Re: [AVTCORE] Query: Reporting SSRC when you send no streams?
Harald Alvestrand <harald@alvestrand.no> Wed, 03 June 2015 14:33 UTC
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Date: Wed, 03 Jun 2015 16:33:42 +0200
From: Harald Alvestrand <harald@alvestrand.no>
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To: Magnus Westerlund <magnus.westerlund@ericsson.com>, avt@ietf.org, pbos@google.com
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Subject: Re: [AVTCORE] Query: Reporting SSRC when you send no streams?
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Thanks for the feedback! One thing I think I overlooked: If I (for other reasons) want to send an RTCP BYE on an SSRC, is that also a promise that I won't be using this SSRC for sending RR reports? If so, do I have to jump to another SSRC (possibly a fresh one)? On 06/01/2015 11:19 AM, Magnus Westerlund wrote: > Harald Alvestrand skrev den 2015-06-01 10:59: >> This came up in a WebRTC-related context: >> >> If you send no streams, what SSRC should you be using in receiver >> reports? > > You obviously need one, and if there are no known intention to send a > stream later, then one have to pick one value at random. > >> >> If you start sending streams, should your reporting SSRC(s) change? > > I think it is okay for one (first) of the streams that will be sent to > use the reporting SSRC. > > If one consider the multiple clock rates RFC > (https://datatracker.ietf.org/doc/rfc7160/) one would in most cases > require a new SSRC. But, the reporting SSRC has no known RTP timestamp > rate bound to it, prior to picking it. Thus, I don't see a requirement > to force to use a new SSRC. > > However, I also don't see that it would be wrong to use a new SSRC and > then stop using the previous reporting one. This will of course have > the down side of reducing the per SSRC bit-rate during the 25+ seconds > of timeout period for the old reporting. > > >> >> If you stop sending streams, what should happen? Keep reporting from the >> stream(s) that are gone, or switch to a new (old?) non-sending SSRC? > > I think you should maintain at least one of the SSRCs as reporting > SSRC. If that has to be replaced if one re-adds streams would depend > on the timestamp rate, media type and other context associated with > the SSRC. > >> >> I'm looking at draft-ietf-avtcore-rtp-multi-stream (and -optimization), >> and they seem to offer plenty of advice for the case where there is more >> than one stream (report on them all in -multi-stream, add them to a >> group in -optimization), but not specifically for the 0->1, 1->0 >> transitions. >> >> Of course, I may have overlooked something... > > No, I don't think you have overlooked anything. > > From my perspective this could be fit into the > draft-ietf-avtcore-rtp-multi-stream set of clarifications to ensure > consistent behaviours. However, I think we need to agree on what the > recommended behaviour is, and if we make clear that several behaviours > may occur. > > Cheers > > Magnus Westerlund > > ---------------------------------------------------------------------- > Services, Media and Network features, Ericsson Research EAB/TXM > ---------------------------------------------------------------------- > Ericsson AB | Phone +46 10 7148287 > Färögatan 6 | Mobile +46 73 0949079 > SE-164 80 Stockholm, Sweden | mailto: magnus.westerlund@ericsson.com > ---------------------------------------------------------------------- >
- [AVTCORE] Query: Reporting SSRC when you send no … Harald Alvestrand
- Re: [AVTCORE] Query: Reporting SSRC when you send… Magnus Westerlund
- Re: [AVTCORE] Query: Reporting SSRC when you send… Harald Alvestrand
- Re: [AVTCORE] Query: Reporting SSRC when you send… Simon Perreault
- Re: [AVTCORE] Query: Reporting SSRC when you send… Simon Perreault
- Re: [AVTCORE] Query: Reporting SSRC when you send… Magnus Westerlund
- Re: [AVTCORE] Query: Reporting SSRC when you send… Simon Perreault
- Re: [AVTCORE] Query: Reporting SSRC when you send… Magnus Westerlund
- Re: [AVTCORE] Query: Reporting SSRC when you send… Simon Perreault
- Re: [AVTCORE] Query: Reporting SSRC when you send… Harald Alvestrand
- Re: [AVTCORE] Query: Reporting SSRC when you send… Simon Perreault
- Re: [AVTCORE] Query: Reporting SSRC when you send… Magnus Westerlund