An XML Schema for the CLUE data model
draft-ietf-clue-data-model-schema-02

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CLUE Working Group                                             R. Presta
Internet-Draft                                               S P. Romano
Intended status: Informational                      University of Napoli
Expires: July 30, 2014                                  January 26, 2014

                 An XML Schema for the CLUE data model
                  draft-ietf-clue-data-model-schema-02

Abstract

   This document provides an XML schema file for the definition of CLUE
   data model types.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on July 30, 2014.

Copyright Notice

   Copyright (c) 2014 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

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   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
   2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  4
   3.  XML Schema . . . . . . . . . . . . . . . . . . . . . . . . . .  6
   4.  <mediaCaptures>  . . . . . . . . . . . . . . . . . . . . . . . 16
   5.  <encodings>  . . . . . . . . . . . . . . . . . . . . . . . . . 17
   6.  <encodingGroups> . . . . . . . . . . . . . . . . . . . . . . . 17
   7.  <captureScenes>  . . . . . . . . . . . . . . . . . . . . . . . 17
   8.  <simultaneousSets> . . . . . . . . . . . . . . . . . . . . . . 17
   9.  <captureEncodings> . . . . . . . . . . . . . . . . . . . . . . 17
   10. <mediaCapture> . . . . . . . . . . . . . . . . . . . . . . . . 17
     10.1.  <capturedMedia> . . . . . . . . . . . . . . . . . . . . . 18
     10.2.  <captureSceneIDREF> . . . . . . . . . . . . . . . . . . . 19
     10.3.  <encGroupIDREF> . . . . . . . . . . . . . . . . . . . . . 19
     10.4.  <spatialInformation>  . . . . . . . . . . . . . . . . . . 19
       10.4.1.  <capturePoint>  . . . . . . . . . . . . . . . . . . . 20
       10.4.2.  <captureArea> . . . . . . . . . . . . . . . . . . . . 21
     10.5.  <nonSpatiallyDefinable> . . . . . . . . . . . . . . . . . 22
     10.6.  <contentCaptureIDs> . . . . . . . . . . . . . . . . . . . 22
     10.7.  <composed>  . . . . . . . . . . . . . . . . . . . . . . . 22
     10.8.  <switching> . . . . . . . . . . . . . . . . . . . . . . . 22
     10.9.  <policy>  . . . . . . . . . . . . . . . . . . . . . . . . 22
     10.10. <maxCaptures> . . . . . . . . . . . . . . . . . . . . . . 22
     10.11. <single>  . . . . . . . . . . . . . . . . . . . . . . . . 23
     10.12. <description> . . . . . . . . . . . . . . . . . . . . . . 23
     10.13. <priority>  . . . . . . . . . . . . . . . . . . . . . . . 23
     10.14. <lang>  . . . . . . . . . . . . . . . . . . . . . . . . . 24
     10.15. <mobility>  . . . . . . . . . . . . . . . . . . . . . . . 24
     10.16. <maxCaptureEncodings> . . . . . . . . . . . . . . . . . . 24
     10.17. <relatedTo> . . . . . . . . . . . . . . . . . . . . . . . 24
     10.18. captureID attribute . . . . . . . . . . . . . . . . . . . 24
   11. Audio captures . . . . . . . . . . . . . . . . . . . . . . . . 24
     11.1.  <audioChannelFormat>  . . . . . . . . . . . . . . . . . . 25
   12. Video captures . . . . . . . . . . . . . . . . . . . . . . . . 25
     12.1.  <embeddedText>  . . . . . . . . . . . . . . . . . . . . . 26
   13. Text captures  . . . . . . . . . . . . . . . . . . . . . . . . 27
   14. <captureScene> . . . . . . . . . . . . . . . . . . . . . . . . 27
     14.1.  <sceneEntries>  . . . . . . . . . . . . . . . . . . . . . 28
     14.2.  sceneID attribute . . . . . . . . . . . . . . . . . . . . 28
     14.3.  scale attribute . . . . . . . . . . . . . . . . . . . . . 28
   15. <sceneEntry> . . . . . . . . . . . . . . . . . . . . . . . . . 29
     15.1.  <mediaCaptureIDs> . . . . . . . . . . . . . . . . . . . . 29
     15.2.  sceneEntryID attribute  . . . . . . . . . . . . . . . . . 30
     15.3.  mediaType attribute . . . . . . . . . . . . . . . . . . . 30
   16. <encoding> . . . . . . . . . . . . . . . . . . . . . . . . . . 30
     16.1.  <encodingName>  . . . . . . . . . . . . . . . . . . . . . 31
     16.2.  <maxBandwidth>  . . . . . . . . . . . . . . . . . . . . . 31
     16.3.  encodingID attribute  . . . . . . . . . . . . . . . . . . 31
   17. Audio encodings  . . . . . . . . . . . . . . . . . . . . . . . 31

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   18. Video encodings  . . . . . . . . . . . . . . . . . . . . . . . 32
     18.1.  <maxWidth>  . . . . . . . . . . . . . . . . . . . . . . . 32
     18.2.  <maxHeight> . . . . . . . . . . . . . . . . . . . . . . . 32
     18.3.  <maxFrameRate>  . . . . . . . . . . . . . . . . . . . . . 32
   19. <encodingGroup>  . . . . . . . . . . . . . . . . . . . . . . . 33
     19.1.  <maxGroupBandwidth> . . . . . . . . . . . . . . . . . . . 33
     19.2.  <encodingIDList>  . . . . . . . . . . . . . . . . . . . . 33
     19.3.  encodingGroupID attribute . . . . . . . . . . . . . . . . 34
   20. <simultaneousSet>  . . . . . . . . . . . . . . . . . . . . . . 34
     20.1.  <captureIDREF>  . . . . . . . . . . . . . . . . . . . . . 34
     20.2.  <sceneEntryIDREF> . . . . . . . . . . . . . . . . . . . . 34
   21. <captureEncoding>  . . . . . . . . . . . . . . . . . . . . . . 34
     21.1.  <mediaCaptureID>  . . . . . . . . . . . . . . . . . . . . 35
     21.2.  <encodingID>  . . . . . . . . . . . . . . . . . . . . . . 35
   22. <clueInfo> . . . . . . . . . . . . . . . . . . . . . . . . . . 35
   23. Sample XML file  . . . . . . . . . . . . . . . . . . . . . . . 36
   24. Diff with  draft-ietf-clue-data-model-schema-00 version  . . . 45
   25. Diff with  draft-ietf-clue-data-model-schema-01 version  . . . 45
   26. Informative References . . . . . . . . . . . . . . . . . . . . 45

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1.  Introduction

   This document provides an XML schema file for the definition of CLUE
   data model types.

   The schema is based on information contained in
   [I-D.ietf-clue-framework].  It encodes information and constraints
   defined in the aforementioned document in order to provide a formal
   representation of the concepts therein presented.  The schema
   definition is intended to be modified according to changes applied to
   the above mentioned CLUE document.

   The document actually represents a strawman proposal aiming at the
   definition of a coherent structure for all the information associated
   with the description of a telepresence scenario.

2.  Terminology

   This document refers to the same terminology used in
   [I-D.ietf-clue-framework].  We briefly recall herein some of the main
   terms exploited in the document.

   Audio Capture:  Media Capture for audio.  Denoted as ACn in the
      example cases in this document.

   Audio Composite:  An audio Stream obtained by mixing multiple audio
      Streams. [?]

   Camera-Left and Right:  For Media Captures, camera-left and
      cameraright are from the point of view of a person observing the
      rendered media.  They are the opposite of Stage-Left and Stage-
      Right.

   Capture:  Same as Media Capture.

   Capture Device:  A device that converts audio and video input into an
      electrical signal, in most cases to be fed into a media encoder.

   Capture Encoding:  A specific encoding of a Media Capture, to be sent
      by a Media Provider to a Media Consumer via RTP.

   Capture Scene:  An abstraction grouping semantically-coupled Media
      Captures available at the Media Provider's side, representing a
      precise portion of the local scene that can be transmitted
      remotely.  Capture Scene MAY correspond to a part of the
      telepresence room or MAY focus only on the presentation media.  A
      Capture Scene is characterized by a set of attributes and by a set
      of Capture Scene Entries.

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   Capture Scene Entry:  A list of Media Captures of the same media type
      that constitute a possible representation of a Capture Scene.
      Media Capture belonging to the same Capture Scene Entry can be
      sent simultaneously by the Media Provider.

   CLUE Participant:  An entity able to use the CLUE protocol within a
      telepresence session.  It can be an Endpoint or a MCU able to use
      the CLUE protocol.

   Consumer:  Same as Media Consumer.

   Encoding or Individual Encoding:  The representation of an encoding
      technology.  In the CLUE datamodel, for each encoding it is
      provided a set of parameters representing the encoding
      constraints, like for example the maximum bandwidth of the Media
      Provider the encoding can consume. s

   Encoding Group:  The representation of a group of encodings.  For
      each group, it is provided a set of parameters representing the
      constraints to be applied to the group as a whole.  An example is
      the maximum bandwidth that can be consumed when using the
      contained encodings together simultaneously.

   Endpoint  The logical point of final termination through receiving,
      decoding and rendering, and/or initiation through capturing,
      encoding, and sending of media streams.  An endpoint consists of
      one or more physical devices which source and sink media streams,
      and exactly one SIP Conferencing Framework Participant (which, in
      turn, includes exactly one SIP User Agent).  Endpoints can be
      anything from multiscreen/multicamera room controllers to handheld
      devices.

