W3C home > Mailing lists > Public > public-ortc@w3.org > April 2016

[ortc] Clarification on usage of ssrc value on RTCRtpReceiver

From: Sergio Garcia Murillo via GitHub <sysbot+gh@w3.org>
Date: Fri, 01 Apr 2016 09:37:07 +0000
To: public-ortc@w3.org
Message-ID: <issues.opened-145134272-1459503426-sysbot+gh@w3.org>
murillo128 has just created a new issue for 
https://github.com/openpeer/ortc:

== Clarification on usage of ssrc value on RTCRtpReceiver ==
```
ssrc of type unsigned long
  The SSRC to be used in the "SSRC of packet sender" field defined in 
[RFC3550]
  Section 6.4.2 (Receiver Report) and [RFC4585] Section 6.1 (Feedback 
Messages),
  as well as the "SSRC" field defined in [RFC3611] Section 2 (Extended
 Reports). 
  This is only set for an RTCRtpReceiver. If unset, ssrc is chosen by 
the browser, 
  and the chosen value is not reflected in RTCRtcpParameters.ssrc. If 
the browser 
  chooses the ssrc it may change it in event of a collision, as 
described in [RFC3550].
```

This is a tricky one. 

The configured ssrc is going to be used at the RTPReceiver for sending
 back RTCP messages to the sender. Typically on a one-to-one situation
 this would be the same ssrc of the RTPSender. As we have no 
relationship between the RTPSenders/RTPReceiver this ssrc s the only 
field that to "match" them and send RTCP SR/RR on same ssrc.

Not sure if it provides really any functionality for the API user, and
 if would be ever be needed. I think this should be handled internally
 by the ortc implementation and not exposed at all. Also note that 
browser may change it at any time without notification,

ORTC spec is already too complex to add stuff that would not be used 
at all. Or do you foresee any use case in which this could be 
usable/needed at all?


Please view or discuss this issue at 
https://github.com/openpeer/ortc/issues/449 using your GitHub account
Received on Friday, 1 April 2016 09:37:09 UTC

This archive was generated by hypermail 2.4.0 : Friday, 17 January 2020 16:39:59 UTC