[gst-devel] dynamic overlaying of images on video

Tim Müller t.i.m at zen.co.uk
Mon Sep 3 11:28:19 CEST 2007

On Wed, 2007-08-29 at 20:01 +0000, gael neuez wrote:

> >The videomixer sink pads all have "xpos", "ypos", "zorder" and "alpha"
> >properties (which you can set in your code using g_object_set()). The
> >documentation should probably mention that somewhere.
> Yes, I've seen that in the code source of videomixer. But these properties 
> are not seen as the plugin ones (using gst-inspect for example), these are 
> pads properties. From my application code, how should I access to them? Pads 
> are generated with random names when I link a new 'image pipeline' to it, so 
> unless I access the GList of sinks and try to use g_object_set() on parsed 
> list elements, I don't get right how to set these properties...

Without seeing your code, it's hard to say how you should access them,
but the most straight-forward way would be to create a new sink pad with
gst_element_get_request_pad(videomixer, ...) and then store the
newly-created sink pad somewhere for further use.  Glancing at the
videomixer code, it seems like it only uses a random pad number if you
use "sink_%d" as template in _get_request_pad() and will use the number
you provide if you do provide one.

You can go through the list of existing pads of an element with
gst_element_iterate_*_pads() etc, don't access the lists in the
GstElement structure directly.


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