Subject: [AVT] Question regarding draft-ietf-avt-rfc2429-bis-09.txt Offer/Answer Mechanism

From: "Osher Hmelnizky" <[email-masked]>
Date: Sun, 4 Jun 2006 16:04:24 +0300

Hi,

According to the draft : " A system that declares support of a specific
MPI for one of the resolutions SHALL also implicitly support a lower
resolution with the same MPI."

If the Answering side supports lower resolution is the following example
is allowed?

For example, if we send an SDP offer:

m=video 6002 RTP/AVP 96

a=rtpmap:96 H263-1998/90000

a=fmtp:96 CIF=2

a=sendrecv

It means that we want to receive CIF with MPI = 2.

If we receive the following answer:

m=video 6002 RTP/AVP 96

a=rtpmap:96 H263-1998/90000

a=fmtp:96 QCIF=2

a=sendrecv

According to H.263 draft: If we receive an offer with a specific MPI for
one of the resolutions, it means that the remote UA also supports a
lower resolution with the same MPI.

Can we negotiate although the parties support different resolutions?

Are these scenarios valid?

What about CUSTOM? How should we negotiate if the parties don't support
the same resolution?

Kind regards

Osher

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