Media Control Policy

1
Media Control Policy

• Chris Boulton, Umesh Chandra, Roni Even, Cullen
  Jennings, Alan Johnston, Brian Rosen, Mark Trayer

2
We started with two approaches

• Rohans Flow Graphs approach
• Cullen and Brians Template approach
• We decided to do both
• All conference servers will support templates,
  which are predefined
• Some may support flow graphs, as a way of
  essentially dynamically creating a template

3
Team fleshed out the template idea

• New draft includes the template language and
  worked out concepts for roles, streams, controls,
  etc.
• Includes a starter set of template definitions
• This will be excerpted into a separate draft in
  the next revision

4
Templates

• A template is a description of the
• Roles one can assume
• Streams one can source or sink
• Controls one has over the streams
• Parameters specializing a template for use
• The template describes how one builds a user
  interface to control a conference using that
  template
• Media Policy Control Protocol primarily is
  concerned with manipulating the controls defined
  by the template
• A conference is defined with the template to be
  used, which must be supported by the conference
  server, and the values of the parameters of that
  template
• Clients can be built to implement a set of
  templates which would have good user interfaces
• The template language is defined such that a
  client could render a reasonable UI for a
  template it did not directly implement.
• Open Issue Can templates be derived from another
  template.

5
Use of templates

• Conference server offers a list of templates it
  supports
• Convener selects one template and specifies
  parameter values
• Participants learn the template in use which
  determines the UI they offer
• Participants and conference server exchange XML
  subsets of the template to manipulate controls
• Open Issue Transport (assume XCAP)

6
Templates

• Defined in an XML form in a public document
• Have an IANA registered name the template is
  known by
• Have Parameters, which are variables used to
  define some flexibility in the templates
• Parameter values are fixed before the conference
  is instantiated
• Fundamentally used to limit the number of
  templates required to describe a range of similar
  conference capabilities
• Define Roles, Streams, Controls, and Lists

7
Roles

• Template defines the allowed roles
• CPCP used to define permissions, actually assume
  roles, announce role changes, etc.
• Roles can define streams (source or sink) and
  controls that are only available to participants
  currently in the role
• Implies that the streams and controls you have
  can change dynamically as your role changes
• Roles can be defined hierarchically (nested)
• Roles defined within a role inherit all the
  streams and controls that are defined in the
  enclosing role
• Note Current examples dont show this

8
Streams

• Define the streams a participant sources or sinks
  to the mixer
• Defined with a name, a type (audio, video, text)
  and a direction (in, out)
• Conference package maps SDP (or whatever) to
  stream names

9
Controls

• UI manipulations of the mixer
• Defined with name, label, type (integer, real,
  Boolean, enumeration,), value, enable, etc.
• Rendered by the client UI with widgets of some
  kind, or automatically calculated.
• Template can include a default (initial) value
• Clients can change the value while the conference
  is in progress
• Clients get notified if the value of a control
  they have changes
• Server can change the value if necessary

10
Floor Control

• Template defines which floors it has support for,
  which might be controlled by parameters
• Templates describe (in English) how the mix
  changes as a result of floor holder changes
• Streams and controls may be restricted to only
  being available to holders of a particular floor
• Open Issues Have not synced up with floor
  control team

11
Open Issues

• The flow graph work is not yet defined
• Will be a separate draft
• The complete set of templates has not yet been
  designed, but this work is started.
• How the CPCP mechanisms work with templates (e.g.
  how do controls work)

12
Proposal

• Let the design team do one more round

13
Basic Audio Template
lttemplate name"basic-audio"gt ltrole
name"Participant"gt ltparameter
type"integer" name"max-streams" min"1"
max"128"/gt ltstream type"audio"
name"AudioIn" dir"in"gt ltcontrol
name"mute" default"false" enable"true"/gt
lt/streamgt ltstream type"audio"
name"AudioOut" dir"out"gt ltcontrol
name"mix-type" type"enumeration",
enable"false" default"1"gt ltitem
label"MixMinus" value"1"gt ltitem
label"Active-Speaker" value"2"gt
lt/controlgt ltcontrol name"mute"
type"boolean" enable"false" default"false/gt
ltcontrolArray name"sourceSelector"
label"source" type"enumeration" enable"false"
default"false"gt ltitem
label"participant 1" value"1"/gt ltitem
label"participant 2" value"2"/gt ltitem
label"participant 3" value"3"/gt
.... .... ltitem label"participant n"
value"n"/gt lt/controlArraygt lt/streamgt
lt/rolegt
14
Changing the value of a control
ltconference template BasicAudiogt ltrole
nameParticipantgt ltstream nameAudioIngt
ltcontrol namemute valuetrue/gt lt/streamgt
lt/rolegtlt/conferencegt