[ODE] Capturing a window , making a movie

[gl]

Another option (if your graphics card has a TV out) is to run that into a
cheap TV capture card.  Least painful solution.
--
gl

----- Original Message -----
From: "David Whittaker" <david@csworkbench.com>
To: <ode@q12.org>
Sent: Monday, April 14, 2003 5:53 PM
Subject: Re: [ODE] Capturing a window , making a movie


> If it's a drawstuff project, there's a ctrl-something (it's on the console
> screen) you can push to output a sequence of ppm files, which can the be
> converted to video with an external program.  I suggest ffmpeg.
>
> If not, you can do the same thing using the glReadPixels command.  It
> returns almost exactly the ppm format, except you _may_ need to swap the
> red and blue color components (I think it's backwards for bmp, but right
> for ppm, but I could be wrong), and skip the every fourth byte (alpha).
> The ppm header for a 640x480 picture with 8 bits per pixel looks like:
> P3
> 640 480
> 255
> ...640*480*3 bytes of binary picture data from glReadPixels...EOF
>
> Alternatively, you can use P6 and output the values in plain text (space
> separated decimal integers), but disk access is slow.
>
> If you want the program to render directly into a movie without the
> intermediate step, then you have a whole other problem.  You still use
> glReadPixels to get your data, but then you have to run it through a codec
> of some sort.  In my experience, all the mpeg codecs out there are some
> combination of too slow, undocumented, or produce files that are too
> large, even with good compression settings.  It seems the least of the
> evils, though, is libavcodec, part of the ffmpeg project.  I believe this
> is a cross-platform solution (I know it works on Linux).  It's problem is
> a severe lack of documentation, though there is a test program to get you
> started, it's quite fast, and can be tweaked to give the exact bitrate
> (i.e. a set number of bytes per second of video) you want.  You might also
> look into Dali.  It's also cross-platform, but suffers from Large File
> Syndrome on Linux (don't ask me why... I might have had a bug, but it
> worked fine on Windows, just made 4x larger files on Linux), and you have
> to do a lot more work yourself.  libavcodec is almost as simple as setting
> up the parameters and sending it frames whenever you feel like it
> (almost... I think you have to do a YUV colorspace conversion in there
> somewhere).  Dali just gives you the functions to go through every step of
> the mpeg creation process, though there is ample documentation to tell you
> what those steps are.
>
> Hope that helps,
> David
>
> > Hi all,
> >  I want to capture an opengl window into a movie, I
> > use windows (but if you have linux tips please send
> > them too), How can I capture that window and make a
> > movie?
> >
> > Thanks,
> > Shaul
> >
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