High CPU usage in multiple audio track in playbin3

[HoonHee Lee]

Dear All.
 
In playbin3(decodebin3) with GST v1.9.1, CPU usage is more high compared with playbin2(decodebin2) when multiple audio track contents.
I tested 1-video and 8-audio stream by launching gst-launch.
 
Multiqueue is set as below in playbin3.
=> g_object_set (dbin->multiqueue, "sync-by-running-time", TRUE, "use-interleave", TRUE, "max-size-buffers", 0, NULL);
In that case, CPU usage is around 210%. And most of them are related with srcpads of multiqueue.
 
In playbin2(decodebin2), CPU usage is around 15%.
 
And I turned off the 'sync-by-running-time' in MQ and CPU usage is similar with playbin2.
 
I am guessing 'sync-by-running-time' mode consumes much more CPU usage than playbin2.

Look at the captured image with top command.

Test Result in Playbin3
:
:
 
Test Result in Playbin2
:
:
 
Test Result in Playbin3 with turning off 'sync-by-running-time'
:
:
 
 
Dear Edward Hervey, Tim-Philipp Müller and Jan Schmidt
1) Do you have similar phenomenon?
2) Do you have a plan to reduce CPU usage when using "sync-by-running-time"?
3) May I get any opinions or guide to reduce CPU usage?
 
Please refer https://bugzilla.gnome.org/show_bug.cgi?id=770225.
 
I am always welcome any questions and opinions.
 
Thanks.