean gray levels.
hPlot = subplot(1,2,2);
hold off;
plot(meanGrayLevels, 'k-', 'LineWidth', 2);
hold on;
plot(meanRedLevels, 'r-');
plot(meanGreenLevels, 'g-');
plot(meanBlueLevels, 'b-');
% Put title back because plot() erases the existing title.
title('Mean Gray Levels', 'FontSize', fontSize);
if frame == 1
xlabel('Frame Number');
yLabel('Gray Level');
% Get size data later for preallocation if we read
% the movie back in from disk.
[rows columns numberOfColorChannels] = size(thisFrame);
end
% Update user with the progress. Display in the command window.
if writeToDisk
progressIndication = sprintf('Wrote frame %4d of %d.', frame, numberOfFrames);
else
progressIndication = sprintf('Processed frame %4d of %d.', frame, numberOfFrames);
end
disp(progressIndication);
% Increment frame count (should eventually = numberOfFrames
% unless an error happens).
numberOfFramesWritten = numberOfFramesWritten + 1;
end
% Alert user that we're done.
if writeToDisk
finishedMessage = sprintf('Done! It wrote %d frames to folder\n"%s"', numberOfFramesWritten, outputFolder);
else
finishedMessage = sprintf('Done! It processed %d frames of\n"%s"', numberOfFramesWritten, movieFullFileName);
end
disp(finishedMessage); % Write to command window.
uiwait(msgbox(finishedMessage)); % Also pop up a message box.
% Exit if they didn't write any individual frames out to disk.
if ~writeToDisk
return;
end
% Ask user if they want to read the individual frames from the disk,
% that they just wrote out, back into a movie and display it.
promptMessage = sprintf('Do you want to recall the individual frames\nback from disk into a movie?\n(This will take several seconds.)');
button = questdlg(promptMessage, 'Recall Movie?', 'Yes', 'No', 'Yes');
if strcmp(button, 'No')
return;
end
% Read the frames back in, and convert them to a movie.
% I don't know of any way to preallocate recalledMovie.
for frame = 1 : numberOfFrames
% Construct an output image file name.
outputBaseFileName = sprintf('Frame %4.4d.png', frame);
outputFullFileName = fullfile(outputFolder, outputBaseFileName);
% Read the image in from disk.
thisFrame = imread(outputFullFileName);
% Convert the image into a "movie frame" structure.
recalledMovie(frame) = im2frame(thisFrame);
end
% Get rid of old image and plot.
delete(hImage);
delete(hPlot);
% Create new axes for our movie.
subPlot(1, 3, 2);
axis off; % Turn off axes numbers.
title('Movie recalled from disk', 'FontSize', fontSize);
% Play the movie in the axes.
movie(recalledMovie);
% Note: if you want to display graphics or text in the overlay
% as the movie plays back then you need to do it like I did at first
% (at the top of this file where you extract and imshow a frame at a time.)
msgbox('Done with this demo!');
catch ME
% Some error happened if you get here.
stError = lasterror;
strErrorMessage = sprintf('Error extracting movie frames from:\n\n%s\n\nError: %s\n\n)', movieFullFileName, stError.message);
uiwait(msgbox(strErrorMessage));
end

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Answer by Ali Noori on 25 May 2015
Edited by Walter Roberson
on 25 May 2015

%%Extracting & Saving of frames from a Video file through Matlab Code%%
clc;
close all;
clear all;
% assigning the name of sample avi file to a variable
filename = 'DSC_0209.avi';
%reading a video file
mov = VideoReader(filename);
% Defining Output folder as 'snaps'
opFolder = fullfile(cd, 'aliiiii');
%if not existing
if ~exist(opFolder, 'dir')
%make directory & execute as indicated in opfolder variable
mkdir(opFolder);
end
%getting no of frames
numFrames = mov.NumberOfFrames;
%setting current status of number of frames written to zero
numFramesWritten = 0;
%for loop to traverse & process from frame '1' to 'last' frames
for t = 1 : numFrames
currFrame = read(mov, t); %reading individual frames
opBaseFileName = sprintf('%3.3d.jpg', t);
opFullFileName = fullfile(opFolder, opBaseFileName);
imwrite(currFrame, opFullFileName, 'jpg'); %saving as 'jpg' file
%indicating the current progress of the file/frame written
progIndication = sprintf('Wrote frame %4d of %d.', t, numFrames);
disp(progIndication);
numFramesWritten = numFramesWritten + 1;
end %end of 'for' loop
progIndication = sprintf('Wrote %d frames to folder "%s"',numFramesWritten, opFolder);
disp(progIndication);

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Answer by Hasti Hayati on 6 Dec 2016

Thanks guys

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