   MCU:  Multipoint Control Unit (MCU) - a device that connects two or
      more endpoints together into one single multimedia conference.  An
      MCU may include a Mixer.

   Media:  Any data that, after suitable encoding, can be conveyed over
      RTP, including audio, video or timed text.

   Media Capture:  A "Media Capture", or simply "Capture", is a source
      of Media of a single type (i.e., audio or video or text).

   Media Stream:  The term "Media Stream", or simply "Stream", is used
      as a synonymous of Capture Encoding.

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   Media Provider:  A CLUE participant (i.e., an Endpoint or a MCU) able
      to send Media Streams.

   Media Consumer:  A CLUE participant (i.e., an Endpoint or a MCU) able
      to receive Media Streams.

   Scene:  Same as Capture Scene.

   Scene Entry:  Same as Capture Scene Entry.

   Stream:  Same of Media Stream.

   Multiple Content Capture:  A Capture that can contain different Media
      Captures of the same media type.  It is denoted as MCC in this
      document.  In the Stream resulting from the MCC, the Stream coming
      from the encoding of the composing Media Captures can appear
      simultaneously, if the MCC is the result of a mixing operation, or
      can appear alternatively over the time, according to a certain
      switching policy.

   Plane of Interest:  The spatial plane containing the most relevant
      subject matter.

   Provider:  Same as Media Provider.

   Render:

   Simultaneous Transmission Set:  a set of Media Captures that can be
      transmitted simultaneously from a Media Provider.

   Single Media Capture:  A Capture representing the Media coming from a
      single-source Capture Device.

   Spatial Information:  Data about the spatial position of a Capture
      Device that generate a Single Media Capture within the context of
      a Capture Scene representing a phisical portion of a Telepresence
      Room.

   Stream Characteristics:  The union of the features used to describe a
      Stream in the CLUE environment and in the SIP-SDP environment

   Video Capture:  A Media Capture for video.

3.  XML Schema

   This section contains the proposed CLUE data model schema definition.

   The element and attribute definitions are formal representation of

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   the concepts needed to describe the capabilities of a media provider
   and the current streams it is transmitting within a telepresence
   session.

   The main groups of information are:

      <mediaCaptures>: the list of media captures available (Section 4)

      <encodings>: the list of individual encodings (Section 5)

      <encodingGroups>: the list of encodings groups (Section 6)

      <captureScenes>: the list of capture scenes (Section 7)

      <simultaneousSets>: the list of simultaneous transmission
      sets(Section 8)

      <captureEncodings>: the list of instantiated capture encodings
      (Section 9)

   All of the above refers to concepts that have been introduced in
   [I-D.ietf-clue-framework] and [I-D.romanow-clue-data-model] and
   further detailed in threads on the mailing list as well as in the
   following of this document.

<?xml version="1.0" encoding="UTF-8" ?>
<xs:schema
   targetNamespace="urn:ietf:params:xml:ns:clue-info"
   xmlns:tns="urn:ietf:params:xml:ns:clue-info"
   xmlns:xs="http://www.w3.org/2001/XMLSchema"
   xmlns="urn:ietf:params:xml:ns:clue-info"
   elementFormDefault="qualified"
   attributeFormDefault="unqualified">

<!-- ELEMENT DEFINITIONS -->
<xs:element name="mediaCaptures" type="mediaCapturesType"/>
<xs:element name="encodings" type="encodingsType"/>
<xs:element name="encodingGroups" type="encodingGroupsType"/>
<xs:element name="captureScenes" type="captureScenesType"/>
<xs:element name="simultaneousSets" type="simultaneousSetsType"/>
<xs:element name="captureEncodings" type="captureEncodingsType"/>

<!-- MEDIA CAPTURES TYPE -->
<!-- envelope of media captures -->
<xs:complexType name="mediaCapturesType">
 <xs:sequence>

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   <xs:element name="mediaCapture" type="mediaCaptureType"
   maxOccurs="unbounded"/>
 </xs:sequence>
</xs:complexType>

<!-- DESCRIPTION element -->
<xs:element name="description">
 <xs:complexType>
  <xs:simpleContent>
   <xs:extension base="xs:string">
     <xs:attribute name="lang" type="xs:language"/>
   </xs:extension>
  </xs:simpleContent>
 </xs:complexType>
</xs:element>

<!-- MEDIA CAPTURE TYPE -->
<xs:complexType name="mediaCaptureType" abstract="true">
  <xs:sequence>
    <!-- mandatory fields -->
    <xs:element name="capturedMedia" type="xs:string"/>
    <xs:element name="captureSceneIDREF" type="xs:IDREF"/>
    <xs:element name="encGroupIDREF" type="xs:IDREF"/>
    <xs:choice>
      <xs:sequence>
        <xs:element name="spatialInformation"
                    type="tns:spatialInformationType"/>
      </xs:sequence>
      <xs:element name="nonSpatiallyDefinable" type="xs:boolean" fixed="true"/>
    </xs:choice>
    <!-- for handling multi-content captures: -->
    <xs:choice>
      <xs:sequence>
        <xs:element name="contentCaptureIDs" type="captureIDListType"/>
        <xs:element name="composed" type="xs:boolean" minOccurs="0"/>
        <xs:element name="switching" type="xs:boolean" minOccurs="0"/>
        <xs:element name="policy" type="xs:string" minOccurs="0"/>
        <xs:element name="maxCaptures" type="xs:unsignedInt" minOccurs="0"/>
      </xs:sequence>
      <xs:element name="single" type="xs:boolean" fixed="true"/>
    </xs:choice>
    <!-- optional fields -->
    <xs:element ref="description" minOccurs="0" maxOccurs="unbounded"/>
    <xs:element name="priority" type="xs:unsignedInt" minOccurs="0"/>
    <xs:element name="lang" type="xs:language" minOccurs="0"/>
    <xs:element name="mobility" type="mobilityType" minOccurs="0"/>
    <xs:element name="presentation" type="presentationType" minOccurs="0"/>

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    <xs:element name="view" type="viewType" minOccurs="0"/>
    <xs:element name="maxCaptureEncodings" type="xs:unsignedInt"
    minOccurs="0"/>
    <xs:element name="relatedTo" type="xs:IDREF" minOccurs="0"/>
    <xs:any namespace="##other" processContents="lax" minOccurs="0"
    maxOccurs="unbounded"/>
  </xs:sequence>
  <xs:attribute name="captureID" type="xs:ID" use="required"/>
  <xs:anyAttribute namespace="##other" processContents="lax"/>
</xs:complexType>

<!-- VIEW TYPE -->
<xs:simpleType name="viewType">
 <xs:restriction base="xs:string">
  <xs:enumeration value="room"/>
  <xs:enumeration value="table"/>
  <xs:enumeration value="lectern"/>
  <xs:enumeration value="individual"/>
  <xs:enumeration value="audience"/>
 </xs:restriction>
</xs:simpleType>

<!-- PRESENTATION TYPE -->
<xs:simpleType name="presentationType">
 <xs:restriction base="xs:string">
  <xs:enumeration value="slides"/>
  <xs:enumeration value="image"/>
  <xs:enumeration value=""/>
 </xs:restriction>
</xs:simpleType>

<!-- SPATIAL INFORMATION TYPE -->
<xs:complexType name="spatialInformationType">
 <xs:sequence>
  <xs:element name="capturePoint" type="capturePointType"/>
  <xs:element name="captureArea" type="captureAreaType"
  minOccurs="0"/>
  <xs:any namespace="##other" processContents="lax" minOccurs="0"
  maxOccurs="unbounded"/>
 </xs:sequence>
 <xs:anyAttribute namespace="##other" processContents="lax"/>
</xs:complexType>

<!-- MOBILITY TYPE -->
<xs:simpleType name="mobilityType">
 <xs:restriction base="xs:string">
  <xs:enumeration value="static"/>
  <xs:enumeration value="dynamic"/>

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  <xs:enumeration value="highly-dynamic"/>
 </xs:restriction>
</xs:simpleType>

<!-- TEXT CAPTURE TYPE -->
<xs:complexType name="textCaptureType">
 <xs:complexContent>
  <xs:extension base="tns:mediaCaptureType">
  </xs:extension>
 </xs:complexContent>
</xs:complexType>

<!-- AUDIO CAPTURE TYPE -->
<xs:complexType name="audioCaptureType">
 <xs:complexContent>
  <xs:extension base="tns:mediaCaptureType">
   <xs:sequence>
    <xs:element name="audioChannelFormat" type="audioChannelFormatType"
    minOccurs="0"/>
   </xs:sequence>
  </xs:extension>
 </xs:complexContent>
</xs:complexType>

<!-- AUDIO CHANNEL FORMAT TYPE -->
<xs:simpleType name="audioChannelFormatType">
 <xs:restriction base="xs:string">
  <xs:enumeration value="mono"/>
  <xs:enumeration value="stereo"/>
 </xs:restriction>
</xs:simpleType>

<!-- VIDEO CAPTURE TYPE -->
<xs:complexType name="videoCaptureType">
 <xs:complexContent>
  <xs:extension base="tns:mediaCaptureType">
   <xs:sequence>
    <xs:element ref="embeddedText" minOccurs="0"/>
   </xs:sequence>
  </xs:extension>
 </xs:complexContent>
</xs:complexType>

<!-- EMBEDDED TEXT ELEMENT -->
<xs:element name="embeddedText">
 <xs:complexType>

