Subject: RE: [AVT] RE: RTP/RTCP Port Sharing (Was: Comedia Issues.)

From: "Christian Huitema" <[email-masked]>
Date: Tue, 17 Jul 2001 19:40:18 -0700

> Out of curiosity, what kind of timeouts do these NAT bindings 
> typically have?

Between 30 seconds and 15 minutes. Depends on the implementation.

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From: John Lazzaro <[email-masked]>
Date: Wed, 18 Jul 2001 11:54:16 -0700

> Lawrence Conroy writes:
>
> In this case one can simply not deal with RTCP (for
> very simple "two party" cases in which there's no absolute need for it).

At least one codec uses information coded in the RTCP RR packets as an
integral part of the forward-channel coding scheme, see Appendix A of
this paper for details:

http://www.cs.berkeley.edu/~lazzaro/sa/pubs/pdf/nossdav01.pdf

While the trick we use (using the "extended highest sequence number 
received" RR field to control resilency coding) is specialized for our
application domain (MIDI control of MPEG 4 Structured Audio), I can
easily imagine designing a mainstream audio or video codec that uses
this approach -- perhaps one already exists, although I'm not aware of one.

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John Lazzaro -- Research Specialist -- CS Division -- EECS -- UC Berkeley
lazzaro [at] cs [dot] berkeley [dot] edu     www.cs.berkeley.edu/~lazzaro
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