Custom Gst.Element in GTK3

[Thibault Saunier]

Hello,

I tried the example. But it seems to be broken. For example it uses
> set_chain_function, which IMHO should be set_chain_function_full.
> (According to
>
> http://lazka.github.io/pgi-docs/Gst-1.0/classes/Pad.html#Gst.Pad.set_chain_function_full
> ).
>

It is overriden:
http://cgit.freedesktop.org/gstreamer/gst-python/tree/gi/overrides/Gst.py#n109
it can thus be used like it is in the example (this override has not been
released yet)


It looks like you should use Gst.BaseTransform (maybe Gst.VideoFilter)
instead of using Gst.Element as a baseclass for your element, it would
handle more things for you (and I guess pool negotation is one of those
things).

Regards,

Thibault


But I noticed two things:
> 1.
> When changing the function names to set_chain_function_full and
> set_event_function_full and adding a source-pad it almost looks like my
> TestFilter-class.
>
> One difference:
> In my code the chain-function tries to push the buffer to the next
> element (self.srcpad.push(buffer)). The example instead just returns
> Gst.FlowReturn.OK. This is where my code produces the error ("We don't
> have a bufferpool negotiated") and the example doesn't. Do I have to do
> something more to be able to push the buffer to the next element?
>

Why don't you implement


> 2.
> In my last email I mentioned that I even didn't get it (my GTK3-example)
> playing with textoverlay and autovideosink in the Bin (without my custom
> element).
> But when I change the GhostPad's name in my GTK3-example to 'sink'
> (instead of 'video_sink' like in my GTK2-example) and remove the
> TestFilter from the Bin then the video is playing fine. I updated the
> example at pastebin. Now I just need to get my filter to work :)
>
> Best regards
>
>
> 17.07.2014 09:29 AM, Thibault Saunier:
> > Hello,
> >
> > I think when you say Gtk3 you mean GStreamer 1.0 with PyGObject.
> >
> > Do you have gst-python installed? It is necessary to be able to create
> > GstElement subclasses.
> >
> > You can have a look at that example:
> >
> http://cgit.freedesktop.org/gstreamer/gst-python/tree/examples/plugins/python/sinkelement.py
> >
> > Regards,
> >
> > Thibault Saunier
> >
> >
> > On Thu, Jul 17, 2014 at 12:07 AM, Manuel <manuel at wenns-um-email-geht.de>
> > wrote:
> >
> >> Custom Gst.Element in GTK3
> >> --------------------------
> >> Hi all,
> >>
> >> I wrote a gst.Element (GTK2), which is a simple filter that just
> >> forwards all buffers it receives on the sink-pad to the src-pad. Later I
> >> will grab some information from the buffer before forwarding it. (More
> >> precisely I will grab the timestamps and show some text based on the
> >> time, like subtitles). The GTK2-version works fine.
> >>
> >> Today I tried to change my code so that it uses the GTK3
> >> gi.repository-package.
> >> Although the new class looks almost the same it doesn't work.
> >>
> >> This is the error printed on the console:
> >> Error: Internal error: can't allocate images xvimagesink.c(979):
> >> gst_xvimagesink_show_frame ():
> >>
> >>
> /GstPlayBin:MultimediaPlayer/GstPlaySink:playsink/GstBin:vbin/GstBin:timed-video-bin/GstAutoVideoSink:autovideosink0/GstXvImageSink:autovideosink0-actual-sink-xvimage:
> >> We don't have a bufferpool negotiated
> >>
> >> Here is my GTK2-version: http://pastebin.com/J2gHfvS4
> >> And here the GTK3-version: http://pastebin.com/9u8zzcTk
> >>
> >> This is a scenario:
> >> A video-file is played using playbin. The playbin's video-sink is set to
> >> a Gtk.Bin that combines my own Gst.Element with textoverlay and an
> >> autovideosink.
> >>
> >> NOTE: If you remove the textoverlay from the GTK3 example then at least
> >> the audio is playing ;)
> >>
> >> I would be very grateful for your help. :)
> >>
> >> Best Regards
> >> _______________________________________________
> >> gstreamer-devel mailing list
> >> gstreamer-devel at lists.freedesktop.org
> >> http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
> >>
> >
> >
> >
> > _______________________________________________
> > gstreamer-devel mailing list
> > gstreamer-devel at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
> >
>
> _______________________________________________
> gstreamer-devel mailing list
> gstreamer-devel at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.freedesktop.org/archives/gstreamer-devel/attachments/20140717/a36ccf49/attachment-0001.html>