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  <xs:simpleContent>
   <xs:extension base="xs:boolean">
    <xs:attribute name="lang" type="xs:language"/>
   </xs:extension>
  </xs:simpleContent>
 </xs:complexType>
</xs:element>

<!-- CAPTURE SCENES TYPE -->
<!-- envelope of capture scenes -->
<xs:complexType name="captureScenesType">
 <xs:sequence>
  <xs:element name="captureScene" type="captureSceneType"
  maxOccurs="unbounded"/>
 </xs:sequence>
</xs:complexType>

<!-- CAPTURE SCENE TYPE -->
<xs:complexType name="captureSceneType">
 <xs:sequence>
  <xs:element ref="description" minOccurs="0" maxOccurs="unbounded"/>
  <!-- <sceneSpace> has been removed from the XML Schema definition -->
  <!--
  <xs:element name="sceneSpace" type="captureSpaceType" minOccurs="0"/>
   -->
  <xs:element name="sceneEntries" type="sceneEntriesType"/>
  <xs:any namespace="##other" processContents="lax" minOccurs="0"
  maxOccurs="unbounded"/>
 </xs:sequence>
 <xs:attribute name="sceneID" type="xs:ID" use="required"/>
 <xs:attribute name="scale" type="scaleType" use="required"/>
 <xs:anyAttribute namespace="##other" processContents="lax"/>
</xs:complexType>

<!-- SCALE TYPE -->
<xs:simpleType name="scaleType">
 <xs:restriction base="xs:string">
  <xs:enumeration value="millimeters"/>
  <xs:enumeration value="unknown"/>
  <xs:enumeration value="noscale"/>
 </xs:restriction>
</xs:simpleType>

<!-- CAPTURE AREA TYPE -->
<xs:complexType name="captureAreaType">
 <xs:sequence>
  <xs:element name="bottomLeft" type="pointType"/>
  <xs:element name="bottomRight" type="pointType"/>

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  <xs:element name="topLeft" type="pointType"/>
  <xs:element name="topRight" type="pointType"/>
 </xs:sequence>
</xs:complexType>

<!-- CAPTURE SPACE TYPE -->
<xs:complexType name="captureSpaceType">
 <xs:sequence>
  <xs:element name="bottomLeftFront" type="pointType"/>
  <xs:element name="bottomRightFront" type="pointType"/>
  <xs:element name="topLeftFront" type="pointType"/>
  <xs:element name="topRightFront" type="pointType"/>
  <xs:element name="bottomLeftBack" type="pointType"/>
  <xs:element name="bottomRightBack" type="pointType"/>
  <xs:element name="topLeftBack" type="pointType"/>
  <xs:element name="topRightBack" type="pointType"/>
 </xs:sequence>
</xs:complexType>

<!-- POINT TYPE -->
<xs:complexType name="pointType">
 <xs:sequence>
  <xs:element name="x" type="xs:decimal"/>
  <xs:element name="y" type="xs:decimal"/>
  <xs:element name="z" type="xs:decimal"/>
 </xs:sequence>
</xs:complexType>

<!-- CAPTURE POINT TYPE -->
<xs:complexType name="capturePointType">
 <xs:complexContent>
  <xs:extension base="pointType">
   <xs:sequence>
    <xs:element name="lineOfCapturePoint" type="tns:pointType"
    minOccurs="0"/>
   </xs:sequence>
   <xs:attribute name="pointID" type="xs:ID"/>
  </xs:extension>
 </xs:complexContent>
</xs:complexType>

<!-- SCENE ENTRIES TYPE -->
<!-- envelope of scene entries of a capture scene -->
<xs:complexType name="sceneEntriesType">
 <xs:sequence>
  <xs:element name="sceneEntry" type="sceneEntryType"
  maxOccurs="unbounded"/>

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 </xs:sequence>
</xs:complexType>

<!-- SCENE ENTRY TYPE -->
<xs:complexType name="sceneEntryType">
 <xs:sequence>
  <xs:element ref="description" minOccurs="0" maxOccurs="unbounded"/>
  <xs:element name="mediaCaptureIDs" type="captureIDListType"/>
 </xs:sequence>
 <xs:attribute name="mediaType" type="xs:string" use="required"/>
</xs:complexType>

<!-- CAPTURE ID LIST TYPE -->
<xs:complexType name="captureIDListType">
 <xs:sequence>
  <xs:element name="captureIDREF" type="xs:IDREF"
  maxOccurs="unbounded"/>
 </xs:sequence>
</xs:complexType>

<!-- ENCODINGS TYPE -->
<xs:complexType name="encodingsType">
 <xs:sequence>
  <xs:element name="encoding" type="encodingType"
  maxOccurs="unbounded"/>
 </xs:sequence>
</xs:complexType>

<!-- ENCODING TYPE -->
<xs:complexType name="encodingType" abstract="true">
 <xs:sequence>
  <xs:element name="encodingName" type="xs:string"/>
  <xs:element name="maxBandwidth" type="xs:unsignedInt"/>
  <xs:any namespace="##other" processContents="lax" minOccurs="0"
  maxOccurs="unbounded"/>
 </xs:sequence>
 <xs:attribute name="encodingID" type="xs:ID" use="required"/>
 <xs:anyAttribute namespace="##any" processContents="lax"/>
</xs:complexType>

<!-- AUDIO ENCODING TYPE -->
<xs:complexType name="audioEncodingType">
 <xs:complexContent>
  <xs:extension base="tns:encodingType">
   <xs:sequence>
    <xs:element name="encodedMedia" type="xs:string" fixed="audio"
    minOccurs="0"/>

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   </xs:sequence>
  </xs:extension>
 </xs:complexContent>
</xs:complexType>

<!-- VIDEO ENCODING TYPE -->
<xs:complexType name="videoEncodingType">
 <xs:complexContent>
  <xs:extension base="tns:encodingType">
   <xs:sequence>
    <xs:element name="encodedMedia" type="xs:string" fixed="video"
    minOccurs="0"/>
    <xs:element name="maxWidth" type="xs:unsignedInt" minOccurs="0"/>
    <xs:element name="maxHeight" type="xs:unsignedInt" minOccurs="0"/>
    <xs:element name="maxFrameRate" type="xs:unsignedInt" minOccurs="0"/>
   </xs:sequence>
  </xs:extension>
 </xs:complexContent>
</xs:complexType>

<!-- ENCODING GROUPS TYPE -->
<xs:complexType name="encodingGroupsType">
 <xs:sequence>
  <xs:element name="encodingGroup" type="tns:encodingGroupType"
  maxOccurs="unbounded"/>
 </xs:sequence>
</xs:complexType>

<!-- ENCODING GROUP TYPE -->
<xs:complexType name="encodingGroupType">
 <xs:sequence>
  <xs:element name="maxGroupBandwidth" type="xs:unsignedInt"/>
  <xs:element name="encodingIDList" type="encodingIDListType"/>
  <xs:any namespace="##other" processContents="lax" minOccurs="0"
  maxOccurs="unbounded"/>
 </xs:sequence>
 <xs:attribute name="encodingGroupID" type="xs:ID" use="required"/>
 <xs:anyAttribute namespace="##any" processContents="lax"/>
</xs:complexType>

<!-- ENCODING ID LIST TYPE -->
<xs:complexType name="encodingIDListType">
 <xs:sequence>
  <xs:element name="encIDREF" type="xs:IDREF" maxOccurs="unbounded"/>
 </xs:sequence>
</xs:complexType>

<!-- SIMULTANEOUS SETS TYPE -->

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<xs:complexType name="simultaneousSetsType">
 <xs:sequence>
  <xs:element name="simultaneousSet" type="simultaneousSetType"
  maxOccurs="unbounded"/>
 </xs:sequence>
</xs:complexType>

<!-- SIMULTANEOUS SET TYPE -->
<xs:complexType name="simultaneousSetType">
 <xs:sequence>
   <xs:element name="captureIDREF" type="xs:IDREF"
   minOccurs="0" maxOccurs="unbounded"/>
   <xs:element name="sceneEntryIDREF" type="xs:IDREF"
   minOccurs="0" maxOccurs="unbounded"/>

 </xs:sequence>
 <xs:attribute name="setID" type="xs:ID" use="required"/>
</xs:complexType>

<!-- CAPTURE ENCODINGS TYPE -->
<xs:complexType name="captureEncodingsType">
 <xs:sequence>
  <xs:element name="captureEncoding" type="captureEncodingType"
  maxOccurs="unbounded"/>
 </xs:sequence>
</xs:complexType>

<!-- CAPTURE ENCODING TYPE -->
<xs:complexType name="captureEncodingType">
 <xs:sequence>
  <xs:element name="mediaCaptureID" type="xs:string"/>
  <xs:element name="encodingID" type="xs:string"/>
  <xs:element name="captureParameters" type="captureParametersType"
              minOccurs="0"/>
  <xs:element name="encodingParameters" type="encodingParametersType"
              minOccurs="0"/>
 </xs:sequence>
 <xs:attribute name="ID" type="xs:ID"/>
</xs:complexType>

<!-- CAPTURE PARAMETERS TYPE -->
<xs:complexType name="captureParametersType">
 <xs:sequence>
        <xs:element name="switchingOption" type="xs:string"/>
        <xs:any namespace="##other" processContents="lax" minOccurs="0"
   maxOccurs="unbounded"/>
 </xs:sequence>

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</xs:complexType>

<!-- ENCODING PARAMETERS TYPE -->
<xs:complexType name="encodingParametersType">
 <xs:sequence>
        <xs:element name="bandwidth" type="xs:unsignedInt" minOccurs="0"/>
        <xs:element name="width" type="xs:unsignedInt" minOccurs="0"/>
        <xs:element name="height" type="xs:unsignedInt" minOccurs="0"/>
        <xs:any namespace="##other" processContents="lax" minOccurs="0"
   maxOccurs="unbounded"/>
 </xs:sequence>
</xs:complexType>

<!-- CLUE INFO ELEMENT -->
<!-- the <clueInfo> envelope can be seen
     as the ancestor of an <advertisement> envelope -->
<xs:element name="clueInfo" type="clueInfoType"/>

<!-- CLUE INFO TYPE -->
<xs:complexType name="clueInfoType">
  <xs:sequence>
   <xs:element ref="mediaCaptures"/>
   <xs:element ref="encodings"/>
   <xs:element ref="encodingGroups"/>
   <xs:element ref="captureScenes"/>
   <xs:element ref="simultaneousSets" minOccurs="0"/>
   <xs:any namespace="##other" processContents="lax" minOccurs="0"
   maxOccurs="unbounded"/>
  </xs:sequence>
  <xs:attribute name="clueInfoID" type="xs:ID" use="required"/>
  <xs:anyAttribute namespace="##other" processContents="lax"/>
</xs:complexType>

</xs:schema>

   Following sections describe the XML schema in more detail.

