[MMUSIC] POF/PAN: Need for more m- lines in the PAN than in the associated POF

[Christer Holmberg <[e-mail]>]

Hi,

The following issue is related to the case where a media description in a POF implicitly affect other media descriptions (not present in the POF), but this e-mail looks at a similar case from a PAN perspective.

Section 5.3 says:

        If the preceding steps have been performed for each media section
        without resulting in a rejection, then the agent forms a partial
        answer consisting of a single o= line, and all of the media sections
        that were generated as part of the preceding steps. Note that this
        processing will always yield the same number of media sections in a
        partial answer as were present in the partial offer.


The text says that the PAN will contain the same number of media sections as the associated POF. But, what if the POF also caused other media sections to change? Those media sections cannot be added to the PAN.

(If the offerer "knows" which media sections will be modified by the answerer in the PAN, it can of course included those in the POF - even if they are not modified in the POF)

The answerer can of course send the PAN, followed by an Offer/POF which modifies the other affected media sections that didn't "fit" into the PAN. But, that may not always be very feasible, especially if some properties in those media sections are removed or changed.

So, I think we would need some text saying that a POF might have to be rejected, if it will affect media sections that cannot be put into associated PAN.

Again, whether situations like this will occur in real-life of course depends on what people will use POFs/PANs for, so some input (re-pinging Justin) would be useful.

Regards,

Christer