Subject: [AVT] RFC 2733 vs 3119

From: McArthor Lee <[email-masked]>
Date: Sat, 11 Sep 2004 02:43:52 -0600

hi list,

as to lost packet recovery of real-time MP3 transmission, which one, among RFC 2733 (FEC) and RFC 3119 (ADU), is more efficient, taking into consideration the tradeoff of redundancy and recovery ability?

also, can RFC 2733 and 3119 be implemented together?

plz give me a decription in detail

=======================

Thanks & Regards

McArthor Lee

Introducing Spymac MailPro: http://www.spymac.com/mailpro/

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

---

From: Ross Finlayson <[email-masked]>
Date: Sat, 11 Sep 2004 02:07:56 -0700

>as to lost packet recovery of real-time MP3 transmission, which one, among 
>RFC 2733 (FEC) and RFC 3119 (ADU), is more efficient, taking into 
>consideration the tradeoff of redundancy and recovery ability?

Note that RFC 3119 (the ADU-based RTP payload format for MP3) does not add 
any redundancy.  It merely rearranges the MP3 frame data so that each 
resulting ADU is self-contained (so that if it's lost, all other received 
data will still be completely usable).

>also, can RFC 2733 and 3119 be implemented together?

I believe that that would work well (although I haven't investigated this 
in detail).

         Ross (the author of RFC 3119).

---

From: "Adam Li" <[email-masked]>
Date: Mon, 13 Sep 2004 11:07:27 -0700

Hi,

I believe RFC 2733 and 3119 should be able to be implemented together.
The two RFCs are improving the robustness in different areas. I can try
to summarize them in some simple word and hope it is helpful.

For example, in 10% error channels, when you send 100 units of data, you
get 90 units. RFC 2733 works in this scenario by sending 115 units of
data, and hope you can get 100 units. RFC 2733 works for any media in
payload.

On the special case of MP3, when you send 100 units through the same
channel, and receive 90 units, maybe only 80 units of them are useful
(because of the dependency). RFC 3119 helps by rearranging the data so
that all received 90 units would be useful. It does not add data
overhead for the MP3 stream.

The explanation is a little over simplified. You might want to read the
RFCs to understand how they work. By the way, RFC 2733 is planned to be
obsolete by a new draft
http://www.ietf.org/internet-drafts/draft-ietf-avt-ulp-10.txt. 

Hope it helps.

Adam

 
-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of
McArthor Lee
Sent: Saturday, September 11, 2004 1:44 AM
To: [email-masked]
Subject: [AVT] RFC 2733 vs 3119

hi list,

as to lost packet recovery of real-time MP3 transmission, which one,
among RFC 2733 (FEC) and RFC 3119 (ADU), is more efficient, taking into
consideration the tradeoff of redundancy and recovery ability?

======================= 
Thanks & Regards 
McArthor Lee