4.  <mediaCaptures>

   <mediaCaptures> represents the list of one ore more media captures
   available on the media provider's side.  Each media capture is
   represented by a <mediaCapture> element (Section 10).

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5.  <encodings>

   <encodings> represents the list of individual encodings available on
   the media provider's side.  Each individual encoding is represented
   by an <encoding> element (Section 16).

6.  <encodingGroups>

   <encodingGroups> represents the list of the encoding groups organized
   on the media provider's side.  Each encoding group is represented by
   a <encodingGroup> element (Section 19).

7.  <captureScenes>

   <captureScenes> represents the list of the capture scenes organized
   on the media provider's side.  Each capture scene is represented by a
   <captureScene> element.  (Section 14).

8.  <simultaneousSets>

   <simultaneousSets> contains the simultaneous sets indicated by the
   media provider.  Each simultaneous set is represented by a
   <simultaneousSet> element.  (Section 20).

9.  <captureEncodings>

   <captureEncodings> is a list of capture encodings.  It can represents
   the list of the desired capture encodings indicated by the media
   consumer or the list of instantiated captures on the provider's side.
   Each capture encoding is represented by a <captureEncoding> element.
   (Section 21).

10.  <mediaCapture>

   According to the CLUE framework, a media capture is the fundamental
   representation of a media flow that is available on the provider's
   side.  Media captures are characterized with a set of features that
   are independent from the specific type of medium, and with a set of
   feature that are media-specific.  We design the media capture type as
   an abstract type, providing all the features that can be common to
   all media types.  Media-specific captures, such as video captures,
   audio captures and others, are specialization of that media capture
   type, as in a typical generalization-specialization hierarchy.

   The following is the XML Schema definition of the media capture type:

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<!-- MEDIA CAPTURE TYPE -->
<xs:complexType name="mediaCaptureType" abstract="true">
  <xs:sequence>
    <!-- mandatory fields -->
    <xs:element name="capturedMedia" type="xs:string"/>
    <xs:element name="captureSceneIDREF" type="xs:IDREF"/>
    <xs:element name="encGroupIDREF" type="xs:IDREF"/>
    <xs:choice>
      <xs:sequence>
        <xs:element name="spatialInformation"
                    type="tns:spatialInformationType"/>
      </xs:sequence>
      <xs:element name="nonSpatiallyDefinable" type="xs:boolean" fixed="true"/>
    </xs:choice>
    <!-- for handling multi-content captures: -->
    <xs:choice>
      <xs:sequence>
        <xs:element name="contentCaptureIDs" type="captureIDListType"/>
        <xs:element name="composed" type="xs:boolean" minOccurs="0"/>
        <xs:element name="switching" type="xs:boolean" minOccurs="0"/>
        <xs:element name="policy" type="xs:string" minOccurs="0"/>
        <xs:element name="maxCaptures" type="xs:unsignedInt" minOccurs="0"/>
      </xs:sequence>
      <xs:element name="single" type="xs:boolean" fixed="true"/>
    </xs:choice>
    <!-- optional fields -->
    <xs:element ref="description" minOccurs="0" maxOccurs="unbounded"/>
    <xs:element name="priority" type="xs:unsignedInt" minOccurs="0"/>
    <xs:element name="lang" type="xs:language" minOccurs="0"/>
    <xs:element name="mobility" type="mobilityType" minOccurs="0"/>
    <xs:element name="presentation" type="presentationType" minOccurs="0"/>
    <xs:element name="view" type="viewType" minOccurs="0"/>
    <xs:element name="maxCaptureEncodings" type="xs:unsignedInt"
    minOccurs="0"/>
    <xs:element name="relatedTo" type="xs:IDREF" minOccurs="0"/>
    <xs:any namespace="##other" processContents="lax" minOccurs="0"
    maxOccurs="unbounded"/>
  </xs:sequence>
  <xs:attribute name="captureID" type="xs:ID" use="required"/>
  <xs:anyAttribute namespace="##other" processContents="lax"/>
</xs:complexType>

10.1.  <capturedMedia>

   <capturedMedia> is a mandatory field specifying the media type of the
   capture ("audio", "video", "text",...).

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10.2.  <captureSceneIDREF>

   <captureSceneIDREF> is a mandatory field containing the identifier of
   the capture scene the media capture belongs to.  Indeed, each media
   capture must be associated with one and only one capture scene.  When
   a media capture is spatially definable, some spatial information is
   provided along with it in the form of point coordinates (see
   Section 10.4).  Such coordinates refers to the space of coordinates
   defined for the capture scene containing the capture.

10.3.  <encGroupIDREF>

   <encGroupIDREF> is a mandatory field containing the identifier of the
   encoding group the media capture is associated with.

10.4.  <spatialInformation>

   Media captures are divided into two categories: non spatially
   definable captures and spatially definable captures.

   Non spatially definable captures are those that do not capture parts
   of the telepresence room.  Capture of this case are for example those
   related to registrations, text captures, DVDs, registered
   presentation, or external streams, that are played in the
   telepresence room and transmitted to remote sites.

   Spatially definable captures are those that capture part of the
   telepresence room.  The captured part of the telepresence room is
   described by means of the <spatialInformation> element.

   This is the definition of the spatial information type:

   <!-- SPATIAL INFORMATION TYPE -->
   <xs:complexType name="spatialInformationType">
    <xs:sequence>
     <xs:element name="capturePoint" type="capturePointType"/>
     <xs:element name="captureArea" type="captureAreaType"
     minOccurs="0"/>
     <xs:any namespace="##other" processContents="lax"
     minOccurs="0" maxOccurs="unbounded"/>
    </xs:sequence>
    <xs:anyAttribute namespace="##other"
    processContents="lax"/>
   </xs:complexType>

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   The <capturePoint> contains the coordinates of the capture device
   that is taking the capture, as well as, optionally, the pointing
   direction (see Section 10.4.1).  It is a mandatory field when the
   media capture is spatially definable, independently from the media
   type.

   The <captureArea> is an optional field containing four points
   defining the captured area represented by the capture (see
   Section 10.4.2).

10.4.1.  <capturePoint>

   The <capturePoint> element is used to represent the position and the
   line of capture of a capture device.  The XML Schema definition of
   the <capturePoint> element type is the following:

   <!-- CAPTURE POINT TYPE -->
   <xs:complexType name="capturePointType">
    <xs:complexContent>
     <xs:extension base="pointType">
      <xs:sequence>
       <xs:element name="lineOfCapturePoint"
       type="tns:pointType"
       minOccurs="0"/>
      </xs:sequence>
      <xs:attribute name="pointID" type="xs:ID"/>
     </xs:extension>
    </xs:complexContent>
   </xs:complexType>

   <!-- POINT TYPE -->
   <xs:complexType name="pointType">
    <xs:sequence>
     <xs:element name="x" type="xs:decimal"/>
     <xs:element name="y" type="xs:decimal"/>
     <xs:element name="z" type="xs:decimal"/>
    </xs:sequence>
   </xs:complexType>

   The point type contains three spatial coordinates ("x","y","z")
   representing a point in the space associated with a certain capture
   scene.

   The capture point type extends the point type, i.e., it is
   represented by three coordinates identifying the position of the

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   capture device, but can add further information.  Such further
   information is conveyed by the <lineOfCapturePoint>, which is another
   point-type element representing the "point on line of capture", that
   gives the pointing direction of the capture device.

   If the point of capture is not specified, it means the consumer
   should not assume anything about the spatial location of the
   capturing device.

   The coordinates of the point on line of capture MUST NOT be identical
   to the capture point coordinates.  If the point on line of capture is
   not specified, no assumptions are made about the axis of the
   capturing device.

10.4.2.  <captureArea>

   <captureArea> is an optional element that can be contained within the
   spatial information associated with a media capture.  It represents
   the spatial area captured by the media capture.

