Re: [AVT] Different sessions, different SSRC

[Randell Jesup <rjesup at wgate.com>]

"Michael Hakimi" <yalakvar at gmail.com> writes:
>As I the RFC describing the RTP says, different sessions should have
>different SSRCs.
>If so, I have a simple question. Let us have a scenario with two endpoints
>having two sessions each. One of the sessions is a P2P session, and the
>other is a conference (the two endpoints participate in the conference).
>Each of the two endpoints will receive two RTP streams with different
>SSRCs containing the same media (lets say voice). An endpoint cannot
>distinguish between the two streams and know that it is actually the same
>voice. The two streams will be played and an echo will be heard.
>This problem get worse when we have more than two streams.
>
>Is there any way to avoid this problem?

Basically: not necessarily - the conference (a single connection to an MCU/
conferencing server) may have a mixture of streams in the RTP session.
You may be able to identify the "duplicate" packets from SSRC and RTCP
SDES/etc.  However, there may be no "duplicate" - the conference system
may well be a mixer that combines them and generates a new stream, etc.

See the avt-topologies draft, among others.

-- 
Randell Jesup, Worldgate (developers of the Ojo videophone), ex-Amiga OS team
rjesup at wgate.com
"The fetters imposed on liberty at home have ever been forged out of the weapons
provided for defence against real, pretended, or imaginary dangers from abroad."
		- James Madison, 4th US president (1751-1836)

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