Re: [Linphone-developers] Support for multiple RTP streams in same RTP session

[Peio Rigaux]

Hello.

I took some time to gather information from one of the developers of this feature.

I have some trouble understanding this but I think that it can be helpful for you.

1. Is it possible to request RTP to open and use multiple streams of the same media and PT between two endpoints? (with just different SSRCs)?

Yes. It is not prohibited to use the same payload type, since these are different streams using different SSRCs and MIDs (stream identifiers in bundle mode).

2. Is it possible to request RTP to accept a new incoming SSRC within an existing RTP session as a new stream with the same PT, and avoid the RTP to deem the new SSRC to be a change of SSRC for an existing stream?

Yes, as long as the RTP stream carries the MID extension header to associate the new SSRC with a stream described in the SDP session.

Regards,

Peio Rigaux
Junior Software Engineer
Belledonne Communications, the company behind Linphone
Linphone.org

Le 18/06/2020 à 13:38, Gunnar Hellström a écrit :

> I saw
>       the good news about bundling RTP streams in Linphone RTP. Here is
>       a slightly related question.
>       
>       
>       1. Is it possible to request RTP to open and use multiple streams
>       of the same media and PT between two endpoints? (with just
>       different SSRCs)?
>       
>       
>       2. Is it possible to request RTP to accept a new incoming SSRC
>       within an existing RTP session as a new stream with the same PT,
>       and avoid the RTP to deem the new SSRC to be a change of SSRC for
>       an existing stream?
>       
>       
>       This is for thoughts of using the RTP translator model without any
>       SDP exchange when new streams are introduced by a conference
>       focus. New SSRCs could be announced by RTCP or conference
>       notifications if needed.
>       
>       
>       Regards
>       
>       
>       
>       Gunnar
>       
>       
>

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