Re: [Vala] GStreamer signal connection in Vala

[Fabian Deutsch <fabian deutsch gmx de>]

Hi,

Am Montag, den 05.03.2012, 20:12 +0000 schrieb Thomas:
> I am new to Vala. I am trying to develop a simple application using
> Gstreamer and Vala, but I fail with the connection of signlas defined
> within the Gstreamer Element cairoooverlay
> (http://developer.gnome.org/gst-plugins-libs/unstable/gst-plugins-good-plugins-cairooverlay.html).
> What i am Trying to do ist the following:
>
> this.pipeline =  (Pipeline)Gst.parse_launch("... cairooverlay
> name=overlay ...");
> ...
> Element ov = this.pipeline.get_by_name("overlay");
> ov.connect("caps_changed", this.caps_changed_cb);

Just one hint about Gstreamer Elements: Use Vala's dynamic keyword.
Using this keyword you can access properties and signals of the lements
without using the getters or connect methods.

dynamic Element ov = ...
ov.name = "overlay";
ov.caps_changed.connect (this.caps_changed_cb);

Sorry that I can't tell you the right sinal, but the docs might help you
here (or gst-inspect cairooverlay)

Greetings
fabian


> The code compiles fine, but I get the runtime warning and the signal
> is not connected.
>
> GLib-GObject-WARNING **: g_object_connect: invalid signal spec "caps_changed"
>
> What is standard way to connect to this signal with a proper callback
> in Vala? The function to connect the signal from C is
> g_signal_connect.
>
> Cheers
> Thomas
>
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