[gst-devel] Plugin creation

Fri Mar 6 14:39:36 CET 2009

My understanding is that v4l2src cannot generate rgb16, so try this:

v4l2src ! ffmpegcolorspace ! "video/x-raw-rgb,bpp=16,depth=16" !
testfilter ! videoscale ! ffmpegcolorspace ! xvimagesink

If that doesn't work then I'm afraid I ran out of answers :)

Iago

El vie, 06-03-2009 a las 14:10 +0100, cammille at polytech.unice.fr
escribió:
> If I try this :
> v4l2src ! "video/x-raw-rgb,bpp=16,depth=16" ! testfilter ! videoscale !
> ffmpegcolorspace ! xvimagesink
> 
> I obtain that :
> (gst-launch-0.10:3704): GStreamer-WARNING **: pad v4l2src0:src returned
> caps which are not a real subset of its template caps
> ERROR: Pipeline doesn't want to pause.
> ERROR: from element /GstPipeline:pipeline0/GstV4l2Src:v4l2src0: Could not
> negotiate format
> 
> 
> 
> > You have to force rgb16 format in the filter src, and I'd also use the
> > videoscale and ffmpegcolorspace elements after the filtering has taken
> > place. Try this:
> >
> > v4l2src ! "video/x-raw-rgb,bpp=16,depth=16" ! testfilter ! videoscale !
> > ffmpegcolorspace ! xvimagesink
> >
> >
> > El vie, 06-03-2009 a las 11:59 +0100, cammille at polytech.unice.fr
> > escribiÃ³:
> >> I resolve the problem !
> >>
> >> But there still is the problem I had at the beginning : Could not
> >> negotiate format...
> >>
> >>
> >> I remember you my pipeline :
> >> v4l2src  !  videoscale !  ffmpegcolorspace ! testfilter ! xvimagesink
> >>
> >> Where testfilter should apply a red mask.
> >>
> >> > Thanks for your help !
> >> >
> >> > I have another problem when I compile my project :  error:
> >> > gst/video/video.h: No such file or directory
> >> >
> >> > So I can't test your code. I searched on google but it seems that
> >> nobody
> >> > have the problem.
> >> >
> >> > Do you know how to resolve the problem ?
> >> >
> >> >> (I sent another email with an implementation of a silly video filter
> >> >> that applies different color masks to an rgb stream, but for some
> >> reason
> >> >> it did not hit the list, guess it does not like attachments so I
> >> removed
> >> >> it, hopefully this one will make it. If you want the code, say so and
> >> >> I'll send it to you directly).
> >> >>
> >> >> In summary, you just need to get the red_mask from the caps:
> >> >>
> >> >> gst_filter_set_caps (GstPad * pad, GstCaps * caps)
> >> >> {
> >> >>   Gstmyvideo *filter;
> >> >>   GstPad *otherpad;
> >> >>
> >> >>   filter = GST_MYVIDEO (gst_pad_get_parent (pad));
> >> >>   otherpad = (pad == filter->srcpad) ? filter->sinkpad :
> >> filter->srcpad;
> >> >>   gst_object_unref (filter);
> >> >>
> >> >>   GstStructure *structure = gst_caps_get_structure (caps, 0);
> >> >>   ...
> >> >>   gst_structure_get_int (structure, "red_mask", &filter->red_mask);
> >> >>   ...
> >> >> }
> >> >>
> >> >> Then, in your process function, apply the mask to the samples,
> >> something
> >> >> like this does the trick:
> >> >>
> >> >> ...
> >> >> guint samples = GST_BUFFER_SIZE (buf) / 2;
> >> >> guint16 *data = (guint16 *) GST_BUFFER_DATA (buf);
> >> >> gint i;
> >> >>
> >> >> for (i=0; i<samples; i++) {
> >> >>     data[i] = data[i] & filter->red_mask;
> >> >>  }
> >> >> ...
