rtcpmanager: new element to allow delegating RTCP management of multiple RTP sessions to a single element, with a single thread

Open Mathieu Duponchelle requested to merge meh/gst-plugins-good:rtcpmanager into master

This adds a new element, a new piece of API in rtpsession to obtain current times through a callback to the session instead of function parameters, and avoid starting the RTCP thread in the rtpsession element when no RTCP source pad was requested.

An example is also implemented, it can be used with and without RTCP management, to allow observing the removal of mostly idle threads when rtcpmanager is used.

Merge request reports