According to RFC4585, AVPF profile allows a device to send feedback earlier than the usual transmission of a regular RTCP packet. But, depending on the bandwidth, number of users and periodicity of regular RTCP packets, it is possible for the participants of a session not be able to use early feedback.
How is this threshold calculated? This is not provided (it'd be nice to have it, at least for the point-to-point case).
From the RFC:
Note that the algorithms do not depend on all senders and receivers agreeing on the same value for this threshold. It is merely intended to provide conceptual guidance to application designers and is not used in any calculations.
So, if this threshold is even implemented (sounds like it's not necessary) it will be implementation specific.
There are open source implementations of AVPF; duobango being one example, and it seems Jingle also implements this. It may be worth looking through their codebase for some help. I wasn't able to find anything more.
Good luck!
