Troubles with Gobject Introspection

pecisk at pecisk at
Mon Jul 25 14:01:52 PDT 2011


2011/7/25 Tim-Philipp Müller <t.i.m at>:
> On Mon, 2011-07-25 at 23:14 +0300, pecisk at wrote:
>> 1) Gst.ElementFactory() has method create(), which is new way to
>> create GstElements.
> It's not really a "new way". In C both gst_element_factory_create() and
> gst_element_factory_make() exist (the latter is more like a
> create-from-factory and the second is a convenience function that looks
> up the factory given the element factory name string, and then call
> create on it).

Sorry, it was in context of Python, where previous method to create
elements was element_factory_make if I'm correct.

>> I checked with Gst-0.10.gir and method description
>> seems to be fine. However, I get this error:
>> (python:3736): GStreamer-CRITICAL **: gst_registry_find_plugin:
>> assertion `name != NULL' failed
>> and GST_DEBUG shows this that null is passed instead of string of element name:
>> 0:00:00.014177244  3751  0x98fddf0 WARN      GST_PLUGIN_LOADING
>> gstpluginfeature.c:132:gst_plugin_feature_load: Failed to load plugin
>> containing feature '(null)'.
>> 0:00:00.014205391  3751  0x98fddf0 WARN     GST_ELEMENT_FACTORY
> gstelementfactory.c:409:gst_elemient_factory_create:<elementfactory280>
>> loading plugin containing feature level returned NULL!
> It looks like the g-i markup for _create() didn't say that NULL names
> are allowed here, but I don't know if that explains your failure. Maybe
> you should make a fuller debug log to see what's going on.

Python script is
element = Gst.ElementFactory().create("level")

GST_DEBUG=*:5 is attached.

>> 2) It feels to me that something is wrong with scanned classes and
>> methods - I can't find where Parse methods (I was looking for
>> bin_from_description) are hidden (by Gst-0.10.gir they are somewhere
>> under Gst.XML namespace but I can't launch them like that - like
>> Gst.XML().parse_bin_from_description), and I can't initalise Parse
>> itself (or ParseContext) correctly.
> They shouldn't be under the Gst.XML namespace. Why would that happen?
> Gst.parse_bin_from_description() or somesuch doesn't work?

It seems to work, my fault for not checking it, I expected it under
Gst.Parse or Gst.ParseContext

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