[pulseaudio-discuss] How to set media role variable ??

Tanu Kaskinen tanu.kaskinen at linux.intel.com
Fri Nov 29 07:44:39 PST 2013

On Thu, 2013-11-28 at 14:48 +0530, sathishkumar sivagurunathan wrote:
> Thanks Tanu for the reply,
> I wanted to test the module "module role cork" . So I started two media
> players using the gst launch tool. One had media role as phone and other
> had media role as music. When I tested using the "module role cork", it
> worked good. The player with media role "music" was paused.
> As the next step, I tested with two different players.
> 1) gst launch tool -- media role = phone
> 2) qt based application ( runs on phonon - gstreamer framework ) -- with
> media role as music.
> When the "module role cork" is used, the music stream is just muted but not
> paused.
> I tried with a few other players too. The low priority stream is just
> paused.
> I could not understand where the difference is coming from.
> Can you help me with this.

It's probably because module-role-cork doesn't actually cork the
streams. Instead, it mutes them and sends a cork request message to the
client. If the client doesn't handle that message, then the stream won't
get corked, only muted.

The reason for doing the corking this way is that when the stream is
corked, the application should update its UI to show that it's paused
(think of a play/pause button in a music player). It's confusing to the
user (and potentially to the application too) if the stream is stuck,
but the UI shows that it's still playing. For this reason we never
forcibly cork streams at the server end. The applications are always in
control of corking.

That said, I do plan to make it possible to forcibly cork streams at the
server end too at some point.


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