Subject: RE: [SIP] Modify media during a call

From: Jonathan Rosenberg <[email-masked]>
Date: Tue, 19 Sep 2000 23:21:10 -0400

-----Original Message-----
>From: Francois-Xavier Guitton
[mailto:[email-masked]]
>Sent: Tuesday, September 19, 2000 4:30 AM
>To: SIP
>Subject: [SIP] Modify media during a call
>
>
>All,
>Just a quick question: Is it possible to modify a media codec type during a
call thanks to 
>a second INVITE ? ( I can not find in the spec RFC 2543 where that case is
described)
>e.g.: A INVITE B with media m=audio 49170 RTP/AVP 0 , and the call is
successfully >
established.
>May A re-INVITE B in replacing the media line by m=audio 49170 RTP/AVP 2
(to replace PCMU 
>by G721) ?
>Fx./.

Yes, I believe that is fine. On re-invite, you can update a media stream by
doing any of the following:

1. change the IP address or port
2. change the list of codecs
3. change any parameters in a lines

The only thing you probably should not do is change the type of the media
itself, that is, change from audio to video. Thats really adding a new media
stream.

-Jonathan R.
----
Jonathan D. Rosenberg                       72 Eagle Rock Ave.
Chief Scientist                             First Floor
dynamicsoft                                 East Hanover, NJ 07936
[email-masked]                     FAX:   (973) 952-5050
http://www.cs.columbia.edu/~jdrosen         PHONE: (732) 741-7244
http://www.dynamicsoft.com 

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