> >> >>
> >> >> Iago
> >> >>
> >> >> El vie, 06-03-2009 a las 09:05 +0100, cammille at polytech.unice.fr
> >> >> escribiÃƒÂ³:
> >> >>> Nobody knows how to filter the red color ?
> >> >>>
> >> >>> If someone can explain me how to manipulate the buffer just to keep
> >> the
> >> >>> red color it would be great.
> >> >>>
> >> >>> Thank you.
> >> >>>
> >> >>> > Thanks everybody !
> >> >>> >
> >> >>> > I'm ok with you Albert, I think the simplest is RGB.. but there
> >> still
> >> >>> is a
> >> >>> > problem.
> >> >>> > If I define a cap I have an error which is :
> >> >>> > ERROR: from element /GstPipeline:pipeline0/GstV4l2Src:v4l2src0:
> >> Could
> >> >>> not
> >> >>> > negotiate format
> >> >>> >
> >> >>> > So I tried to force the format in the pipeline and I have the same
> >> >>> error !
> >> >>> >
> >> >>> > here is my command : gst-launch
> >> >>> > --gst-plugin-path=$HOME/gst-template/gst-plugin/src/.libs/ v4l2src
> >>  !
> >> >>> > videoscale !  ffmpegcolorspace ! testfilter ! xvimagesink
> >> >>> >
> >> >>> > I have searched in vain other examples...
> >> >>> >
> >> >>> > It's strange, because in my code, if I change my buffer like that
> >> :
> >> >>> > int i;
> >> >>> > int size = GST_BUFFER_CAST(buf)->size;
> >> >>> >
> >> >>> > for(i=1; i < size; i++) {
> >> >>> >   (buf->data)[i] = 0;
> >> >>> > }
> >> >>> >
> >> >>> > The images become all green... I really don't understand why.
> >> >>> >
> >> >>> > I think there is a simple way to just keep the red color.. but I
> >> >>> don't
> >> >>> > find it.
> >> >>> >
> >> >>> >
> >> >>> >
> >> >>> >> Hi,
> >> >>> >> the plugin name and description can (must...) be changed in the
> >> >>> >> plugin_init function and GST_PLUGIN_DEFINE macro definition in
> >> the
> >> >>> code
> >> >>> >> that must be present in your code.
> >> >>> >> Concerning the filtering itself, you must check that you have RGB
> >> (I
> >> >>> >> guess
> >> >>> >> that's the simplest) image buffers coming to your plugin in order
> >> to
> >> >>> >> make
> >> >>> >> your processing in the chain function. Best way would be to set
> >> the
> >> >>> caps
> >> >>> >> of your sink pad to video/x-rgb flow. Check other exisitng
> >> plugins
> >> >>> to
> >> >>> >> see
> >> >>> >> how to do this. You'll need a ffmpegcolorspace element before
> >> your
> >> >>> >> plugin
> >> >>> >> to let the flow be in the good format.
> >> >>> >> The example plugin is just a skeleton, you need now to specialize
> >> it
> >> >>> >> with
> >> >>> >> your own code... Read the gstreamer plugin writer's guide, it
> >> will
> >> >>> give
> >> >>> >> you information.
> >> >>> >> Regards,
> >> >>> >> Al
> >> >>> >>
> >> >>> >>
> >> >>> >>
> >> >>> >> ________________________________
> >> >>> >> De : "cammille at polytech.unice.fr" <cammille at polytech.unice.fr>
> >> >>> >> Ãƒâ‚¬ : Discussion of the development of GStreamer
> >> >>> >> <gstreamer-devel at lists.sourceforge.net>
> >> >>> >> EnvoyÃƒÂ© le : Jeudi, 5 Mars 2009, 12h15mn 55s
> >> >>> >> Objet : Re: [gst-devel] Plugin creation
> >> >>> >>
> >> >>> >> I found the problem ! The fact is that my plugin is not named
> >> >>> >> "testfilter".. It's named "plugin". How can I change this name ?
> >> >>> >> beacause
> >> >>> >> I have never specified that my plugin is named "plugin".
