Subject: [rtcweb] Fwd: New Version Notification for draft-alvestrand-mmusic-simulcast-ssrc-00.txt

From: Harald Alvestrand <[email-masked]>
Date: Thu, 11 Apr 2019 12:30:13 +0200

I have made a proposal.

Note: This is strictly a *personal* contribution. Do not attach undue
authority to it.

Harald

-------- Forwarded Message --------
Subject: 	New Version Notification for
draft-alvestrand-mmusic-simulcast-ssrc-00.txt
Date: 	Thu, 11 Apr 2019 03:28:17 -0700
From: 	[email-masked]
To: 	Harald Alvestrand <[email-masked]>

A new version of I-D, draft-alvestrand-mmusic-simulcast-ssrc-00.txt
has been successfully submitted by Harald Alvestrand and posted to the
IETF repository.

Name: draft-alvestrand-mmusic-simulcast-ssrc
Revision: 00
Title: Using SSRC with WebRTC Simulcast
Document date: 2019-04-11
Group: Individual Submission
Pages: 6
URL:
https://www.ietf.org/internet-drafts/draft-alvestrand-mmusic-simulcast-ssrc-00.txt
Status:
https://datatracker.ietf.org/doc/draft-alvestrand-mmusic-simulcast-ssrc/
Htmlized:
https://tools.ietf.org/html/draft-alvestrand-mmusic-simulcast-ssrc-00
Htmlized:
https://datatracker.ietf.org/doc/html/draft-alvestrand-mmusic-simulcast-ssrc

Abstract:
This document describes a convention for sending "a=ssrc" attributes
in SDP together with "a=simulcast" attributes. This allows SFUs that
need SSRC information to have this info easily accessible.

Given that it is intended as an interim measure, it does not aim for
being published as an RFC.

Please note that it may take a couple of minutes from the time of submission
until the htmlized version and diff are available at tools.ietf.org.

The IETF Secretariat

---

From: Sergio Garcia Murillo <[email-masked]>
Date: Thu, 11 Apr 2019 16:45:01 +0200

Hi Harald,

Just one quick comment in case you find it useful.

I have been using this format for signaling both rids and ssrcs (and 
association between both):

a=simulcast:send c;b;a a=rid:c send ssrc=2564467881 a=rid:b send ssrc=1 
a=rid:a send ssrc=3 a=ssrc-group:FID 2564467881 32941417 
a=ssrc-group:FID 1 2 a=ssrc-group:FID 3 4 a=ssrc:2564467881 
cname:eRUkt2XxiSTlri77 a=ssrc:32941417 cname:eRUkt2XxiSTlri77 a=ssrc:1 
cname:eRUkt2XxiSTlri77 a=ssrc:2 cname:eRUkt2XxiSTlri77 a=ssrc:3 
cname:eRUkt2XxiSTlri77 a=ssrc:4 cname:eRUkt2XxiSTlri77

Note that the ssrc param (as a rid-param-other) in rid attribute is 
valid per the ABNF in:

https://tools.ietf.org/html/draft-ietf-mmusic-rid-15#page-19 
<https://tools.ietf.org/html/draft-ietf-mmusic-rid-15#page-18>

  rid-param = rid-width-param
                        / rid-height-param
                        / rid-fps-param
                        / rid-fs-param
                        / rid-br-param
                        / rid-pps-param
                        / rid-bpp-param
                        / rid-depend-param
                        / rid-param-other
  rid-param-other   = 1*(alpha-numeric / "-") [ "=" param-val ]
  param-val         = *( %x20-58 / %x60-7E ) ; Any printable character 
except semicolon

IMHO the usage of FID for signaling the "SIM" group is not a good choice 
as it is being used today for signaling the rtx association, and should 
be still present in the SDP if not using rids/rrids (which I understand 
that is the goal of the draft)

Best regards
Sergio

On 11/04/2019 12:30, Harald Alvestrand wrote:
> _______________________________________________
> rtcweb mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/rtcweb

---

From: Lorenzo Miniero <[email-masked]>
Date: Thu, 11 Apr 2019 18:19:51 +0200

Hi Harald,

why drop SSRC advertisement for rtx for simulcast? While I understand
rtx is still there if you use the repaired-rid extension, Chrome was
able to do both using different ssrc-groups. I realize SIM was not
standard, but it gave the right context, and FID provided the rtx
mappings instead. As such, as an interim solution, that sounded like an
easier approach. Anyway, the rest looks good to me!

Lorenzo

On Thu, 11 Apr 2019 12:30:13 +0200
Harald Alvestrand <[email-masked]> wrote:

> Please note that it may take a couple of minutes from the time of
> submission until the htmlized version and diff are available at
> tools.ietf.org.
> 
> The IETF Secretariat
> 

-- 
I'm getting older but, unlike whisky, I'm not getting any better
https://twitter.com/elminiero