[gst-devel] State changes from PLAY -> READY -> PLAY only work with mad plugin?

Georg Sauthoff g_sauthoff at web.de
Thu Mar 4 20:56:52 CET 2010

On 2010-03-04, Tim-Philipp Müller <t.i.m at zen.co.uk> wrote:


> The problem is with the 'dynamic pads' of oggdemux and decodebin2. The
> first pipeline is very simple: all elements have pads at all times, even
> in NULL state, and you can link all those elements from the start.

thanks for this info!

> The other pipelines however have elements with dynamic pads where the
> pads don't exist yet in NULL state but will only be created once you
> start the data flow. gst-launch does a lot of magic for these things
> under the hood, so that you can just write decodebin2 ! audioconvert
> etc. and it will try to create that link when decodebin2 creates a
> suitable pad. The problem is that gst-launch/gst_parse_launch() simply
> don't set up things in a way that would allow you to re-start the
> pipeline with that magic. Fixable, probably, but no one could be
> bothered to do that yet.

I see - it would be very orthogonal, if this is fixed at some point.

> You should probably just create a new pipeline in youre case, or use
> something like playbin2 which does all that internally for you.

Ok. Should I open a documentation improvement request in the bug tracker


? I mean, the paragraph could mention, what state transitions are likely
to fail with elements involving 'dynamic pads' (including an example


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