Playbin missing state notifications

[Henning Riis]

Filed it as bug along with a small code-sample:
https://bugzilla.gnome.org/show_bug.cgi?id=767601


-----Original Message-----
From: gstreamer-devel [mailto:gstreamer-devel-bounces at lists.freedesktop.org] On Behalf Of Sebastian Dröge
Sent: Monday, June 13, 2016 9:06 AM
To: Discussion of the development of and with GStreamer
Subject: Re: Playbin missing state notifications

On Mo, 2016-06-13 at 06:12 +0000, Henning Riis wrote:
> 
> In my bus callback I then look for GST_MESSAGE_STATE_CHANGED in order 
> to know when the pipeline starts playing. Sometimes this works as 
> expected, I get: NULL->READY, READY->PAUSED, PAUSED->PLAYING.
>  
> Sometimes I only get first: NULL->READY. The video starts playing 
> anyway however, so something is working but my application just has no 
> idea that playback has started.
>  
> This is just on application startup, so preconditions should be the 
> same for all runs. I'm guessing something is racing but cannot figure 
> out what.
>  
> My only vague guess is that it’s somehow not allowed to set 
> GST_STATE_PLAYING before the first full transition from NULL to PAUSED 
> (via READY) has completed. But I cannot find documentation that 
> confirms this, and it would take a lot of code to queue up my state 
> changes like that, so I’d rather not do it unless it’s totally 
> necessary.

This seems like a bug and should work as you expect really. Can you provide a standalone testcase with instructions how to reproduce it and put it into Bugzilla here:
https://bugzilla.gnome.org/enter_bug.cgi?product=GStreamer 

--
Sebastian Dröge, Centricular Ltd · http://www.centricular.com