Setting different RTP SSRCs with GStreamer and multiudpsink

Question

In a C++ program I'm using a GStreamer pipeline to generate an RTP stream and send it to two destinations at the same time with a multiudpsink element.

This works fine, except that both streams have the same RTP SSRC. Is there a way to set different SSRCs for the two streams ?

Answer 1

The solution I found was to use a tee element and have multiple legs that each have their own RTP encoder (in my case rtpopuspay) and multiupdsink element.

That way each feeds gets a different SSRC.

Answer 2

There is no way.

The SSRC is a unique identifier of the participant to a RTP session. The RTP session manager hold the SSRCs of all participants. The Unique Identifier SSRC cannot be duplicated and different SSRCs correspond to different participants to the session. So SSRC is not the identifier of the session or of a pair of participants, is the identifier of a single user.

In your case, the SSRC is the identifier of the generator of the RTP stream so is impossible to have 2 different SSRC in this case.

Further read here