[gst-devel] Buses of the pipeline.

[Edward Hervey]

On Wed, 2010-04-21 at 06:08 -0800, wl2776 wrote:
> How many buses can have a pipeline?

  Every element (and therefore bins and pipelines) only have one bus.

  But bins (And pipelines) will set a separate bus for the elements
within it to use. The bin will properly aggregate/proxy messages to its
bus (i.e. the one you get when you do _get_bus() on that
element/bin/pipeline).

  Therefore it's perfectly normal that you see a different GstBus.

  You should never have to use any other bus except for the pipeline bus
if you're an application.

> 
> I've found that if I create a playbin2 instance and a videosink instance and
> set playbin2's "video-sink" property, the instances have different buses.
> 
> Can anyone clarify the bus mechanism? When and why are they created, how are
> used?
>