Subject: [AVT] WGLC on draft-ietf-avt-rtp-g711wb-03.txt

From: "Even, Roni" <[email-masked]>
Date: Tue, 6 May 2008 20:31:53 +0300

Hi,

This is to announce a working group last call on the RTP Payload Format for ITU-T Recommendation G.711.1

Please send any final comments to the mailing list by May 27th 2008.  

If no issues are raised, we will request the IESG consider the document for publication.

A New Internet-Draft is available from the on-line Internet-Drafts directories.

This draft is a work item of the Audio/Video Transport Working Group of the IETF.

            Title           : RTP Payload Format for ITU-T Recommendation G.711.1

            Author(s)       : A. Sollaud

            Filename        : draft-ietf-avt-rtp-g711wb-03.txt

            Pages           : 15

            Date            : 2008-04-28

This document specifies a Real-time Transport Protocol (RTP) payload format to be used for the International Telecommunication Union

(ITU-T) G.711.1 audio codec.  Two media type registrations are also included.

A URL for this Internet-Draft is:

http://www.ietf.org/internet-drafts/draft-ietf-avt-rtp-g711wb-03.txt

Internet-Drafts are also available by anonymous FTP at:

ftp://ftp.ietf.org/internet-drafts/

Thanks

Roni Even

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

---

From: Hitoshi Ohmuro <[email-masked]>
Date: Fri, 23 May 2008 10:37:32 +0900

Hi,

Sorry for my delayed comment.

I found an alignment problem for implementing the 1-octet payload header.

We are thinking of low-cost implementation of G.711.1 codec and RTP 
stack on a DSP.
Generally, a G.711.1 codec and an RTP stack are implemented as 
independent functions.

An G.711.1 encoder generates even-size audio data, 40, 50, or 60 byte 
data. RTP header always has 4-octet boundary.

If the payload header has a even-size, the RTP stack can combine the RTP 
header, the payload header and the audio data easily, i.e. a DSP has 
only to copy data word by word.

If the payload header has a odd-size, however, a 16-bit DSP has to copy 
the audio data byte by byte using byte swapping like endian conversion. 
This is due to 16-bit DSP memory architecture. This processing causes 
much more overheads than even-size payload header.

I know that the communication protocol should not depend on a specific 
hardware architecture.
However, I know also that most of DSPs designed for speech signal 
processing are optimized for 16-bit data.

I would like to propose that the payload header should be 2-octet and 
the latter 1-octet is treated as a reserved byte which is default to zero.

This reserved byte might waste the bit rate, but we might be able to use 
this byte for an optional purpose in the future, without 
interoperability problems.

Please let me know your comments.

Regards,

Hitoshi Ohmuro

> Please send any final comments to the mailing list by May 27^th 2008. 
> 
>  
> 
> This document specifies a Real-time Transport Protocol (RTP) payload 
> format to be used for the International Telecommunication Union
> 
> ------------------------------------------------------------------------
>

---

From: Hitoshi Ohmuro <[email-masked]>
Date: Tue, 27 May 2008 10:25:02 +0900

Hi,

I discussed with some interested parties.

The number of parties who supported my proposal was limited.
It seems that most parties do not prefer even-size payload header or 
zero-padding to 1-octet one, because the significance of the processing 
problem is small, compared to the whole codec complexity.

I am ok with the current 1-octet payload header format.

I thank you for good discussions.

Regards,

Hitoshi Ohmuro

---

From: "Even, Roni" <[email-masked]>
Date: Tue, 27 May 2008 14:48:58 +0300

Hi,

I read the draft and have no comments. My previous ones are resolved.

Two typos

1.       Section 3  in the marker definition should be
"Codec-independent"

2.       In section 6 tile and in ToC should be "interoperability"

Roni Even

From: [email-masked] [mailto:[email-masked]] On Behalf Of
Even, Roni
Sent: Tuesday, May 06, 2008 8:32 PM
To: [email-masked]
Cc: Colin Perkins; [email-masked]
Subject: [AVT] WGLC on draft-ietf-avt-rtp-g711wb-03.txt

Hi,

This is to announce a working group last call on the RTP Payload Format
for ITU-T Recommendation G.711.1

If no issues are raised, we will request the IESG consider the document
for publication.

A New Internet-Draft is available from the on-line Internet-Drafts
directories.

This draft is a work item of the Audio/Video Transport Working Group of
the IETF.

            Title           : RTP Payload Format for ITU-T
Recommendation G.711.1

            Author(s)       : A. Sollaud

            Pages           : 15

            Date            : 2008-04-28

(ITU-T) G.711.1 audio codec.  Two media type registrations are also
included.

Thanks

Roni Even

---

From: "Even, Roni" <[email-masked]>
Date: Wed, 28 May 2008 14:07:55 +0300

Hi,

The WGLC has ended. There were comments from Colin, Hitoshi Ohmuro and
Roni but there are no open issues.

The document will be sent to publication

Thanks

Roni Even

Hi,

 

 

            Author(s)       : A. Sollaud

            Pages           : 15

            Date            : 2008-04-28

Thanks

Roni Even