> >> >>> >>
> >> >>> >> Another question, : now, I would like to create a simple plugin :
> >> >>> >> I would like to filter the video taken by my webcam and filter
> >> the
> >> >>> red
> >> >>> >> color (i would like to apply an effect like the effectv plugin).
> >> >>> >> I know the algorithm, but I'm not sure how to do that.
> >> >>> >>
> >> >>> >> Do you think I should create this plugin by using the example
> >> plugin
> >> >>> ?
> >> >>> >>
> >> >>> >>
> >> >>> >>> assuming that the shared library name is libgsttestfilters.so
> >> >>> >>>
> >> >>> >>> On Thu, Mar 5, 2009 at 4:28 PM, ved kpl <ved.kpl at gmail.com>
> >> wrote:
> >> >>> >>>> Try gst-inspect on your plugin
> >> >>> >>>>
> >> >>> >>>> Assuming that the plugin is installed in
> >> >>> >>>> "$HOME/gst-template/gst-plugin/src/.libs/"
> >> >>> >>>> do the following and see what you get
> >> >>> >>>>
> >> >>> >>>>  gst-inspect
> >> >>> >>>> $HOME/gst-template/gst-plugin/src/.libs/libgsttestfilters.so
> >> >>> >>>>
> >> >>> >>>> On Thu, Mar 5, 2009 at 4:15 PM,  <cammille at polytech.unice.fr>
> >> >>> wrote:
> >> >>> >>>>> Hello !
> >> >>> >>>>> I would like to create a simple plugin such as effectv..
> >> >>> >>>>>
> >> >>> >>>>> But, first of all, I would like to create a "test plugin".
> >> >>> >>>>> So, I tried to make the example described in the GStreamer
> >> Plugin
> >> >>> >>>>> Writer's
> >> >>> >>>>> Guide.
> >> >>> >>>>>
> >> >>> >>>>> I compiled the "test plugin" with the makefile, and now I'm
> >> >>> trying
> >> >>> to
> >> >>> >>>>> launch this plugin, but I have an error..
> >> >>> >>>>>
> >> >>> >>>>> What's wrong with :
> >> >>> >>>>>
> >> >>> >>>>> $ gst-launch
> >> >>> >>>>> --gst-plugin-path=$HOME/gst-template/gst-plugin/src/.libs/
> >> >>> >>>>> fakesrc ! testfilters ! fakesink silent=TRUE
> >> >>> >>>>>  > WARNING: erroneous pipeline: no element "testfilters"
> >> >>> >>>>>
> >> >>> >>>>> Maybe I have forgotten something ?
> >> >>> >>>>>
> >> >>> >>>>>
> >> >>> >>>>> Thank you.
> >> >>> >>>>>
> >> >>> >>>>>
> >> >>> >>>>>
> >> >>> >>>>> ------------------------------------------------------------------------------
> >> >>> >>>>> Open Source Business Conference (OSBC), March 24-25, 2009, San
> >> >>> >>>>> Francisco, CA
> >> >>> >>>>> -OSBC tackles the biggest issue in open source: Open Sourcing
> >> the
> >> >>> >>>>> Enterprise
> >> >>> >>>>> -Strategies to boost innovation and cut costs with open source
> >> >>> >>>>> participation
> >> >>> >>>>> -Receive a $600 discount off the registration fee with the
> >> source
> >> >>> >>>>> code:
> >> >>> >>>>> SFAD
> >> >>> >>>>> http://p.sf.net/sfu/XcvMzF8H
> >> >>> >>>>> _______________________________________________
> >> >>> >>>>> gstreamer-devel mailing list
> >> >>> >>>>> gstreamer-devel at lists.sourceforge.net
> >> >>> >>>>> https://lists.sourceforge.net/lists/listinfo/gstreamer-devel
> >> >>> >>>>>
> >> >>> >>>>
> >> >>> >>>
> >> >>> >>> ------------------------------------------------------------------------------
> >> >>> >>> Open Source Business Conference (OSBC), March 24-25, 2009, San
> >> >>> >>> Francisco,
> >> >>> >>> CA
> >> >>> >>> -OSBC tackles the biggest issue in open source: Open Sourcing
> >> the
> >> >>> >>> Enterprise
> >> >>> >>> -Strategies to boost innovation and cut costs with open source
> >> >>> >>> participation
> >> >>> >>> -Receive a $600 discount off the registration fee with the
> >> source
> >> >>> code:
> >> >>> >>> SFAD
