OK, after a couple of postings it looks like you're having trouble figuring it out. So, here's a full demo for how to resize a video. Change the output size to whatever you want.
% Demo to extract frames from a input video, resize them, and build a new movie of a different size.
% Illustrates the use of the VideoReader and VideoWriter classes.
% A Mathworks demo (different than mine) is located here http://www.mathworks.com/help/matlab/examples/convert-between-image-sequences-and-video.html
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 = 22;
% Open the rhino.avi demo movie that ships with MATLAB.
% First get the folder that it lives in.
folder = fileparts(which('rhinos.avi')); % Determine where demo folder is (works with all versions).
% Pick one of the two demo movies shipped with the Image Processing Toolbox.
% Comment out the other one.
inputFullFileName = fullfile(folder, 'rhinos.avi');
% movieFullFileName = fullfile(folder, 'traffic.avi');
% Check to see that it exists.
if ~exist(inputFullFileName, 'file')
strErrorMessage = sprintf('File not found:\n%s\nYou can choose a new one, or cancel', inputFullFileName);
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)
inputFullFileName = fullfile(folderName, baseFileName);
else
return;
end
else
return;
end
end
% Open up the VideoReader for reading an input video file.
inputVideoReaderObject = VideoReader(inputFullFileName)
% Determine how many frames there are.
numberOfFrames = inputVideoReaderObject.NumberOfFrames;
inputVideoRows = inputVideoReaderObject.Height
inputVideoColumns = inputVideoReaderObject.Width
% Create a VideoWriter object to write the video out to a new, different file.
outputFullFileName = fullfile(pwd, 'NewRhinos.avi');
outputVideoWriterObject = VideoWriter(outputFullFileName);
open(outputVideoWriterObject);
% Specify the output video size.
shrinkFactor = 4; % Shrink by a factor of 4 in both directions.
outputVideoRows = round(inputVideoRows / shrinkFactor)
outputVideoColumns = round(inputVideoColumns / shrinkFactor)
numberOfFramesWritten = 0;
% Prepare a figure to show the images in the upper half of the screen.
figure;
% screenSize = get(0, 'ScreenSize');
% Enlarge figure to full screen.
set(gcf, 'units','normalized','outerposition',[0 0 1 1]);
% Loop through the movie, writing all frames out.
for frame = 1 : numberOfFrames
% Extract the frame from the movie structure.
thisInputFrame = read(inputVideoReaderObject, frame);
% Display it
image(thisInputFrame);
axis on;
axis image;
caption = sprintf('Frame %4d of %d.', frame, numberOfFrames);
title(caption, 'FontSize', fontSize);
drawnow; % Force it to refresh the window.
% Resize the image.
outputFrame = imresize(thisInputFrame, [outputVideoRows, outputVideoColumns]);
% Write this new, resized frame out to the new video file.
writeVideo(outputVideoWriterObject, outputFrame);
% Update user with the progress. Display in the command window.
progressIndication = sprintf('Processed frame %4d of %d.', frame, numberOfFrames);
disp(progressIndication);
% Increment frame count (should eventually = numberOfFrames
% unless an error happens).
numberOfFramesWritten = numberOfFramesWritten + 1;
end
% Close the output video object. You don't need to close the input video reader..
close(outputVideoWriterObject);
%================================================================================
% NOW WE'RE DONE!
%================================================================================
% Show input frame and output frame side by side:
subplot(1, 2, 1);
image(thisInputFrame);
axis on;
axis image;
caption = sprintf('Input Frame: %d rows by %d columns', inputVideoRows, inputVideoColumns);
title(caption, 'FontSize', fontSize);
% Show the smaller output frame.
subplot(1, 2, 2);
image(outputFrame);
axis on;
axis image;
caption = sprintf('Output Frame: %d rows by %d columns.', outputVideoRows, outputVideoColumns);
title(caption, 'FontSize', fontSize);
% Alert user that we're done.
finishedMessage = sprintf('Done! It processed %d frames of\n"%s" and created output video\n%s.\nClick OK to see the output video.', numberOfFramesWritten, inputFullFileName, outputFullFileName);
fprintf('%s\n', finishedMessage); % Write to command window.
uiwait(msgbox(finishedMessage)); % Also pop up a message box.
% Play the movie.
winopen(outputFullFileName);
%================================================================================
% OPTIONAL: OPEN THE NEW VIDEO TO DOUBLE-CHECK/PROVE ITS SIZE.
% Open up the VideoReader for reading an input video file.
inputVideoReaderObject = VideoReader(outputFullFileName)
% Determine how many frames there are.
numberOfFrames = inputVideoReaderObject.NumberOfFrames;
inputVideoRows = inputVideoReaderObject.Height;
inputVideoColumns = inputVideoReaderObject.Width;
fprintf('The output video has %d rows and %d columns.\n', inputVideoRows, inputVideoColumns);
%================================================================================
