Stephane van Hardeveld schrieb: > > ----- Original Message ----- From: "Klaus Darilion" > <[email protected]> > To: "sip-implementors" <[email protected]> > Sent: Wednesday, February 25, 2009 9:29 AM > Subject: [Sip-implementors] asymmetric audio codecs > > >> Hi! >> >> For a certain application where uplink is low bandwidth and downlink is >> high bandwidth I want to use the best available codec - ie. up G729, >> down G.711. >> >> How can I setup such an asymmetric session? >> >> eg. >> high down >> Alice ------------ Bob >> up low >> >> I think if Alice announces G711 and G729, and Bob answers with G.729, >> Alice must send with G729 and Bob can send with G711 too. Is this >> correct? >> >> Nevertheless, as this requires that Alice's SIP client support this. Is >> there also a method to explicitly define the asymmetric behavior? >> >> Thanks >> Klaus > > You 'should' be able to indicate this with the recvonly and sendonly > media attributes in the SDP. > However, not all SIP clients seem currently to support this feature > correctly. See also: > rfc 3264, par. 5.1 Unicast streams, or rfc 4566, par. 6 SDP attributes: > quote: > 'a=recvonly > This specifies that the tools should be started in receive-only mode > where applicable. It can be either a session- or medialevel attribute, > and it is not dependent on charset. Note that recvonly applies to the > media only, not to any associated control protocol (e.g., an RTP-based > system in recvonly mode SHOULD still send RTCP packets). '
So I have to setup 2 unidirectional streams (one recvonly and one sendonly) instead of a single bidirectional stream? I think this is even less supported :-( regards klaus _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