> >> >>> >>> http://p.sf.net/sfu/XcvMzF8H
> >> >>> >>> _______________________________________________
> >> >>> >>> gstreamer-devel mailing list
> >> >>> >>> gstreamer-devel at lists.sourceforge.net
> >> >>> >>> https://lists.sourceforge.net/lists/listinfo/gstreamer-devel
> >> >>> >>>
> >> >>> >>
> >> >>> >>
> >> >>> >>
> >> >>> >> ------------------------------------------------------------------------------
> >> >>> >> Open Source Business Conference (OSBC), March 24-25, 2009, San
> >> >>> >> Francisco,
> >> >>> >> CA
> >> >>> >> -OSBC tackles the biggest issue in open source: Open Sourcing the
> >> >>> >> Enterprise
> >> >>> >> -Strategies to boost innovation and cut costs with open source
> >> >>> >> participation
> >> >>> >> -Receive a $600 discount off the registration fee with the source
> >> >>> code:
> >> >>> >> SFAD
> >> >>> >> http://p.sf.net/sfu/XcvMzF8H
> >> >>> >> _______________________________________________
> >> >>> >> gstreamer-devel mailing list
> >> >>> >> gstreamer-devel at lists.sourceforge.net
> >> >>> >> https://lists.sourceforge.net/lists/listinfo/gstreamer-devel
> >> >>> >>
> >> >>> >>
> >> >>> >>
> >> >>> >>       ------------------------------------------------------------------------------
> >> >>> >> Open Source Business Conference (OSBC), March 24-25, 2009, San
> >> >>> >> Francisco,
> >> >>> >> CA
> >> >>> >> -OSBC tackles the biggest issue in open source: Open Sourcing the
> >> >>> >> Enterprise
> >> >>> >> -Strategies to boost innovation and cut costs with open source
> >> >>> >> participation
> >> >>> >> -Receive a $600 discount off the registration fee with the source
> >> >>> code:
> >> >>> >> SFAD
> >> >>> >> http://p.sf.net/sfu/XcvMzF8H_______________________________________________
> >> >>> >> gstreamer-devel mailing list
> >> >>> >> gstreamer-devel at lists.sourceforge.net
> >> >>> >> https://lists.sourceforge.net/lists/listinfo/gstreamer-devel
> >> >>> >>
> >> >>> >
> >> >>> >
> >> >>> >
> >> >>> > ------------------------------------------------------------------------------
> >> >>> > Open Source Business Conference (OSBC), March 24-25, 2009, San
> >> >>> Francisco,
> >> >>> > CA
> >> >>> > -OSBC tackles the biggest issue in open source: Open Sourcing the
> >> >>> > Enterprise
> >> >>> > -Strategies to boost innovation and cut costs with open source
> >> >>> > participation
> >> >>> > -Receive a $600 discount off the registration fee with the source
> >> >>> code:
> >> >>> > SFAD
> >> >>> > http://p.sf.net/sfu/XcvMzF8H
> >> >>> > _______________________________________________
> >> >>> > gstreamer-devel mailing list
> >> >>> > gstreamer-devel at lists.sourceforge.net
> >> >>> > https://lists.sourceforge.net/lists/listinfo/gstreamer-devel
> >> >>> >
> >> >>>
> >> >>>
> >> >>>
> >> >>> ------------------------------------------------------------------------------
> >> >>> Open Source Business Conference (OSBC), March 24-25, 2009, San
> >> >>> Francisco, CA
> >> >>> -OSBC tackles the biggest issue in open source: Open Sourcing the
> >> >>> Enterprise
> >> >>> -Strategies to boost innovation and cut costs with open source
> >> >>> participation
> >> >>> -Receive a $600 discount off the registration fee with the source
> >> code:
> >> >>> SFAD
> >> >>> http://p.sf.net/sfu/XcvMzF8H
> >> >>> _______________________________________________
> >> >>> gstreamer-devel mailing list
> >> >>> gstreamer-devel at lists.sourceforge.net
> >> >>> https://lists.sourceforge.net/lists/listinfo/gstreamer-devel
