[gst-devel] Troubles with gstreamer, pygtk and ubuntu karmic

[Jan Schmidt]

On Mon, 2009-11-16 at 11:37 -0800, Ron McOuat wrote:
> I had the same problem. The tutorial version of the code for handling 
> the assignment of the "prepare-xwindow-id" message is incomplete. 
> Looking in the example code under gst-python reveals a few more steps. I 
> changed the tutorial code to look like the following and it worked.
> 
>     def on_sync_message(self, bus, message):
>         if message.structure is None:
>             return
>                 
>         if message.structure.get_name() == "prepare-xwindow-id":           
>             # Assign the viewport
>             gtk.gdk.threads_enter()
>             gtk.gdk.display_get_default().sync()
>             imagesink = message.src
>             imagesink.set_property("force-aspect-ratio", True)
>             imagesink.set_xwindow_id(self.movie_window.window.xid)
>             gtk.gdk.threads_leave()

This is due to GTK+ making a subtle change in the handling of GdkWindow
XIDs, for the Client Side Windows support. You now need to be sure to
take the GDK lock, because they replaced a simple accessor macro with a
function that tries to create a native X server window if one doesn't
yet exist.

See bug https://bugzilla.gnome.org/show_bug.cgi?id=599885

> The code form the examples directory in gst-python is not the same as 
> above but I pulled in the thread sync code to make it work.
> 
> Here is the code (commented out) from the examples
> 
>             # Example code from
>             # 
> http://cgit.freedesktop.org/gstreamer/gst-python/tree/examples/maemogst.py
>             #
>             # all this is needed to sync with the X server before giving the
>             # x id to the sink
>             #gtk.gdk.threads_enter()
>             #gtk.gdk.display_get_default().sync()
>             #self.video_widget.set_sink(message.src)
>             #message.src.set_property("force-aspect-ratio", True)
>             #gtk.gdk.threads_leave()
> 
> 
> 
> I have also had trouble with the NVidia X server not displaying the 
> video with the proper colour map. If I move a recorded file off a cam to 
> another machine it displays the correct colour map but I am sure that is 
> a separate issue.

I had this (one time) issue as well. Going into Totem, opening the
Preferences->Display tab, and resetting the Hue slider to the center
fixes it. I think NVidia changed the meaning of the Hue slider values,
making totem's cached value actually cause incorrect hue.

J.
 
> 
> Hope that helps,
> 
> Ron
> 
> 
> Nicolas Bertrand wrote:
> > Hi,
> > I use gstreamer and pygtk for webcam acquisition. Since I upgraded to
> > ubuntu karmic 9.10, I was facing some application freeze/crash.
> >
> > Most of the time the application freeze and webcam application does
> >  not start.
> >
> > For illusrate my problem I use the example from pygst tutorial ( simple
> > webcam acquisition and display) :
> > http://pygstdocs.berlios.de/pygst-tutorial/webcam-viewer.html
> >
> > This program operates normaly on ubuntu dapper drake and ubuntu jaunty
> > jackalope. I execute the program at least 5 times and webcam
> > acquisition, is always OK.
> >
> > If  I execute the same script on ubuntu karmic, sometimes its ok and
> > sometimes not. Most of the the time the webcam acquisition fails.
> >
> > What I noticed under karmic  :
> >     If I use videotestsrc instead of v4l2src, I still having the problem
> > --> so its seems not due to webcam acquisition.
> >     When display is not 'forced' to a Drawing area, i.e. the 
> > acquisition starts in another window in place of application window, the
> > script never crash and webcam acquisition is good. For doin that doin I
> > don't connect the signal 'sync-message::element'
> >
> > Do anyone has facing this problem or have an idea for how to
> > understand/debug this problem.
> >
> > I post this message on gstreamer and pygtk, because I do not know where
> > the problem or bad usage come from ?
> >
> > Thanks in advance for help.
> >
> > Nico
> > https://launchpad.net/~nico-inattendu
> >
> >    
> >
> >
> >
> >
> >
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-- 
Jan Schmidt <thaytan at noraisin.net>