Re: [Sip-implementors] Is it possible to fork early media?
Rodrigo Pimenta Carvalho writes: > For example, when user U1 calls and his call is forked (parallel > fork) to users U2 e U3, if there is early media negotiation between > the caller and the callees, can U1 keep the media stream with U2 and > U3 simultaneously? It is possible, the establishment of media between the caller and each callee is independent. The difficulties are how to recognize the situation and how the caller can handle it. The caller will usually see the two media streams coming from different IP addresses/ports. Usually, the source addresses of the streams correspond to the addresses given in the SDP the callees send, but not always. And the media may start arriving at the caller before the SDP arrives. In a perfect world, the caller would test each media stream for whether it is "silent", and then all of those that are not silent would be mixed for presentation to the user. (Humans can usually parse multiple audio sources.) If an early dialog receives a 18x response but there is no media stream that can be matched with that callee, it may be valuable for the calling UA to include an appropriate audio signal in the mix -- a ringing tone for a 180, a forwarding tone for a 181, etc. Dale ___ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
Re: [Sip-implementors] Is it possible to fork early media?
On 7/4/17 12:55 PM, Rodrigo Pimenta Carvalho wrote: Hi. I still have to study and learn about forking calls via SIP. But, before starting my studies, I would like to know if it is possible to do fork + early media. For example, when user U1 calls and his call is forked (parallel fork) to users U2 e U3, if there is early media negotiation between the caller and the callees, can U1 keep the media stream with U2 and U3 simultaneously? If it is not possible to keep such early media streams, is it a matter of SIP capacity ? It's *possible* - it could happen. It just depends on how the alternative forks behave. It is up to the caller to decide how to cope in this case. The first step is to realize it can happen (that seems to be where you are) and then decide on a strategy to deal with it. You could try to mix the streams for playout to your caller. But that is a bother and is unlikely to provide a good user experience. Or you can play out one stream and ignore the others. Of course you would like to play out the one that is going to answer first, but you don't know which one that is. If you guess right then you will have a good user experience. If you guess wrong then things will seem odd to the user when you eventually switch to the stream from the answerer. That will require you to start playing out a stream you had been ignoring - you need to figure out when to do that. It won't necessarily be obvious from the answer sdp which stream that is. Good luck, Paul ___ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
[Sip-implementors] Is it possible to fork early media?
Hi. I still have to study and learn about forking calls via SIP. But, before starting my studies, I would like to know if it is possible to do fork + early media. For example, when user U1 calls and his call is forked (parallel fork) to users U2 e U3, if there is early media negotiation between the caller and the callees, can U1 keep the media stream with U2 and U3 simultaneously? If it is not possible to keep such early media streams, is it a matter of SIP capacity ? Any hint will be very helpful! Best regards! RODRIGO PIMENTA CARVALHO Inatel Competence Center Software Ph: +55 35 3471 9200 RAMAL 979 ___ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
