1. What is the problem we are solving? How a conference aware participant manipulates media streams at the mixer The client is a UA (in sip) The server is the focus (which directly controls the mixer) Ultimately, we have to render a UI that controls the media flow

2. What’s wrong with draft-mahy- xcon-media-policy-control? It’s way too complicated It doesn’t address the problem, except indirectly It will be very hard to create interoperable implementations

3. Not addressing the problem It’s a language to describe media flow graphs Real devices have fixed flows, with specific controls Real interfaces twist knobs, push buttons and make selections on specific controls

4. Not facilitating interoperable implementations Either the client must impose it’s concept of flow graphs on the server, or the server must impose it’s concept of flow graphs on the client But the client doesn’t know, and the proposal doesn’t say, how it discovers the capabilities of the server And the server doesn’t know, and the proposal doesn’t say, how it discovers the UI capabilities of the client And the language allows arbitrary manipulation of arbitrary flows, so this is a very hard problem Infinite number of graphs create the same mixed media

5. What to do Essentially, drop the lower levels (streams. Groups, operators,…) Leaves you with “collections” AKA Templates

6. What is a template? A predefined function block with a predefined set of parameters, a predefined set of controls, and a set of roles Parameters let you keep the number of templates small Controls lets you build UIs that reasonably match the other side’s view of the world Roles define what controls in the template that a given user sees

7. Example of a template – simple mix-minus audio mixer Inputs - n input audio streams Outputs - m output audio streams Parameters: –n/m Controls –MixVolume(n,m) –Mute(n,m), t/f, * permitted –MasterVolume(m)

8. What do you do with a template Server declares availability of a (set of) templates, with parameter values Client specifies which role it is taking and values for the controls available to that role Templates could have events Templates could interact (video follows audio)

9. Non-problems How the focus manipulates the mixer How one describes what a mixer is capable of doing

10. Other Problems Who does media policy eg. who is allowed to mute. Is that CPCP or MPCP? No crisp boundary between CP and MP