From: Rashid Shakil <[EMAIL PROTECTED]>
Quick question I was analyzing the SDP which my softswtich is
sending in response to an INVITE for an inbound call I received
from my SIP peer. I noticed that I can see two codec choices in
media description (m=) line but the rtpmap attribute of the SDP
just showing one. Can any one tell what does it means and which one
has precedence if I have media description and rtpmap present in an
SDP?
c=IN IP4 5.5.5.2
t=0 0
m=audio 21092 RTP/AVP 18 0 100
a=rtpmap:18 G729/8000
a=rtpmap:100 telephone-event/8000
a=fmtp:100 0-11
There are *three* codecs, because "telephone-event" is also processed
as a codec (though you can't encode ordinary audio with it).
The order in the m-line is the preference order of the sender of the
SDP, but there is no (enforceable) requirement that the recipient will
respect that order, since it may have different preferences.
Dale
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