Hi folks,
Going through RFC3264, I find some inconsistency between offerer and
answerer.
Suppose offer/answer below
Offer:
m=audio 49170 RTP/AVP 0 4
a=rtpmap:0 PCMU/8000
a=rtpmap:4 G723/8000
Answer:
m=audio 49172 RTP/AVP 0 18
a=rtpmap:0 PCMU/8000
a=rtpmap:18 G729/8000
I think answerer can add additional codec G729 here per sec 6.1 of
rfc3264
<snip>
The stream MAY indicate additional media formats, not listed in the
corresponding stream in the offer, that the answerer is willing to
send or receive
</snip>
However, here comes the inconsistency.
When answerer send media, it cannot send G723 packets to offerer per sec
6.1 of RFC3264
<snip>
The answerer MUST send using a media format in the offer
that is also listed in the answer,
</snip>
Whereas RFC3264 does not forbid offerer to send G729 packets to answerer
per sec 7
<snip>
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.
</snip>
NOTE: there's some explanation that tells us why this is only a SHOULD,
not must,
which clearly indicates offerer can send G729 to answerer on
the fly
Any thoughts on this issue?
Thanks
Regards,
-Rockson
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