   The XML representation of that area is provided through a set of four
   point-type element, <bottomLeft>, <bottomRight>, <topLeft>, and
   <topRight>, as it can be seen from the following definition:

   <!-- CAPTURE AREA TYPE -->
   <xs:complexType name="captureAreaType">
    <xs:sequence>
     <xs:element name="bottomLeft" type="pointType"/>
     <xs:element name="bottomRight" type="pointType"/>
     <xs:element name="topLeft" type="pointType"/>
     <xs:element name="topRight" type="pointType"/>
    </xs:sequence>
   </xs:complexType>

   <bottomLeft>, <bottomRight>, <topLeft>, and <topRight> should be co-
   planar.

   By comparing the capture area of different media captures within the
   same capture scene, a consumer can determine the spatial
   relationships between them and render them correctly.  If the area of
   capture is not specified, it means the Media Capture is not spatially
   related to any other media capture.

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10.5.  <nonSpatiallyDefinable>

   When media captures are non spatially definable, they are marked with
   the boolean <nonSpatiallyDefinable> element set to "true".

10.6.  <contentCaptureIDs>

   A media capture can be alternatively or a single media capture or a
   multiple content capture.  A multiple content capture is made by
   different captures that can be arranged spatially (by a mixing
   operation), or temporally (by a switching operation), or that can
   result from the orchestration of both the techniques.  If a media
   capture is a MCC, then it must show in its XML data model
   representation the <contentCaptureIDs>.  It is the identifiers list
   of the media captures that can be part of the content of the multiple
   content capture.

   [containedCaptureIDs or contentIDs or contentCaptureIDs?]

10.7.  <composed>

   <composed> is an optional boolean element that can be used only for
   multiple content captures.  It indicates wheter or not a multiple
   content capture is a mix (audio) or a composition (video) of streams.
   This attribute is useful for a media consumer for example to avoid
   nesting a composed video capture into another composed capture or
   rendering.

10.8.  <switching>

   <switching> is an optional boolean element that can be used only for
   multiple content captures.  It indicates wheter or not a multiple
   content capture switches over the time.

10.9.  <policy>

   <policy> is an optional element that can be used only for multiple
   content captures.  It indicates the criteria applied to build the
   multiple content capture using the media captures referenced in
   <contentCaptureIDs>.  Such element can assume a list of pre-defined
   values ([todo]).

10.10.  <maxCaptures>

   <maxCaptures> is an optional element that can be used only for
   multiple content captures.  It indicates the maximum number of media
   captures that can be represented in the multiple content capture at a
   time.

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10.11.  <single>

   <single> is a mandatory boolean element that must be used for single-
   content captures.  Its value is fixed and set to "true".  Such
   element indicates the capture that is being described is not a
   multiple content capture.

10.12.  <description>

   <description> is used to provide optionally human-readable textual
   information.  It is used to describe media captures, capture scenes
   and capture scene entries.  A media capture can be described by using
   multiple <description> elements, each one providing information in a
   different language.  Indeed, the <description> element definition is
   the following:

   <!-- DESCRIPTION element -->
   <xs:element name="description">
    <xs:complexType>
     <xs:simpleContent>
      <xs:extension base="xs:string">
        <xs:attribute name="lang" type="xs:language"/>
      </xs:extension>
     </xs:simpleContent>
    </xs:complexType>
   </xs:element>

   As it can be seen, <description> is a string element with an
   attribute ("lang") indicating the language used in the textual
   description.

10.13.  <priority>

   <priority> ([I-D.groves-clue-capture-attr]) is an optional unsigned
   integer field indicating the importance of a media capture according
   to the media provider's perspective.  It can be used on the
   receiver's side to automatically identify the most "important"
   contribution available from the media provider.  The higher the
   importance, the lower the contained value.  When media captures are
   marked with a "0" priority value, it means that they are "not subject
   to priority".

   [edt's note: discussion needed]

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10.14.  <lang>

   <lang> is an optional element containing the language used in the
   capture, if any.  The purpose of the element could match the one of
   the "language" attribute proposed in [I-D.groves-clue-capture-attr].

10.15.  <mobility>

   <mobility> is an optional element indicating whether or not the
   capture device originating the capture may move during the
   telepresence session.  That optional element can assume one of the
   three following values: static, dynamic or highly dynamic, defined as
   in [I-D.ietf-clue-framework].

10.16.  <maxCaptureEncodings>

   The optional <maxCaptureEncodings> contains an unsigned integer
   indicating the maximum number of capture encodings that can be
   simultaneously active for the media capture.  If absent, this
   parameter defaults to 1.  The minimum value for this attribute is 1.
   The number of simultaneous capture encodings is also limited by the
   restrictions of the encoding group the media capture refers to my
   means of the <encGroupIDREF> element.

10.17.  <relatedTo>

   The optional <relatedTo> element contains the value of the ID
   attribute of the media capture it refers to.  The media capture
   marked with a <relatedTo> element can be for example the translation
   of a main media capture in a different language.  The <relatedTo>
   element could be interpreted the same manner of the supplementary
   information attribute proposed in [I-D.groves-clue-capture-attr] and
   further discussed in
   http://www.ietf.org/mail-archive/web/clue/current/msg02238.html.

10.18.  captureID attribute

   The "captureID" attribute is a mandatory field containing the
   identifier of the media capture.

11.  Audio captures

   Audio captures inherit all the features of a generic media capture
   and present further audio-specific characteristics.  The XML Schema
   definition of the audio capture type is reported below:

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 <!-- AUDIO CAPTURE TYPE -->
 <xs:complexType name="audioCaptureType">
  <xs:complexContent>
   <xs:extension base="tns:mediaCaptureType">
    <xs:sequence>
     <xs:element name="audioChannelFormat" type="audioChannelFormatType"
     minOccurs="0"/>
    </xs:sequence>
   </xs:extension>
  </xs:complexContent>
 </xs:complexType>

   Audio-specific information about the audio capture is contained in
   <audioChannelFormat> (Section 11.1).

11.1.  <audioChannelFormat>

   The optional <audioChannelFormat> element is a field with enumerated
   values ("mono" and "stereo") which describes the method of encoding
   used for audio.  A value of "mono" means the audio capture has one
   channel.  A value of "stereo" means the audio capture has two audio
   channels, left and right.  A single stereo capture is different from
   two mono captures that have a left-right spatial relationship.  A
   stereo capture maps to a single RTP stream, while each mono audio
   capture maps to a separate RTP stream.

   The XML Schema definition of the <audioChannelFormat> element type is
   provided below:

   <!-- AUDIO CHANNEL FORMAT TYPE -->
   <xs:simpleType name="audioChannelFormatType">
    <xs:restriction base="xs:string">
     <xs:enumeration value="mono"/>
     <xs:enumeration value="stereo"/>
    </xs:restriction>
   </xs:simpleType>

12.  Video captures

   Video captures, similarly to audio captures, extend the information
   of a generic media capture with video-specific features, such as
   <embeddedText> (Section 12.1).

   The XML Schema representation of the video capture type is provided

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   in the following:

   <!-- VIDEO CAPTURE TYPE -->
   <xs:complexType name="videoCaptureType">
    <xs:complexContent>
     <xs:extension base="tns:mediaCaptureType">
      <xs:sequence>
       <xs:element ref="embeddedText" minOccurs="0"/>
      </xs:sequence>
     </xs:extension>
    </xs:complexContent>
   </xs:complexType>

12.1.  <embeddedText>

   The <embeddedText> element is a boolean element indicating that there
   is text embedded in the video capture.  The language used in such
   embedded textual description is reported in <embeddedText> "lang"
   attribute.

   The XML Schema definition of the <embeddedText> element is:

   <!-- EMBEDDED TEXT ELEMENT -->
   <xs:element name="embeddedText">
    <xs:complexType>
     <xs:simpleContent>
      <xs:extension base="xs:boolean">
       <xs:attribute name="lang" type="xs:language"/>
      </xs:extension>
     </xs:simpleContent>
    </xs:complexType>

   </xs:element>

   The <embeddedText> element could correspond to the embedded-text
   attribute introduced in [I-D.groves-clue-capture-attr]

   [edt note: no final consensus has been reached yet about the adoption
   of such element]

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13.  Text captures

   Also text captures can be described by extending the generic media
   capture information, similarly to audio captures and video captures.

   The XML Schema representation of the text capture type is currently
   lacking text-specific information, as it can be seen by looking at
   the definition below:

   <!-- TEXT CAPTURE TYPE -->
   <xs:complexType name="textCaptureType">
    <xs:complexContent>
     <xs:extension base="tns:mediaCaptureType">
     </xs:extension>
    </xs:complexContent>
   </xs:complexType>

14.  <captureScene>

   A media provider organizes the available capture in capture scenes in
   order to help the receiver both in the rendering and in the selection
   of the group of captures.  Capture scenes are made of capture scene
   entries, that are set of media captures of the same media type.  Each
   capture scene entry represents an alternative to represent completely
   a capture scene for a fixed media type.

   The XML Schema representation of a <captureScene> element is the
   following:

   <!-- CAPTURE SCENE TYPE -->
   <xs:complexType name="captureSceneType">
    <xs:sequence>
     <xs:element ref="description" minOccurs="0" maxOccurs="unbounded"/>
     <xs:element name="sceneEntries" type="sceneEntriesType"/>
     <xs:any namespace="##other" processContents="lax" minOccurs="0"
     maxOccurs="unbounded"/>
    </xs:sequence>
    <xs:attribute name="sceneID" type="xs:ID" use="required"/>
    <xs:attribute name="scale" type="scaleType" use="required"/>
    <xs:anyAttribute namespace="##other" processContents="lax"/>
   </xs:complexType>

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   The <captureScene> element can contain zero or more textual
   <description> elements, defined as in Section 10.12.  Besides
   <description>, there the <sceneEntries> element (Section 14.1), which
   is the list of the capture scene entries.

