Subject: Re: [codec] Codec Standardization Expertise

From: Lars Eggert <[email-masked]>
Date: Tue, 4 Aug 2009 11:45:34 +0300

On 2009-7-31, at 19:08, Gerard Fernando wrote:
> BTW, you can give a look from IESG BOF report: “- understanding it  
> would not be possible to guarantee that resulting codecs would be  
> royalty free”

Clarification: what you cite from is the report of the *sponsoring AD*  
and not something an IESG consensus call was run on. (In other words,  
it's a report *to* the IESG and not *from* the IESG.)

Lars

---

From: "Sergey Ikonin" <[email-masked]>
Date: Tue, 4 Aug 2009 18:04:24 +0400

For IP-MR only base layer is required for reconstruction of speech. This
reconstruction is just regular decoding without running of PLC (Packet
Loss Concealment) procedure. It is important to avoid running of PLC
because it introduces artifacts and error propagation.
Of course each new layer increases quality of synthesized speech. But
for packet loss resilience it's betted to spread duplicates of base
layer in time (in packets n+1, n+2, etc).

Best regards,
Sergey Ikonin
www.spiritDSP.com
-----Original Message-----
From: Stefan Sayer [mailto:[email-masked]] 
Sent: Friday, July 31, 2009 11:07 PM
To: stephen botzko
Cc: [email-masked]
Subject: Re: [codec] Codec Standardization Expertise

Hello,

o stephen botzko [07/30/09 23:02]:
> itself.  G.719's packetization RFC allows for interleaved and
overlapped 
> (redundant) audio frames, and permits the duplicate frames to be at 
> lower rates.  That allows for good quality to be maintained under
packet 
> loss conditions (though if the network is congested, of course you
need 
How much additional packet loss resilience would be possible to achieve 
from a true multiple description mode for the codec and interleaved 
packetization, where reconstruction of a lower quality signal would be 
possible in the presence of one description, or some out of a few 
descriptions?

For this to work, not only the RTP packetization has to support it so 
that the receiver understands what it is that was received, but the 
codec itself must support this mode. (I would assume that for efficiency

reasons, this needs to be an alternate coding mode, which the sender 
could switch to if it detects, e.g. with the help of RTCP, excessive
loss.)

I see that in the IP-MR RTP format it is possible to reconstruct from 
the base layer, which may be sent redundantly. How much better could 
this work if reconstruction from any combination of layers would be 
possible?

Thanks
Stefan Sayer

---

From: Lars Eggert <[email-masked]>
Date: Tue, 4 Aug 2009 21:38:41 +0300

Hi,

it's been pointed out to me that my email below makes it look like  
Gerard made the statement I was referring to. This is incorrect, the  
statement was made by Herve Taddei.

Looking at the email I responded to, I see that the problem is that it  
is a multipart/alternative MIME email, and the text/plain part that my  
MUA renders is missing some HTML quotation that the text/html part  
has. The problem of non-equivalent multipart/alternative emails rears  
its ugly head again...

Lars

On 2009-8-4, at 11:45, Eggert Lars (Nokia-NRC/Espoo) wrote:
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