issue with snapshots from command line via gstreamer

Richard A. Smith richard at
Wed Jun 17 17:31:08 EDT 2009

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 

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.

Richard Smith  <richard at>
One Laptop Per Child

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