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On Nov 23, 7:47 am, "Ace Gerrard" <shasiphoenix_ferra...@hotmail.com>
wrote:
> I really new to matlab. I got a project where i need to carryout object detection on a video. the problem is i dont know how to read or write out a code to read the video on matlab for it. Can someone please help me on this and if possble some extra advised that can help me.
>
> Thank you
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What format is the video in?
Here's some demo code for extracting and writing frames to separate
disk files from an avi-format movie. It might help you get started.
Be sure to fix any line breaks introduced by the newsreader -
newsreaders can break apart lines.
% Demo macro to extract frames from an avi movie to separate files.
% by ImageAnalyst
clc;
close all;
% Open the rhino.avi demo movie that ships with MATLAB.
movieFullFileName = 'C:\Program Files\MAT1LAB\R2008b\toolbox\images
\imdemos\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
mov = aviread(movieFullFileName);
% movie(mov);
% Make a special output folder to hold all the separate movie frames
% as their own image files.
outputFolder = fullfile(cd, 'Rhino Movie');
if ~exist(outputFolder, 'dir')
mkdir(outputFolder);
end
% Determine how many frames there are.
numberOfFrames = size(mov, 2);
numberOfFramesWritten = 0;
% Prepare a figure to show the images.
figure;
screenSize = get(0, 'ScreenSize');
newWindowPosition = [1 1 screenSize(3)/2 screenSize(4)/2];
set(gcf, 'Position', newWindowPosition); % Maximize figure.
% Loop through the movie, writing all frames out.
% Each frame will be in a separate file with unique name.
for frame = 1 : numberOfFrames
% Extract the frame from the movie structure.
thisFrame = mov(frame).cdata;
% Display it
image(thisFrame);
drawnow; % Force it to refresh the window.
% Construct an output iamge file name.
outputBaseFileName = sprintf('Frame %4.4d.png', frame);
outputFullFileName = fullfile(outputFolder, outputBaseFileName);
% Write the image array to the output file.
imwrite(thisFrame, outputFullFileName, 'png');
% Update user with the progress. Display in the command window.
progressIndication = sprintf('Wrote frame %4d of %d.', frame,
numberOfFrames);
disp(progressIndication);
% Increment frame count (should eventually = numberOfFrames
% unless an error happens).
numberOfFramesWritten = numberOfFramesWritten + 1;
end
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);
msgboxw(strErrorMessage);
end
% Alert user that we're done.
finishedMessage = sprintf('Done! It wrote %d frames to folder\n"%s"',
numberOfFramesWritten, outputFolder);
disp(finishedMessage); % Write to command window.
msgbox(finishedMessage); % Also pop up a message box.
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