> >> >>>
> >> >>
> >> >>
> >> >> ------------------------------------------------------------------------------
> >> >> Open Source Business Conference (OSBC), March 24-25, 2009, San
> >> >> Francisco,
> >> >> CA
> >> >> -OSBC tackles the biggest issue in open source: Open Sourcing the
> >> >> Enterprise
> >> >> -Strategies to boost innovation and cut costs with open source
> >> >> participation
> >> >> -Receive a $600 discount off the registration fee with the source
> >> code:
> >> >> SFAD
> >> >> http://p.sf.net/sfu/XcvMzF8H
> >> >> _______________________________________________
> >> >> gstreamer-devel mailing list
> >> >> gstreamer-devel at lists.sourceforge.net
> >> >> https://lists.sourceforge.net/lists/listinfo/gstreamer-devel
> >> >>
> >> >
> >> >
> >> >
> >> > ------------------------------------------------------------------------------
> >> > Open Source Business Conference (OSBC), March 24-25, 2009, San
> >> Francisco,
> >> > CA
> >> > -OSBC tackles the biggest issue in open source: Open Sourcing the
> >> > Enterprise
> >> > -Strategies to boost innovation and cut costs with open source
> >> > participation
> >> > -Receive a $600 discount off the registration fee with the source
> >> code:
> >> > SFAD
> >> > http://p.sf.net/sfu/XcvMzF8H
> >> > _______________________________________________
> >> > gstreamer-devel mailing list
> >> > gstreamer-devel at lists.sourceforge.net
> >> > https://lists.sourceforge.net/lists/listinfo/gstreamer-devel
> >> >
> >>
> >>
> >>
> >> ------------------------------------------------------------------------------
> >> Open Source Business Conference (OSBC), March 24-25, 2009, San
> >> Francisco, CA
> >> -OSBC tackles the biggest issue in open source: Open Sourcing the
> >> Enterprise
> >> -Strategies to boost innovation and cut costs with open source
> >> participation
> >> -Receive a $600 discount off the registration fee with the source code:
> >> SFAD
> >> http://p.sf.net/sfu/XcvMzF8H
> >> _______________________________________________
> >> gstreamer-devel mailing list
> >> gstreamer-devel at lists.sourceforge.net
> >> https://lists.sourceforge.net/lists/listinfo/gstreamer-devel
> >>
> >
> >
> > ------------------------------------------------------------------------------
> > Open Source Business Conference (OSBC), March 24-25, 2009, San Francisco,
> > CA
> > -OSBC tackles the biggest issue in open source: Open Sourcing the
> > Enterprise
> > -Strategies to boost innovation and cut costs with open source
> > participation
> > -Receive a $600 discount off the registration fee with the source code:
> > SFAD
> > http://p.sf.net/sfu/XcvMzF8H
> > _______________________________________________
> > gstreamer-devel mailing list
> > gstreamer-devel at lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/gstreamer-devel
> >
> 
> 
> 
> ------------------------------------------------------------------------------
> Open Source Business Conference (OSBC), March 24-25, 2009, San Francisco, CA
> -OSBC tackles the biggest issue in open source: Open Sourcing the Enterprise
> -Strategies to boost innovation and cut costs with open source participation
> -Receive a $600 discount off the registration fee with the source code: SFAD
> http://p.sf.net/sfu/XcvMzF8H
> _______________________________________________
> gstreamer-devel mailing list
> gstreamer-devel at lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/gstreamer-devel
> 