Re: [rtcweb] H.264 SVC and BUNDLE

[Harald Alvestrand <[e-mail]>]

On 08/30/2012 11:19 PM, Bernard Aboba wrote:
> Harald said:
>
> > My assumption has always been that if you were operating on a network
> > that could only apply diffserv to separate 5-tuples, you would allocate
> > the SSRCs comprising a multilayer encoding to different 5-tuples.
>
> [BA] RFC 6190 Section 1 says:
>
>     This memo defines two basic modes for transmission of SVC data,
>     single-session transmission (SST) and multi-session transmission
>     (MST).  In SST, a single RTP session is used for the transmission of
>     all scalability layers comprising an SVC bitstream; in MST, the
>     scalability layers are transported on different RTP sessions.
>
> [BA] So it is possible either to use multiple 5-tuples (MST) or a 
> single 5-tuple (SST).  However, my understanding
> is that the SST approach is more popular than MST.
>
> > This choice seems to be a choice that the application writer should 
> take
> > before deciding whether or not to use BUNDLE, so it's a little hard to
> > see what the relationship to BUNDLE is.
>
> [BA] The open question has been how to indicate the desire for both 
> layered coding and BUNDLE in SDP,
> given the backward compatibility issues we have talked about. For 
> example, if it is desired to do SST and
> BUNDLE, do you signal MST and BUNDLE on different ports in the offer 
> and then if SST and BUNDLE are
> supported by the answer, have the answer respond with BUNDLE as well 
> as dependency groups using
> the same port?  That would seem to imply an assumption that every MST 
> implementation can also do SST.
> Or do do you signal SST and BUNDLE on the same port, and then if the 
> response indicates that the SDP
> was rejected, formulate an alternative offer (MST with BUNDLE?  
> H.264/AVC with BUNDLE?
> SST without BUNDLE??)
I lack the background to think about this... in existing equipment, if 
you want to do SST, but would be willing to do MST if the other end did 
not support SST, how would your offer look (without BUNDLE)?

My head hurts a little when trying to guess, but from your question it 
sounds like you've done it, so it's better if you just paste an example.

(BTW, this is really an MMUSIC discussion)