Subject: RE: [AVT] Support for wideband audio in G.722.1

From: "Even, Roni" <[email-masked]>
Date: Sun, 19 Jun 2005 14:23:54 +0300

Colin
In section 3 second parahraph it says

"The encoding and decoding algorithm can change the bit rate at any
   20ms frame boundary, but no bit rate change notification is provided
   in-band with the bit stream.  Therefore, a separate out-of-band
   method is REQUIRED to indicate the bit rate (see section 6 for an
   example of signaling bit rate information using SDP).  An application
   MAY switch bit rates from packet to packet by defining two payload
   type values and switching between them."

The example in section 5.1 define two payload types.

I am not sure I mentioned anywhere that the bit rate can change using a
single payload type or did I make a mistake some place.

Thanks
Roni

-----Original Message-----
From: Colin Perkins [mailto:[email-masked]] 
Sent: Friday, June 17, 2005 2:24 PM
To: Even, Roni
Cc: [email-masked]
Subject: Re: [AVT] Support for wideband audio in G.722.1

Roni,

On 16 Jun 2005, at 07:20, Even, Roni wrote:
> I submitted a new draft that updates the SDP parameters of RFC3047 
> adding support for wide-band audio mode for G.722.1.
>
> http://www.ietf.org/internet-drafts/draft-even-avt-rfc3047-bis-00.txt

One comment: should the draft require SDP signalling to indicate that
the bit rate can change on a packet-by-packet basis with a single
payload type?  This change doesn't seem backwards compatible, so it
needs to be negotiated.

Colin

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Audio/Video Transport Working Group
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---

From: Colin Perkins <[email-masked]>
Date: Mon, 20 Jun 2005 09:13:31 +0100

Roni,

> single payload type or did I make a mistake some place.

RFC 3047 has "For the payload format specified here, the bit rate  
MUST remain constant for a particular payload type value" in section  
3, yet this has been removed in the bis document. This led me to  
believe that it allowed a single payload type to change rates. If  
this is not the case, I suggest that sentence is added back.

Colin