Hi Attila,
> Despite your answer, I'm still not convinced
> that you are right (and I'm not convinced that
> my proposed theory is right).
>
> We agree that the answerer must transmit RTP with
> a payload field set as specified in the offerer's SDP:
>
> "In the case of RTP, it [the answerer] MUST use
> the payload type numbers from the offer, even
> if they differ from those in the answer."
Oops... my apologies, I got a bit confused in the last
mail that you sent... we indeed concur on that :">
> However, I cannot see any explicit statement
> regarding the payload field in the offerer's
> RTP packets.
And apologies again since I wrongly extrapolated that
text from the draft for the offerer too. Your theory
seems to be correct regarding the offerer.
A more detailed study and I found the following text
in Page 6 (section 5.1) of the offer/answer-02 draft:
"For sendrecv RTP streams, the payload type numbers
indicate the value of the payload type field the
offerer expects to receive, and would prefer to send.
^^^^^^
However, for sendonly and sendrecv streams, the answer
might indicate different payload type numbers for the
same codecs, in which case, the offerer MUST send with
the payload type numbers from the answer."
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
So, .... that would be the right thing to do. Each person
MUST use the payload numbers that the other party wants to
see in the RTP payload.
I (as the offerer) want to see 119 in whatever RTP I receive
so I give that in the SDP and you MUST use 119 in the RTP packet.
You, on the other hand, want to see 97 in your RTP payload,
so you send 97 in the answer SDP and I MUST use 97 for the
RTP payload.
Everyone would be happy then and get to see what they want
to see ;) I think I got it right this time (finally :)
Cheers,
Siddharth.
-----------------
Siddharth Toshniwal @ Hughes Software Systems
http://www.hssworld.com
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