On 16 December 2010 15:05,  <[email protected]> wrote:
> Hi All!
>
> There is 2 endpoint.
> Endpoint1 fmtp - 34 CIF=1 QCIF=1
> Endpoint2 fmtp - 34 QCIF=1 CIF=1
>
> How to define priority format properly?
>
> 1. Endpoint1 is caller, then priority format is QCIF=1
> 2. Endpoint2 is caller, then priority format is CIF=1
>
> right?

I'm not sure why your subjects says "re-INVITE", as the interpretation
of preferred order of these H.261/H.263 fmtp parameters applies to any
offer/answer - the initial or subsequent ones.

Anyway, what is important here is that the resolutions are listed in
the receiver's order of preference regardless of who initiates the
call.

In your example EP1 prefers receiving CIF and EP2 prefers receiving QCIF.
So, EP1 should send QCIF towards EP2, while EP2 should send CIF towards EP1.

Cf. detailed description in
http://tools.ietf.org/html/rfc4629#section-8.2.1 for what is called
"Picture sizes and MPI" parameters.

-- Tom

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