14.1.  <sceneEntries>

   The <sceneEntries> element is a mandatory field of a capture scene
   containing the list of scene entries.  Each scene entry is
   represented by a <sceneEntry> element (Section 15).

   <!-- SCENE ENTRIES TYPE -->
   <!-- envelope of scene entries of a capture scene -->
   <xs:complexType name="sceneEntriesType">
    <xs:sequence>
     <xs:element name="sceneEntry" type="sceneEntryType"
     maxOccurs="unbounded"/>
    </xs:sequence>
   </xs:complexType>

14.2.  sceneID attribute

   The sceneID attribute is a mandatory attribute containing the
   identifier of the capture scene.

14.3.  scale attribute

   The scale attribute is a mandatory attribute that specifies the scale
   of the coordinates provided in the spatial information of the media
   capture belonging to the considered capture scene.  The scale
   attribute can assume three different values:

      "millimeters" - the scale is in millimeters.  Systems which know
      their physical dimensions (for example professionally installed
      telepresence room systems) should always provide those real-world
      measurements.

      "unknown" - the scale is not necessarily millimeters, but the
      scale is the same for every media capture in the capture scene.
      Systems which don't know specific physical dimensions but still
      know relative distances should select "unknown" in the scale
      attribute of the capture scene to be described.

      "noscale" - there is no a common physical scale among the media
      captures of the capture scene.  That means the scale could be

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      different for each media capture.

   <!-- SCALE TYPE -->
   <xs:simpleType name="scaleType">
    <xs:restriction base="xs:string">
     <xs:enumeration value="millimeters"/>
     <xs:enumeration value="unknown"/>
     <xs:enumeration value="noscale"/>
    </xs:restriction>
   </xs:simpleType>

15.  <sceneEntry>

   A <sceneEntry> element represents a capture scene entry, which
   contains a set of media capture of the same media type describing a
   capture scene.

   A <sceneEntry> element is characterized as follows.

   <!-- SCENE ENTRY TYPE -->
   <xs:complexType name="sceneEntryType">
    <xs:sequence>
     <xs:element ref="description" minOccurs="0" maxOccurs="unbounded"/>
     <xs:element name="mediaCaptureIDs" type="captureIDListType"/>
    </xs:sequence>
    <xs:attribute name="sceneEntryID" type="xs:ID" use="required"/>
    <xs:attribute name="mediaType" type="xs:string" use="required"/>
   </xs:complexType>

   One or more optional <description> elements provide human-readable
   information about what the scene entry contains. <description> is
   defined as already seen in Section 10.12.

   The remaining child elements are described in the following
   subsections.

15.1.  <mediaCaptureIDs>

   The <mediaCaptureIDs> is the list of the identifiers of the media
   captures included in the scene entry.  It is an element of the
   captureIDListType type, which is defined as a sequence of
   <captureIDREF> each one containing the identifier of a media capture

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   listed within the <mediaCaptures> element:

   <!-- CAPTURE ID LIST TYPE -->
   <xs:complexType name="captureIDListType">
    <xs:sequence>
     <xs:element name="captureIDREF" type="xs:IDREF"
     maxOccurs="unbounded"/>
    </xs:sequence>
   </xs:complexType>

15.2.  sceneEntryID attribute

   The sceneEntryID attribute is a mandatory attribute containing the
   identifier of the capture scene entry represented by the <sceneEntry>
   element.

15.3.  mediaType attribute

   The mediaType attribute contains the media type of the media captures
   included in the scene entry.

16.  <encoding>

   The <encoding> element represents an individual encoding, i.e., a way
   to encode a media capture.  Individual encodings can be characterized
   with features that are independent from the specific type of medium,
   and with features that are media-specific.  We design the individual
   encoding type as an abstract type, providing all the features that
   can be common to all media types.  Media-specific individual
   encodings, such as video encodings, audio encodings and others, are
   specialization of that type, as in a typical generalization-
   specialization hierarchy.

   <!-- ENCODING TYPE -->
   <xs:complexType name="encodingType" abstract="true">
    <xs:sequence>
     <xs:element name="encodingName" type="xs:string"/>
     <xs:element name="maxBandwidth" type="xs:integer"/>
     <xs:any namespace="##other" processContents="lax" minOccurs="0"
     maxOccurs="unbounded"/>
    </xs:sequence>
    <xs:attribute name="encodingID" type="xs:ID" use="required"/>
    <xs:anyAttribute namespace="##any" processContents="lax"/>

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   </xs:complexType>

16.1.  <encodingName>

   <encodingName> is a mandatory field containing the name of the
   encoding (e.g., G711, H264, ...).

16.2.  <maxBandwidth>

   <maxBandwidth> represent the maximum bitrate the media provider can
   instantiate for that encoding.

16.3.  encodingID attribute

   The encodingID attribute is a mandatory attribute containing the
   identifier of the individual encoding.

17.  Audio encodings

   Audio encodings inherit all the features of a generic individual
   encoding and can present further audio-specific encoding
   characteristics.  The XML Schema definition of the audio encoding
   type is reported below:

   <!-- AUDIO ENCODING TYPE -->
   <xs:complexType name="audioEncodingType">
    <xs:complexContent>
     <xs:extension base="tns:encodingType">
      <xs:sequence>
       <xs:element name="encodedMedia" type="xs:string" fixed="audio"
       minOccurs="0"/>
      </xs:sequence>
     </xs:extension>
    </xs:complexContent>
   </xs:complexType>

   Up to now the only audio-specific information is the <encodedMedia>
   element containing the media type of the media captures that can be
   encoded with the considered individual encoding.  In the case of
   audio encoding, that element is forced to "audio".

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18.  Video encodings

   Similarly to audio encodings, video encodings can extend the
   information of a generic individual encoding with video-specific
   encoding features, such as <maxWidth>, <maxHeight> and
   <maxFrameRate>.

   The <encodedMedia> element contains the media type of the media
   captures that can be encoded with the considered individual encoding.
   In the case of video encoding, that element is forced to "video".

   <!-- VIDEO ENCODING TYPE -->
   <xs:complexType name="videoEncodingType">
    <xs:complexContent>
     <xs:extension base="tns:encodingType">
      <xs:sequence>
       <xs:element name="encodedMedia" type="xs:string" fixed="video"
       minOccurs="0"/>
       <xs:element name="maxWidth" type="xs:integer" minOccurs="0"/>
       <xs:element name="maxHeight" type="xs:integer" minOccurs="0"/>
       <xs:element name="maxFrameRate" type="xs:integer" minOccurs="0"/>
      </xs:sequence>
     </xs:extension>
    </xs:complexContent>
   </xs:complexType>

18.1.  <maxWidth>

   <maxWidth> represents the video resolution's maximum width supported
   by the video encoding, expressed in pixels.

   [edt note: to be removed?]

18.2.  <maxHeight>

   <maxHeight> representd the video resolution's maximum heith supported
   by the video encoding, expressed in pixels.

   [edt note:to be removed?]

18.3.  <maxFrameRate>

   <maxFrameRate> provides the maximum frame rate supported by the video
   encoding for the video capture to be encoded.

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   [edt note: to be removed?]

19.  <encodingGroup>

   The <encodingGroup> element represents an encoding group, which is a
   set of one or more individual encodings, and parameters that apply to
   the group as a whole.  The definition of the <encodingGroup> element
   is the following:

   <!-- ENCODING GROUP TYPE -->
   <xs:complexType name="encodingGroupType">
    <xs:sequence>
     <xs:element name="maxGroupBandwidth" type="xs:integer"/>
     <xs:element name="encodingIDList" type="encodingIDListType"/>
     <xs:any namespace="##other" processContents="lax" minOccurs="0"
     maxOccurs="unbounded"/>
    </xs:sequence>
    <xs:attribute name="encodingGroupID" type="xs:ID" use="required"/>
    <xs:anyAttribute namespace="##any" processContents="lax"/>
   </xs:complexType>

   In the following, the contained elements are further described.

19.1.  <maxGroupBandwidth>

   <maxGroupBandwidth> is an optional field containing the maximum
   bitrate supported for all the individual encodings included in the
   encoding group.

19.2.  <encodingIDList>

   <maxGroupBandwidth> is the list of the individual encoding grouped
   together.  Each individual encoding is represented through its
   identifier contained within an <encIDREF> element.

   <!-- ENCODING ID LIST TYPE -->
   <xs:complexType name="encodingIDListType">
    <xs:sequence>
     <xs:element name="encIDREF" type="xs:IDREF" maxOccurs="unbounded"/>
    </xs:sequence>
   </xs:complexType>

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19.3.  encodingGroupID attribute

   The encodingGroupID attribute contains the identifier of the encoding
   group.

20.  <simultaneousSet>

   <simultaneousSet> represents a simultaneous set, i.e. a list of
   capture of the same type that cab be transmitted at the same time by
   a media provider.  There are different simultaneous transmission sets
   for each media type.

   <!-- SIMULTANEOUS SET TYPE -->
   <xs:complexType name="simultaneousSetType">
    <xs:sequence>
      <xs:element name="captureIDREF" type="xs:IDREF"
      minOccurs="0" maxOccurs="unbounded"/>
      <xs:element name="sceneEntryIDREF" type="xs:IDREF"
      minOccurs="0" maxOccurs="unbounded"/>
    </xs:sequence>
   </xs:complexType>

   [edt note: need to be checked]

20.1.  <captureIDREF>

   <captureIDREF> contains the identifier of the media capture that
   belongs to the simultanous set.

