If you prefer the probe method this links could help you: <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/manual/html/chapter-dataaccess.html">http://gstreamer.freedesktop.org/data/doc/gstreamer/head/manual/html/chapter-dataaccess.html</a> <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/manual/html/section-dynamic-pipelines.html">http://gstreamer.freedesktop.org/data/doc/gstreamer/head/manual/html/section-dynamic-pipelines.html</a> If you prefer a output-selector this one (ossbuild example): <a href="http://code.google.com/p/ossbuild/source/browse/trunk/Main/GStreamer/Source/gst-plugins-bad/tests/icles/output-selector-test.c?r=926">http://code.google.com/p/ossbuild/source/browse/trunk/Main/GStreamer/Source/gst-plugins-bad/tests/icles/output-selector-test.c?r=926</a> <div class="gmail_quote">2013/6/5 a b <<a href="mailto:genericgroupmail@gmail.com" target="_blank">genericgroupmail@gmail.com</a>> <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> Hi Angel, Thanks for the quick reply! So sounds like these methods are for programming a solution. I had planned to look into the python pygst module in order to get away from relying on executing system calls to gst-launch. Maybe now is the time to do that. Cheers! <div class="HOEnZb"><div class="h5"> On Wed, Jun 5, 2013 at 12:52 PM, Angel Martin <<a href="mailto:amartin@vicomtech.org">amartin@vicomtech.org</a>> wrote: > Hi, > > Check valve gst element or the probes to check the buffers timestamp to drop > or pass the buffer. > > Best, > > Angel > > 2013/6/5 a b <<a href="mailto:genericgroupmail@gmail.com">genericgroupmail@gmail.com</a>> >> >> Hi all, >> >> I have an issue with capturing a single snapshot from one particular >> device. >> Very often when starting to stream from one of our capture cards using >> the decklinksrc element the first few seconds of video are badly >> tuned/rendered before things finally correct themselves and the video >> appears normal. >> The way in which i am taking a screen shot means that the first video >> frame is output to an image file, which for this device means a very >> poor snapshot. >> There is no issue with the v4l2src capture cards as the first frame is >> always perfectly tuned/rendered. >> >> Here is how i am doing it: >> >> gst-launch decklinksrc mode=2 connection=4 ! ffmpegcolorspace ! >> video/x-raw-rgb ! pngenc snapshot=true ! filesink location="frame.png" >> >> Is there anyway or any element i can use to drop the first few seconds >> of video or the first e.g. 90 frames before taking the snapshot? >> I had read about the valve element and played with it but didn't see >> how it was going to work (for a start it causes execution to block). >> Ideally I'd like the command to run and finish with no further >> interaction as it does at the moment. >> If there is no real way to do it via a command line, then it would be >> useful if anyone could point to a way to do it programatically via >> python. >> >> Thanks in advance. >> _______________________________________________ >> gstreamer-devel mailing list >> <a href="mailto:gstreamer-devel@lists.freedesktop.org">gstreamer-devel@lists.freedesktop.org</a> >> <a href="http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel" target="_blank">http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel</a> > > > > _______________________________________________ > gstreamer-devel mailing list > <a href="mailto:gstreamer-devel@lists.freedesktop.org">gstreamer-devel@lists.freedesktop.org</a> > <a href="http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel" target="_blank">http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel</a> > _______________________________________________ gstreamer-devel mailing list <a href="mailto:gstreamer-devel@lists.freedesktop.org">gstreamer-devel@lists.freedesktop.org</a> <a href="http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel" target="_blank">http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel</a> </div></div></blockquote></div>