Re: [MMUSIC] IETF#89: BUNDLE: Q9: What are the criteria for allowing usage of the same PT value within multiple m- lines?

Hi,

I did suggest a definition of “codec configuration” in my message. If that’s not acceptable, then I suggest forbidding payload number reuse across m= lines.

Colin

On 3 Mar 2014, at 10:08, Christer Holmberg <christer.holmberg@ericsson.com> wrote:
> Hi Colin,
>  
> We tried to define “codec configuration”, but we never got text that people could agree to.
>  
> Personally I don’t have any strong opinion which way we go (personally I am also ok forbidding re-usage of the same PT value). I just want to close the issue, and not once again “take it to the list”.
>  
> Regards,
>  
> Christer
>  
> From: Colin Perkins [mailto:csp@csperkins.org] 
> Sent: 03 March 2014 11:34
> To: Christer Holmberg
> Cc: mmusic@ietf.org
> Subject: Re: [MMUSIC] IETF#89: BUNDLE: Q9: What are the criteria for allowing usage of the same PT value within multiple m- lines?
>  
> Christer,
>  
> The bundled m= lines form a single RTP session. That means that they share a single RTP payload number space. The rule therefore has to be that you can only reuse the payload type across bundled m= lines if it refers to the exact same configuration of the exact same codec in all cases, where “exact same configuration” means that the a=fmtp: line and all other SDP attributes that configure the codec and packetisation of the media are identical.
>  
> If that’s not specific enough, then MUST NOT reuse payload types across m= lines in a bundled group is the safe choice. I believe your propose that it’s okay if you can handle the media is too vague, and will cause us problems down the line.
>  
> Colin
>  
>  
>  
>  
> On 2 Mar 2014, at 08:44, Christer Holmberg <christer.holmberg@ericsson.com> wrote:
> Hi,
>  
> One of the open issues we have in BUNDLE, is when it is allowed to use the same PT value within multiple m- lines.
>  
> We tried to come up with different criteria, including a “codec configuration” concept, but we never managed to agree on something.
>  
> So, in London, I intend to suggest that we simply say: if you offer the same PT value within multiple m- line, make sure you can handle the associated media when it arrives – period (keep in mind that you always indicate what you want to RECEIVE – the remote peer can still ask you to SEND using different PT values).
>  
> If you don’t like this, please provide an alternative solution, because I want to close this issue in London. There is no idea to keep “taking the issue back to the list”. We’ve done that for a few meetings already.
>  
> Regards,
>  
> Christer
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> 
> -- 
> Colin Perkins
> http://csperkins.org/
>  
>  
>  

-- 
Colin Perkins
http://csperkins.org/