20.2.  <sceneEntryIDREF>

   <captureIDREF> contains the identifier of the scene entry containing
   a group of capture that are able to be sent simultaneously with the
   other capture of the simultaneous set.

21.  <captureEncoding>

   A <captureEncoding> is given from the association of a media capture
   and an individual encoding, to form a capture stream as defined in
   [I-D.ietf-clue-framework].  A media consumer expresses for each
   capture encoding its preferences about the capture parameters (such
   as the desired switching policy) and the encoding parameters (such as
   the bandwidth).  A possible solution to model such entity is provided
   in the following.

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   <!-- CAPTURE ENCODING TYPE -->
   <xs:complexType name="captureEncodingType">
    <xs:sequence>
     <xs:element name="mediaCaptureID" type="xs:string"/>
     <xs:element name="encodingID" type="xs:string"/>
     <xs:element name="captureParameters" type="captureParametersType"
                 minOccurs="0"/>
     <xs:element name="encodingParameters" type="encodingParametersType"
                 minOccurs="0"/>
    </xs:sequence>
    <xs:attribute name="ID" type="xs:ID"/>
   </xs:complexType>

   <!-- CAPTURE PARAMETERS TYPE -->
   <xs:complexType name="captureParametersType">
    <xs:sequence>
           <xs:element name="switchingOption" type="xs:string"/>
           <xs:any namespace="##other" processContents="lax" minOccurs="0"
      maxOccurs="unbounded"/>
    </xs:sequence>
   </xs:complexType>

   <!-- ENCODING PARAMETERS TYPE -->
   <xs:complexType name="captureParametersType">
    <xs:sequence>
           <xs:element name="bandwidth" type="xs:unsignedInt"/>
           <xs:any namespace="##other" processContents="lax" minOccurs="0"
      maxOccurs="unbounded"/>
    </xs:sequence>
   </xs:complexType>

21.1.  <mediaCaptureID>

   <mediaCaptureID> contains the identifier of the media capture that
   has been encoded to form the capture encoding.

21.2.  <encodingID>

   <encodingID> contains the identifier of the applied individual
   encoding.

22.  <clueInfo>

   The <clueInfo> element has been left within the XML Schema for the
   sake of convenience when representing a prototype of ADVERTISEMENT
   message (see the example section).

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   <!-- CLUE INFO ELEMENT -->
   <!-- the <clueInfo> envelope can be seen
        as the ancestor of an <advertisement> envelope -->
   <xs:element name="clueInfo" type="clueInfoType"/>

   <!-- CLUE INFO TYPE -->
   <xs:complexType name="clueInfoType">
     <xs:sequence>
      <xs:element ref="mediaCaptures"/>
      <xs:element ref="encodings"/>
      <xs:element ref="encodingGroups"/>
      <xs:element ref="captureScenes"/>
      <xs:element ref="simultaneousSets"/>
      <xs:any namespace="##other" processContents="lax" minOccurs="0"
      maxOccurs="unbounded"/>
     </xs:sequence>
     <xs:attribute name="clueInfoID" type="xs:ID" use="required"/>
     <xs:anyAttribute namespace="##other" processContents="lax"/>
   </xs:complexType>

23.  Sample XML file

   [**** v2: TO BE UPDATED ****]

   The following XML document represents a schema compliant example of a
   CLUE telepresence scenario.

   There are 5 video captures:

   VC0:  the video from the left camera

   VC1:  the video from the central camera

   VC2:  the video from the right camera

   VC3:  the overall view of the telepresence room taken from the
      central camera

   VC4:  the video associated with the slide stream

   There are 2 audio captures:

   AC0:  the overall room audio taken from the central camera

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   AC1:  the audio associated with the slide stream presentation

   The captures are organized into two capture scenes:

   CS1:  this scene contains captures associated with the participants
      that are in the telepresence room.

   CS2:  this scene contains captures associated with the slide
      presentation, which is a pre-registered presentation played within
      the context of the telepresence session.

   Within the capture scene CS1, there are three scene entries
   available:

   CS1_SE1:  this entry contains the partipants' video captures taken
      from the three cameras (VC0, VC1, VC2).

   CS1_SE2:  this entry contains the zoomed-out view of the overall
      telepresence room (VC3)

   CS1_SE3:  this entry contains the overall telepresence room audio
      (AC0)

   On the other hand, capture scene CS2 presents two scene entries:

   CS2_SE1:  this entry contains the presentation audio stream (AC1)

   CS2_SE2:  this entry contains the presentation video stream (VC4)

   There are two encoding groups:

   EG0  This encoding groups involves video encodings ENC0, ENC1, ENC2

   EG1  This encoding groups involves audio encodings ENC3, ENC4

   As to the simultaneous sets, only VC1 and VC3 cannot be transmitted
   simultaneously since they are captured by the same device. i.e. the
   central camera (VC3 is a zoomed-out view while VC1 is a focused view
   of the front participants).  The simultaneous sets would then be the
   following:

   SS1  made by VC0, VC1, VC2, VC4

   SS2  made by VC0, VC3, VC2, VC4

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   SS3  made by AC0 and AC1

 <t>[**** v2: TO BE UPDATED ****]</t>

 <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
 <clueInfo xmlns="urn:ietf:params:xml:ns:clue-info" clueInfoID="prova">
     <mediaCaptures>
         <mediaCapture
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:type="audioCaptureType" captureID="AC1">
             <capturedMedia>audio</capturedMedia>
             <captureSceneIDREF>CS2</captureSceneIDREF>
             <encGroupIDREF>EG1</encGroupIDREF>
             <nonSpatiallyDefinable>true</nonSpatiallyDefinable>
             <description lang="en">presentation audio</description>
             <audioChannelFormat>mono</audioChannelFormat>
         </mediaCapture>
         <mediaCapture
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:type="videoCaptureType" captureID="VC4">
             <capturedMedia>video</capturedMedia>
             <captureSceneIDREF>CS2</captureSceneIDREF>
             <encGroupIDREF>EG0</encGroupIDREF>
             <nonSpatiallyDefinable>true</nonSpatiallDefinablee>
             <description lang="en">presentation video</description>
         </mediaCapture>
         <mediaCapture
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:type="audioCaptureType" captureID="AC0">
             <capturedMedia>audio</capturedMedia>
             <captureSceneIDREF>CS1</captureSceneIDREF>
             <encGroupIDREF>EG1</encGroupIDREF>
             <spatialInformation>
                 <capturePoint>
                     <x>0.5</x>
                     <y>1.0</y>
                     <z>0.5</z>
                     <lineOfCapturePoint>
                         <x>0.5</x>
                         <y>0.0</y>
                         <z>0.5</z>
                     </lineOfCapturePoint>
                 </capturePoint>
             </spatialInformation>
             <description lang="en">

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             audio from the central camera mic</description>
             <audioChannelFormat>mono</audioChannelFormat>
         </mediaCapture>
         <mediaCapture
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:type="videoCaptureType" captureID="VC3">
             <capturedMedia>video</capturedMedia>
             <captureSceneIDREF>CS1</captureSceneIDREF>
             <encGroupIDREF>EG0</encGroupIDREF>
             <spatialInformation>
                 <capturePoint>
                     <x>1.5</x>
                     <y>1.0</y>
                     <z>0.5</z>
                     <lineOfCapturePoint>
                         <x>1.5</x>
                         <y>0.0</y>
                         <z>0.5</z>
                     </lineOfCapturePoint>
                 </capturePoint>
                 <captureArea>
                     <bottomLeft>
                         <x>0.0</x>
                         <y>3.0</y>
                         <z>0.0</z>
                     </bottomLeft>
                     <bottomRight>
                         <x>3.0</x>
                         <y>3.0</y>
                         <z>0.0</z>
                     </bottomRight>
                     <topLeft>
                         <x>0.0</x>
                         <y>3.0</y>
                         <z>3.0</z>
                     </topLeft>
                     <topRight>
                         <x>3.0</x>
                         <y>3.0</y>
                         <z>3.0</z>
                     </topRight>
                 </captureArea>
             </spatialInformation>
             <description lang="en">
             zoomed out view of the room</description>
         </mediaCapture>
         <mediaCapture
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

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         xsi:type="videoCaptureType" captureID="VC2">
             <capturedMedia>video</capturedMedia>
             <captureSceneIDREF>CS1</captureSceneIDREF>
             <encGroupIDREF>EG0</encGroupIDREF>
             <spatialInformation>
                 <capturePoint>
                     <x>2.5</x>
                     <y>1.0</y>
                     <z>0.5</z>
                     <lineOfCapturePoint>
                         <x>2.5</x>
                         <y>0.0</y>
                         <z>0.5</z>
                     </lineOfCapturePoint>
                 </capturePoint>
                 <captureArea>
                     <bottomLeft>
                         <x>2.0</x>
                         <y>3.0</y>
                         <z>0.0</z>
                     </bottomLeft>
                     <bottomRight>
                         <x>3.0</x>
                         <y>3.0</y>
                         <z>0.0</z>
                     </bottomRight>
                     <topLeft>
                         <x>2.0</x>
                         <y>3.0</y>
                         <z>3.0</z>
                     </topLeft>
                     <topRight>
                         <x>3.0</x>
                         <y>3.0</y>
                         <z>3.0</z>
                     </topRight>
                 </captureArea>
             </spatialInformation>
             <description lang="en">right camera video</description>
         </mediaCapture>
         <mediaCapture
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:type="videoCaptureType" captureID="VC1">
             <capturedMedia>video</capturedMedia>
             <captureSceneIDREF>CS1</captureSceneIDREF>
             <encGroupIDREF>EG0</encGroupIDREF>
             <spatialInformation>
                 <capturePoint>

