Re: [Sipping] RE: draft-stein-great-00.txt

[Magnus Westerlund <[e-mail]>]

Hi,

>>Another item you mention in your draft and in the thread is a 
>>> standardized wideband codec. Are you proposing that IETF 
>>> standardize one?
> 
> 
> Sounds like a good idea to me.
> And we should design it from day one for the modern Internet
> environment.
> 
> The G-series codecs put 90% effort into low rate, and 10% into low
> delay.
> It is critical for them to be CBR, and there is no attention to packet
> loss, etc. 
> 
> Only the IETF has the motivation to design a codec for:
> 1) no 4kHz (or 8kHz) limitation 
> 2) high perceptual quality (not "toll quality")
> 3) not necessarily CBR
> 4) low delay
> 5) resilient to bursty packet loss

As AVT chair and having been part of the process of the publication of 
RFC 3951 (iLBC) I have the following comment. IETF is not suitable to do 
codec work at all. We are totally lacking the expertise to do good work 
in the source coding business. We are also lacking the working methods 
for determining if a codec proposal would be beneficiary.

iLBC was basically rubber stamping, the chairs ensured through IETF 
external reviewers that iLBC was mature enough. But none in AVT had 
sufficient expertise to provide much more than editorial comments on 
that RFC.

The only thing I see that IETF can provide is better requirements to 
people who know codecs to make them more suitable for IP and it´s 
properties. And I would actually quite strongly object against IETF 
doing more codec work.

Henry Sinnreich wrote:
 > The assertion on codecs is quite amazing, if it is meant as a reproach to
 > the IETF.
 >
 >
 >>Only the IETF has the motivation to design a codec for:
 >>1) no 4kHz (or 8kHz) limitation
 >>2) high perceptual quality (not "toll quality")
 >>3) not necessarily CBR
 >>4) low delay
 >>5) resilient to bursty packet loss
 >
 >
 > The IETF has published RFCs on the iLBC audio codec, and is doing a 
lot of
 > other work in this area.
 >
 > - RFC 3951: Internet Low Bit Rate Codec (iLBC)
 >
 > - RFC 3952: Real-time Transport Protocol (RTP) Payload Format for 
internet
 > Low Bit Rate Codec (iLBC) Speech
 >
 > - RTP Payload Format for the Speex Codec
 > <draft-herlein-speex-rtp-profile-02>
 >

In regards to RTP payload formats, any codec desiring a RTP payload 
format are welcome to come to IETF for standardizing it. And they are 
also doing that, thus no surprise that you find that most of the used 
codecs have IETF standardized RTP payload formats. RTP payload format is 
something AVT WG knows well and have a lot of experience in. However RTP 
payload formats still requires some knowledge about both the codec and 
RTP to be designed successfully.

Cheers

Magnus Westerlund
AVT Chair
--

Multimedia Technologies, Ericsson Research EAB/TVA/A
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