[gst-devel] Issues gstreamer using videomixer and udpsrc

Wim Taymans wim.taymans at gmail.com
Fri Feb 26 18:25:42 CET 2010


On Fri, 2010-02-26 at 11:15 -0600, Sean Truman wrote:
> All,
>  
> I am streaming two webcam's from VLC via UDP.  I am trying to use
> videomix to mix both streams into a single stream.  I can view the
> stream correctly if I use the following command.
>  
> gst-launch udpsrc port=2341 ! mpegtsdemux ! mpeg2dec !
> ffmpegcolorspace ! ximagesink sync=false
>  
> now when I add the videomixer like so
>  
> gst-launch udpsrc port=2341 ! mpegtsdemux ! mpeg2dec !
> ffmpegcolorspace ! videomixer name=zone1 ! ximagesink sync=false
>  
> I get a the following error.
>  
> ERROR: from element /GstPipeline:pipeline0/GstUDPSrc:udpsrc0: Internal
> data flow error.
> Additional debug info:
> gstbasesrc.c(2388): gst_base_src_loop
> (): /GstPipeline:pipeline0/GstUDPSrc:udpsrc0:
> streaming task paused, reason not-negotiated (-4)
>  
> Both streams are 640x480 MPEG2/TS and from the documentation I should
> be able to mix the two UDP streams like so.
>  
> gst-launch udpsrc port=2341 ! mpegtsdemux ! mpeg2dec !
> ffmpegcolorspace ! videobox left=0 top=0 ! videomixer name=zone1 !
> videomixer name=zone2 ! ffmpegcolorspace ! xvimagesink sync=false
> videotestsrc ! videobox left=-640 top=0 ! zone2.
>  
> But I still get the same error, if I replace the udpsrc with
> videotestsrc and remove the demux and decoders everything is fine.
>  
> Any help is greatly appreciated for I am going to be bald by the end
> of the day. ;)

Use the -v option of gst-launch to see what pad got negotiated last.
>From that point on you have a format problem downstream. Then you see
where the format problem is and you insert ffmpegcolorspace. In your
first pipeline that would likely be before xvimagesink.

Wim

>  
> Sean Truman
>  
>  
>  
> 
>  
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