Just a thought, may not be realted to this specific issue of yours Writing your own gstreamer plugin to do image processing stuff would make it more cleaner and better. like v4l2src ! ffmpegcolorspace ! your_image_processing_plugin ! xvimagesink ? Best - Kapil <div class="gmail_quote">On Sat, Oct 29, 2011 at 2:23 AM, wally_bkg <<a href="mailto:wb666greene@gmail.com">wb666greene@gmail.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;"> <div class="im"> Edward Hervey wrote: > > Why aren't you using the v4l2src/v4l2sink elements ? If you have > issues with them, please explain it in detail and/or file a bug report. > </div>I have vrl2src elements at the start of my pipeline that ends with an appsink, this worked fine with fixed video frame sizes, but now that I've removed that restriction in the image processing algorithm the question is how do I get the frame size from v4l2 without setting the pipeline to playing? I've had lots of issues with the gstreamer v4l2src tuner interface and never could get it to reliably set the norm and select the input across the various v4l2 capture devices on hand. As to bug reports, the answer was always to try a newer version, but when I tried the Ubuntu 10.04 gstreamer PPA it broke all things multimedia and wasted a fair amount of time recovering. At that point it became easier to just use v4l2 calls to set the norm and select the input, then build the pipeline. Grossly simplified my code is V4l2src->ffmpegcolorspace->fixed caps filter->appsink duplicate the appsink buffer data do some image processing on the duplicated buffer data appsrc->xvimagesink (for realtime viewing, of the processed data) appsrc->mp4 encoding->filesink ( original data to allow non-realtime processing afterwards) Works quite well with fixed caps. I'm stuck on how to get the frame height and width without fixed caps before the pipeline runs. I have to build a bunch of tables that depend on the frame size and takes a couple of seconds to do (perhaps not the most efficient recursive code, but it only runs once). I could work around this by pre-building tables of the possibilities (640x480, 704x480, & 720x480 so far, depending on the capture device, fixed caps was just set to 640x480) but the real issue is I'd like the v4l2 timestamps from the driver to use to synchronize A/D data from another process running on the same machine. I asked about this earlier but got no response: <a href="http://gstreamer-devel.966125.n4.nabble.com/Getting-V4l2-timestamps-from-v4l2src-td3915764.html" target="_blank">http://gstreamer-devel.966125.n4.nabble.com/Getting-V4l2-timestamps-from-v4l2src-td3915764.html</a> Dealing with various frame sizes is at this point only needed to test my changes (which I quickly did by changing the fixed caps to match the different capture card possibilities) in anticipation of someday using HD video. The timestamps to synchronize the A/D data with the video is an action item. -- View this message in context: <a href="http://gstreamer-devel.966125.n4.nabble.com/Get-v4l2src-width-and-height-before-pipeline-runs-tp3942212p3949188.html" target="_blank">http://gstreamer-devel.966125.n4.nabble.com/Get-v4l2src-width-and-height-before-pipeline-runs-tp3942212p3949188.html</a> <div><div></div><div class="h5">Sent from the GStreamer-devel mailing list archive at Nabble.com. _______________________________________________ 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> -- <a href="http://www.linkedin.com/in/kapilagrawal" target="_blank">http://www.linkedin.com/in/kapilagrawal</a> <a href="http://www.mediamagictechnologies.com" target="_blank">www.mediamagictechnologies.com</a> (Consultancy - Multimedia, Gstreamer, ffmpeg, Streaming for platforms- linux, windows, TI, android)