issue with snapshots from command line via gstreamer

Tomeu Vizoso tomeu at
Thu Jun 18 05:02:47 EDT 2009

On Wed, Jun 17, 2009 at 23:31, Richard A. Smith<richard at> wrote:
> I'm using a small script to take snapshots with an OLPC every 30 seconds
> using a gstreamer command line.
> The wiki ( lists the
> following as one method of doing this.
> gst-launch-0.10 v4l2src ! ffmpegcolorspace ! pngenc ! filesink
> location=foo.png
> However, this has a flaw because the camera is powered off when not in
> use.  When powered up the AGC circuit has to calibrate and that takes
> more time than the above allows.  You end up with pictures that have
> various funky types of brightness and white balance  issues.
> Anybody know if there is a way to make gstreamer take multiple snapshots
> and then just use the last one.

Maybe with a python script that uses the gstreamer bindings? You can
check the code of any of the activities that use the camera.



> --
> Richard Smith  <richard at>
> One Laptop Per Child
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