Re: [MMUSIC] RFC 6190 Single Session Transport

["Roni Even" <[e-mail]>]

Hi Jonathan,

Maybe if you want to use FEC only on the base layer and not on all layers.

Roni

 

From: [e-mail] [mailto:[e-mail]] On Behalf Of
Jonathan Lennox
Sent: 19 July, 2013 5:54 PM
To: Bernard Aboba
Cc: [e-mail]
Subject: Re: [MMUSIC] RFC 6190 Single Session Transport

 

 

On Jul 18, 2013, at 10:02 PM, Bernard Aboba <[e-mail]>
wrote:





Jonathan said: 

"I don't understand how single-session multi-source transmission will work
without either a) signaling "a=ssrc-group DDP" decoding dependencies, or b)
making various implementation-specific assumptions about the structure of
the SVC streams."
 
[BA] In terms of SDP choices for expressing layering within a single m line,
you can either go the a=ssrc-group:DDP route, or use distinct payload types
for each layer and RFC 5583 a=group:DDP (this is what "Unified Plan" Section
4.7 appears to advocate).  

I'm not sure how "MST within a single session" could be expressed in SDP
without BUNDLE.  Was the idea to use multiple m lines and group them
together but use the same port? 

 

I think the authors of RFC 6190 didn't see a use case for MST within a
single RTP session -- all of the interesting MST use cases they saw involved
separate transport flows for the separate layers, and if you're sending all
the layers on a single transport flow, SST is significantly simpler.

 

What requirement are you trying to achieve that's met by MST in a single
session, but not by SST?

 

--

Jonathan Lennox
[e-mail]