Subject: [AVT] H.264 payload format and packet duplication

From: Magnus Westerlund <[email-masked]>
Date: Wed, 20 Nov 2002 23:34:37 +0100

Hi,

As I mentioned in today's meeting there is reason why the payload format 
should not suggest to use packet replication:
- By replicating whole UDP/RTP/payload packets the RTCP statistics does 
not count the replicated packets. This prevents adaptation mechanisms 
relying on RTCP statistics to make the correct decision.
- Replication increase bandwidth and may cause congestion and therefore 
needs some type of congestion control.
So packet replication increase the need for congestion control and at 
the same time makes the statistics less correct.

Therefore this notion should be removed and instead if the functionality 
is wanted, the draft should point to some type of FEC, for example RFC 
2733 or rather a successor.

Best Regards

Magnus

_______________________________________________
Audio/Video Transport Working Group
[email-masked]
https://www1.ietf.org/mailman/listinfo/avt

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From: Stephen Casner <[email-masked]>
Date: Wed, 20 Nov 2002 16:56:47 -0800 (PST)

> 2733 or rather a successor.

I agree, this is an important point.  Our congestion control mechanism
depends upon accurately measuring loss.  If packets are replicated,
the receiver can't do that.  This is essential.

                                                        -- Steve

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From: Stephan Wenger <[email-masked]>
Date: Thu, 21 Nov 2002 10:35:28 +0100

Sounds reasonable -- stay tuned for the next revision.

Stephan