Save a movie smaller than avi

Hi,

I was wondering if there's a snippet of code that can save movies smaller than the typical avi? My system cannot find any codecs, so I thought mp4 would be better. But that's getting complex fast as I read about it. Here' my sample:

Z = peaks;
surf(Z)
axis tight manual
ax = gca;
ax.NextPlot = 'replaceChildren';

loops = 40;
F(loops) = struct('cdata',[],'colormap',[]);
for j = 1:loops
    X = sin(j*pi/10)*Z;
    surf(X,Z)
    drawnow
    F(j) = getframe(gcf);
end

fig = figure;
movie(fig,F,2);

movie2avi(F, 'awesomeMovie', 'compression', 'None');

Seems videowriter may have potential, but I cannot find an example I understand, based on my example above.

Hoping for some help, and thank you. Dave

[Walter Roberson]

'compression', 'none' would be much bigger than AVI.

Which operating system are you using?

[David Pesetsky]

Windows 7 professional. It creates an avi. A big one.

Answer 1

[Image Analyst]

Here's an example of how to use VideoWriter. Try it for different formats: wmv, mp4, etc.

[David Pesetsky]

Is there a way to convert the F array to an mp4?

[Image Analyst]

It's easy enough to try it and see, isn't it?

[David Pesetsky]

Apparently not. I ran it, and chose not to save to disk, and after processing 114 frames of c:\Apps\Matlab\v2014b_x64\Local\toolbox\images\imdata\rhinos.avi, there was no movie anywhere. Maybe I missed the save-as-mp4 option.

[Image Analyst]

In your adapted code of this line:

writerObj = VideoWriter('NewRhinos.avi');

what filename did you put? Something with an mp4 extension? I know you did, but just humor me and show me that line anyway.

[David Pesetsky]

Ran as-is. I don't have an mp4, trying to create one. Does this code take an avi and convert it to mp4?

[Image Analyst]

VideoWriter can do MP4 - the help says so. Alright, let me see if I can do the modifications for you.

[EDIT] David, see my attached code that converts an avi movie to a mp4 movie.

[David Pesetsky]

OK, that crushes the avi from 27.5mb to 826kb. Amazing!

But the mp4 plays really fast, so I guess that was compressed in time...which is OK if I put it in a loop so I don't miss any action...

[Image Analyst]

There is a "FrameRate" option you can specify to slow it down.

[David Pesetsky]

Very nice!

Thank you. Will study this a bit more for adjusting http://www.mathworks.com/help/matlab/ref/videowriter-object.html