Maxim Sobolev schreef: > stephane wrote: >> I am a bit confused now. Didn't you mean example 2.4? In 2.2 it says >> explicitly >> <quote> ... uses either PCMU or PCMA codecs (payload type in RTP >> packet tells which >> is being used).... </quote>, where in 2.4 two seperate audio streams >> are established. > > No, I did not. So, what's unclear about it? You can either have an > option to use several codecs within one RTP stream (by accepting more > than on payload type in the SDP answer), or establish *two > independent* RTP streams with different codecs in each of those streams. > > What I am talking about is exchange as follows: > > Alice to Bob: > SDP offer: > m=audio XXXXX RTP/AVP 18 8 0 > > Bob to Alice: > SDP answer: > m=audio YYYYY RTP/AVP 0 18 > > Regards, I am probably reading too much in the word 'either', but I understood this to mean one or the other should be present, not both. RFC 3264 seemed to indicate to me that only the first format both list would be used: par 7: <quote> It MUST send using a media format listed in the answer, and it SHOULD use the first media format listed in the answer when it does send.</quote>. But I misread it, obviously, as is stated in the lines following it, I read the SHOULD as a MUST.
Thanks for clarifying this for me! Stephane _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
