Re: [AVTCORE] Fwd: I-D Action:draft-westerlund-avtcore-multistream-and-simulcast-00.txt

Hi,
I have read this draft and think it is well written. Several comments below:
Section 1.2.  Simulcast
"
   Simulcast is the act of simultaneously sending multiple different
   versions of a media content.  This can be done in several ways and
   for different purposes.  This document focuses on the case where one
   wants to provide multiple different encodings towards a intermediary
   so that the intermediary can select which version to forward to other
   participants in the session.  More discussion on the different ways
   of doing simulcast, which is the focus of this document in "Simulcast
   Usage and Applicability" (Section 3).
"

   [Qin]:Suppose the multiple different version of the same media content
   is transmitted simultaneously to the receivers, how do you make sure
   these multiple streams can be recieved by the intermediary in between 
   at the same time and processed at the same time?

Section 1.2:

[Qin]: Have you considered the case where multiple streams are sent simultaneously to the same 
RTP receiver and Intermediary does not involve in simulcast processing. In other words,
the intermediary is transparent to simulcasting and the RTP receiver is powerful and intelligent enough to
deal with simucasting multiple streams.

Section 3.2.  Simulcasting to Consuming End-Point
"
   This usage is based on an RTP Transport Translator (Section 3.3:
   Topo-Trn-Translator) [RFC5117]. ........................
"

[Qin] It seems to me translator in the case described in section 3.2 
      also can send same encoding to multiple destinations or send
      different encoding to independent destination, It look like to me
      the case described in section 3.3 and section 3.4 are just two sub-cases
      under the case described in section 3.2.
      Also the mixer case described in section 3.1 has the same issue.
      would you like to clarify a little bit about this?

Section 3.3 Simulcasting to Consuming End-Point
"
  ...................... Thus some
   consideration and mechanism are needed to support such a use case so
   that it doesn't break RTCP reception reporting.

"
    [Qin] Do you have solution to the translator case since the translator is 
    transparent to the RTP receivers?

Section 3.3 Same Encoding to Multiple Destinations
"
  ... As this type of simulcast is analog to ASM usage and RTP has good
   support for ASM sessions, no further consideration for this case is
   done.
"

   [Qin]: Have you considered SSM case or ASM case which are also simucasted in this document?
Is the solution for SSM case different from the case you described in this document?

Regards!
-Qin
----- Original Message ----- 
From: "Magnus Westerlund" <magnus.westerlund@ericsson.com>
To: "IETF AVTCore WG" <avt@ietf.org>
Sent: Tuesday, July 05, 2011 6:54 PM
Subject: [AVTCORE] Fwd: I-D Action:draft-westerlund-avtcore-multistream-and-simulcast-00.txt

> WG,
> 
> As an individual Bo Burman and I have written this internet draft that
> discusses multistream and simulcast issues and proposes a set of
> extensions to resolve the issues. Feedback is much appreciated.
> 
> Cheers
> 
> Magnus
>

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