Re: [MMUSIC] Channel descriptions

"Charles Eckel (eckelcu)" <eckelcu@cisco.com> Wed, 18 July 2012 22:02 UTC

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From: "Charles Eckel (eckelcu)" <eckelcu@cisco.com>
To: Kevin Gross <kevin.gross@avanw.com>
Thread-Topic: [MMUSIC] Channel descriptions
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Date: Wed, 18 Jul 2012 22:03:22 +0000
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Cc: mmusic <mmusic@ietf.org>
Subject: Re: [MMUSIC] Channel descriptions
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It looks as if RFC 3190 defines some conventions for the channels for L24.
Otherwise, perhaps an extension to RFC 5576, assuming you are using different SSRCs for each channel.
In general, there are ongoing discussions ongoing in AVTCORE, RTCWEB, and CLUE regarding multiplexing and some mechanism to describe the multiplexed streams will likely result.

Cheers,
Charles

> -----Original Message-----
> From: Kevin Gross [mailto:kevin.gross@avanw.com]
> Sent: Wednesday, July 18, 2012 10:35 AM
> To: Charles Eckel (eckelcu)
> Cc: mmusic
> Subject: Re: [MMUSIC] Channel descriptions
> 
> Yes. For a multichannel media specification such as:
> 
> 
> 	m=audio 49152 RTP/AVP 96
> 	i=Channels 1-8
> 	a=rtpmap:96 L24/48000/8
> 	a=sendonly
> 
> I get one description ("Channels 1-8") for all 8 channels in this stream. I'd
> like to also have the ability to supply a description per channel.
> 
> 
> Kevin Gross
> 
> +1-303-447-0517
> Media Network Consultant
> 
> AVA Networks - www.AVAnw.com <http://www.avanw.com/> ,
> www.X192.org
> 
> 
> 
> On Wed, Jul 18, 2012 at 9:58 AM, Charles Eckel (eckelcu)
> <eckelcu@cisco.com> wrote:
> 
> 
> 	Hi Kevin,
> 
> 	Just to clarify my understanding of what you are asking, you can
> already have an i-line at the session level and/or at the media level (i.e. per
> m-line). Are you looking for something that lets you differentiate between
> multiple channels within a single m-line?
> 
> 	Cheers,
> 	Charles
> 
> 
> 	> -----Original Message-----
> 	> From: mmusic-bounces@ietf.org [mailto:mmusic-
> bounces@ietf.org] On
> 	> Behalf Of Kevin Gross
> 	> Sent: Tuesday, July 17, 2012 4:58 PM
> 	> To: mmusic
> 	> Subject: [MMUSIC] Channel descriptions
> 	>
> 	> The i= attribute provides a means to describe a session. Sessions
> often have
> 	> multiple media streams or channels. Although RFC 3551 (page 8)
> suggests a
> 	> convention for ordering of channels for surround sound
> applications, other
> 	> applications use multiple channels in different ways. It would be
> useful if
> 	> there were a mechanism analogous to i= for describing individual
> channels
> 	> in a session. Does such a thing exist anywhere? I've searched the
> archives
> 	> here and didn't find anything.
> 	>
> 	> Kevin Gross
> 	>
> 	> +1-303-447-0517 <tel:%2B1-303-447-0517>
> 	> Media Network Consultant
> 	>
> 
> 	> AVA Networks - www.AVAnw.com <http://www.avanw.com/> ,
> 	> www.X192.org
> 
> 
>