Subject: [payload] WGLC on draft-ietf-avt-rtp-isac-02

From: "Roni Even" <[email-masked]>
Date: Thu, 13 Dec 2012 08:34:58 +0200

Hi,

I would like to start a WGLC on
http://tools.ietf.org/html/draft-ietf-avt-rtp-isac-02 , RTP Payload Format
for the iSAC Codec

The WGLC will end on January 2nd, 2013

Please review the draft and send comments to the list.

For the draft authors;  Are you aware of any IPR that applies to
draft-ietf-avt-rtp-isac-02? If so,

has this IPR been disclosed in compliance with IETF IPR rules (see RFCs
3979, 4879, 3669 and 5378 for more details)?
The above question is needed for the document write-up when sent to
publication.

Thanks

Roni Even

Payload  co-chair

---

From: "Roni Even" <[email-masked]>
Date: Wed, 26 Dec 2012 14:42:05 +0200

Hi,

I reviewed the draft and have some questions and comments

1.       In section 2 there is a mention of target bit rate. It is not clear
how is it calculated and what does average during peaks mean? How is this
parameter related to the ibitrate parameter defined in the IANA section.

2.       In section 2 "The  available bandwidth is continuously estimated at
the receiving iSAC and signaled in-band in the iSAC bit stream". How does it
work?

3.       In section 3 second paragraph please discuss using dynamic payload
type number maybe add "The assignment of an RTP payload type for the format
defined in this  memo is outside the scope of this document.  The RTP
profiles in use  currently mandate binding the payload type dynamically for
this  payload format."

4.       In section 3.2  what are the BEI and FL values  and how many bits
each one uses.

5.       In section 3.3 what is bandwidth probe, how does it work. Is it
specified elsewhere, in which case provide a reference.

6.       In section 3.3 "The user can choose to lower the maximum allowed
payload length ". Who is the user(sender / receiver) and how is it done.

7.       In section 3.4 how does a receiver know if he receives a wideband
or super-wideband payload in order to decode correctly.

8.       In section 3.5 "signaled inband". What is inband, any reference?

9.       Looking at figure 6 I am not clear from the text how does the
receiver know that there is padding and not payload?

10.  In section 4 change the beginning to "This RTP payload format is
identified using the media type audio/isac, which is registered in
accordance with [RFC4855 <http://tools.ietf.org/html/rfc4855> ] and uses the
template of [RFC4288 <http://tools.ietf.org/html/rfc4288> ]."

11.  Please verify that the registration follows the template. Currently the
order is not correct and there are missing subscetions.

12.  Since ibitrate and maxbitrate are optional parameters what are the
default values if not specified. I saw 20000 for ibitrate for channel
adaptive mode in section 2. 

13.  What are the units for ibitrate and maxbitrate

14.   In section 4 the change controller should be the payload working
group.

15.  In section 5 what is the clock rate in rtpmap.

16.  Can you switch from wideband to super wideband without any signaling
using the same payload type number. Can you use a 32000 clock rate also for
the wideband.

17.   The document should have a congestion control section see
http://tools.ietf.org/html/draft-ietf-payload-rtp-howto-02

18.   The security section need to be expanded see for example section 10 of
RFC 5404.

Thanks

Roni Even

From: Roni Even [mailto:[email-masked]] 
Sent: 13 December, 2012 8:35 AM
To: [email-masked]'
Cc: [email-masked]'
Subject: WGLC on draft-ietf-avt-rtp-isac-02

Hi,

Thanks

Roni Even

Payload  co-chair

  _____