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                     <x>1.5</x>
                     <y>1.0</y>
                     <z>0.5</z>
                     <lineOfCapturePoint>
                         <x>1.5</x>
                         <y>0.0</y>
                         <z>0.5</z>
                     </lineOfCapturePoint>
                 </capturePoint>
                 <captureArea>
                     <bottomLeft>
                         <x>1.0</x>
                         <y>3.0</y>
                         <z>0.0</z>
                     </bottomLeft>
                     <bottomRight>
                         <x>2.0</x>
                         <y>3.0</y>
                         <z>0.0</z>
                     </bottomRight>
                     <topLeft>
                         <x>1.0</x>
                         <y>3.0</y>
                         <z>3.0</z>
                     </topLeft>
                     <topRight>
                         <x>2.0</x>
                         <y>3.0</y>
                         <z>3.0</z>
                     </topRight>
                 </captureArea>
             </spatialInformation>
             <description lang="en">central camera video</description>
         </mediaCapture>
         <mediaCapture
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:type="videoCaptureType" captureID="VC0">
             <capturedMedia>video</capturedMedia>
             <captureSceneIDREF>CS1</captureSceneIDREF>
             <encGroupIDREF>EG0</encGroupIDREF>
             <spatialInformation>
                 <capturePoint>
                     <x>0.5</x>
                     <y>1.0</y>
                     <z>0.5</z>
                     <lineOfCapturePoint>
                         <x>0.5</x>
                         <y>0.0</y>

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                         <z>0.5</z>
                     </lineOfCapturePoint>
                 </capturePoint>
                 <captureArea>
                     <bottomLeft>
                         <x>0.0</x>
                         <y>3.0</y>
                         <z>0.0</z>
                     </bottomLeft>
                     <bottomRight>
                         <x>1.0</x>
                         <y>3.0</y>
                         <z>0.0</z>
                     </bottomRight>
                     <topLeft>
                         <x>0.0</x>
                         <y>3.0</y>
                         <z>3.0</z>
                     </topLeft>
                     <topRight>
                         <x>1.0</x>
                         <y>3.0</y>
                         <z>3.0</z>
                     </topRight>
                 </captureArea>
             </spatialInformation>
             <description lang="en">left camera video</description>
         </mediaCapture>
     </mediaCaptures>
     <encodings>
         <encoding xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:type="videoEncodingType" encodingID="ENC0">
             <encodingName>h263</encodingName>
             <maxBandwidth>4000000</maxBandwidth>
             <encodedMedia>video</encodedMedia>
             <maxWidth>1920</maxWidth>
             <maxHeight>1088</maxHeight>
         </encoding>
         <encoding xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:type="videoEncodingType" encodingID="ENC1">
             <encodingName>h263</encodingName>
             <maxBandwidth>4000000</maxBandwidth>
             <encodedMedia>video</encodedMedia>
             <maxWidth>1920</maxWidth>
             <maxHeight>1088</maxHeight>
         </encoding>
         <encoding xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:type="videoEncodingType" encodingID="ENC2">

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             <encodingName>h263</encodingName>
             <maxBandwidth>4000000</maxBandwidth>
             <encodedMedia>video</encodedMedia>
             <maxWidth>1920</maxWidth>
             <maxHeight>1088</maxHeight>
         </encoding>
         <encoding xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:type="audioEncodingType" encodingID="ENC3">
             <encodingName>g711</encodingName>
             <maxBandwidth>64000</maxBandwidth>
             <encodedMedia>audio</encodedMedia>
         </encoding>
         <encoding xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:type="audioEncodingType" encodingID="ENC4">
             <encodingName>g711</encodingName>
             <maxBandwidth>64000</maxBandwidth>
             <encodedMedia>audio</encodedMedia>
         </encoding>
     </encodings>
     <encodingGroups>
         <encodingGroup encodingGroupID="EG0">
             <maxGroupBandwidth>12000000</maxGroupBandwidth>
             <encodingIDList>
                 <encIDREF>ENC0</encIDREF>
                 <encIDREF>ENC1</encIDREF>
                 <encIDREF>ENC2</encIDREF>
             </encodingIDList>
         </encodingGroup>
         <encodingGroup encodingGroupID="EG1">
             <maxGroupBandwidth>12000000</maxGroupBandwidth>
             <encodingIDList>
                 <encIDREF>ENC3</encIDREF>
                 <encIDREF>ENC4</encIDREF>
             </encodingIDList>
         </encodingGroup>
     </encodingGroups>
     <captureScenes>
         <captureScene scale="unknown" sceneID="CS1">
             <description lang="en">main scene</description>
             <sceneEntries>
                 <sceneEntry mediaType="video" sceneEntryID="SE1">
                     <description lang="en">
                     participants streams</description>
                     <mediaCaptureIDs>
                         <captureIDREF>VC0</captureIDREF>
                         <captureIDREF>VC1</captureIDREF>
                         <captureIDREF>VC2</captureIDREF>
                     </mediaCaptureIDs>

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                 </sceneEntry>
                 <sceneEntry mediaType="video" sceneEntryID="SE2">
                     <description lang="en">room stream</description>
                     <mediaCaptureIDs>
                         <captureIDREF>VC3</captureIDREF>
                     </mediaCaptureIDs>
                 </sceneEntry>
                 <sceneEntry mediaType="audio" sceneEntryID="SE3">
                     <description lang="en">room audio</description>
                     <mediaCaptureIDs>
                         <captureIDREF>AC0</captureIDREF>
                     </mediaCaptureIDs>
                 </sceneEntry>
             </sceneEntries>
         </captureScene>
         <captureScene scale="noscale" sceneID="CS2">
             <description lang="en">presentation</description>
             <sceneEntries>
                 <sceneEntry mediaType="video" sceneEntryID="CS2_SE1">
                     <description lang="en">
                     presentation video</description>
                     <mediaCaptureIDs>
                         <captureIDREF>VC4</captureIDREF>
                     </mediaCaptureIDs>
                 </sceneEntry>
                 <sceneEntry mediaType="audio" sceneEntryID="CS2_SE2">
                     <description lang="en">
                     presentation audio</description>
                     <mediaCaptureIDs>
                         <captureIDREF>AC1</captureIDREF>
                     </mediaCaptureIDs>
                 </sceneEntry>
             </sceneEntries>
         </captureScene>
     </captureScenes>
     <simultaneousSets>
         <simultaneousSet setID="SS1">
             <captureIDREF>VC0</captureIDREF>
             <captureIDREF>VC1</captureIDREF>
             <captureIDREF>VC2</captureIDREF>
             <captureIDREF>VC4</captureIDREF>
         </simultaneousSet>
         <simultaneousSet setID="SS2">
             <captureIDREF>VC0</captureIDREF>
             <captureIDREF>VC3</captureIDREF>
             <captureIDREF>VC2</captureIDREF>
             <captureIDREF>VC4</captureIDREF>
         </simultaneousSet>

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         <simultaneousSet setID="SS3">
             <captureIDREF>AC0</captureIDREF>
             <captureIDREF>AC1</captureIDREF>
         </simultaneousSet>
     </simultaneousSets>
 </clueInfo>

24.  Diff with  draft-ietf-clue-data-model-schema-00 version

      the definition of the <mobility> element has been corrected (from
      "xs:mobilityType" to "mobilityType")

      the definition of the <encodingParameter> element has been
      corrected (from "captureParameterType" to "encodingParameterType")

25.  Diff with  draft-ietf-clue-data-model-schema-01 version

      Terminology has been added.

      Switching policies has been removed from capture scene entry
      attributes list.

      multiple content captures can now be modeled by using the schema.
      Related attributes (composed, switching, maxCaptures, captureIDs)
      have been added in the definition of the media capture type.

      H26X encoding type has been removed.

      maxGroupPps (max pixels per second for encoding groups) removed

      Presentation attribute for media captures has been added.

      View attribute for media captures has been added.

26.  Informative References

   [I-D.groves-clue-capture-attr]  Groves, C., Yang, W., and R. Even,
                                   "CLUE media capture description",
                                   draft-groves-clue-capture-attr-01
                                   (work in progress), February 2013.

   [I-D.ietf-clue-framework]       Duckworth, M., Pepperell, A., and S.
                                   Wenger, "Framework for Telepresence
                                   Multi-Streams",
                                   draft-ietf-clue-framework-13 (work in
                                   progress), December 2013.

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   [I-D.romanow-clue-data-model]   Romanow, A. and A. Pepperell, "Data
                                   model for the CLUE Framework",
                                   draft-romanow-clue-data-model-01
                                   (work in progress), June 2012.

   [RFC4796]                       Hautakorpi, J. and G. Camarillo, "The
                                   Session Description Protocol (SDP)
                                   Content Attribute", RFC 4796,
                                   February 2007.

Authors' Addresses

   Roberta Presta
   University of Napoli
   Via Claudio 21
   Napoli  80125
   Italy

   EMail: roberta.presta@unina.it

   Simon Pietro Romano
   University of Napoli
   Via Claudio 21
   Napoli  80125
   Italy

   EMail: spromano@unina.it

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